Science.gov

Sample records for abiotic factors including

  1. Arctic plant responses to changing abiotic factors in northern Alaska.

    PubMed

    Barrett, Robert T S; Hollister, Robert D; Oberbauer, Steven F; Tweedie, Craig E

    2015-12-01

    Understanding the relationship between plants and changing abiotic factors is necessary to document and anticipate the impacts of climate change. We used data from long-term research sites at Barrow and Atqasuk, Alaska, to investigate trends in abiotic factors (snow melt and freeze-up dates, air and soil temperature, thaw depth, and soil moisture) and their relationships with plant traits (inflorescence height, leaf length, reproductive effort, and reproductive phenology) over time. Several abiotic factors, including increasing air and soil temperatures, earlier snowmelt, delayed freeze-up, drier soils, and increasing thaw depths, showed nonsignificant tendencies over time that were consistent with the regional warming pattern observed in the Barrow area. Over the same period, plants showed consistent, although typically nonsignificant tendencies toward increasing inflorescence heights and reproductive efforts. Air and soil temperatures, measured as degree days, were consistently correlated with plant growth and reproductive effort. Reproductive effort was best predicted using abiotic conditions from the previous year. We also found that varying the base temperature used to calculate degree days changed the number of significant relationships between temperature and the trait: in general, reproductive phenologies in colder sites were better predicted using lower base temperatures, but the opposite held for those in warmer sites. Plant response to changing abiotic factors is complex and varies by species, site, and trait; however, for six plant species, we have strong evidence that climate change will cause significant shifts in their growth and reproductive effort as the region continues to warm. © 2015 Botanical Society of America.

  2. The impact of abiotic factors on cellulose synthesis.

    PubMed

    Wang, Ting; McFarlane, Heather E; Persson, Staffan

    2016-01-01

    As sessile organisms, plants require mechanisms to sense and respond to changes in their environment, including both biotic and abiotic factors. One of the most common plant adaptations to environmental changes is differential regulation of growth, which results in growth either away from adverse conditions or towards more favorable conditions. As cell walls shape plant growth, this differential growth response must be accompanied by alterations to the plant cell wall. Here, we review the impact of four abiotic factors (osmotic conditions, ionic stress, light, and temperature) on the synthesis of cellulose, an important component of the plant cell wall. Understanding how different abiotic factors influence cellulose production and addressing key questions that remain in this field can provide crucial information to cope with the need for increased crop production under the mounting pressures of a growing world population and global climate change.

  3. Biotic and abiotic factors predicting the global distribution and population density of an invasive large mammal.

    PubMed

    Lewis, Jesse S; Farnsworth, Matthew L; Burdett, Chris L; Theobald, David M; Gray, Miranda; Miller, Ryan S

    2017-03-09

    Biotic and abiotic factors are increasingly acknowledged to synergistically shape broad-scale species distributions. However, the relative importance of biotic and abiotic factors in predicting species distributions is unclear. In particular, biotic factors, such as predation and vegetation, including those resulting from anthropogenic land-use change, are underrepresented in species distribution modeling, but could improve model predictions. Using generalized linear models and model selection techniques, we used 129 estimates of population density of wild pigs (Sus scrofa) from 5 continents to evaluate the relative importance, magnitude, and direction of biotic and abiotic factors in predicting population density of an invasive large mammal with a global distribution. Incorporating diverse biotic factors, including agriculture, vegetation cover, and large carnivore richness, into species distribution modeling substantially improved model fit and predictions. Abiotic factors, including precipitation and potential evapotranspiration, were also important predictors. The predictive map of population density revealed wide-ranging potential for an invasive large mammal to expand its distribution globally. This information can be used to proactively create conservation/management plans to control future invasions. Our study demonstrates that the ongoing paradigm shift, which recognizes that both biotic and abiotic factors shape species distributions across broad scales, can be advanced by incorporating diverse biotic factors.

  4. Biotic and abiotic factors predicting the global distribution and population density of an invasive large mammal

    PubMed Central

    Lewis, Jesse S.; Farnsworth, Matthew L.; Burdett, Chris L.; Theobald, David M.; Gray, Miranda; Miller, Ryan S.

    2017-01-01

    Biotic and abiotic factors are increasingly acknowledged to synergistically shape broad-scale species distributions. However, the relative importance of biotic and abiotic factors in predicting species distributions is unclear. In particular, biotic factors, such as predation and vegetation, including those resulting from anthropogenic land-use change, are underrepresented in species distribution modeling, but could improve model predictions. Using generalized linear models and model selection techniques, we used 129 estimates of population density of wild pigs (Sus scrofa) from 5 continents to evaluate the relative importance, magnitude, and direction of biotic and abiotic factors in predicting population density of an invasive large mammal with a global distribution. Incorporating diverse biotic factors, including agriculture, vegetation cover, and large carnivore richness, into species distribution modeling substantially improved model fit and predictions. Abiotic factors, including precipitation and potential evapotranspiration, were also important predictors. The predictive map of population density revealed wide-ranging potential for an invasive large mammal to expand its distribution globally. This information can be used to proactively create conservation/management plans to control future invasions. Our study demonstrates that the ongoing paradigm shift, which recognizes that both biotic and abiotic factors shape species distributions across broad scales, can be advanced by incorporating diverse biotic factors. PMID:28276519

  5. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses

    PubMed Central

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention. PMID:26904076

  6. The Plant Heat Stress Transcription Factors (HSFs): Structure, Regulation, and Function in Response to Abiotic Stresses.

    PubMed

    Guo, Meng; Liu, Jin-Hong; Ma, Xiao; Luo, De-Xu; Gong, Zhen-Hui; Lu, Ming-Hui

    2016-01-01

    Abiotic stresses such as high temperature, salinity, and drought adversely affect the survival, growth, and reproduction of plants. Plants respond to such unfavorable changes through developmental, physiological, and biochemical ways, and these responses require expression of stress-responsive genes, which are regulated by a network of transcription factors (TFs), including heat stress transcription factors (HSFs). HSFs play a crucial role in plants response to several abiotic stresses by regulating the expression of stress-responsive genes, such as heat shock proteins (Hsps). In this review, we describe the conserved structure of plant HSFs, the identification of HSF gene families from various plant species, their expression profiling under abiotic stress conditions, regulation at different levels and function in abiotic stresses. Despite plant HSFs share highly conserved structure, their remarkable diversification across plants reflects their numerous functions as well as their integration into the complex stress signaling and response networks, which can be employed in crop improvement strategies via biotechnological intervention.

  7. AP2/ERF family transcription factors in plant abiotic stress responses.

    PubMed

    Mizoi, Junya; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2012-02-01

    In terrestrial environments, temperature and water conditions are highly variable, and extreme temperatures and water conditions affect the survival, growth and reproduction of plants. To protect cells and sustain growth under such conditions of abiotic stress, plants respond to unfavourable changes in their environments in developmental, physiological and biochemical ways. These responses require expression of stress-responsive genes, which are regulated by a network of transcription factors. The AP2/ERF family is a large family of plant-specific transcription factors that share a well-conserved DNA-binding domain. This transcription factor family includes DRE-binding proteins (DREBs), which activate the expression of abiotic stress-responsive genes via specific binding to the dehydration-responsive element/C-repeat (DRE/CRT) cis-acting element in their promoters. In this review, we discuss the functions of the AP2/ERF-type transcription factors in plant abiotic stress responses, with special emphasis on the regulations and functions of two major types of DREBs, DREB1/CBF and DREB2. In addition, we summarise the involvement of other AP2/ERF-type transcription factors in abiotic stress responses, which has recently become clear. This article is part of a Special Issue entitled: Plant gene regulation in response to abiotic stress.

  8. Structure, function and networks of transcription factors involved in abiotic stress responses.

    PubMed

    Lindemose, Søren; O'Shea, Charlotte; Jensen, Michael Krogh; Skriver, Karen

    2013-03-13

    Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic disorder (ID), referring to their lack of fixed tertiary structures. ID is now an emerging topic in plant science. Furthermore, the importance of the ubiquitin-proteasome protein degradation systems and modification by sumoylation is also apparent from the interactomes. Therefore; TF interaction partners such as E3 ubiquitin ligases and TF regions with ID represent future targets for engineering improved abiotic stress tolerance in crops.

  9. Structure, Function and Networks of Transcription Factors Involved in Abiotic Stress Responses

    PubMed Central

    Lindemose, Søren; O’Shea, Charlotte; Jensen, Michael Krogh; Skriver, Karen

    2013-01-01

    Transcription factors (TFs) are master regulators of abiotic stress responses in plants. This review focuses on TFs from seven major TF families, known to play functional roles in response to abiotic stresses, including drought, high salinity, high osmolarity, temperature extremes and the phytohormone ABA. Although ectopic expression of several TFs has improved abiotic stress tolerance in plants, fine-tuning of TF expression and protein levels remains a challenge to avoid crop yield loss. To further our understanding of TFs in abiotic stress responses, emerging gene regulatory networks based on TFs and their direct targets genes are presented. These revealed components shared between ABA-dependent and independent signaling as well as abiotic and biotic stress signaling. Protein structure analysis suggested that TFs hubs of large interactomes have extended regions with protein intrinsic disorder (ID), referring to their lack of fixed tertiary structures. ID is now an emerging topic in plant science. Furthermore, the importance of the ubiquitin-proteasome protein degradation systems and modification by sumoylation is also apparent from the interactomes. Therefore; TF interaction partners such as E3 ubiquitin ligases and TF regions with ID represent future targets for engineering improved abiotic stress tolerance in crops. PMID:23485989

  10. Soil abiotic factors influence interactions between belowground herbivores and plant roots.

    PubMed

    Erb, Matthias; Lu, Jing

    2013-03-01

    Root herbivores are important ecosystem drivers and agricultural pests, and, possibly as a consequence, plants protect their roots using a variety of defensive strategies. One aspect that distinguishes belowground from aboveground plant-insect interactions is that roots are constantly exposed to a set of soil-specific abiotic factors. These factors can profoundly influence root resistance, and, consequently, the outcome of the interaction with belowground feeders. In this review, we synthesize the current literature on the impact of soil moisture, nutrients, and texture on root-herbivore interactions. We show that soil abiotic factors influence the interaction by modulating herbivore abundance and behaviour, root growth and resistance, beneficial microorganisms, as well as natural enemies of the herbivores. We suggest that abiotic heterogeneity may explain the high variability that is often encountered in root-herbivore systems. We also propose that under abiotic stress, the relative fitness value of the roots and the potential negative impact of herbivory increases, which may lead to a higher defensive investment and an increased recruitment of beneficial microorganisms by the plant. At the same time, both root-feeding herbivores and natural enemies are likely to decrease in abundance under extreme environmental conditions, leading to a context- and species-specific impact on plant fitness. Only by using tightly controlled experiments that include soil abiotic heterogeneity will it be possible to understand the impact of root feeders on an ecosystem scale and to develop predictive models for pest occurrence and impact.

  11. Abiotic and Microbiotic Factors Controlling Biofilm Formation by Thermophilic Sporeformers

    PubMed Central

    Zhao, Yu; Caspers, Martien P. M.; Metselaar, Karin I.; de Boer, Paulo; Roeselers, Guus; Moezelaar, Roy; Nierop Groot, Masja; Montijn, Roy C.; Abee, Tjakko

    2013-01-01

    One of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon sequencing analysis was carried out on milk, final products, and fouling samples taken from dairy concentrate production lines. The analysis of these samples revealed the presence of DNA from a broad range of bacterial taxa, including a majority of mesophiles and a minority of (thermophilic) spore-forming bacteria. Enrichments of fouling samples at 55°C showed the accumulation of predominantly Brevibacillus and Bacillus, whereas enrichments at 65°C led to the accumulation of Anoxybacillus and Geobacillus species. Bacterial population analysis of biofilms grown using fouling samples as an inoculum indicated that both Anoxybacillus and Geobacillus preferentially form biofilms on surfaces at air-liquid interfaces rather than on submerged surfaces. Three of the most potent biofilm-forming strains isolated from the dairy factory industrial samples, including Geobacillus thermoglucosidans, Geobacillus stearothermophilus, and Anoxybacillus flavithermus, have been characterized in detail with respect to their growth conditions and spore resistance. Strikingly, Geobacillus thermoglucosidans, which forms the most thermostable spores of these three species, is not able to grow in dairy intermediates as a pure culture but appears to be dependent for growth on other spoilage organisms present, probably as a result of their proteolytic activity. These results underscore the importance of abiotic and microbiotic factors in niche colonization in dairy factories, where the presence of thermophilic sporeformers can affect the quality of end products. PMID:23851093

  12. Relationships between advance oak regeneration and biotic and abiotic factors.

    PubMed

    Fei, Songlin; Steiner, Kim C

    2008-07-01

    Relationships between advance regeneration of four tree species (red maple (Acer rubrum L.), white oak (Quercus alba L.), chestnut oak (Q. montana Willd.) and northern red oak (Q. rubra L.)) and biotic (non-tree vegetation and canopy composition) and abiotic (soil series and topographic variables) factors were investigated in 52, mature mixed-oak stands in the central Appalachians. Aggregate height was used as a composite measure of regeneration abundance. Analyses were carried out separately for two physiographic provinces. Associations with tree regeneration were found for all biotic and abiotic factors both in partial models and full models. Red maple was abundant on most of the sites, but high red maple abundance was commonly associated with wet north-facing slopes with little or no cover of mountain-laurel (Kalmia latifolia L.) and hay-scented fern (Dennstaedtia punctilobula (Michx.) Moore). Regeneration of the three oak species was greatly favored by the abundance of overstory trees of their own kind. White oak regeneration was most abundant on south-facing, gentle, lower slopes with soils in the Buchanan series. Chestnut oak regeneration was more common on south-facing, steep upper slopes with stony soils. There was a positive association between chestnut oak and huckleberry (Gaylussacia baccata (Wangh.) Koch) cover classes. Northern red oak was more abundant on north-facing wet sites with Hazleton soil, and was associated with low occurrence of mountain-laurel and hay-scented fern.

  13. Abiotic factors influence plant storage lipid accumulation and composition.

    PubMed

    Singer, Stacy D; Zou, Jitao; Weselake, Randall J

    2016-02-01

    The demand for plant-derived oils has increased substantially over the last decade, and is sure to keep growing. While there has been a surge in research efforts to produce plants with improved oil content and quality, in most cases the enhancements have been small. To add further complexity to this situation, substantial differences in seed oil traits among years and field locations have indicated that plant lipid biosynthesis is also influenced to a large extent by multiple environmental factors such as temperature, drought, light availability and soil nutrients. On the molecular and biochemical levels, the expression and/or activities of fatty acid desaturases, as well as diacylglycerol acyltransferase 1, have been found to be affected by abiotic factors, suggesting that they play a role in the lipid content and compositional changes seen under abiotic stress conditions. Unfortunately, while only a very small number of strategies have been developed as of yet to minimize these environmental effects on the production of storage lipids, it is clear that this feat will be of the utmost importance for developing superior oil crops with the capability to perform in a consistent manner in field conditions in the future.

  14. Influence of abiotic factors on the antimicrobial activity of chitosan.

    PubMed

    Tavaria, Freni K; Costa, Eduardo M; Gens, Eduardo J; Malcata, Francisco Xavier; Pintado, Manuela E

    2013-12-01

    In an effort to bypass the adverse secondary effects attributed to the traditional therapeutic approaches used to treat skin disorders (such as atopic dermatitis), alternative antimicrobials have recently been suggested. One such antimicrobial is chitosan, owing to the already proved biological properties associated with its use. However, the influence of abiotic factors on such activities warrants evaluation. This research effort assessed the antimicrobial activity of chitosan upon skin microorganisms (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) in vitro when subject to a combination of different abiotic factors such as pH, ionic strength, organic acids and free fatty acids. Free fatty acids, ionic strength and pH significantly affected chitosan's capability of reducing the viable numbers of S. aureus. This antimicrobial action was potentiated in the presence of palmitic acid and a lower ionic strength (0.2% NaCl), while a higher ionic strength (0.4% NaCl) favored chitosan's action upon the reduction of viable numbers of S. epidermidis and E. coli. Although further studies are needed, these preliminary results advocate that chitosan can in the future be potentially considered as an antimicrobial of choice when handling symptoms associated with atopic dermatitis.

  15. The Effect of Different Oceanic Abiotic Factors on Prokaryotic Body Sizes

    NASA Astrophysics Data System (ADS)

    Pidathala, S.; Bellon, M.; Heim, N.; Payne, J.

    2016-12-01

    We are studying the impact of abiotic factors in the Pacific and Atlantic on prokaryotic body sizes and genome sizes because we are interested in the manner in which abiotic factors influence genome sizes independent of their influence on body sizes. Some research has been done in the past on marine bacterial evolution, including data collection on marine ecology in relation to bacterial body sizes (Straza 2009). We are using the abiotic factors: temperature, salinity, and pH to compare the biovolumes/genome sizes of different phyla by using R. We made 9 scatter plots to model these relationships. Regardless of the phyla or the ocean, we found that there is no relation between pH, temperature, and body size, with several exceptions: Deinococcus. thermus has an indirect relationship with size in respect to temperature; size only correlates to temperature for phyla that are thermophiles. We also found that bacteria like D. thermus and Thermotogae are taxa only found in higher temperatures. Additionally, almost all phyla have genome sizes restricted by certain pH levels:, Proteobacteria only reach genomes with acidity levels greater than 6. In terms of salinity levels, certain bacteria are only found within a small range, and others, like Proteobacteria, can only reach genomes at low salinity levels. Finally, Proteobacteria have large genome sizes between 30 and 40 °, and Crenarchaeota have constant genome sizes in higher temperatures. Conclusively, we discovered that these abiotic factors generally do not affect body size, with the exception of D. thermus' indirect relationship to temperature due to its small biovolume in high temperatures. However, we determined that these abiotic factors have a great impact on genome sizes. This is due to genome size independence from body size. Also, genome size could have served as an adaptive feature for bacteria in marine environments, explaining why different phyla may have diverged to accommodate their lifestyles.

  16. Novel NAC Transcription Factor TaNAC67 Confers Enhanced Multi-Abiotic Stress Tolerances in Arabidopsis

    PubMed Central

    Mao, Xinguo; Chen, Shuangshuang; Li, Ang; Zhai, Chaochao; Jing, Ruilian

    2014-01-01

    Abiotic stresses are major environmental factors that affect agricultural productivity worldwide. NAC transcription factors play pivotal roles in abiotic stress signaling in plants. As a staple crop, wheat production is severely constrained by abiotic stresses whereas only a few NAC transcription factors have been characterized functionally. To promote the application of NAC genes in wheat improvement by biotechnology, a novel NAC gene designated TaNAC67 was characterized in common wheat. To determine its role, transgenic Arabidopsis overexpressing TaNAC67-GFP controlled by the CaMV-35S promoter was generated and subjected to various abiotic stresses for morphological and physiological assays. Gene expression showed that TaNAC67 was involved in response to drought, salt, cold and ABA treatments. Localization assays revealed that TaNAC67 localized in the nucleus. Morphological analysis indicated the transgenics had enhanced tolerances to drought, salt and freezing stresses, simultaneously supported by enhanced expression of multiple abiotic stress responsive genes and improved physiological traits, including strengthened cell membrane stability, retention of higher chlorophyll contents and Na+ efflux rates, improved photosynthetic potential, and enhanced water retention capability. Overexpression of TaNAC67 resulted in pronounced enhanced tolerances to drought, salt and freezing stresses, therefore it has potential for utilization in transgenic breeding to improve abiotic stress tolerance in crops. PMID:24427285

  17. Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids.

    PubMed

    Becker, Christine; Desneux, Nicolas; Monticelli, Lucie; Fernandez, Xavier; Michel, Thomas; Lavoir, Anne-Violette

    2015-01-01

    In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and "green leaf volatiles." Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant's growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change.

  18. Effects of Abiotic Factors on HIPV-Mediated Interactions between Plants and Parasitoids

    PubMed Central

    Becker, Christine; Desneux, Nicolas; Monticelli, Lucie; Fernandez, Xavier; Michel, Thomas; Lavoir, Anne-Violette

    2015-01-01

    In contrast to constitutively emitted plant volatiles (PV), herbivore-induced plant volatiles (HIPV) are specifically emitted by plants when afflicted with herbivores. HIPV can be perceived by parasitoids and predators which parasitize or prey on the respective herbivores, including parasitic hymenoptera. HIPV act as signals and facilitate host/prey detection. They comprise a blend of compounds: main constituents are terpenoids and “green leaf volatiles.” Constitutive emission of PV is well known to be influenced by abiotic factors like temperature, light intensity, water, and nutrient availability. HIPV share biosynthetic pathways with constitutively emitted PV and might therefore likewise be affected by abiotic conditions. However, the effects of abiotic factors on HIPV-mediated biotic interactions have received only limited attention to date. HIPV being influenced by the plant's growing conditions could have major implications for pest management. Quantitative and qualitative changes in HIPV blends may improve or impair biocontrol. Enhanced emission of HIPV may attract a larger number of natural enemies. Reduced emission rates or altered compositions, however, may render blends imperceptible to parasitoides and predators. Predicting the outcome of these changes is highly important for food production and for ecosystems affected by global climate change. PMID:26788501

  19. The transcriptional regulatory network in the drought response and its crosstalk in abiotic stress responses including drought, cold, and heat

    PubMed Central

    Nakashima, Kazuo; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo

    2014-01-01

    Drought negatively impacts plant growth and the productivity of crops around the world. Understanding the molecular mechanisms in the drought response is important for improvement of drought tolerance using molecular techniques. In plants, abscisic acid (ABA) is accumulated under osmotic stress conditions caused by drought, and has a key role in stress responses and tolerance. Comprehensive molecular analyses have shown that ABA regulates the expression of many genes under osmotic stress conditions, and the ABA-responsive element (ABRE) is the major cis-element for ABA-responsive gene expression. Transcription factors (TFs) are master regulators of gene expression. ABRE-binding protein and ABRE-binding factor TFs control gene expression in an ABA-dependent manner. SNF1-related protein kinases 2, group A 2C-type protein phosphatases, and ABA receptors were shown to control the ABA signaling pathway. ABA-independent signaling pathways such as dehydration-responsive element-binding protein TFs and NAC TFs are also involved in stress responses including drought, heat, and cold. Recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress responses. The important roles of these TFs in crosstalk among abiotic stress responses will be discussed. Control of ABA or stress signaling factor expression can improve tolerance to environmental stresses. Recent studies using crops have shown that stress-specific overexpression of TFs improves drought tolerance and grain yield compared with controls in the field. PMID:24904597

  20. NAC transcription factors in plant multiple abiotic stress responses: progress and prospects

    PubMed Central

    Shao, Hongbo; Wang, Hongyan; Tang, Xiaoli

    2015-01-01

    Abiotic stresses adversely affect plant growth and agricultural productivity. According to the current climate prediction models, crop plants will face a greater number of environmental stresses, which are likely to occur simultaneously in the future. So it is very urgent to breed broad-spectrum tolerant crops in order to meet an increasing demand for food productivity due to global population increase. As one of the largest families of transcription factors (TFs) in plants, NAC TFs play vital roles in regulating plant growth and development processes including abiotic stress responses. Lots of studies indicated that many stress-responsive NAC TFs had been used to improve stress tolerance in crop plants by genetic engineering. In this review, the recent progress in NAC TFs was summarized, and the potential utilization of NAC TFs in breeding abiotic stress tolerant transgenic crops was also be discussed. In view of the complexity of field conditions and the specificity in multiple stress responses, we suggest that the NAC TFs commonly induced by multiple stresses should be promising candidates to produce plants with enhanced multiple stress tolerance. Furthermore, the field evaluation of transgenic crops harboring NAC genes, as well as the suitable promoters for minimizing the negative effects caused by over-expressing some NAC genes, should be considered. PMID:26579152

  1. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (hymenoptera: bethylidae)

    USDA-ARS?s Scientific Manuscript database

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we examined the effects of biotic and abiotic factors including temperature, photoperiod, light intensity,...

  2. Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation

    PubMed Central

    Agler, Matthew T.; Ruhe, Jonas; Kroll, Samuel; Morhenn, Constanze; Kim, Sang-Tae; Weigel, Detlef; Kemen, Eric M.

    2016-01-01

    Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe–microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe–microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial “hubs,” are strongly interconnected and have a severe effect on communities. By documenting these microbe–microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on “hub” microbes, which, via microbe–microbe interactions, transmit the effects to the microbial community. We analyzed two “hub” microbes (the

  3. The NAC family transcription factor OsNAP confers abiotic stress response through the ABA pathway.

    PubMed

    Chen, Xu; Wang, Yaofeng; Lv, Bo; Li, Jie; Luo, Liqiong; Lu, Songchong; Zhang, Xuan; Ma, Hong; Ming, Feng

    2014-03-01

    Plants respond to environmental stresses by altering gene expression, and several genes have been found to mediate stress-induced expression, but many additional factors are yet to be identified. OsNAP is a member of the NAC transcription factor family; it is localized in the nucleus, and shows transcriptional activator activity in yeast. Analysis of the OsNAP transcript levels in rice showed that this gene was significantly induced by ABA and abiotic stresses, including high salinity, drought and low temperature. Rice plants overexpressing OsNAP did not show growth retardation, but showed a significantly reduced rate of water loss, enhanced tolerance to high salinity, drought and low temperature at the vegetative stage, and improved yield under drought stress at the flowering stage. Microarray analysis of transgenic plants overexpressing OsNAP revealed that many stress-related genes were up-regulated, including OsPP2C06/OsABI2, OsPP2C09, OsPP2C68 and OsSalT, and some genes coding for stress-related transcription factors (OsDREB1A, OsMYB2, OsAP37 and OsAP59). Our data suggest that OsNAP functions as a transcriptional activator that plays a role in mediating abiotic stress responses in rice.

  4. Explicit modeling of abiotic and landscape factors reveals precipitation and forests associated with aphid abundance.

    PubMed

    Stack Whitney, Kaitlin; Meehan, Timothy D; Kucharik, Christopher J; Zhu, Jun; Townsend, Philip A; Hamilton, Krista; Gratton, Claudio

    2016-12-01

    Increases in natural or noncrop habitat surrounding agricultural fields have been shown to be correlated with declines in insect crop pests. However, these patterns are highly variable across studies suggesting other important factors, such as abiotic drivers, which are rarely included in landscape models, may also contribute to variability in insect population abundance. The objective of this study was to explicitly account for the contribution of temperature and precipitation, in addition to landscape composition, on the abundance of a widespread insect crop pest, the soybean aphid (Aphis glycines Matsumura), in Wisconsin soybean fields. We hypothesized that higher soybean aphid abundance would be associated with higher heat accumulation (e.g., growing degree days) and increasing noncrop habitat in the surrounding landscape, due to the presence of the overwintering primary hosts of soybean aphid. To evaluate these hypotheses, we used an ecoinformatics approach that relied on a large dataset collected across Wisconsin over a 9-year period (2003-2011), for an average of 235 sites per year (n = 2,110 fields total). We determined surrounding landscape composition (1.5-km radius) using publicly available satellite-derived land cover imagery and interpolated daily temperature and precipitation information from the National Weather Service COOP weather station network. We constructed linear mixed models for soybean aphid abundance based on abiotic and landscape explanatory variables and applied model averaging for prediction using an information theoretic framework. Over this broad spatial and temporal extent in Wisconsin, we found that variation in growing season precipitation was positively related to soybean aphid abundance, while higher precipitation during the nongrowing season had a negative effect on aphid populations. Additionally, we found that aphid populations were higher in areas with proportionally more forest but were lower in areas where minor crops

  5. Inter-annual variability of carbon fluxes in temperate forest ecosystems: effects of biotic and abiotic factors

    NASA Astrophysics Data System (ADS)

    Chen, M.; Keenan, T. F.; Hufkens, K.; Munger, J. W.; Bohrer, G.; Brzostek, E. R.; Richardson, A. D.

    2014-12-01

    Carbon dynamics in terrestrial ecosystems are influenced by both abiotic and biotic factors. Abiotic factors, such as variation in meteorological conditions, directly drive biophysical and biogeochemical processes; biotic factors, referring to the inherent properties of the ecosystem components, reflect the internal regulating effects including temporal dynamics and memory. The magnitude of the effect of abiotic and biotic factors on forest ecosystem carbon exchange has been suggested to vary at different time scales. In this study, we design and conduct a model-data fusion experiment to investigate the role and relative importance of the biotic and abiotic factors for inter-annual variability of the net ecosystem CO2 exchange (NEE) of temperate deciduous forest ecosystems in the Northeastern US. A process-based model (FöBAAR) is parameterized at four eddy-covariance sites using all available flux and biometric measurements. We conducted a "transplant" modeling experiment, that is, cross- site and parameter simulations with different combinations of site meteorology and parameters. Using wavelet analysis and variance partitioning techniques, analysis of model predictions identifies both spatial variant and spatially invariant parameters. Variability of NEE was primarily modulated by gross primary productivity (GPP), with relative contributions varying from hourly to yearly time scales. The inter-annual variability of GPP and NEE is more regulated by meteorological forcing, but spatial variability in certain model parameters (biotic response) has more substantial effects on the inter-annual variability of ecosystem respiration (Reco) through the effects on carbon pools. Both the biotic and abiotic factors play significant roles in modulating the spatial and temporal variability in terrestrial carbon cycling in the region. Together, our study quantifies the relative importance of both, and calls for better understanding of them to better predict regional CO2

  6. Relationships between biotic and abiotic factors and regeneration of chestnut oak, white oak, and northern red oak

    Treesearch

    Songlin Fei; Kim C. Steiner; James C. Finley; Marc E. McDill

    2003-01-01

    A series of substantial field surveys of 38 mixed-oak stands in central Pennsylvania were carried out during 1996-2000. All the stands were surveyed 1 year prior to harvest, and 16 stands have been surveyed 1 year after harvest. Three abiotic factors at stand scale, four abiotic factors at plot scale, and two biotic factors and one abiotic factor at subplot scale was...

  7. Can plant-natural enemy communication withstand disruption by biotic and abiotic factors?

    PubMed

    Clavijo McCormick, Andrea

    2016-12-01

    The attraction of natural enemies towards herbivore-induced plant volatiles is a well-documented phenomenon. However, the majority of published studies are carried under optimal water and nutrient regimes and with just one herbivore. But what happens when additional levels of ecological complexity are added? Does the presence of a second herbivore, microorganisms, and abiotic stress interfere with plant-natural enemy communication? or is communication stable enough to withstand disruption by additional biotic and abiotic factors?Investigating the effects of these additional levels of ecological complexity is key to understanding the stability of tritrophic interactions in natural ecosystems and may aid to forecast the impact of environmental disturbances on these, especially in climate change scenarios, which are often associated with modifications in plant and arthropod species distribution and increased levels of abiotic stress.This review explores the literature on natural enemy attraction to herbivore-induced volatiles when, besides herbivory, plants are challenged by additional biotic and abiotic factors.The aim of this review was to establish the impact of different biotic and abiotic factors on plant-natural enemy communication and to highlight critical aspects to guide future research efforts.

  8. Earth, wind, and fire: Abiotic factors and the impacts of global environmental change on forest health

    Treesearch

    J.E. Lundquist; A.E. Camp; M.L. Tyrell; S.J. Seybold; P. Cannon; D.J. Lodge

    2011-01-01

    Trees do not just die; there is always a primary cause, and often contributing factors. Trees need adequate quantities of water, heat, light, nutrients, carbon dioxide, oxygen, and other abiotic resources to sustain life, growth, and reproduction. When these factors are deficient or excessive, they cause mortality. According to the concept of baseline mortality (...

  9. [Relationship between antophyte foliar morphology and abiotic factors in the main rainforests of Eastern Cuba].

    PubMed

    Quesada, Eddy Martínez

    2009-01-01

    Relationship between antophyte foliar morphology and abiotic factors in the main rainforests of Eastern Cuba. The foliar morphology of representative antophytes in four rainforest types of Eastern Cuba was studied in relation to the main abiotic factors. Although there are several leaf types in these forests, the microphyll type is the most important among endemic species in the ophiolites complex and the Montane rainforest. At the Lowland rainforest (metamorphic complex) the mesophyll leaf was the most important. Most foliar epidermis had structures normally found in mesomorphic plants, but xeromorphic and higromorphic morphologies were also present.

  10. Abiotic factors influencing deer browsing in West Virginia

    Treesearch

    Tyler A. Campbell; Benjamin R. Laseter; W. Mark Ford; Richard H. Odom; Karl V. Miller

    2006-01-01

    We present a comparison of woody browse availability and white-tailed deer (Odocoileus virginianus) use among clearcut interiors, skidder trail edges, and mature forest and an evaluation of the relative importance of aboitic factors in predicting browsing pressure within regenerating clearcuts in the central Appalachians of West Virginia. We sampled...

  11. Comprehensive analysis suggests overlapping expression of rice ONAC transcription factors in abiotic and biotic stress responses.

    PubMed

    Sun, Lijun; Huang, Lei; Hong, Yongbo; Zhang, Huijuan; Song, Fengming; Li, Dayong

    2015-02-17

    NAC (NAM/ATAF/CUC) transcription factors comprise a large plant-specific gene family that contains more than 149 members in rice. Extensive studies have revealed that NAC transcription factors not only play important roles in plant growth and development, but also have functions in regulation of responses to biotic and abiotic stresses. However, biological functions for most of the members in the NAC family remain unknown. In this study, microarray data analyses revealed that a total of 63 ONAC genes exhibited overlapping expression patterns in rice under various abiotic (salt, drought, and cold) and biotic (infection by fungal, bacterial, viral pathogens, and parasitic plants) stresses. Thirty-eight ONAC genes exhibited overlapping expression in response to any two abiotic stresses, among which 16 of 30 selected ONAC genes were upregulated in response to exogenous ABA. Sixty-five ONAC genes showed overlapping expression patterns in response to any two biotic stresses. Results from the present study suggested that members of the ONAC genes with overlapping expression pattern may have pleiotropic biological functions in regulation of defense response against different abiotic and biotic stresses, which provide clues for further functional analysis of the ONAC genes in stress tolerance and pathogen resistance.

  12. Comprehensive Analysis Suggests Overlapping Expression of Rice ONAC Transcription Factors in Abiotic and Biotic Stress Responses

    PubMed Central

    Sun, Lijun; Huang, Lei; Hong, Yongbo; Zhang, Huijuan; Song, Fengming; Li, Dayong

    2015-01-01

    NAC (NAM/ATAF/CUC) transcription factors comprise a large plant-specific gene family that contains more than 149 members in rice. Extensive studies have revealed that NAC transcription factors not only play important roles in plant growth and development, but also have functions in regulation of responses to biotic and abiotic stresses. However, biological functions for most of the members in the NAC family remain unknown. In this study, microarray data analyses revealed that a total of 63 ONAC genes exhibited overlapping expression patterns in rice under various abiotic (salt, drought, and cold) and biotic (infection by fungal, bacterial, viral pathogens, and parasitic plants) stresses. Thirty-eight ONAC genes exhibited overlapping expression in response to any two abiotic stresses, among which 16 of 30 selected ONAC genes were upregulated in response to exogenous ABA. Sixty-five ONAC genes showed overlapping expression patterns in response to any two biotic stresses. Results from the present study suggested that members of the ONAC genes with overlapping expression pattern may have pleiotropic biological functions in regulation of defense response against different abiotic and biotic stresses, which provide clues for further functional analysis of the ONAC genes in stress tolerance and pathogen resistance. PMID:25690040

  13. Abiotic factors in colony formation: effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

    NASA Astrophysics Data System (ADS)

    Yang, Zhen; Kong, Fanxiang

    2013-07-01

    Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide (EPS) has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS productionin M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field (28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity: 100 μmol/(m2 · s)). These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

  14. Influence of intraspecific variability and abiotic factors on mycotoxin production in Penicillium roqueforti.

    PubMed

    Fontaine, Kévin; Hymery, Nolwenn; Lacroix, Marlène Z; Puel, Sylvie; Puel, Olivier; Rigalma, Karim; Gaydou, Vincent; Coton, Emmanuel; Mounier, Jérôme

    2015-12-23

    Penicillium roqueforti has the ability to produce secondary metabolites, including roquefortine C (ROQC) and mycophenolic acid (MPA). In a previous study, the presence of these mycotoxins, alone or in co-occurrence, has been reported in blue-veined cheese. A high variability of mycotoxin content has also been observed, although the majority of samples exhibited relatively low concentrations. The observed variability raises the question of the factors impacting ROQC and MPA production. In this context, the mycotoxigenic potential of 96 P. roqueforti strains (biotic factor) and the effect of some abiotic factors (pH, temperature, NaCl and O2 contents, and C/N ratio) on mycotoxin production were evaluated. A high intraspecific diversity, established via genotypic (RAPD) and phenotypic (FTIR) approaches, was observed. It was associated with mycotoxigenic potential variability and may thus explain part of the observed variability in mycotoxin content of blue-veined cheese. Moreover, a significant decrease of ROQC and MPA production was observed for conditions (temperature, C/N ratio, O2 and NaCl concentrations) encountered during cheese-making compared with optimal growth conditions. The results also highlighted that there was no significant effect of addition of ROQC amino-acid precursor on the production of both mycotoxins whereas a pH increase from 4.5 to 6.5 slightly reduced MPA but not ROQC production.

  15. Abiotic Factors Shape Microbial Diversity in Sonoran Desert Soils

    PubMed Central

    Fitak, Robert R.; Munguia-Vega, Adrian; Racolta, Adriana; Martinson, Vincent G.; Dontsova, Katerina

    2012-01-01

    High-throughput, culture-independent surveys of bacterial and archaeal communities in soil have illuminated the importance of both edaphic and biotic influences on microbial diversity, yet few studies compare the relative importance of these factors. Here, we employ multiplexed pyrosequencing of the 16S rRNA gene to examine soil- and cactus-associated rhizosphere microbial communities of the Sonoran Desert and the artificial desert biome of the Biosphere2 research facility. The results of our replicate sampling approach show that microbial communities are shaped primarily by soil characteristics associated with geographic locations, while rhizosphere associations are secondary factors. We found little difference between rhizosphere communities of the ecologically similar saguaro (Carnegiea gigantea) and cardón (Pachycereus pringlei) cacti. Both rhizosphere and soil communities were dominated by the disproportionately abundant Crenarchaeota class Thermoprotei, which comprised 18.7% of 183,320 total pyrosequencing reads from a comparatively small number (1,337 or 3.7%) of the 36,162 total operational taxonomic units (OTUs). OTUs common to both soil and rhizosphere samples comprised the bulk of raw sequence reads, suggesting that the shared community of soil and rhizosphere microbes constitute common and abundant taxa, particularly in the bacterial phyla Proteobacteria, Actinobacteria, Planctomycetes, Firmicutes, Bacteroidetes, Chloroflexi, and Acidobacteria. The vast majority of OTUs, however, were rare and unique to either soil or rhizosphere communities and differed among locations dozens of kilometers apart. Several soil properties, particularly soil pH and carbon content, were significantly correlated with community diversity measurements. Our results highlight the importance of culture-independent approaches in surveying microbial communities of extreme environments. PMID:22885757

  16. Buccal pumping mechanics of Xenopus laevis tadpoles: effects of biotic and abiotic factors.

    PubMed

    Ryerson, William G; Deban, Stephen M

    2010-07-15

    Biotic factors such as body size and shape have long been known to influence kinematics in vertebrates. Movement in aquatic organisms can also be strongly affected by abiotic factors such as the viscosity of the medium. We examined the effects of both biotic factors and abiotic factors on buccal pumping kinematics in Xenopus tadpoles using high-speed imaging of an ontogenetic series of tadpoles combined with experimental manipulation of the medium over a 10-fold range of viscosity. We found influences of both biotic and abiotic factors on tadpole movements; absolute velocities and excursions of the jaws and hyoid were greater in higher viscosity fluid but durations of movements were unaffected. Smaller tadpoles have relatively wider heads and more robust hyoid muscles used in buccal expansion and compression. Lever arm ratios were found to be constant at all sizes; therefore, smaller tadpoles have relatively higher resolved muscle forces and, like tadpoles in more viscous medium, displayed higher absolute velocities of jaw and hyoid movements. Nonetheless, small tadpoles drew in water at lower Reynolds numbers (Re) than predicted by kinematics, due to negative allometry of the buccal pump. Finally, tadpoles transitioned from a flow regime dominated by viscous forces (Re=2) to an intermediate regime (Re=106).

  17. Distribution of the Euryhaline Squid Lolliguncula brevis in Chesapeake Bay: Effects of Selected Abiotic Factors

    DTIC Science & Technology

    2002-01-31

    significant aquatic habitats where cephalopods are poorly represented. One notable squid, the brief squid Lolliguncula brevis, is the only species of... cephalopod frequently found in low-salinity estuaries (Vecchione 1991a), where it tolerates salinities as low as 8.5‰ for brief periods (Laughlin...effects of selected abiotic factors I. K. Bartol1,*, R. Mann2, M. Vecchione3 1Department of Organismic Biology, Ecology, and Evolution , University of

  18. DREB1/CBF transcription factors: their structure, function and role in abiotic stress tolerance in plants.

    PubMed

    Akhtar, M; Jaiswal, A; Taj, G; Jaiswal, J P; Qureshi, M I; Singh, N K

    2012-01-01

    Drought, high salinity and low temperature are major abiotic stresses that influence survival, productivity and geographical distribution of many important crops across the globe. Plants respond to these environmental challenges via physiological, cellular and molecular processes, which results in adjusted metabolic and structural alterations. The dehydration-responsiveelement-binding (DREB) protein / C-repeat binding factors (CBFs) belong to APETALA2 (AP2) family transcription factors that bind to DRE/CRT cis-element and regulate the expression of stress-responsive genes. DREB1/CBF genes, therefore, play an important role in increasing stress tolerance in plants and their deployment using transgenic technology seems to be a potential alternative in management of abiotic stresses in crop plants. This review is mainly focussed on the structural characteristics as well as transcriptional regulation of gene expression in response to various abiotic stresses, with particular emphasis on the role of DREB1/CBF regulon in stress-responsive gene expression. The recent progress related to genetic engineering of DREB1/CBF transcription factors in various crops and model plants is also summarized.

  19. Soybean transcription factor ORFeome associated with drought resistance: a valuable resource to accelerate research on abiotic stress resistance.

    PubMed

    Chai, Chenglin; Wang, Yongqin; Joshi, Trupti; Valliyodan, Babu; Prince, Silvas; Michel, Lydia; Xu, Dong; Nguyen, Henry T

    2015-08-13

    Whole genome sequencing provides the most comprehensive collection of an organism's genetic information. The availability of complete genome sequences is expected to dramatically deliver a high impact on biology. However, to achieve this impact in the area of crop improvement, significant efforts are still required on functional genomics, including the areas of gene annotation, cloning, expression profiling, and functional validation. Here we report our efforts in generating the first transcription factor (TF) open reading frame (ORF)eome resource associated with drought resistance in soybean (Glycine max), a major oil/protein crop grown worldwide. This study provides a highly annotated soybean TF-ORFeome associated with drought resistance. It contains information from experimentally verified protein-coding sequences (CDS), expression profiling under several abiotic stresses (drought, salinity, dehydration and ABA), and computationally predicted protein subcellular localization and cis-regulatory elements (CREs) analysis. All the information is available to plant researchers through a freely accessible and user-friendly database, Soybean Knowledge Base (SoyKB). The soybean TF-ORFeome provides a valuable public resource for functional genomics studies, especially in the area of plant abiotic stresses. It will accelerate findings in the areas of abiotic stresses and lead to the generation of crops with enhanced resistance to multiple stresses.

  20. Recent Advances in Utilizing Transcription Factors to Improve Plant Abiotic Stress Tolerance by Transgenic Technology

    PubMed Central

    Wang, Hongyan; Wang, Honglei; Shao, Hongbo; Tang, Xiaoli

    2016-01-01

    Agricultural production and quality are adversely affected by various abiotic stresses worldwide and this will be exacerbated by the deterioration of global climate. To feed a growing world population, it is very urgent to breed stress-tolerant crops with higher yields and improved qualities against multiple environmental stresses. Since conventional breeding approaches had marginal success due to the complexity of stress tolerance traits, the transgenic approach is now being popularly used to breed stress-tolerant crops. So identifying and characterizing the critical genes involved in plant stress responses is an essential prerequisite for engineering stress-tolerant crops. Far beyond the manipulation of single functional gene, engineering certain regulatory genes has emerged as an effective strategy now for controlling the expression of many stress-responsive genes. Transcription factors (TFs) are good candidates for genetic engineering to breed stress-tolerant crop because of their role as master regulators of many stress-responsive genes. Many TFs belonging to families AP2/EREBP, MYB, WRKY, NAC, bZIP have been found to be involved in various abiotic stresses and some TF genes have also been engineered to improve stress tolerance in model and crop plants. In this review, we take five large families of TFs as examples and review the recent progress of TFs involved in plant abiotic stress responses and their potential utilization to improve multiple stress tolerance of crops in the field conditions. PMID:26904044

  1. Effect of abiotic and biotic factors on the abundance of waterbirds in Grado-Marano Lagoon (Italy)

    NASA Astrophysics Data System (ADS)

    Altobelli, Alfredo; Hubina, Tatsiana; Sponza, Stefano; Sisto, Alberto

    2008-10-01

    The purpose of this paper is to assess the influence of several biotic and abiotic factors on the abundance of waterbirds in the Grado-Marano Lagoon. The Grado-Marano Lagoon is situated in the Northeast of the Adriatic Sea with an extension of approximately 160 km2. ASTER satellite images were utilized to classify different types of morphologies and habitat, including sea grass meadows. Four abiotic factors (total nitrogen, total phosphorous, alkalinity and sediment texture) and three biotic factors (benthic community, sea grass meadows and waterbird guild abundance) were integrated into a GIS. A regular UTM grid of square cells (Operational Geographic Units, OGUs), 1km x 1km, was superimposed on the entire lagoon. Using the Hierarchical Cluster Analysis (HCA) technique it was possible to delineate ecological units (clusters of OGUs) and Principal Component Analysis (PCA) was used to reduce the dimensionality of the factors considered. Subsequently, Correspondence Analysis (CA) was used to examine the relationship between waterbird guild abundance and ecological units.

  2. Spatially dependent biotic and abiotic factors drive survivorship and physical structure of green roof vegetation.

    PubMed

    Aloisio, Jason M; Palmer, Matthew I; Giampieri, Mario A; Tuininga, Amy R; Lewis, James D

    2017-01-01

    Plant survivorship depends on biotic and abiotic factors that vary at local and regional scales. This survivorship, in turn, has cascading effects on community composition and the physical structure of vegetation. Survivorship of native plant species is variable among populations planted in environmentally stressful habitats like urban roofs, but the degree to which factors at different spatial scales affect survivorship in urban systems is not well understood. We evaluated the effects of biotic and abiotic factors on survivorship, composition, and physical structure of two native perennial species assemblages, one characterized by a mixture of C4 grasses and forbs (Hempstead Plains, HP) and one characterized by a mixture of C3 grasses and forbs (Rocky Summit, RS), that were initially sown at equal ratios of growth forms (5:1:4; grass, N-fixing forb and non-N-fixing forb) in replicate 2-m(2) plots planted on 10 roofs in New York City (New York, USA). Of 24 000 installed plants, 40% survived 23 months after planting. Within-roof factors explained 71% of variation in survivorship, with biotic (species identity and assemblage) factors accounting for 54% of the overall variation, and abiotic (growing medium depth and plot location) factors explaining 17% of the variation. Among-roof factors explained 29% of variation in survivorship and increased solar radiation correlated with decreased survivorship. While growing medium properties (pH, nutrients, metals) differed among roofs there was no correlation with survivorship. Percent cover and sward height increased with increasing survivorship. At low survivorship, cover of the HP assemblage was greater compared to the RS assemblage. Sward height of the HP assemblage was about two times greater compared to the RS assemblage. These results highlight the effects of local biotic and regional abiotic drivers on community composition and physical structure of green roof vegetation. As a result, initial green roof plant

  3. GhATAF1, a NAC transcription factor, confers abiotic and biotic stress responses by regulating phytohormonal signaling networks.

    PubMed

    He, Xin; Zhu, Longfu; Xu, Lian; Guo, Weifeng; Zhang, Xianlong

    2016-10-01

    Dual function of GhATAF1 in the responses to salinity stress and Verticillium dahliae infection in cotton. NAC (NAM/ATAF1/2/CUC2) is a large plant-specific transcription factor family that plays important roles in the response to abiotic stresses. We previously isolated a cotton NAC transcription factor gene, GhATAF1, which was up-regulated by ABA, cold and salt stresses and classified into AFAT1/2, a sub-family of NAC. Here, we report that GhATAF1 was also highly induced by MeJA, SA and Verticillium dahliae inoculation, which implied that GhATAF1 was involved not only in the response to abiotic stress but also in the response to biotic stress. GhATAF1 was localized in the nucleus and possessed transactivation activity. Overexpression of GhATAF1 enhanced cotton plant tolerance to salt stress by enhancing the expression of various stress-related genes, including the ABA response gene GhABI4; the transporter gene GhHKT1, involved in Na(+)/K(+) homeostasis; and several stress-response genes (GhAVP1, GhRD22, GhDREB2A, GhLEA3, and GhLEA6). Additionally, overexpressing GhATAF1 increased cotton plant susceptibility to the fungal pathogens V. dahliae and Botrytis cinerea, coupled with the suppression of JA-mediated signaling and the activation of SA-mediated signaling. Our results suggested that GhATAF1, the cotton stress-responsive NAC transcription factor, plays important roles in the response to both abiotic stress and biotic stress by coordinating the phytohormone signaling networks.

  4. Roles of NAC transcription factors in the regulation of biotic and abiotic stress responses in plants.

    PubMed

    Nuruzzaman, Mohammed; Sharoni, Akhter M; Kikuchi, Shoshi

    2013-09-03

    NAC transcription factors are one of the largest families of transcriptional regulators in plants, and members of the NAC gene family have been suggested to play important roles in the regulation of the transcriptional reprogramming associated with plant stress responses. A phylogenetic analysis of NAC genes, with a focus on rice and Arabidopsis, was performed. Herein, we present an overview of the regulation of the stress responsive NAC SNAC/(IX) group of genes that are implicated in the resistance to different stresses. SNAC factors have important roles for the control of biotic and abiotic stresses tolerance and that their overexpression can improve stress tolerance via biotechnological approaches. We also review the recent progress in elucidating the roles of NAC transcription factors in plant biotic and abiotic stresses. Modification of the expression pattern of transcription factor genes and/or changes in their activity contribute to the elaboration of various signaling pathways and regulatory networks. However, a single NAC gene often responds to several stress factors, and their protein products may participate in the regulation of several seemingly disparate processes as negative or positive regulators. Additionally, the NAC proteins function via auto-regulation or cross-regulation is extensively found among NAC genes. These observations assist in the understanding of the complex mechanisms of signaling and transcriptional reprogramming controlled by NAC proteins.

  5. Roles of NAC transcription factors in the regulation of biotic and abiotic stress responses in plants

    PubMed Central

    Nuruzzaman, Mohammed; Sharoni, Akhter M.; Kikuchi, Shoshi

    2013-01-01

    NAC transcription factors are one of the largest families of transcriptional regulators in plants, and members of the NAC gene family have been suggested to play important roles in the regulation of the transcriptional reprogramming associated with plant stress responses. A phylogenetic analysis of NAC genes, with a focus on rice and Arabidopsis, was performed. Herein, we present an overview of the regulation of the stress responsive NAC SNAC/(IX) group of genes that are implicated in the resistance to different stresses. SNAC factors have important roles for the control of biotic and abiotic stresses tolerance and that their overexpression can improve stress tolerance via biotechnological approaches. We also review the recent progress in elucidating the roles of NAC transcription factors in plant biotic and abiotic stresses. Modification of the expression pattern of transcription factor genes and/or changes in their activity contribute to the elaboration of various signaling pathways and regulatory networks. However, a single NAC gene often responds to several stress factors, and their protein products may participate in the regulation of several seemingly disparate processes as negative or positive regulators. Additionally, the NAC proteins function via auto-regulation or cross-regulation is extensively found among NAC genes. These observations assist in the understanding of the complex mechanisms of signaling and transcriptional reprogramming controlled by NAC proteins. PMID:24058359

  6. Connecting RNA Processing to Abiotic Environmental Response in Arabidopsis: the role of a polyadenylation factor

    NASA Astrophysics Data System (ADS)

    Li, Q. Q.; Xu, R.; Hunt, A. G.; Falcone, D. L.

    Plants are constantly challenged by numerous environmental stresses both biotic and abiotic It is clear that plants have evolved to counter these stresses using all but limited means We recently discovered the potential role of a messenger RNA processing factor namely the Arabidopsis cleavage and polyadenylation specificity factor 30 kDa subunit AtCPSF30 when a mutant deficient in this factor displayed altered responses to an array of abiotic stresses This AtCPSF30 mutant named oxt6 exhibited an elevated tolerance to oxidative stress Microarray experiments of oxt6 and its complemented lines revealed an altered gene expression profile among which were antioxidative defense genes Interestingly the same gene encoding AtCPSF30 can also be transcribed into a large transcript that codes for a potential splicing factor Both protein products have a domain for RNA binding and a calmodulin binding domain activities of which have been confirmed by biochemical assays Surprisingly binding of AtCPSF30 to calmodulin inhibits the RNA-binding activity of the protein Mutational analysis shows that a small part of the protein is responsible for calmodulin binding and point mutations in this region abolished both RNA binding activity and the inhibition of this activity by calmodulin Analyses of the potential splicing factor are on going and the results will be presented The interesting possibilities for both the interplay between splicing and polyadenylation and the regulation of these processes by stimuli that act through

  7. Mediterranean coastal dune systems: Which abiotic factors have the most influence on plant communities?

    NASA Astrophysics Data System (ADS)

    Ruocco, Matteo; Bertoni, Duccio; Sarti, Giovanni; Ciccarelli, Daniela

    2014-08-01

    Mediterranean coastal dunes are dynamic and heterogeneous ecosystems characterised by a strong interaction between abiotic and biotic factors. The present study aimed to adopt a multidisciplinary approach - integrating data on dune morphology, sediment texture and soil parameters as well as shoreline trend - in order to define which are the abiotic factors that most affect the distribution and composition of Mediterranean plant dune communities. The study was carried out in two protected areas, located in central Italy, subjected to different shoreline trends in recent years. 75 plots were identified along eleven randomly positioned cross-shore transects, starting from the beach continuing up to the plant communities of the backdunes. In each plot floristic and environmental data - such as distance to the coastline, plot altitude, inclination, shoreline trend, mean grain-size, sorting, pH, conductivity and organic matter concentration - were collected. The analyses revealed significant changes of vegetational cover, dune morphology and geopedological features along the coast-to-inland gradient. Relationships between vegetation composition and environmental factors were investigated through Canonical Correspondence Analysis (CCA). Four factors - distance to the coastline, mean grain-size, shoreline trend and organic matter - were found to be closely correlated with the floristic composition of plant communities. Finally, soil properties were highlighted as the most determinant factors of community zonation in these Mediterranean coastal dune ecosystems. These results could be taken into account by local managers in conservation actions such as protecting the eroding foredunes as well as in artificial dune reconstructions.

  8. Multiple NUCLEAR FACTOR Y transcription factors respond to abiotic stress in Brassica napus L.

    PubMed

    Xu, Li; Lin, Zhongyuan; Tao, Qing; Liang, Mingxiang; Zhao, Gengmao; Yin, Xiangzhen; Fu, Ruixin

    2014-01-01

    Members of the plant NUCLEAR FACTOR Y (NF-Y) family are composed of the NF-YA, NF-YB, and NF-YC subunits. In Brassica napus (canola), each of these subunits forms a multimember subfamily. Plant NF-Ys were reported to be involved in several abiotic stresses. In this study, we demonstrated that multiple members of thirty three BnNF-Ys responded rapidly to salinity, drought, or ABA treatments. Transcripts of five BnNF-YAs, seven BnNF-YBs, and two BnNF-YCs were up-regulated by salinity stress, whereas the expression of thirteen BnNF-YAs, ten BnNF-YBs, and four BnNF-YCs were induced by drought stress. Under NaCl treatments, the expression of one BnNF-YA10 and four NF-YBs (BnNF-YB3, BnNF-YB7, BnNF-YB10, and BnNF-YB14) were greatly increased. Under PEG treatments, the expression levels of four NF-YAs (BnNF-YA9, BnNF-YA10, BnNF-YA11, and BnNF-YA12) and five NF-YBs (BnNF-YB1, BnNF-YB8, BnNF-YB10, BnNF-YB13, and BnNF-YB14) were greatly induced. The expression profiles of 20 of the 27 salinity- or drought-induced BnNF-Ys were also affected by ABA treatment. The expression levels of six NF-YAs (BnNF-YA1, BnNF-YA7, BnNF-YA8, BnNF-YA9, BnNF-YA10, and BnNF-YA12) and seven BnNF-YB members (BnNF-YB2, BnNF-YB3, BnNF-YB7, BnNF-YB10, BnNF-YB11, BnNF-YB13, and BnNF-YB14) and two NF-YC members (BnNF-YC2 and BnNF-YC3) were greatly up-regulated by ABA treatments. Only a few BnNF-Ys were inhibited by the above three treatments. Several NF-Y subfamily members exhibited collinear expression patterns. The promoters of all stress-responsive BnNF-Ys harbored at least two types of stress-related cis-elements, such as ABRE, DRE, MYB, or MYC. The cis-element organization of BnNF-Ys was similar to that of Arabidopsis thaliana, and the promoter regions exhibited higher levels of nucleotide sequence identity with Brassica rapa than with Brassica oleracea. This work represents an entry point for investigating the roles of canola NF-Y proteins during abiotic stress responses and provides insight into

  9. Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

    SciTech Connect

    Meike, A.; Stroes-Gascoyne, S.

    2000-08-01

    A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behavior into performance assessment models. One effort was to expand an existing modeling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated as well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories: (1) abiotic factors, (2) community dynamics and in-situ considerations, (3) nutrient considerations and (4) transport of radionuclides. The complete bibliography represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain.

  10. Abscisic-acid-dependent basic leucine zipper (bZIP) transcription factors in plant abiotic stress.

    PubMed

    Banerjee, Aditya; Roychoudhury, Aryadeep

    2017-01-01

    One of the major causes of significant crop loss throughout the world is the myriad of environmental stresses including drought, salinity, cold, heavy metal toxicity, and ultraviolet-B (UV-B) rays. Plants as sessile organisms have evolved various effective mechanism which enable them to withstand this plethora of stresses. Most of such regulatory mechanisms usually follow the abscisic-acid (ABA)-dependent pathway. In this review, we have primarily focussed on the basic leucine zipper (bZIP) transcription factors (TFs) activated by the ABA-mediated signalosome. Upon perception of ABA by specialized receptors, the signal is transduced via various groups of Ser/Thr kinases, which phosphorylate the bZIP TFs. Following such post-translational modification of TFs, they are activated so that they bind to specific cis-acting sequences called abscisic-acid-responsive elements (ABREs) or GC-rich coupling elements (CE), thereby influencing the expression of their target downstream genes. Several in silico techniques have been adopted so far to predict the structural features, recognize the regulatory modification sites, undergo phylogenetic analyses, and facilitate genome-wide survey of TF under multiple stresses. Current investigations on the epigenetic regulation that controls greater accessibility of the inducible regions of DNA of the target gene to the bZIP TFs exclusively under stress situations, along with the evolved stress memory responses via genomic imprinting mechanism, have been highlighted. The potentiality of overexpression of bZIP TFs, either in a homologous or in a heterologous background, in generating transgenic plants tolerant to various abiotic stressors have also been addressed by various groups. The present review will provide a coherent documentation on the functional characterization and regulation of bZIP TFs under multiple environmental stresses, with the major goal of generating multiple-stress-tolerant plant cultivars in near future.

  11. A membrane-bound NAC transcription factor as an integrator of biotic and abiotic stress signals.

    PubMed

    Seo, Pil Joon; Park, Chung-Mo

    2010-05-01

    Transcription factors are central components of gene regulatory networks that mediate virtually all aspects of growth and developmental processes in biological systems. The activity of transcription factors is regulated at multiple steps, such as gene transcription, posttranscriptional RNA processing, posttranslational modification, protein-protein interactions, and controlled protein turnover. Controlled activation of dormant, membrane-bound transcription factor (MTF) is an intriguing regulatory mechanism that ensures quick transcriptional responses to environmental fluctuations in plants, in which various stress hormones serve as signaling mediators. NTL6 is proteolytically activated upon exposure to cold and induces expression of the Pathogenesis-Related (PR) genes. The membrane-mediated cold signaling in inducing pathogen resistance is considered to be an adaptive strategy that protects plants against infection by hydrophilic pathogens frequently occurring during cold season. We found that NTL6 also mediates abscisic acid (ABA) regulation of abiotic stress responses in Arabidopsis. NTL6 is proteolytically activated by ABA. Transgenic plants overexpressing a nuclear NTL6 form (35S:6ΔC) exhibited a hypersensitive response to ABA and high salinity in seed germination. Taken together, these observations indicate that NTL6 plays an integrative role in plant responses to both biotic and abiotic stress conditions.

  12. Influence of Abiotic Factors on Flight Initiation by Asian Citrus Psyllid (Hemiptera: Liviidae).

    PubMed

    Martini, Xavier; Stelinski, Lukasz L

    2017-04-01

    Predicting the emergence and arrival of insect pests is paramount for integrated pest management. To achieve this goal, it is important to understand how abiotic factors influence pest dispersal behavior. We investigated the effects of abiotic conditions on flight initiation by the Asian citrus psyllid, Diaphorina citri Kuwayama. We first explored the effect of barometric pressure changes on flight initiation. We used a custom-made barometric chamber and observed the activity of D. citri as measured by the number of psyllids captured on yellow cardboard panels coated with adhesive. We found that psyllid flight initiation changed in response to variations in barometric pressure rather than to differences in stable pressures. Diaphorina citri were equally active at 1,009 mbar and 1,022 mbar. However, D. citri dispersed more as barometric pressure increased, and less when barometric pressure decreased. In a subsequent experiment, we manipulated temperature and relative humidity and observed how D. citri dispersed between citrus plants. Psyllids dispersal increased linearly with temperature. Changes in humidity did not affect dispersal of D. citri. Less than 1% of psyllids dispersed at 15 °C, compared with 7.7% at 21 °C and 27% at 25 °C. The minimal threshold for D. citri to initiate flight is estimated to be 16.5 °C. Collectively, our results provide an initial step toward developing predictive models of D. citri movement as influenced by abiotic factors. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. The Red Queen and the Court Jester: species diversity and the role of biotic and abiotic factors through time.

    PubMed

    Benton, Michael J

    2009-02-06

    Evolution may be dominated by biotic factors, as in the Red Queen model, or abiotic factors, as in the Court Jester model, or a mixture of both. The two models appear to operate predominantly over different geographic and temporal scales: Competition, predation, and other biotic factors shape ecosystems locally and over short time spans, but extrinsic factors such as climate and oceanographic and tectonic events shape larger-scale patterns regionally and globally, and through thousands and millions of years. Paleobiological studies suggest that species diversity is driven largely by abiotic factors such as climate, landscape, or food supply, and comparative phylogenetic approaches offer new insights into clade dynamics.

  14. Environmental Selenium Transformations: Distinguishing Abiotic and Biotic Factors Influencing Se Redox Transformations

    NASA Astrophysics Data System (ADS)

    Rosenfeld, C.; Kenyon, J.; James, B. R.; Santelli, C. M.

    2014-12-01

    Worldwide, selenium (Se) is proving to be a significant environmental concern, with many anthropogenic activities (e.g. coal mining and combustion, phosphate mining and agricultural irrigation) releasing potentially hazardous concentrations into surface and subsurface ecosystems. The US EPA is currently considering aquatic Se regulations, however no guidelines exist for excess soil Se, despite its ability to act as a persistent Se source. Various abiotic and biological processes mediate Se oxidation/reduction (redox) transformations in soils, thus influencing its solubility and bioavailability. In this research we assess (1) the ability of metal-transforming fungal species to aerobically reduce Se (Se (IV and/or VI) to Se(0)), and (2) the relative contribution of biotic and abiotic pathways for aerobic Se transformation. The primary objective of this research is to determine what abiotic and biotic factors enhance or restrict Se bioavailability. Results indicate that fungal-mediated Se reduction may be quite widespread, with at least 7 out of 10 species of known Mn(II)-oxidizing fungi isolated from metal impacted environments also identified as capable of aerobically reducing Se(IV) and/or Se(VI) to Se(0). Increasing concentrations of selenite (SeO32-; Se(IV)) and selenate (SeO42-; Se(VI)) generally reduced fungal growth rates, although selenate was more likely to inhibit fungal growth than selenite. To study oxidation, Se(0) was combined with Mn(III/IV) (hydr)oxides (henceforth referred to as Mn oxides), Se-transforming fungi (Alternaria alternata), and oxalic acid to mimic Se biogeochemistry at the plant-soil interface. Increased pH in the presence of fungi (7.2 with fungi, 6.8 without fungi after 24 days) was observed. Additionally, a slight decrease in redox potential was measured for incubations without Mn oxides (236 mV with Mn oxides, 205 mV without Mn oxides after 24 days), indicating that Mn oxides may enhance Se oxidation. Elemental Se oxidation rates to

  15. Abiotic and biotic factors modulate carrion fate and vertebrate scavenging communities.

    PubMed

    Turner, Kelsey L; Abernethy, Erin F; Conner, L Mike; Rhodes, Olin E; Beasley, James C

    2017-09-01

    Carrion is a valuable nutrient resource used by a diversity of vertebrates across the globe. However, vertebrate scavenging ecology remains an understudied area of science, especially in regards to how biotic and abiotic factors influence scavenging community composition. Here we elucidate how fundamental biotic and abiotic factors interact to modulate the efficiency and composition of vertebrate scavengers by investigating scavenging dynamics across a large gradient in carcass sizes and habitat types representative of many temperate ecosystems, as well as between two seasons reflecting differences in invertebrate activity. We found carcass size and season influenced carcass fate and persistence, as well as the richness and composition of vertebrate scavenger communities utilizing carrion resources. Species richness, which increased as carcass size increased and was higher during the cool season, had a significant effect on carcass persistence. In addition, habitat type influenced carcass detection times by vertebrates, and we observed relatively distinct scavenging communities associated with carcasses of differing sizes. This research highlights a pervasive limitation to the interpretation of results of previous studies as research failing to incorporate carcass size and habitat type could result in the over or underrepresentation of vertebrate scavengers in food web dynamics. © 2017 by the Ecological Society of America.

  16. Effect of abiotic factors on seasonal population dynamics of Lutzomyia longipalpis (Diptera: Psychodidae) in northeastern Brazil.

    PubMed

    Ximenes, Maria de Fátima Freire de Melo; Castellón, Eloy G; De Souza, Maria de Fátima; Menezes, Alexandre A Lara; Queiroz, José Wilton; Macedo e Silva, Virgínia Penéllope; Jerônimo, Selma M B

    2006-09-01

    The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz and Neiva) (Diptera: Psychodidae), the vector of Leishmania infantum, the causative agent of visceral leishmaniasis in Brazil. Sand flies were captured in peridomestic habitats biweekly for 3 yr. Cross-correlation tests and spectral analysis were used to analyze the simultaneous and lag-time correlations between Lu. longipalpis population densities and abiotic factors of temperature, relative humidity, wind velocity, and rainfall. Distinct seasonal patterns were observed for males and females, with intervals of 6 mo between population peaks for males and 12 mo for females. Peak female population densities lagged 3 mo behind the maximum annual temperature. Female population density was negatively correlated with relative humidity. An increase in average wind velocity was followed by a decrease in the number of females for 2 wk. Understanding the relationship between the seasonal population dynamics of Lu. longipalpis and abiotic factors will contribute to the design of better control measures to decrease transmission of L. infantum and consequently the incidence of leishmaniasis.

  17. Effect of abiotic factors on initiation of red flour beetle (Coleoptera: Tenebrionidae) flight.

    PubMed

    Perez-Mendoza, Joel; Campbell, James F; Throne, James E

    2014-02-01

    Traps baited with pheromones are used to monitor the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera-Tenebrionidae), populations in flour mills to aid in making pest management decisions, but the factors that influence T. castaneum movement are not fully understood. We investigated the impact of photoperiod, light intensity, temperature, and relative humidity on flight initiation. The percentage of adults initiating flight reached a maximum at 30 -35 degrees C, and then fell to zero at 22.5 and 45 degrees C. Only 2% of beetles flew in complete darkness, and the number of beetles initiating flight increased to 41% under 18 h of light and then decreased slightly to 37% under 24 h of light. Rates of flight initiation did not vary with light intensities from 1,784 to 4,356 lux or relative humidities from 25 to 85%. Thus, temperature and photoperiod are the main abiotic factors tested that impact flight initiation in T castaneum, which have broad ranges of temperatures and photoperiods over which they can fly. The current results should be useful in helping to interpret trap catches based on abiotic conditions during the trapping period, and the results should be useful in helping to understand T. castaneum movement outside grain storages and processing facilities and their potential to infest structures.

  18. The Miscanthus NAC transcription factor MlNAC9 enhances abiotic stress tolerance in transgenic Arabidopsis.

    PubMed

    Zhao, Xun; Yang, Xuanwen; Pei, Shengqiang; He, Guo; Wang, Xiaoyu; Tang, Qi; Jia, Chunlin; Lu, Ying; Hu, Ruibo; Zhou, Gongke

    2016-07-15

    NAC (NAM, ATAF1/2, and CUC2) transcription factors are known to play important roles in responses to abiotic stresses in plants. Currently, little information regarding the functional roles of NAC genes in stress tolerance is available in Miscanthus lutarioriparius, a promising bioenergy plant for cellulosic ethanol production. In this study, we carried out the functional characterization of MlNAC9 in abiotic stresses. MlNAC9 was shown to act as a nuclear localized transcription activator with the activation domain in its C-terminus. The overexpression of MlNAC9 in Arabidopsis conferred hypersensitivity to abscisic acid (ABA) at seed germination and root elongation stages. In addition, the overexpression of MlNAC9 led to increased seed germination rate and root growth under salt (NaCl) treatment. Meanwhile, the transgenic Arabidopsis overexpressing MlNAC9 showed enhanced tolerance to drought and cold stresses. The expression of stress-responsive marker genes was significantly increased in MlNAC9 overexpression lines compared to that of WT under ABA, drought, salt, and cold stresses. Correspondingly, the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly increased and the malondialdehyde (MDA) content was lower accumulated in MlNAC9 overexpression lines under drought and salt treatments. These results indicated that the overexpression of MlNAC9 improved the tolerance to abiotic stresses via an ABA-dependent pathway, and the enhanced tolerance of transgenic plants was mainly attributed to the increased expression of stress-responsive genes and the enhanced scavenging capability of reactive oxygen species (ROS).

  19. The WRKY transcription factors in the diploid woodland strawberry Fragaria vesca: Identification and expression analysis under biotic and abiotic stresses.

    PubMed

    Wei, Wei; Hu, Yang; Han, Yong-Tao; Zhang, Kai; Zhao, Feng-Li; Feng, Jia-Yue

    2016-08-01

    WRKY proteins comprise a large family of transcription factors that play important roles in response to biotic and abiotic stresses and in plant growth and development. To date, little is known about the WRKY gene family in strawberry. In this study, we identified 62 WRKY genes (FvWRKYs) in the wild diploid woodland strawberry (Fragaria vesca, 2n = 2x = 14) accession Heilongjiang-3. According to the phylogenetic analysis and structural features, these identified strawberry FvWRKY genes were classified into three main groups. In addition, eight FvWRKY-GFP fusion proteins showed distinct subcellular localizations in Arabidopsis mesophyll protoplasts. Furthermore, we examined the expression of the 62 FvWRKY genes in 'Heilongjiang-3' under various conditions, including biotic stress (Podosphaera aphanis), abiotic stresses (drought, salt, cold, and heat), and hormone treatments (abscisic acid, ethephon, methyl jasmonate, and salicylic acid). The expression levels of 33 FvWRKY genes were upregulated, while 12 FvWRKY genes were downregulated during powdery mildew infection. FvWRKY genes responded to drought and salt treatment to a greater extent than to temperature stress. Expression profiles derived from quantitative real-time PCR suggested that 11 FvWRKY genes responded dramatically to various stimuli at the transcriptional level, indicating versatile roles in responses to biotic and abiotic stresses. Interaction networks revealed that the crucial pathways controlled by WRKY proteins may be involved in the differential response to biotic stress. Taken together, the present work may provide the basis for future studies of the genetic modification of WRKY genes for pathogen resistance and stress tolerance in strawberry. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. The Effects of Abiotic Factors on Induced Volatile Emissions in Corn Plants1

    PubMed Central

    Gouinguené, Sandrine P.; Turlings, Ted C.J.

    2002-01-01

    Many plants respond to herbivory by releasing a specific blend of volatiles that is attractive to natural enemies of the herbivores. In corn (Zea mays), this induced odor blend is mainly composed of terpenoids and indole. The induced signal varies with plant species and genotype, but little is known about the variation due to abiotic factors. Here, we tested the effect of soil humidity, air humidity, temperature, light, and fertilization rate on the emission of induced volatiles in young corn plants. Each factor was tested separately under constant conditions for the other factors. Plants released more when standing in dry soil than in wet soil, whereas for air humidity, the optimal release was found at around 60% relative humidity. Temperatures between 22°C and 27°C led to a higher emission than lower or higher temperatures. Light intensity had a dramatic effect. The emission of volatiles did not occur in the dark and increased steadily with an increase in the light intensity. An experiment with an unnatural light-dark cycle showed that the release was fully photophase dependent. Fertilization also had a strong positive effect; the emission of volatiles was minimal when plants were grown under low nutrition, even when results were corrected for plant biomass. Changes in all abiotic factors caused small but significant changes in the relative ratios among the different compounds (quality) in the induced odor blends, except for air humidity. Hence, climatic conditions and nutrient availability can be important factors in determining the intensity and variability in the release of induced plant volatiles. PMID:12114583

  1. Identification of important abiotic and biotic factors in the biodegradation of poly(l-lactic acid).

    PubMed

    Husárová, Lucie; Pekařová, Silvie; Stloukal, Petr; Kucharzcyk, Pavel; Verney, Vincent; Commereuc, Sophie; Ramone, Audrey; Koutny, Marek

    2014-11-01

    The biodegradation of four poly(l-lactic acid) (PLA) samples with molecular weights (MW) ranging from approximately 34 to 160kgmol(-1) was investigated under composting conditions. The biodegradation rate decreased, and initial retardation was discernible in parallel with the increasing MW of the polymer. Furthermore, the specific surface area of the polymer sample was identified as the important factor accelerating biodegradation. Microbial community compositions and dynamics during the biodegradation of different PLA were monitored by temperature gradient gel electrophoresis, and were found to be virtually identical for all PLA materials and independent of MW. A specific PLA degrading bacteria was isolated and tentatively designated Thermopolyspora flexuosa FTPLA. The addition of a limited amount of low MW PLA did not accelerate the biodegradation of high MW PLA, suggesting that the process is not limited to the number of specific degraders and/or the induction of specific enzymes. In parallel, abiotic hydrolysis was investigated for the same set of samples and their courses found to be quasi-identical with the biodegradation of all four PLA samples investigated. This suggests that the abiotic hydrolysis represented a rate limiting step in the biodegradation process and the organisms present were not able to accelerate depolymerization significantly by the action of their enzymes.

  2. Geographic variation of floral traits in Nicotiana glauca : Relationships with biotic and abiotic factors

    NASA Astrophysics Data System (ADS)

    Nattero, Julieta; Sérsic, Alicia N.; Cocucci, Andrea A.

    2011-09-01

    Geographic pattern of phenotypic variation can appear in a clinal or a mosaic fashion and can evidence adaptive or non-adaptive variation. To shed light on the mechanisms underlying this variation, we studied the relationships between geographic variation of floral traits and both biotic and abiotic factors of the hummingbird-pollinated plant, Nicotiana glauca, across its natural range. We obtained floral measures of 38 populations from an area about 1600 km long and 1050 km wide and an altitude range from 7 to over 3400 m. We used a MANOVA to detect between-population differentiations in flower traits and a DFA to determine the traits that best discriminate between populations. To test for associations between floral traits and climatic variables we used correlation analysis. We explored any possible distance-based pattern of variation (either geographic or altitudinal) in floral traits or bill length of pollinators using Mantel tests. Finally, we used a multiple regression to analyze simultaneously the effects and relative importance of abiotic predictor variables and bill length on corolla length. We found a high variation in flower traits among populations. Morphometric traits were the ones that best discriminated across populations. There was a clinal pattern of floral phenotypic variation explained by climatic factors. Differences in floral phenotypic distances were structured by altitudinal distances but not by geographic distances. Bill length of the hummingbird pollinators was structured both by altitudinal and geographic distances. Differences in bill length of hummingbird pollinators explained differences in corolla length across populations. Our findings support the assumption of flower evolution at a broad geographic scale. Floral traits seem to be structured not only by altitude but also by climatic factors.

  3. Influence of biotic and abiotic factors on dissipating metalaxyl in soil.

    PubMed

    Sukul, P; Spiteller, M

    2001-11-01

    Under laboratory condition, dissipation of metalaxyl in sterile and non-sterile soils, its sorption behaviour and fate in presence of light have been studied. The half-life value of metalaxyl was found in the range of 36-73 d in non-sterile soil. 5.3-14.7% dissipation was observed due to abiotic factors other than light. Metalaxyl was found photostable in soil showing half-life of 188- 502 h under simulated sunlight. In adsorption study, a non-linear relationship between concentration of metalaxyl and its adsorption into soils was observed. Estimated koc value increased as organic carbon content decreased. Adsorption and desorption kD values ranged between 53.5 and 151.1.

  4. Effects of biotic and abiotic factors on the temporal dynamic of bat-fruit interactions

    NASA Astrophysics Data System (ADS)

    Laurindo, Rafael de Souza; Gregorin, Renato; Tavares, Davi Castro

    2017-08-01

    Mutualistic interactions between animals and plants vary over time and space based on the abundance of fruits or animals and seasonality. Little is known about this temporal dynamic and the influence of biotic and abiotic factors on the structure of interaction networks. We evaluated changes in the structure of network interactions between bats and fruits in relation to variations in rainfall. Our results suggest that fruit abundance is the main variable responsible for temporal changes in network attributes, such as network size, connectance, and number of interactions. In the same way, temperature positively affected the abundance of fruits and bats. An increase in temperature and alterations in rainfall patterns, due to human induced climate change, can cause changes in phenological patterns and fruit production, with negative consequences to biodiversity maintenance, ecological interactions, and ecosystem functioning.

  5. The abiotic and biotic factors limiting establishment of predatory fishes at their expanding northern range boundaries in Ontario, Canada.

    PubMed

    Alofs, Karen M; Jackson, Donald A

    2015-06-01

    There is a poor understanding of the importance of biotic interactions in determining species distributions with climate change. Theory from invasion biology suggests that the success of species introductions outside of their historical ranges may be either positively (biotic acceptance) or negatively (biotic resistance) related to native biodiversity. Using data on fish community composition from two survey periods separated by approximately 28 years during which climate was warming, we examined the factors influencing the establishment of three predatory centrarchids: Smallmouth Bass (Micropterus dolomieu), Largemouth Bass (M. salmoides), and Rock Bass (Ambloplites rupestris) in lakes at their expanding northern range boundaries in Ontario. Variance partitioning demonstrated that, at a regional scale, abiotic factors play a stronger role in determining the establishment of these species than biotic factors. Pairing lakes within watersheds where each species had established with lakes sharing similar abiotic conditions where the species had not established revealed both positive and negative relationships between the establishment of centrarchids and the historical presence of other predatory species. The establishment of these species near their northern range boundaries is primarily determined by abiotic factors at a regional scale; however, biotic factors become important at the lake-to-lake scale. Studies of exotic species invasions have previously highlighted how spatial scale mediates the importance of abiotic vs. biotic factors on species establishment. Our study demonstrates how concepts from invasion biology can inform our understanding of the factors controlling species distributions with changing climate. © 2014 John Wiley & Sons Ltd.

  6. Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4

    NASA Astrophysics Data System (ADS)

    Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

    2017-03-01

    Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R2 = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2.

  7. Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4.

    PubMed

    Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

    2017-03-02

    Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R(2) = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2.

  8. Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4

    PubMed Central

    Li, Jingxin; Yang, Birong; Shi, Manman; Yuan, Kai; Guo, Wei; Wang, Qian; Wang, Gejiao

    2017-01-01

    Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2 content and H2O2 degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2 resistance. Furthermore, linear correlations were observed between cellular H2O2 and Sb(V) content in vivo and chemical H2O2 and Sb(V) content in vitro (R2 = 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2 induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2 which contributes to microbial detoxification of both Sb(III) and cellular H2O2. PMID:28252030

  9. The role of abiotic factors in the Cambrian Substrate Revolution: A review from the benthic community replacements of West Gondwana

    NASA Astrophysics Data System (ADS)

    Álvaro, J. Javier; Zamora, Samuel; Clausen, Sébastien; Vizcaïno, Daniel; Smith, Andrew B.

    2013-03-01

    The Cambrian Substrate Revolution refers to a substantial and "rapid" change to the nature of marine sedimentary substrates in the early Cambrian and is widely interpreted as a biologically-driven event, a direct response to evolutionary innovations in metazoan burrowing and the development of new shelly faunas. However, abiotic factors such as tectonic and climatic evolution also had the potential to restructure Cambrian substrates, and are here shown to be more plausible drivers of change in the benthic faunas of western Gondwana. The western Mediterranean region underwent a southward drift during Cambrian times, which drove a switch from subtropical carbonates to temperate siliciclastic substrates with short-term episodes of temperate carbonate productivity. As a result, microbial and shelly carbonates disappeared diachronously in a stepwise manner across the lower-middle Cambrian boundary interval. Archaeocyathan-microbial reefs were replaced by chancelloriid-eocrinoid-(spiculate) sponge meadows, in which the stepwise immigration of new echinoderm taxa was primarily controlled by extensional tectonic events, first recorded in rifting settings and later in passive-margin platforms. Availability of new kinds of substrate was thus the primary factor that controlled where and when evolutionary innovations in benthic strategies arose. Examples of this include the early Cambrian colonization of phosphatic hardgrounds and thrombolite crusts by chancelloriids, archaeocyathan and spiculate sponges, and the exploitation by benthos to the increasingly widespread availability of shelly grounds and carbonate firmgrounds by early-diagenetic cementation. A microbial mat/epifaunal antagonistic relationship is demonstrated for echinoderm pelmatozoans based on the non-overlapping palaeogeographic distributions of microbial reefs and mats versus mud-sticker pelmatozoans. Cambrian benthic communities thus evolved in parallel with substrates in response to abiotic factors rather

  10. Biotic and abiotic factors affecting stemflow variability in downy oak and Scots pine stands in Mediterranean conditions

    NASA Astrophysics Data System (ADS)

    Cayuela, Carles; Garcia-Estringana, Pablo; Latron, Jérôme; Llorens, Pilar

    2015-04-01

    Although stemflow is only a small portion of rainfall, it may represent an important local input of water and nutrients at the plant stem. Previous studies have shown that stemflow has a significant influence on hydrological and biogeochemical processes. Stemflow volume is affected by many biotic factors as species, age, branch or bark characteristics. Moreover, the seasonality of the rainfall regime in Mediterranean areas, which includes both frontal rainfall events and short convective storms, can add complexity to the rainfall-stemflow relationship. This work investigates stemflow dynamics and the influence of biotic and abiotic factors on stemflow rates in two Mediterranean stands during the leafed period - from May to October. The monitored stands are a Downy oak forest (Quercus pubescens) and a Scots pine forest (Pinus sylvestris), both located in the Vallcebre research catchments (NE Spain, 42° 12'N, 1° 49'E). The monitoring design of each plot consists of 7 stemflow rings connected to tipping-buckets, bulk rainfall measured in a nearby clearing and meteorological conditions above the canopies. All data were recorded at 5 min interval. Biometric characteristics of the measured trees were also measured. The analysis of 39 rainfall events (65% smaller than 10 mm) shows that stemflow accounted for less than 1% of the bulk rainfall in both stands. Results also show that, on average, the rainfall amount required for the start of the stemflow and the time delay between the beginning of the precipitation and the start of stemflow are higher in the Downy oak forest. As suggested by stemflow funneling ratios, these differences might be linked to the canopy structure and bark water storage capacity of the trees, indicating that during low magnitude events, oaks have more difficulty to reach storage capacity. The role of other biotic and abiotic parameters on stemflow variability in both stands is still under investigation.

  11. ANALYSIS OF BIOTIC AND ABIOTIC FACTORS INFLUENCING THE OCCURRENCE OF WEST NILE VIRUS INFECTION IN TUNISIA.

    PubMed

    Ben Hassine, Th; Calistri, P; Ippoliti, C; Conte, A; Danzetta, M L; Bruno, R; Lelli, R; Bejaoui, M; Hammami, S

    2014-01-01

    Eco-climatic conditions are often associated with the occurrence of West Nile Disease (WND) cases. Among the complex set of biotic and abiotic factors influencing the emergence and spread of this vector-borne disease, two main variables have been considered to have a great influence on the probability of West Nile Virus (WNV) introduction and circulation in Tunisia: the presence of susceptible bird populations and the existence of geographical areas where the environmental and climatic conditions are more favourable to mosquito multiplications. The aim of this study was to identify and classify the climatic and environmental variables possibly associated with the occurrence of WNVhuman cases in Tunisia. The following environmental and climatic variables have been considered: wetlands and humid areas, Normalised Difference Vegetation Index (NDVI), temperatures and elevation. A preliminary analysis for the characterization of main variables associated with areas with a history of WNV human cases in Tunisia between 1997 and 2011 has been made. This preliminary analysis clearly indicates the closeness to marshes ecosystem, where migratory bird populations are located, as an important risk factor for WNV infection. On the contrary the temperature absolute seems to be not a significant factor in Tunisian epidemiological situation. In relation to NDVI values, more complex considerations should be made.

  12. De Novo Transcriptome Sequence Assembly and Identification of AP2/ERF Transcription Factor Related to Abiotic Stress in Parsley (Petroselinum crispum)

    PubMed Central

    Wang, Feng; Jiang, Qian; Xu, Zhi-Sheng; Tian, Chang; Xiong, Ai-Sheng

    2014-01-01

    Parsley is an important biennial Apiaceae species that is widely cultivated as herb, spice, and vegetable. Previous studies on parsley principally focused on its physiological and biochemical properties, including phenolic compound and volatile oil contents. However, little is known about the molecular and genetic properties of parsley. In this study, 23,686,707 high-quality reads were obtained and assembled into 81,852 transcripts and 50,161 unigenes for the first time. Functional annotation showed that 30,516 unigenes had sequence similarity to known genes. In addition, 3,244 putative simple sequence repeats were detected in curly parsley. Finally, 1,569 of the identified unigenes belonged to 58 transcription factor families. Various abiotic stresses have a strong detrimental effect on the yield and quality of parsley. AP2/ERF transcription factors have important functions in plant development, hormonal regulation, and abiotic response. A total of 88 putative AP2/ERF factors were identified from the transcriptome sequence of parsley. Seven AP2/ERF transcription factors were selected in this study to analyze the expression profiles of parsley under different abiotic stresses. Our data provide a potentially valuable resource that can be used for intensive parsley research. PMID:25268141

  13. De novo transcriptome sequence assembly and identification of AP2/ERF transcription factor related to abiotic stress in parsley (Petroselinum crispum).

    PubMed

    Li, Meng-Yao; Tan, Hua-Wei; Wang, Feng; Jiang, Qian; Xu, Zhi-Sheng; Tian, Chang; Xiong, Ai-Sheng

    2014-01-01

    Parsley is an important biennial Apiaceae species that is widely cultivated as herb, spice, and vegetable. Previous studies on parsley principally focused on its physiological and biochemical properties, including phenolic compound and volatile oil contents. However, little is known about the molecular and genetic properties of parsley. In this study, 23,686,707 high-quality reads were obtained and assembled into 81,852 transcripts and 50,161 unigenes for the first time. Functional annotation showed that 30,516 unigenes had sequence similarity to known genes. In addition, 3,244 putative simple sequence repeats were detected in curly parsley. Finally, 1,569 of the identified unigenes belonged to 58 transcription factor families. Various abiotic stresses have a strong detrimental effect on the yield and quality of parsley. AP2/ERF transcription factors have important functions in plant development, hormonal regulation, and abiotic response. A total of 88 putative AP2/ERF factors were identified from the transcriptome sequence of parsley. Seven AP2/ERF transcription factors were selected in this study to analyze the expression profiles of parsley under different abiotic stresses. Our data provide a potentially valuable resource that can be used for intensive parsley research.

  14. Effects of abiotic factors and species interactions on estimates of male plant function: a meta-analysis.

    PubMed

    Schaeffer, Robert N; Manson, Jessamyn S; Irwin, Rebecca E

    2013-03-01

    The majority of angiosperms are hermaphroditic with total fitness comprised of both male and female components of reproduction. However, most studies examining the effects of abiotic factors and species interactions on fitness have focussed on female reproduction, potentially biasing our understanding of the consequences of environmental factors on total fitness. Here, we use meta-analysis to test how environmental factors affect male function. We obtained 278 effect sizes from 96 studies that measured male function responses to manipulated environmental factors. We found significant effects of abiotic factors and species interactions on estimates of male function, with responses varying depending on environmental factor identity. Male and female responses were correlated for abiotic factor manipulations, but varied based on the type of species interaction (antagonistic or mutualistic). This suggests that measuring only female function may misrepresent whole-plant reproduction depending on context. Finally, we found differences amongst components of male function in response to environmental factors, suggesting that some male function estimates may fail to capture the effects of environmental factors on male fitness. Our results demonstrate the importance of incorporating male function into ecological and evolutionary studies to provide a more accurate understanding of the effects of environmental factors on total fitness.

  15. The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish.

    PubMed

    Wenger, Amelia S; Whinney, James; Taylor, Brett; Kroon, Frederieke

    2016-06-28

    Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change.

  16. Relative contribution of biotic and abiotic factors to the population density of the cassava green mite, Mononychellus tanajoa (Acari: Tetranychidae).

    PubMed

    Rêgo, Adriano S; Teodoro, Adenir V; Maciel, Anilde G S; Sarmento, Renato A

    2013-08-01

    The cassava green mite, Mononychellus tanajoa, is a key pest of cassava, Manihot esculenta Crantz (Euphorbiaceae), and it may be kept in check by naturally occurring predatory mites of the family Phytoseiidae. In addition to predatory mites, abiotic factors may also contribute to regulate pest mite populations in the field. Here, we evaluated the population densities of both M. tanajoa and the generalist predatory mite Euseius ho DeLeon (Acari: Phytoseiidae) over the cultivation cycle (11 months) of cassava in four study sites located around the city of Miranda do Norte, Maranhão, Brazil. The abiotic variables rainfall, temperature and relative humidity were also recorded throughout the cultivation cycle of cassava. We determined the relative importance of biotic (density of E. ho) and abiotic (rainfall, temperature and relative humidity) factors to the density of M. tanajoa. The density of M. tanajoa increased whereas the density of E. ho remained constant throughout time. A hierarchical partitioning analysis revealed that most of the variance for the density of M. tanajoa was explained by rainfall and relative humidity followed by E. ho density and temperature. We conclude that abiotic factors, especially rainfall, were the main mechanisms driving M. tanajoa densities.

  17. The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish

    PubMed Central

    Wenger, Amelia S.; Whinney, James; Taylor, Brett; Kroon, Frederieke

    2016-01-01

    Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change. PMID:27350589

  18. Flowering phenology, growth forms, and pollination syndromes in tropical dry forest species: Influence of phylogeny and abiotic factors.

    PubMed

    Cortés-Flores, Jorge; Hernández-Esquivel, Karen Beatriz; González-Rodríguez, Antonio; Ibarra-Manríquez, Guillermo

    2017-01-01

    Analyses of the influence of temporal variation in abiotic factors on flowering phenology of tropical dry forest species have not considered the possible response of species with different growth forms and pollination syndromes, while controlling for phylogenetic relationships among species. Here, we investigated the relationship between flowering phenology, abiotic factors, and plant functional attributes, while controlling for phylogenetic relationship among species, in a dry forest community in Mexico. We characterized flowering phenology (time and duration) and pollination syndromes of 55 tree species, 49 herbs, 24 shrubs, 15 lianas, and 11 vines. We tested the influence of pollination syndrome, growth form, and abiotic factors on flowering phenology using phylogenetic generalized least squares. We found a relationship between flowering duration and time. Growth form was related to flowering time, and the pollination syndrome had a more significant relationship with flowering duration. Flowering time variation in the community was explained mainly by abiotic variables, without an important phylogenetic effect. Flowering time in lianas and trees was negatively and positively correlated with daylength, respectively. Functional attributes, environmental cues, and phylogeny interact with each other to shape the diversity of flowering patterns. Phenological differentiation among species groups revealed multiples strategies associated with growth form and pollination syndromes that can be important for understanding species coexistence in this highly diverse plant community. © 2017 Botanical Society of America.

  19. The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish

    NASA Astrophysics Data System (ADS)

    Wenger, Amelia S.; Whinney, James; Taylor, Brett; Kroon, Frederieke

    2016-06-01

    Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change.

  20. The relationships among biotic and abiotic factors as control soil degradation processes along a Mediterranean pluviometric gradient.

    NASA Astrophysics Data System (ADS)

    Damian Ruiz Sinoga, Jose; Romero Diaz, Asunción

    2010-05-01

    The shifts to soil properties that resulted from changes in water availability along a pluviometric gradient from humid to semiarid/arid Mediterranean climate were analyzed. The study was carried out at eight experimental sites in southern Spain and assessed the influence of a reduction in annual average rainfall along the pluviometric gradient on various physical, chemical and hydrological properties of the topsoil, and on the biotic characteristics of the environment. The aims were to assess the soil degradation status, and to determine if any of the soil variables studied could be used as soil degradation indicators. For each experimental site the relationships among a series of edaphic, hydrological and biological properties were investigated, and the principal factors affecting soil degradation were determined using principal component analysis. The properties included the clay, silt and sand content; organic matter; retained organic carbon; salinity; cation exchange capacity; structural stability; USLE K factor; bulk density; saturated hydraulic conductivity; soil moisture; the number of vegetal species; and vegetation cover. The results showed that relationships between biotic and abiotic factors controlled the soil degradation status along a pluviometric gradient from wet to semiarid/arid conditions in the Mediterranean area, and therefore the stability of the eco-geomorphological system depends on the dominant factor. A precipitation-based soil degradation threshold of approximately 500 mm/yr was established, as below this level the vegetation is no longer associated with the presence of greater soil moisture content, but adapts to degradation, as evidenced by the appearance of xerophytic species.

  1. Effects of Abiotic Factors on the Phylogenetic Diversity of Bacterial Communities in Acidic Thermal Springs▿

    PubMed Central

    Mathur, Jayanti; Bizzoco, Richard W.; Ellis, Dean G.; Lipson, David A.; Poole, Alexander W.; Levine, Richard; Kelley, Scott T.

    2007-01-01

    Acidic thermal springs offer ideal environments for studying processes underlying extremophile microbial diversity. We used a carefully designed comparative analysis of acidic thermal springs in Yellowstone National Park to determine how abiotic factors (chemistry and temperature) shape acidophile microbial communities. Small-subunit rRNA gene sequences were PCR amplified, cloned, and sequenced, by using evolutionarily conserved bacterium-specific primers, directly from environmental DNA extracted from Amphitheater Springs and Roaring Mountain sediment samples. Energy-dispersive X-ray spectroscopy, X-ray diffraction, and colorimetric assays were used to analyze sediment chemistry, while an optical emission spectrometer was used to evaluate water chemistry and electronic probes were used to measure the pH, temperature, and Eh of the spring waters. Phylogenetic-statistical analyses found exceptionally strong correlations between bacterial community composition and sediment mineral chemistry, followed by weaker but significant correlations with temperature gradients. For example, sulfur-rich sediment samples contained a high diversity of uncultured organisms related to Hydrogenobaculum spp., while iron-rich sediments were dominated by uncultured organisms related to a diverse array of gram-positive iron oxidizers. A detailed analysis of redox chemistry indicated that the available energy sources and electron acceptors were sufficient to support the metabolic potential of Hydrogenobaculum spp. and iron oxidizers, respectively. Principal-component analysis found that two factors explained 95% of the genetic diversity, with most of the variance attributable to mineral chemistry and a smaller fraction attributable to temperature. PMID:17220248

  2. Abiotic and biotic factors that influence the bioavailability of gold nanoparticles to aquatic macrophytes.

    PubMed

    Glenn, J Brad; Klaine, Stephen J

    2013-09-17

    This research identified and characterized factors that influenced nanomaterial bioavailability to three aquatic plants: Azolla caroliniana Willd, Egeria densa Planch., and Myriophyllum simulans Orch. Plants were exposed to 4-, 18-, and 30-nm gold nanoparticles. Uptake was influenced by nanoparticle size, the presence of roots on the plant, and dissolved organic carbon in the media. Statistical analysis of the data also revealed that particle uptake was influenced by a 4-way (plant species, plant roots, particle size, and dissolved organic carbon) interaction suggesting nanoparticle bioavailability was a complex result of multiple parameters. Size and species dependent absorption was observed that was dependent on the presence of roots and nanoparticle size. The presence of dissolved organic carbon was found to associate with 4- and 18-nm gold nanoparticles in suspension and form a nanoparticle/organic matter complex that resulted in (1) minimized particle aggregation and (2) a decrease of nanoparticle absorption by the aquatic plants. The same effect was not observed with the 30-nm nanoparticle treatment. These results indicate that multiple factors, both biotic and abiotic, must be taken into account when predicting bioavailability of nanomaterials to aquatic plants.

  3. Observations on the balance between abiotic and biotic factors in plant-morphodynamic feedbacks (Invited)

    NASA Astrophysics Data System (ADS)

    Manners, R.; Lightbody, A.; Wilcox, A. C.; Sklar, L. S.; Stella, J. C.; Kui, L.

    2013-12-01

    The strength and direction of feedbacks between riparian vegetation and fluvial processes depend on the balance between abiotic (i.e., sediment supply, transport capacity) and biotic factors (i.e., plant morphology, stem density). We present results from flume experiments that test the influence of these factors on plant-morphodynamic feedbacks. For equilibrium (balance between sediment transport and supply) and supply-limited (transport exceeds sediment supply) conditions, we evaluated the impact of plant morphology (shrubby versus characteristically single-stemmed woody seedlings), height (10 to 120 cm), and configuration (individual and patches) on bed topography, velocity fields, and sediment flux. We conducted the experiments in a 28-meter long, sand-bedded flume (60 cm wide and 71 cm deep) at the UC-Berkeley Richmond Field Station, into which plants harvested from field sites were transplanted in a manner that maintained the root structure. Under equilibrium conditions, all sizes of the individual shrubby plants induced scour around the base of the plant and increased deposition downstream. Individual single-stemmed plants, however, did not greatly alter the flow and sediment transport field (when compared to baseline conditions). When transport capacity exceeded the supply of sediment, the impact of all plants diminished, and bed scour would lead to plant dislodgement. More rapid dislodgement for the shrubby species occurred as a result of the increased drag on the plant. Our results illustrate that the morphology of shrubby plants, with multiple stems and greater near-bed frontal area (compared to the single-stem plant), not only increases the influence of the plant on the flow and sediment transport fields but also may, under certain sediment supply conditions, contribute to its own mortality via scour. The results from these experiments highlight the importance of both abiotic and biotic conditions, and the balance between them, in determining the

  4. Effects of two abiotic factors and their interaction on Soil Carbon Dioxide flux

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Armstrong, Alona; Gristina, Luciano; Quinton, John

    2010-05-01

    Soils release more carbon per annum than current global anthropogenic emissions (Luo and Zhou, 2006). Soils emit carbon dioxide through mineralization and decomposition of organic matter and respiration of roots and soil organism (Houghton 2007) Evaluation of the effects of abiotic factors on microbial activity is of major importance in the context of mitigation greenhouse gases emissions. One of the key greenhouse gases is carbon dioxide (CO2) and previous studies demonstrate that soil CO2 emission is significantly affected by temperature and soil water content. There are a limited number of studies that examine the impact of bulk density and soil surface characteristics as a result of exposure to rain on CO2 emission, however, none examine their relative importance. Therefore, this study investigated the effects of soil compaction and exposure of the soil surface to rainfall and their interaction on CO2 release. We conducted a factorial soil core experiment with three different bulk densities (1.1 g cm-3, 1.3 g cm-3, 1.5 g cm-3) and three difference exposures to rainfall (no rain, 30 minutes and 90 minutes of rainfall). Water was poured on to the cores not exposed to rain and those exposed for 30 minutes through a gauze to ensure all cores received the same volume of water. Immediately the rainfall treatments the soil cores were incubated and soil CO2 efflux and water content were measured 1, 2, 5, 6, 9, and 10 days after the start of the incubation. The results indicate soil CO2 emissions and rate changes significantly through time and with different bulk densities and rain exposures. The relationship between rain exposure and CO2 is positive: CO2 emission was 53% and 42% greater for the 90 min and 30 min rainfall exposure, respectively, compared to those not exposed to rain. Bulk density exhibited a negative relationship with CO2 emission: soil compacted to a bulk density of 1.1 g cm-3 emitted 32% more CO2 than soil compacted to 1.5 g cm-3. Furthermore we found

  5. Crosstalk between biotic and abiotic stress responses in tomato is mediated by the AIM1 transcription factor.

    PubMed

    Abuqamar, Synan; Luo, Hongli; Laluk, Kristin; Mickelbart, Michael V; Mengiste, Tesfaye

    2009-04-01

    Plants deploy diverse molecular and cellular mechanisms to survive in stressful environments. The tomato (Solanum lycopersicum) abscisic acid-induced myb1 (SlAIM1) gene encoding an R2R3MYB transcription factor is induced by pathogens, plant hormones, salinity and oxidative stress, suggesting a function in pathogen and abiotic stress responses. Tomato SlAIM1 RNA interference (RNAi) plants with reduced SlAIM1 gene expression show an increased susceptibility to the necrotrophic fungus Botrytis cinerea, and increased sensitivity to salt and oxidative stress. Ectopic expression of SlAIM1 is sufficient for tolerance to high salinity and oxidative stress. These responses correlate with reduced sensitivity to abscisic acid (ABA) in the SlAIM1 RNAi, but increased sensitivity in the overexpression plants, suggesting SlAIM1-mediated ABA responses are required to integrate tomato responses to biotic and abiotic stresses. Interestingly, when exposed to high root-zone salinity levels, SlAIM1 RNAi plants accumulate more Na(+), whereas the overexpression lines accumulate less Na(+) relative to wild-type plants, suggesting that SlAIM1 regulates ion fluxes. Transmembrane ion flux is a hallmark of early responses to abiotic stress and pathogen infection preceding hypersensitive cell death and necrosis. Misregulation of ion fluxes can result in impaired plant tolerance to necrotrophic infection or abiotic stress. Our data reveal a previously uncharacterized connection between ABA, Na(+) homeostasis, oxidative stress and pathogen response, and shed light on the genetic control of crosstalk between plant responses to pathogens and abiotic stress. Together, our data suggest SlAIM1 integrates plant responses to pathogens and abiotic stresses by modulating responses to ABA.

  6. Multifaceted role of cycling DOF factor 3 (CDF3) in the regulation of flowering time and abiotic stress responses in Arabidopsis.

    PubMed

    Corrales, Alba-Rocio; Carrillo, Laura; Lasierra, Pilar; Nebauer, Sergio G; Dominguez-Figueroa, Jose; Renau-Morata, Begoña; Pollmann, Stephan; Granell, Antonio; Molina, Rosa-Victoria; Vicente-Carbajosa, Jesús; Medina, Joaquín

    2017-05-01

    DNA-binding with one finger (DOF)-type transcription factors are involved in many fundamental processes in higher plants, from responses to light and phytohormones to flowering time and seed maturation, but their relation with abiotic stress tolerance is largely unknown. Here, we identify the roles of CDF3, an Arabidopsis DOF gene in abiotic stress responses and developmental processes like flowering time. CDF3 is highly induced by drought, extreme temperatures and abscisic acid treatment. The CDF3 T-DNA insertion mutant cdf3-1 is much more sensitive to drought and low temperature stress, whereas CDF3 overexpression enhances the tolerance of transgenic plants to drought, cold and osmotic stress and promotes late flowering. Transcriptome analysis revealed that CDF3 regulates a set of genes involved in cellular osmoprotection and oxidative stress, including the stress tolerance transcription factors CBFs, DREB2A and ZAT12, which involve both gigantea-dependent and independent pathways. Consistently, metabolite profiling disclosed that the total amount of some protective metabolites including γ-aminobutyric acid, proline, glutamine and sucrose were higher in CDF3-overexpressing plants. Taken together, these results indicate that CDF3 plays a multifaceted role acting on both flowering time and abiotic stress tolerance, in part by controlling the CBF/DREB2A-CRT/DRE and ZAT10/12 modules. © 2017 John Wiley & Sons Ltd.

  7. Abiotic factors controlling bioavailability and bioaccessibility of polycyclic aromatic hydrocarbons in soil: Putting together a bigger picture.

    PubMed

    Yu, Linbo; Duan, Luchun; Naidu, Ravi; Semple, Kirk T

    2017-09-23

    The bioavailability and bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in soil underpin the risk assessment of contaminated land with these contaminants. Despite a significant volume of research conducted in the past few decades, comprehensive understanding of the factors controlling the behaviour of soil PAHs and a set of descriptive soil parameters to explain variations in PAH bioavailability and bioaccessibility are still lacking. This review focuses on the role of source materials on bioavailability and bioaccessibility of soil PAHs, which is often overlooked, along with other abiotic factors including contaminant concentration and mixture, soil composition and properties, as well as environmental factors. It also takes into consideration the implications of different types of risk assessment (ecological and human health) on bioavailability and bioaccessibility of PAHs in soil. We recommend that future research should (1) account for the effects of source materials on bioavailability and bioaccessibility of soil PAHs; (2) adopt non-disruptive methods to analyse soil components controlling PAH sequestration; (3) integrate both natural organic matter (NOM) and xenobiotic organic matter (XOM) while evaluating the influences of soil organic matter (SOM) on the behaviour of PAHs; and (4) consider the dissimilar desorption scenarios in ecological risk assessment and human health risk assessment while assessing PAH bioavailability and bioaccessibility. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. The Effect of Abiotic Factors on Marine Animal Body Size Evolution

    NASA Astrophysics Data System (ADS)

    Wang, X. F.; Wong, W.; Heim, N.; Payne, J.

    2015-12-01

    While there is evidence of a general increase in body size over time, there has been no comprehensive attempt to determine the influence of abiotic factors on body size. Although an increase in maximum body size has been observed during and after the Precambrian oxidation events in the Late Archean and at the onset of the Cambrian, these observations took into account the appearance of eukaryotic life and multicellular life respectively. Using a database of marine animal body sizes spanning the Phanerozoic, we conducted a series of Pearson product-moment correlation tests with igneous rock weathering (Strontium-87: Strontium-86), rate of carbon cycle (δ13C), temperature (δ18O), CO2 concentration, sulfate mineral weathering (δ34S), atmospheric oxygen concentration, and sea level as independent variables, and mean body size as the dependent variable. Our test yielded a correlation coefficient of 0.81 between δ18O and body size, and -0.78 between rCO2 and body size; since δ18O is inversely correlated with temperature, these results indicate that both temperature and CO2 have strong inverse relationships with body size. Atmospheric oxygen yielded a correlation coefficient of 0.09, demonstrating that it ceased to play an influential role in shaping body sizes following the start of the Phanerozoic.

  9. Effect of abiotic factors on the unique glitter-like iridescence of Cellulophaga lytica.

    PubMed

    Kientz, Betty; Marié, Pauline; Rosenfeld, Eric

    2012-08-01

    Iridescence is a property of structural color that has been poorly documented in the prokaryotic kingdom. We recently isolated a Cellulophaga lytica strain that exhibits, on solid media, a unique intense glitter-like iridescence in reflection. Iridescence of C. lytica CECT 8139 was optically and physically characterized but physiological significance of the phenomenon was not. In the present work, we investigated the effect of key abiotic factors on C. lytica's growth and iridescence. Special attention was paid to conditions that mimic rocky shore ecosystem, the natural biotope of C. lytica. We found that C. lytica's iridescence required the presence of seawater. The phenomenon was not influenced by light exposure or plate orientation during growth. Cellulophaga lytica's iridescence occurred under a wide range of culture conditions notably under psychrophilic, halophilic, and hydric stress conditions. Changes in colonies' colors (blue, violet, red, yellow, and green) were linked to cell density. These data indicate that iridescence is induced under conditions that mimic the natural biotope of C. lytica.

  10. Impact of Abiotic Factors on Onion Thrips (Thysanoptera: Thripidae) Aerial Dispersal in an Onion Ecosystem.

    PubMed

    Smith, Erik A; Shields, E J; Nault, B A

    2016-10-01

    Onion thrips, Thrips tabaci Lindeman, is a significant pest of onion crops worldwide, but little is known about its patterns of aerial dispersal in the context of abiotic environmental factors. Thrips tabaci adults were passively collected from the air column above onion fields in western New York using clear sticky cards over a series of sampling periods in 2012, 2013, and 2014 while on-site weather conditions were recorded. Results indicated that T. tabaci adult densities on aerial traps during daylight averaged 279 times greater per hour than densities on similar traps at night. Adult dispersal also tended to spike during presunset, indicating that thrips initiated flight diurnally and within 1 h before sunset. Densities of T. tabaci on aerial traps increased significantly as temperature increased above 17 °C and 90% of the thrips were captured between 20.8 and 27.7 °C; no thrips were captured above 30.6 °C. Densities of T. tabaci on aerial traps decreased significantly as wind speed increased, with no thrips captured at winds exceeding 3.8 m/s (13.7 kph). In 2013 and 2014, T. tabaci densities on aerial traps prior to the passage of a cold front (relatively high atmospheric pressure and temperature with low wind speed) were significantly greater than densities after passage of the front, suggesting that T. tabaci disperses on synoptic weather systems.

  11. Feeding in deep-sea demosponges: Influence of abiotic and biotic factors

    NASA Astrophysics Data System (ADS)

    Robertson, Leah M.; Hamel, Jean-François; Mercier, Annie

    2017-09-01

    In shallow benthic communities, sponges are widely recognized for their ability to contribute to food webs by cycling nutrients and mediating carbon fluxes through filter feeding. In comparison, little is known about filter feeding in deep-sea species and how it may be modulated by environmental conditions. Here, a rare opportunity to maintain live healthy deep-sea sponges for an extended period led to a preliminary experimental study of their feeding metrics. This work focused on demosponges collected from the continental slope of eastern Canada at 1000 m depth. Filtration rates (as clearance of phytoplankton cells) at holding temperature (6 °C) were positively correlated with food particle concentration, ranging on average from 18.8 to 160.6 cells ml-1 h-1 at nominal concentrations of 10,000-40,000 cells ml-1. Cell clearance was not significantly affected by decreasing seawater temperature, from 6 °C to 3 °C or 0 °C, although two of the sponges showed decreased filtration rates. Low pH ( 7.5) and the presence of a predatory sea star markedly depressed or inhibited feeding activity in all sponges tested. While performed under laboratory conditions on a limited number of specimens, this work highlights the possible sensitivity of deep-sea demosponges to various types and levels of biotic and abiotic factors, inferring a consequent vulnerability to natural and anthropogenic disturbances.

  12. Abiotic factors affecting summer distribution and movement of male paddlefish, Polyodon spathula, in a prairie reservoir

    USGS Publications Warehouse

    Paukert, C.P.; Fisher, W.L.

    2000-01-01

    Six male paddlefish, Polyodon spathula, were implanted with ultrasonic temperature-sensing transmitters and tracked during June through August 1997 to quantify effects of physicochemical conditions on their distribution and movement in Keystone Reservoir, Oklahoma. Paddlefish moved about twice as much during night than day. Movement rate of paddlefish was related to reservoir water level, inflow, and discharge from the reservoir at night; however, none of these variables was significant during the day. Location in the reservoir (distance from the dam) was negatively related to water level and positively related to inflow during day and night periods. Location in the reservoir was negatively related to discharge during the day. Paddlefish avoided the highest available water temperatures, but did not always avoid low dissolved oxygen concentrations. Paddlefish avoided the Cimarron River arm of the reservoir in summer, possibly because of high salinity. Our study demonstrates that distribution of paddlefish during summer and movement in Keystone Reservoir was influenced by physicochemical and hydrologic conditions in the system. However, biotic factors (e.g., food availability) not measured in this study may have been influenced by abiotic conditions in the reservoir.

  13. Abiotic Factors Affecting Benthic Invertebrate Biomass and Community Structure in a Fourth-Order Rocky Mountain Watershed

    NASA Astrophysics Data System (ADS)

    Chanat, J. G.; Clements, W. H.; MacDonald, L. H.

    2005-05-01

    The potential ecological impact of excess streambed sediment resulting from forest management activities is a persistent concern for land managers. This study examined the relationship between streambed sediment, along with other site- and reach-scale abiotic factors, and benthic macroinvertebrate community structure in a 272 km2 basin in the Colorado Front Range. Physical habitat parameters and invertebrates were sampled in late summer at 68 sites located in sixteen stream reaches. Invertebrate data were used to formulate twenty indices of community structure. Multiple regression identified site-level substrate particle size as the most important predictor of six indices, including total density (R2 = 0.22), biomass (R2 = 0.17), and taxa richness (R2 = 0.32). All of the remaining fourteen indices were most strongly predicted by reach-level variables, including discharge (percent shredders, R2 = 0.24; Plecoptera density, R2 = 0.29), and elevation (percent collector-filterers, R2 = 0.28; Trichoptera density, R2 = 0.37). Although the sites represented a wide range of substrate composition and embeddedness, no physical variable associated with fine sediment appeared as a strong predictor of any of the twenty indices. Thus, sediment is not among the most important factors associated with site-to-site variability of benthic community structure in this relatively pristine watershed.

  14. Abiotic factors and trap design modulate the performance of traps used to monitor the plum curculio.

    PubMed

    Lamothe, Steve; Chouinard, Gérald; Vincent, Charles

    2008-12-01

    All published studies on effects of abiotic factors on plum curculio, Conotrachelus nenuphar (Hersbt), adults have taken a retrospective approach. Here, we present the results of experiments where factors and their levels were determined and controlled a priori. We compared the effectiveness of miniature pyramidal traps (45 by 20 by 20 cm) constructed of four kind of materials--wood, geotextile, nylon screening, and corrugated plastic--to monitor overwintered and summer adults of univoltine plum curculio. We also studied the effects of photoperiod, temperature, wind, and rain on pyramidal trap effectiveness. The experiments, which were replicated over time, were done in two controlled chambers that were divided into four sections, corresponding to simulated combinations (wind or no wind/rain or no rain). The temperatures tested (15, 20, and 25 degrees C) were randomly assigned in the chambers. During scotophase, geotextile traps captured significantly more overwintered and summer adults than traps made of other materials. The maximum proportion of captures (for overwintered and summer adults) during photophase was obtained at 25 degrees C, and it was significantly different than captures at 15 and 20 degrees C. During scotophase, significantly more overwintered and summer plum curculios were caught at 20 and 25 degrees C than at 15 degrees C. Our experiments demonstrated that geotextile is a good alternative to wooden pyramidal trap. Our results suggest that captures were higher 1) at night, 2) during warmer periods (20 and 25 degrees C), 3) when wind velocity was low and 4) during or shortly after rainfall, and 5) that photoperiod is a factor having an important predictive value for plum curculio captures.

  15. The importance of disturbance by fire and other abiotic and biotic factors in driving cheatgrass invasion varies based on invasion stage

    Treesearch

    Becky K. Kerns; Michelle A. Day

    2017-01-01

    Disturbances create fluctuations in resource availability that alter abiotic and biotic constraints. Exotic invader response may be due to multiple factors related to disturbance regimes and complex interactions between other small- and largescale abiotic and biotic processes that may vary across invasion stages. We explore how cheatgrass responds to both frequency and...

  16. Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors.

    PubMed

    Garchitorena, Andrés; Guégan, Jean-François; Léger, Lucas; Eyangoh, Sara; Marsollier, Laurent; Roche, Benjamin

    2015-07-28

    Host-parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors.

  17. Understanding plant community responses to combinations of biotic and abiotic factors in different phases of the plant growth cycle.

    PubMed

    Wood, Kevin A; Stillman, Richard A; Clarke, Ralph T; Daunt, Francis; O'Hare, Matthew T

    2012-01-01

    Understanding plant community responses to combinations of biotic and abiotic factors is critical for predicting ecosystem response to environmental change. However, studies of plant community regulation have seldom considered how responses to such factors vary with the different phases of the plant growth cycle. To address this deficit we studied an aquatic plant community in an ecosystem subject to gradients in mute swan (Cygnus olor) herbivory, riparian shading, water temperature and distance downstream of the river source. We quantified abundance, species richness, evenness, flowering and dominance in relation to biotic and abiotic factors during the growth-, peak-, and recession-phases of the plant growth cycle. We show that the relative importance of biotic and abiotic factors varied between plant community properties and between different phases of the plant growth cycle. Herbivory became more important during the later phases of peak abundance and recession due to an influx of swans from adjacent pasture fields. Shading by riparian vegetation also had a greater depressing effect on biomass in later seasons, probably due to increased leaf abundance reducing light intensity reaching the aquatic plants. The effect of temperature on community diversity varied between upstream and downstream sites by altering the relative competitiveness of species at these sites. These results highlight the importance of seasonal patterns in the regulation of plant community structure and function by multiple factors.

  18. Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors

    PubMed Central

    Garchitorena, Andrés; Guégan, Jean-François; Léger, Lucas; Eyangoh, Sara; Marsollier, Laurent; Roche, Benjamin

    2015-01-01

    Host–parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors. DOI: http://dx.doi.org/10.7554/eLife.07616.001 PMID:26216042

  19. Understanding Plant Community Responses to Combinations of Biotic and Abiotic Factors in Different Phases of the Plant Growth Cycle

    PubMed Central

    Wood, Kevin A.; Stillman, Richard A.; Clarke, Ralph T.; Daunt, Francis; O’Hare, Matthew T.

    2012-01-01

    Understanding plant community responses to combinations of biotic and abiotic factors is critical for predicting ecosystem response to environmental change. However, studies of plant community regulation have seldom considered how responses to such factors vary with the different phases of the plant growth cycle. To address this deficit we studied an aquatic plant community in an ecosystem subject to gradients in mute swan (Cygnus olor) herbivory, riparian shading, water temperature and distance downstream of the river source. We quantified abundance, species richness, evenness, flowering and dominance in relation to biotic and abiotic factors during the growth-, peak-, and recession-phases of the plant growth cycle. We show that the relative importance of biotic and abiotic factors varied between plant community properties and between different phases of the plant growth cycle. Herbivory became more important during the later phases of peak abundance and recession due to an influx of swans from adjacent pasture fields. Shading by riparian vegetation also had a greater depressing effect on biomass in later seasons, probably due to increased leaf abundance reducing light intensity reaching the aquatic plants. The effect of temperature on community diversity varied between upstream and downstream sites by altering the relative competitiveness of species at these sites. These results highlight the importance of seasonal patterns in the regulation of plant community structure and function by multiple factors. PMID:23166777

  20. Abiotic Factors Affecting the Persistence of Avian Influenza Virus in Surface Waters of Waterfowl Habitats

    PubMed Central

    Dalton, Melinda S.; Cressler, Alan M.; Berghaus, Roy D.; Stallknecht, David E.

    2014-01-01

    Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-μm filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats. PMID:24584247

  1. Impact of abiotic factor changes in blowfly, Achoetandrus rufifacies (Diptera: Calliphoridae), in northern Thailand.

    PubMed

    Klong-Klaew, Tunwadee; Sukontason, Kom; Ngoen-klan, Ratchadawan; Moophayak, Kittikhun; Irvine, Kim N; Kurahashi, Hiromu; Prangkio, Chira; Sanit, Sangob; Sukontason, Kabkaew L

    2014-04-01

    Understanding how medically important flies respond to abiotic factor changes is necessary for predicting their population dynamics. In this study, we investigated the geographical distribution of the medically important blowfly, Achoetandrus rufifacies (Macquart) (Diptera: Calliphoridae), and ascertained the response to climatic and physio-environmental factors in Chiang Mai, northern Thailand. Adult fly surveys were carried out every 2 weeks from May 2009 to May 2010 at 18 systematically randomized study sites in three districts of Chiang Mai province (Mueang Chiang Mai, Mae Rim, and Hang Dong), using reconstructable funnel traps with 1-day tainted beef offal as bait. During the study period, 8,861 adult A. rufifacies were captured, with peak densities being observed at the end of winter (i.e., late February) and throughout most of the summer (May to March). Population density had a weak but significant (α = 0.05) positive correlation with temperature (r = 0.329) and light intensity (r = 0.231), and a weak but significant (α = 0.05) negative correlation with relative humidity (r = -0.236). From the six ecological land use types (disturbed mixed deciduous forest, mixed deciduous forest, mixed orchard, lowland village, city town, and paddy field), greater fly densities were observed generally in the disturbed mixed deciduous forest and lowland village, but not in the paddy fields. In conclusion, A. rufifacies are abundant from the end of winter and throughout most of the summer in northern Thailand, with population density being weakly positively correlated with temperature and light intensity, but weakly negatively correlated with relative humidity. The greatest densities of this fly species were collected in disturbed mixed deciduous forest and lowland village land uses. The prediction of annual and season specific distributions of A. rufifacies were provided in each season and all-year patterns using a co-kriging approach (ArcGIS9.2).

  2. Crepuscular Flight Activity of an Invasive Insect Governed by Interacting Abiotic Factors

    PubMed Central

    Chen, Yigen; Seybold, Steven J.

    2014-01-01

    Seasonal and diurnal flight patterns of the invasive walnut twig beetle, Pityophthorus juglandis, were assessed between 2011 and 2014 in northern California, USA in the context of the effects of ambient temperature, light intensity, wind speed, and barometric pressure. Pityophthorus juglandis generally initiated flight in late January and continued until late November. This seasonal flight could be divided approximately into three phases (emergence: January–March; primary flight: May–July; and secondary flight: September–October). The seasonal flight response to the male-produced aggregation pheromone was consistently female-biased (mean of 58.9% females). Diurnal flight followed a bimodal pattern with a minor peak in mid-morning and a major peak at dusk (76.4% caught between 1800 and 2200 h). The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed. A model selection procedure indicated that the four abiotic factors collectively and interactively governed P. juglandis diurnal flight. For both sexes, flight peaked under the following second-order interactions among the factors when: 1) temperature between was 25 and 30°C and light intensity was less than 2000 lux; 2) temperature was between 25 and 35°C and barometric pressure was between 752 and 762 mba (and declined otherwise); 3) barometric pressure was between 755 and 761 mba and light intensity was less than 2000 lux (and declined otherwise); and 4) temperature was ca. 30°C and wind speed was ca. 2 km/h. Thus, crepuscular flight activity of this insect can be best explained by the coincidence of moderately high temperature, low light intensity, moderate wind speed, and low to moderate barometric pressure. The new knowledge provides physical and temporal guidelines for the application of semiochemical-based control techniques as part of an IPM program for

  3. Abiotic factors affecting the persistence of avian influenza virus in surface waters of waterfowl habitats.

    PubMed

    Keeler, Shamus P; Dalton, Melinda S; Cressler, Alan M; Berghaus, Roy D; Stallknecht, David E

    2014-05-01

    Avian influenza (AI) virus can remain infectious in water for months, and virus-contaminated surface water is considered to be a source of infection within wild waterfowl populations. Previous work has characterized the effects of pH, salinity, and temperature on viral persistence in water, but most of that work was done with modified distilled water. The objective of this study was to identify the abiotic factors that influence the duration of AI virus persistence in natural surface water. Surface water samples were collected from 38 waterfowl habitats distributed across the United States. Samples were submitted to the U.S. Geological Survey National Water Quality Laboratory for chemical analysis and the University of Georgia for viral reduction time analysis. Samples were filtered with 0.22-μm filters, and the durations of persistence of three wild-bird-derived influenza A viruses within each water sample at 10, 17, and 28°C were determined. The effects of the surface water physicochemical factors on the duration of AI viral persistence in laboratory experiments were evaluated by multivariable linear regression with robust standard errors. The duration of AI virus persistence was determined to be longest in filtered surface water with a low temperature (<17°C), a neutral-to-basic pH (7.0 to 8.5), low salinity (<0.5 ppt), and a low ammonia concentration (<0.5 mg/liter). Our results also highlighted potential strain-related variation in the stability of AI virus in surface water. These results bring us closer to being able to predict the duration of AI virus persistence in surface water of waterfowl habitats.

  4. Crepuscular flight activity of an invasive insect governed by interacting abiotic factors.

    PubMed

    Chen, Yigen; Seybold, Steven J

    2014-01-01

    Seasonal and diurnal flight patterns of the invasive walnut twig beetle, Pityophthorus juglandis, were assessed between 2011 and 2014 in northern California, USA in the context of the effects of ambient temperature, light intensity, wind speed, and barometric pressure. Pityophthorus juglandis generally initiated flight in late January and continued until late November. This seasonal flight could be divided approximately into three phases (emergence: January-March; primary flight: May-July; and secondary flight: September-October). The seasonal flight response to the male-produced aggregation pheromone was consistently female-biased (mean of 58.9% females). Diurnal flight followed a bimodal pattern with a minor peak in mid-morning and a major peak at dusk (76.4% caught between 1800 and 2200 h). The primarily crepuscular flight activity had a Gaussian relationship with ambient temperature and barometric pressure but a negative exponential relationship with increasing light intensity and wind speed. A model selection procedure indicated that the four abiotic factors collectively and interactively governed P. juglandis diurnal flight. For both sexes, flight peaked under the following second-order interactions among the factors when: 1) temperature between was 25 and 30 °C and light intensity was less than 2000 lux; 2) temperature was between 25 and 35 °C and barometric pressure was between 752 and 762 mba (and declined otherwise); 3) barometric pressure was between 755 and 761 mba and light intensity was less than 2000 lux (and declined otherwise); and 4) temperature was ca. 30 °C and wind speed was ca. 2 km/h. Thus, crepuscular flight activity of this insect can be best explained by the coincidence of moderately high temperature, low light intensity, moderate wind speed, and low to moderate barometric pressure. The new knowledge provides physical and temporal guidelines for the application of semiochemical-based control techniques as part of an IPM program for this

  5. Spatial variation in abiotic and biotic factors in a floodplain determine anuran body size and growth rate at metamorphosis.

    PubMed

    Indermaur, Lukas; Schmidt, Benedikt R; Tockner, Klement; Schaub, Michael

    2010-07-01

    Body size at metamorphosis is a critical trait in the life history of amphibians. Despite the wide-spread use of amphibians as experimental model organisms, there is a limited understanding of how multiple abiotic and biotic factors affect the variation in metamorphic traits under natural conditions. The aim of our study was to quantify the effects of abiotic and biotic factors on spatial variation in the body size of tadpoles and size at metamorphosis of the European common toad (Bufo b. spinosus). Our study population was distributed over the riverbed (active tract) and the fringing riparian forest of a natural floodplain. The riverbed had warm ponds with variable hydroperiod and few predators, whereas the forest had ponds with the opposite characteristics. Spatial variation in body size at metamorphosis was governed by the interactive effects of abiotic and biotic factors. The particular form of the interaction between water temperature and intraspecific tadpole density suggests that abiotic factors laid the foundation for biotic factors: intraspecific density decreased growth only at high temperature. Predation and intraspecific density jointly reduced metamorphic size. Interspecific density had a negligible affect on body size at metamorphosis, suggesting weak inter-anuran interactions in the larval stage. Population density at metamorphosis was about one to two orders of magnitudes higher in the riverbed ponds than in the forest ponds, mainly because of lower tadpole mortality. Based on our results, we conclude that ponds in the riverbed appear to play a pivotal role for the population because tadpole growth and survival is best in this habitat.

  6. Vascular plant one-zinc-finger protein 1/2 transcription factors regulate abiotic and biotic stress responses in Arabidopsis.

    PubMed

    Nakai, Yusuke; Nakahira, Yoichi; Sumida, Hiroki; Takebayashi, Kosuke; Nagasawa, Yumiko; Yamasaki, Kanako; Akiyama, Masako; Ohme-Takagi, Masaru; Fujiwara, Sumire; Shiina, Takashi; Mitsuda, Nobutaka; Fukusaki, Eiichiro; Kubo, Yasuyuki; Sato, Masa H

    2013-03-01

    Plants adapt to abiotic and biotic stresses by activating abscisic acid-mediated (ABA) abiotic stress-responsive and salicylic acid-(SA) or jasmonic acid-mediated (JA) biotic stress-responsive pathways, respectively. Although the abiotic stress-responsive pathway interacts antagonistically with the biotic stress-responsive pathways, the mechanisms that regulate these pathways remain largely unknown. In this study, we provide insight into the function of vascular plant one-zinc-finger proteins (VOZs) that modulate various stress responses in Arabidopsis. The expression of many stress-responsive genes was changed in the voz1voz2 double mutant under normal growth conditions. Consistent with altered stress-responsive gene expression, freezing- and drought-stress tolerances were increased in the voz1voz2 double mutant. In contrast, resistance to a fungal pathogen, Colletotrichum higginsianum, and to a bacterial pathogen, Pseudomonas syringae, was severely impaired. Thus, impairing VOZ function simultaneously conferred increased abiotic tolerance and biotic stress susceptibility. In a chilling stress condition, both the VOZ1 and VOZ2 mRNA expression levels and the VOZ2 protein level gradually decreased. VOZ2 degradation during cold exposure was completely inhibited by the addition of the 26S proteasome inhibitor, MG132, a finding that suggested that VOZ2 degradation is dependent on the ubiquitin/26S proteasome system. In voz1voz2, ABA-inducible transcription factor CBF4 expression was enhanced significantly even under normal growth conditions, despite an unchanged endogenous ABA content. A finding that suggested that VOZs negatively affect CBF4 expression in an ABA-independent manner. These results suggest that VOZs function as both negative and positive regulators of the abiotic and biotic stress-responsive pathways, and control Arabidopsis adaptation to various stress conditions. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  7. Combined Effects of Soil Biotic and Abiotic Factors, Influenced by Sewage Sludge Incorporation, on the Incidence of Corn Stalk Rot

    PubMed Central

    Fortes, Nara Lúcia Perondi; Navas-Cortés, Juan A; Silva, Carlos Alberto; Bettiol, Wagner

    2016-01-01

    The objectives of this study were to evaluate the combined effects of soil biotic and abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two types of sewage sludge into soil in a 5-years field assay under tropical conditions and to predict the effects of these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. A multiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil. PMID:27176597

  8. Combined Effects of Soil Biotic and Abiotic Factors, Influenced by Sewage Sludge Incorporation, on the Incidence of Corn Stalk Rot.

    PubMed

    Ghini, Raquel; Fortes, Nara Lúcia Perondi; Navas-Cortés, Juan A; Silva, Carlos Alberto; Bettiol, Wagner

    2016-01-01

    The objectives of this study were to evaluate the combined effects of soil biotic and abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two types of sewage sludge into soil in a 5-years field assay under tropical conditions and to predict the effects of these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. A multiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil.

  9. Effects of biotic and abiotic factors on the distribution of trout and salmon along a longitudinal stream gradient

    USGS Publications Warehouse

    De La, Hoz; Budy, P.

    2005-01-01

    We examined the influence of biotic and abiotic factors on the distribution, abundance, and condition of salmonid fishes along a stream gradient. We observed a longitudinal change in fish distribution with native cutthroat trout, Oncorhynchus clarki utah, and introduced brown trout, Salmo trutta, demonstrating a distinct pattern of allopatry. Cutthroat trout dominated high elevation reaches, while reaches at lower elevations were dominated by brown trout. A transition zone between these populations was associated with lower total trout abundance, consistent changes in temperature and discharge, and differences in dietary preference. Variation in cutthroat trout abundance was best explained by a model including the abundance of brown trout and diel temperature, whereas variation in brown trout abundance was best explained by a model including the abundance of cutthroat trout and discharge. These results suggest the potential for condition-mediated competition between the two species. The results from our study can aid biologists in prioritizing conservation activities and in developing robust management strategies for cutthroat trout. ?? Springer 2005.

  10. Molecular characterization of BZR transcription factor family and abiotic stress induced expression profiling in Brassica rapa.

    PubMed

    Saha, Gopal; Park, Jong-In; Jung, Hee-Jeong; Ahmed, Nasar Uddin; Kayum, Md Abdul; Kang, Jong-Goo; Nou, Ill-Sup

    2015-07-01

    BRASSINAZOLE-RESISTANT (BZR) transcription factors (TFs) are primarily well known as positive regulators of Brassinosteroid (BR) signal transduction in different plants. BR is a plant specific steroid hormone, which has multiple stress resistance functions besides various growth regulatory roles. Being an important regulator of the BR synthesis, BZR TFs might have stress resistance related activities. However, no stress resistance related functional study of BZR TFs has been reported in any crop plants so far. Therefore, this study identified 15 BZR TFs of Brassica rapa (BrBZR) from a genome-wide survey and characterized them through sequence analysis and expression profiling against several abiotic stresses. Various systematic in silico analysis of these TFs validated the fundamental properties of BZRs, where a high degree of similarity also observed with recognized BZRs of other plant species from the comparison studies. In the organ specific expression analyses, 6 BrBZR TFs constitutively expressed in flower developmental stages indicating their flower specific functions. Subsequently, from the stress resistance related expression profiles differential transcript abundance levels were observed by 6 and 11 BrBZRs against salt and drought stresses, respectively. All BrBZRs showed several folds up-regulation against exogenous ABA treatment. All BrBZRs also showed differential expression against low temperature stress treatments and these TFs were proposed as transcriptional activators of CBF cold response pathway of B. rapa. Notably, three BrBZRs gave co-responsive expression against all the stresses tested here, suggesting their multiple stress resistance related functions. Thus, the findings would be helpful in resolving the complex regulatory mechanism of BZRs in stress resistance and further functional genomics study of these potential TFs in different Brassica crops.

  11. Soybean NAC transcription factors promote abiotic stress tolerance and lateral root formation in transgenic plants.

    PubMed

    Hao, Yu-Jun; Wei, Wei; Song, Qing-Xin; Chen, Hao-Wei; Zhang, Yu-Qin; Wang, Fang; Zou, Hong-Feng; Lei, Gang; Tian, Ai-Guo; Zhang, Wan-Ke; Ma, Biao; Zhang, Jin-Song; Chen, Shou-Yi

    2011-10-01

    NAC transcription factors play important roles in plant growth, development and stress responses. Previously, we identified multiple NAC genes in soybean (Glycine max). Here, we identify the roles of two genes, GmNAC11 and GmNAC20, in stress responses and other processes. The two genes were differentially induced by multiple abiotic stresses and plant hormones, and their transcripts were abundant in roots and cotyledons. Both genes encoded proteins that localized to the nucleus and bound to the core DNA sequence CGT[G/A]. In the protoplast assay system, GmNAC11 acts as a transcriptional activator, whereas GmNAC20 functions as a mild repressor; however, the C-terminal end of GmANC20 has transcriptional activation activity. Over-expression of GmNAC20 enhances salt and freezing tolerance in transgenic Arabidopsis plants; however, GmNAC11 over-expression only improves salt tolerance. Over-expression of GmNAC20 also promotes lateral root formation. GmNAC20 may regulate stress tolerance through activation of the DREB/CBF-COR pathway, and may control lateral root development by altering auxin signaling-related genes. GmNAC11 probably regulates DREB1A and other stress-related genes. The roles of the two GmNAC genes in stress tolerance were further analyzed in soybean transgenic hairy roots. These results provide a basis for genetic manipulation to improve the agronomic traits of important crops. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  12. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

    PubMed Central

    Wang, Ce; Bi, Jun; Fath, Brian D.

    2017-01-01

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained. PMID:28220835

  13. Seasonal dynamics of wheat aphid complex and predator Coccinella septempunctata in relation to abiotic and biotic factors.

    PubMed

    Soni, Rajesh; Deol, G S; Singh, Satnam

    2013-07-01

    Seasonal dynamics studies on wheat aphid complex, comprising of four major species and its predator Coccinella septempunctata were conducted in context to abiotic and biotic factors. The alate form of aphids appeared on the crop during the 1st week of December. The colony build up of aphid complex started during the 2nd week of January and peak was observed after the 1st week of March. Wheat aphid complex started declining in the last week of March and disappeared by mid April. The abiotic factors like maximum temperature and evaporation were most important for the build up of aphids. The grubs and adults of C. septempunctata appeared on the crop during mid February and their population increased with the increase in aphid population. The grubs and adult population showed a strong positive correlation with aphid complex. The population of predators had significant positive correlation with maximum, minimum, mean temperature, sunshine and vapour pressure. The population of aphids declined after the 2nd week of March due to the rise in temperature, crop maturity and this in turn resulted in the lowering of the predator population. The studies evaluate in detail the abiotic and biotic factors regulating the wheat aphid complex and C. septempunctata populations under wheat agro-ecosystem.

  14. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory.

    PubMed

    Wang, Ce; Bi, Jun; Fath, Brian D

    2017-02-21

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

  15. Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

    NASA Astrophysics Data System (ADS)

    Wang, Ce; Bi, Jun; Fath, Brian D.

    2017-02-01

    A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

  16. Developing standards for environmental toxicants: the need to consider abiotic environmental factors and microbe-mediated ecologic processes.

    PubMed Central

    Babich, H; Stotzky, G

    1983-01-01

    This article suggests and discusses two novel aspects for the formulation of standards for environmental toxicants. First, uniform national standards for each pollutant will be underprotective for some ecosystems and overprotective for others, inasmuch as the toxicity of a pollutant to the indigenous biota is dependent on the physicochemical properties of the recipient environment. As the number of chemicals that need regulation is immense and as microbes appear to respond similarly to pollutant-abiotic factor interactions as do plants and animals, it is suggested that microbial assays be used initially to identify those abiotic factors that most influence the toxicity of specific pollutants. Thereafter, additional studies using plants and animals can focus on these pollutant-abiotic factor interactions, and more meaningful standards can then be formulated more rapidly and inexpensively. Second, it is suggested that the response to pollutants of microbe-mediated ecologic processes be used to quantitate the sensitivity of different ecosystems to various toxicants. Such a quantification, expressed in terms of an "ecological dose 50%" (EcD50), could be easily incorporated into the methodologies currently used to set water quality criteria and would also be applicable to setting criteria for terrestrial ecosystems. PMID:6339225

  17. Kresoxim-methyl primes Medicago truncatula plants against abiotic stress factors via altered reactive oxygen and nitrogen species signalling leading to downstream transcriptional and metabolic readjustment.

    PubMed

    Filippou, Panagiota; Antoniou, Chrystalla; Obata, Toshihiro; Van Der Kelen, Katrien; Harokopos, Vaggelis; Kanetis, Loukas; Aidinis, Vassilis; Van Breusegem, Frank; Fernie, Alisdair R; Fotopoulos, Vasileios

    2016-03-01

    Biotic and abiotic stresses, such as fungal infection and drought, cause major yield losses in modern agriculture. Kresoxim-methyl (KM) belongs to the strobilurins, one of the most important classes of agricultural fungicides displaying a direct effect on several plant physiological and developmental processes. However, the impact of KM treatment on salt and drought stress tolerance is unknown. In this study we demonstrate that KM pre-treatment of Medicago truncatula plants results in increased protection to drought and salt stress. Foliar application with KM prior to stress imposition resulted in improvement of physiological parameters compared with stressed-only plants. This protective effect was further supported by increased proline biosynthesis, modified reactive oxygen and nitrogen species signalling, and attenuation of cellular damage. In addition, comprehensive transcriptome analysis identified a number of transcripts that are differentially accumulating in drought- and salinity-stressed plants (646 and 57, respectively) after KM pre-treatment compared with stressed plants with no KM pre-treatment. Metabolomic analysis suggests that the priming role of KM in drought- and to a lesser extent in salinity-stressed plants can be attributed to the regulation of key metabolites (including sugars and amino acids) resulting in protection against abiotic stress factors. Overall, the present study highlights the potential use of this commonly used fungicide as a priming agent against key abiotic stress conditions. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. Kresoxim-methyl primes Medicago truncatula plants against abiotic stress factors via altered reactive oxygen and nitrogen species signalling leading to downstream transcriptional and metabolic readjustment

    PubMed Central

    Filippou, Panagiota; Antoniou, Chrystalla; Obata, Toshihiro; Van Der Kelen, Katrien; Harokopos, Vaggelis; Kanetis, Loukas; Aidinis, Vassilis; Van Breusegem, Frank; Fernie, Alisdair R; Fotopoulos, Vasileios

    2016-01-01

    Biotic and abiotic stresses, such as fungal infection and drought, cause major yield losses in modern agriculture. Kresoxim-methyl (KM) belongs to the strobilurins, one of the most important classes of agricultural fungicides displaying a direct effect on several plant physiological and developmental processes. However, the impact of KM treatment on salt and drought stress tolerance is unknown. In this study we demonstrate that KM pre-treatment of Medicago truncatula plants results in increased protection to drought and salt stress. Foliar application with KM prior to stress imposition resulted in improvement of physiological parameters compared with stressed-only plants. This protective effect was further supported by increased proline biosynthesis, modified reactive oxygen and nitrogen species signalling, and attenuation of cellular damage. In addition, comprehensive transcriptome analysis identified a number of transcripts that are differentially accumulating in drought- and salinity-stressed plants (646 and 57, respectively) after KM pre-treatment compared with stressed plants with no KM pre-treatment. Metabolomic analysis suggests that the priming role of KM in drought- and to a lesser extent in salinity-stressed plants can be attributed to the regulation of key metabolites (including sugars and amino acids) resulting in protection against abiotic stress factors. Overall, the present study highlights the potential use of this commonly used fungicide as a priming agent against key abiotic stress conditions. PMID:26712823

  19. Effect of abiotic factors on the mercury reduction process by humic acids in aqueous systems

    USDA-ARS?s Scientific Manuscript database

    Mercury (Hg) in the environment can have serious toxic effects on a variety of living organisms, and is a pollutant of concern worldwide. The reduction of mercury from the toxic Hg2+ form to Hg0 is especially important. One pathway for this reduction to occur is through an abiotic process with humic...

  20. Interactions of biotic and abiotic environmental factors in an ectomycorrhizal symbiosis, and the potential for selection mosaics

    PubMed Central

    Piculell, Bridget J; Hoeksema, Jason D; Thompson, John N

    2008-01-01

    Background Geographic selection mosaics, in which species exert different evolutionary impacts on each other in different environments, may drive diversification in coevolving species. We studied the potential for geographic selection mosaics in plant-mycorrhizal interactions by testing whether the interaction between bishop pine (Pinus muricata D. Don) and one of its common ectomycorrhizal fungi (Rhizopogon occidentalis Zeller and Dodge) varies in outcome, when different combinations of plant and fungal genotypes are tested under a range of different abiotic and biotic conditions. Results We used a 2 × 2 × 2 × 2 factorial experiment to test the main and interactive effects of plant lineage (two maternal seed families), fungal lineage (two spore collections), soil type (lab mix or field soil), and non-mycorrhizal microbes (with or without) on the performance of plants and fungi. Ecological outcomes, as assessed by plant and fungal performance, varied widely across experimental environments, including interactions between plant or fungal lineages and soil environmental factors. Conclusion These results show the potential for selection mosaics in plant-mycorrhizal interactions, and indicate that these interactions are likely to coevolve in different ways in different environments, even when initially the genotypes of the interacting species are the same across all environments. Hence, selection mosaics may be equally as effective as genetic differences among populations in driving divergent coevolution among populations of interacting species. PMID:18507825

  1. Transcriptional profiling of Medicago truncatula under salt stress identified a novel CBF transcription factor MtCBF4 that plays an important role in abiotic stress responses

    PubMed Central

    2011-01-01

    Background Salt stress hinders the growth of plants and reduces crop production worldwide. However, different plant species might possess different adaptive mechanisms to mitigate salt stress. We conducted a detailed pathway analysis of transcriptional dynamics in the roots of Medicago truncatula seedlings under salt stress and selected a transcription factor gene, MtCBF4, for experimental validation. Results A microarray experiment was conducted using root samples collected 6, 24, and 48 h after application of 180 mM NaCl. Analysis of 11 statistically significant expression profiles revealed different behaviors between primary and secondary metabolism pathways in response to external stress. Secondary metabolism that helps to maintain osmotic balance was induced. One of the highly induced transcription factor genes was successfully cloned, and was named MtCBF4. Phylogenetic analysis revealed that MtCBF4, which belongs to the AP2-EREBP transcription factor family, is a novel member of the CBF transcription factor in M. truncatula. MtCBF4 is shown to be a nuclear-localized protein. Expression of MtCBF4 in M. truncatula was induced by most of the abiotic stresses, including salt, drought, cold, and abscisic acid, suggesting crosstalk between these abiotic stresses. Transgenic Arabidopsis over-expressing MtCBF4 enhanced tolerance to drought and salt stress, and activated expression of downstream genes that contain DRE elements. Over-expression of MtCBF4 in M. truncatula also enhanced salt tolerance and induced expression level of corresponding downstream genes. Conclusion Comprehensive transcriptomic analysis revealed complex mechanisms exist in plants in response to salt stress. The novel transcription factor gene MtCBF4 identified here played an important role in response to abiotic stresses, indicating that it might be a good candidate gene for genetic improvement to produce stress-tolerant plants. PMID:21718548

  2. Transcriptome-Based Analysis of Dof Family Transcription Factors and Their Responses to Abiotic Stress in Tea Plant (Camellia sinensis).

    PubMed

    Li, Hui; Huang, Wei; Liu, Zhi-Wei; Wang, Yong-Xin; Zhuang, Jing

    2016-01-01

    Tea plant (Camellia sinensis (L.) O. Kuntze) is affected by abiotic stress during its growth and development. DNA-binding with one finger (Dof) transcription factors (TFs) play important roles in abiotic stress tolerance of plants. In this study, a total of 29 putative Dof TFs were identified based on transcriptome of tea plant, and the conserved domains and common motifs of these CsDof TFs were predicted and analyzed. The 29 CsDof proteins were divided into 7 groups (A, B1, B2, C1, C2.1, C2.2, and D2), and the interaction networks of Dof proteins in C. sinensis were established according to the data in Arabidopsis. Gene expression was analyzed in "Yingshuang" and "Huangjinya" under four experimental stresses by qRT-PCR. CsDof genes were expressed differentially and related to different abiotic stress conditions. In total, our results might suggest that there is a potential relationship between CsDof factors and tea plant stress resistance.

  3. Transcriptome-Based Analysis of Dof Family Transcription Factors and Their Responses to Abiotic Stress in Tea Plant (Camellia sinensis)

    PubMed Central

    Li, Hui; Huang, Wei; Liu, Zhi-Wei; Wang, Yong-Xin

    2016-01-01

    Tea plant (Camellia sinensis (L.) O. Kuntze) is affected by abiotic stress during its growth and development. DNA-binding with one finger (Dof) transcription factors (TFs) play important roles in abiotic stress tolerance of plants. In this study, a total of 29 putative Dof TFs were identified based on transcriptome of tea plant, and the conserved domains and common motifs of these CsDof TFs were predicted and analyzed. The 29 CsDof proteins were divided into 7 groups (A, B1, B2, C1, C2.1, C2.2, and D2), and the interaction networks of Dof proteins in C. sinensis were established according to the data in Arabidopsis. Gene expression was analyzed in “Yingshuang” and “Huangjinya” under four experimental stresses by qRT-PCR. CsDof genes were expressed differentially and related to different abiotic stress conditions. In total, our results might suggest that there is a potential relationship between CsDof factors and tea plant stress resistance. PMID:27872842

  4. The soybean GmbZIP1 transcription factor enhances multiple abiotic stress tolerances in transgenic plants.

    PubMed

    Gao, Shi-Qing; Chen, Ming; Xu, Zhao-Shi; Zhao, Chang-Ping; Li, Liancheng; Xu, Hui-jun; Tang, Yi-miao; Zhao, Xin; Ma, You-Zhi

    2011-04-01

    Abscisic acid (ABA)-responsive element binding proteins (AREBs) are basic domain/leucine zipper transcription factors that bind to the ABA-responsive element (ABRE) in the promoter regions of ABA-inducible genes in plants. A novel bZIP transcription factor gene, GmbZIP1, encoding 438 amino acids with a conserved bZIP domain composed of 60 amino acids was isolated from salt-tolerant soybean cv. Tiefeng 8. Southern blotting showed that only one copy was present in the soybean genome. Phylogenetic analyses showed that GmbZIP1 belonged to the AREB subfamily of the bZIP family and was most closely related to AtABF2 and OsTRAB1. The expression of GmbZIP1 was highly induced by ABA, drought, high salt and low temperature; and GmbZIP1 was expressed in soybean roots, stems and leaves under different stress conditions. GmbZIP1 was localized inside the nuclei of transformed onion epidermal cells. Overexpression of GmbZIP1 enhanced the responses of transgenic plants to ABA and triggered stomatal closure under stresses, potentially leading to improved tolerances to several abiotic stresses such as high salt, low temperature and drought in transgenic plants. Furthermore, overexpression of GmbZIP1 affected the expression of some ABA or stress-related genes involved in regulating stomatal closure in Arabidopsis under ABA, drought and high salt stress conditions. A few AREB elements were detected in the promoter region of those ABA or stress-related genes, suggesting that GmbZIP1 regulates the ABA response or stomatal closure mediated by those downstream genes in transgenic Arabidopsis. Moreover, GmbZIP1 was used to improve the drought tolerance trait of Chinese wheat varieties BS93. Functional analysis showed that overexpression of GmbZIP1 enhanced the drought tolerance of transgenic wheat, and transcripts of GmbZIP1 were detected in transgenic wheat using RT-PCR. In addition, GmbZIP1 overexpression did not result in growth retardation in all transgenic plants, suggesting that Gmb

  5. Variation in stability of elk and red deer populations with abiotic and biotic factors at the species-distribution scale.

    PubMed

    Ahrestani, Farshid S; Smith, William K; Hebblewhite, Mark; Running, Steven; Post, Eric

    2016-11-01

    abiotic conditions, both reduce stability, but in opposing fashion: one through weakened direct density dependence and the other through strengthened delayed density dependence. Importantly, however, no single abiotic or biotic environmental factor emerged as generally predictive of the strengths of direct or delayed density dependence, nor of the stability properties emerging from their interaction. Our results emphasize the challenges inherent to ascribing primacy to drivers of such parameters at the species level and distribution scale.

  6. Reduced tolerance to abiotic stress in transgenic Arabidopsis overexpressing a Capsicum annuum multiprotein bridging factor 1

    PubMed Central

    2014-01-01

    Background The pepper fruit is the second most consumed vegetable worldwide. However, low temperature affects the vegetative development and reproduction of the pepper, resulting in economic losses. To identify cold-related genes regulated by abscisic acid (ABA) in pepper seedlings, cDNA representational difference analysis was previously performed using a suppression subtractive hybridization method. One of the genes cloned from the subtraction was homologous to Solanum tuberosum MBF1 (StMBF1) encoding the coactivator multiprotein bridging factor 1. Here, we have characterized this StMBF1 homolog (named CaMBF1) from Capsicum annuum and investigated its role in abiotic stress tolerance. Results Tissue expression profile analysis using quantitative RT-PCR showed that CaMBF1 was expressed in all tested tissues, and high-level expression was detected in the flowers and seeds. The expression of CaMBF1 in pepper seedlings was dramatically suppressed by exogenously supplied salicylic acid, high salt, osmotic and heavy metal stresses. Constitutive overexpression of CaMBF1 in Arabidopsis aggravated the visible symptoms of leaf damage and the electrolyte leakage of cell damage caused by cold stress in seedlings. Furthermore, the expression of RD29A, ERD15, KIN1, and RD22 in the transgenic plants was lower than that in the wild-type plants. On the other hand, seed germination, cotyledon greening and lateral root formation were more severely influenced by salt stress in transgenic lines compared with wild-type plants, indicating that CaMBF1-overexpressing Arabidopsis plants were hypersensitive to salt stress. Conclusions Overexpression of CaMBF1 in Arabidopsis displayed reduced tolerance to cold and high salt stress during seed germination and post-germination stages. CaMBF1 transgenic Arabidopsis may reduce stress tolerance by downregulating stress-responsive genes to aggravate the leaf damage caused by cold stress. CaMBF1 may be useful for genetic engineering of novel

  7. A novel wheat bZIP transcription factor, TabZIP60, confers multiple abiotic stress tolerances in transgenic Arabidopsis.

    PubMed

    Zhang, Lina; Zhang, Lichao; Xia, Chuan; Zhao, Guangyao; Liu, Ji; Jia, Jizeng; Kong, Xiuying

    2015-04-01

    The basic region/leucine zipper (bZIP) transcription factors (TFs) play vital roles in the response to abiotic stress. However, little is known about the function of bZIP genes in wheat abiotic stress. In this study, we report the isolation and functional characterization of the TabZIP60 gene. Three homologous genome sequences of TabZIP60 were isolated from hexaploid wheat and mapped to the wheat homoeologous group 6. A subcellular localization analysis indicated that TabZIP60 is a nuclear-localized protein that activates transcription. Furthermore, TabZIP60 gene transcripts were strongly induced by polyethylene glycol, salt, cold and exogenous abscisic acid (ABA) treatments. Further analysis showed that the overexpression of TabZIP60 in Arabidopsis resulted in significantly improved tolerances to drought, salt, freezing stresses and increased plant sensitivity to ABA in seedling growth. Meanwhile, the TabZIP60 was capable of binding ABA-responsive cis-elements that are present in promoters of many known ABA-responsive genes. A subsequent analysis showed that the overexpression of TabZIP60 led to enhanced expression levels of some stress-responsive genes and changes in several physiological parameters. Taken together, these results suggest that TabZIP60 enhances multiple abiotic stresses through the ABA signaling pathway and that modifications of its expression may improve multiple stress tolerances in crop plants.

  8. Abiotic and biotic factors affecting the replication and pathogenicity of bee viruses.

    PubMed

    McMenamin, Alexander J; Brutscher, Laura M; Glenny, William; Flenniken, Michelle L

    2016-08-01

    Bees are important pollinators of plants in both agricultural and non-agricultural landscapes. Recent losses of both managed and wild bee species have negative impacts on crop production and ecosystem diversity. Therefore, in order to mitigate bee losses, it is important to identify the factors most responsible. Multiple factors including pathogens, agrochemical exposure, lack of quality forage, and reduced habitat affect bee health. Pathogen prevalence is one factor that has been associated with colony losses. Numerous pathogens infect bees including fungi, protists, bacteria, and viruses, the majority of which are RNA viruses including several that infect multiple bee species. RNA viruses readily infect bees, yet there is limited understanding of their impacts on bee health, particularly in the context of other stressors. Herein we review the influence environmental factors have on the replication and pathogenicity of bee viruses and identify research areas that require further investigation. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  9. Survival of the biological control agent Candida sake CPA-1 on grapes under the influence of abiotic factors.

    PubMed

    Calvo-Garrido, C; Viñas, I; Usall, J; Rodríguez-Romera, M; Ramos, M C; Teixidó, N

    2014-09-01

    As reliability of preharvest applications of biological control agents (BCAs) to control fruit pathogens is highly dependent on the survival of the selected organism, this study aimed to describe the population dynamics of the yeast-BCA Candida sake (Saito & Ota) CPA-1 on grape berries under the effect of abiotic factors such as temperature, relative humidity, sunlight and rainfall. Candida sake (5 × 10(7) CFU ml(-1)), combined with different concentrations of the food additive Fungicover(®), was applied on grape berry clusters. Treated clusters were then exposed to abiotic factors in field or laboratory conditions, recovering populations to describe C. sake population dynamics. The addition of Fungicover significantly increased C. sake multiplication under optimal growth conditions and improved survival under fluctuating abiotic factors. After field applications, significant differences in populations on grape bunches exposed or covered by fine foliage were detected. Simulated rainfall washed off C. sake populations by 0·6-0·9 log units after 20 mm of rain volume. Allowing populations to establish for 24 h or more, prior to a rain event, persistence on grape berries significantly increased and the effect of rain intensity was not observable. Candida sake demonstrated high survival ability under unfavourable environmental conditions and persistence under intense rain. The study evidenced the importance of the first period just after application for C. sake survival on grape tissues and also the protective effect of the additive Fungicover. This research provides new information on the survival of C. sake under field conditions and its practical implications for recommending timing of spray with this antagonist. Our results could be useful for other yeast antagonists applied before harvest. This work, for the first time, defines population dynamics of a yeast BCA using simulated rainfall. © 2014 The Society for Applied Microbiology.

  10. Influence of Various Levels of Iron and Other Abiotic Factors on Siderophorogenesis in Paddy Field Cyanobacterium Anabaena oryzae.

    PubMed

    Singh, Anumeha; Mishra, Arun Kumar

    2015-05-01

    Siderophore production in Anabaena oryzae was investigated under the influence of various levels of iron and other abiotic factors such as pH, temperature, light and different nitrogen sources. Optimization of culture conditions under controlled mechanisms of these abiotic factors lead to the siderophore production in significant amount. Under iron-starved condition, A. oryzae extracellularly releases 89.17% hydroxymate-type siderophore. Slightly alkaline pH and 30 °C temperature was found stimulatory for the cyanobacterial growth and siderophorogenesis (88.52% SU and 83.87% SU, respectively). Excess iron loading had a negative impact on siderophore production along with the alterations in the morphology and growth. Further, scanning electron microphotographs signified that higher concentrations of iron lead to complete damage of the cells and alterations in membrane proteins possibly transporters responsible for exchange of siderophore complex from environment to the cell. SDS-PAGE analysis of whole cell proteins showed overexpression of low molecular weight proteins ranges between 20.1 to 29.0 kDa up to 100-μM iron concentrations. These polypeptides/proteins might be involved in maintaining iron homeostasis by regulating siderophore production. Results suggest that lower concentrations of iron ≤ 50 μM along with other abiotic factors are stimulatory, whereas higher concentrations (>50 μM) are toxic. Data further suggested that cyanobacterium A. oryzae can serve as a potential biofertilizer especially in iron-rich soil through sequestration by the power of natural Fe(III)-siderophore complex formation.

  11. Factors controlling the abiotic photo-degradation of monomethylmercury in surface waters

    NASA Astrophysics Data System (ADS)

    Black, Frank J.; Poulin, Brett A.; Flegal, A. Russell

    2012-05-01

    Photo-decomposition is among the most important mechanisms responsible for degrading monomethylmercury (MMHg) in aquatic systems, but this process is not fully understood. We investigated the relative importance of different factors in controlling the rate of MMHg photo-decomposition in surface waters in experiments using DOM isolated from natural waters. We found no evidence of net abiotic production of MMHg in any dark or light exposed treatments. The average (mean ± s.d.) MMHg photo-decomposition rate constant for all light exposed samples using DOM concentrated from three coastal wetlands was 0.0099 ± 0.0020 E-1m2 (range of 0.006-0.015 E-1m2) when expressed in photon flux from 330-700 nm. This was roughly 3-fold higher than the average MMHg photo-decomposition rate constant in coastal seawater of 0.0032 ± 0.0010 E-1m2. MMHg photo-degradation was highly wavelength dependent. The ratio of MMHg photo-decomposition rate constants, with respect to photon flux, was 400:37:1 for UVB:UVA:PAR. However, when integrated across the entire water column over which MMHg photo-demethylation occurs, PAR was responsible for photo-degrading more MMHg than UVB and UVA combined in the three wetland sites because of the more rapid attenuation of UV light with depth. MMHg half-lives in the wetlands were calculated for the upper 250 cm where photo-degradation occurred, and ranged from 7.6 to 20 days under typical summer sunlight conditions at 37°N. Rates of MMHg photo-decomposition decreased with increasing salinity, and were 27% higher at a salinity of 5 than those at a salinity of 25. This difference could not be accounted for by changes in the complexation of MMHg by DOM and chloride. Differences in MMHg photo-degradation rate constants of up to 18% were measured between treatments using DOM concentrated from three different wetlands. Surprisingly, increasing DOM concentration from 1.5 to 11.3 mg OC L-1 had only a small (6%) effect on MMHg photo-decomposition, which was much

  12. ABI-like transcription factor gene TaABL1 from wheat improves multiple abiotic stress tolerances in transgenic plants.

    PubMed

    Xu, Dong-Bei; Gao, Shi-Qing; Ma, You-Zhi; Xu, Zhao-Shi; Zhao, Chang-Ping; Tang, Yi-Miao; Li, Xue-Yin; Li, Lian-Cheng; Chen, Yao-Feng; Chen, Ming

    2014-12-01

    The phytohormone abscisic acid (ABA) plays crucial roles in adaptive responses of plants to abiotic stresses. ABA-responsive element binding proteins (AREBs) are basic leucine zipper transcription factors that regulate the expression of downstream genes containing ABA-responsive elements (ABREs) in promoter regions. A novel ABI-like (ABA-insensitive) transcription factor gene, named TaABL1, containing a conserved basic leucine zipper (bZIP) domain was cloned from wheat. Southern blotting showed that three copies were present in the wheat genome. Phylogenetic analyses indicated that TaABL1 belonged to the AREB subfamily of the bZIP transcription factor family and was most closely related to ZmABI5 in maize and OsAREB2 in rice. Expression of TaABL1 was highly induced in wheat roots, stems, and leaves by ABA, drought, high salt, and low temperature stresses. TaABL1 was localized inside the nuclei of transformed wheat mesophyll protoplast. Overexpression of TaABL1 enhanced responses of transgenic plants to ABA and hastened stomatal closure under stress, thereby improving tolerance to multiple abiotic stresses. Furthermore, overexpression of TaABL1 upregulated or downregulated the expression of some stress-related genes controlling stomatal closure in transgenic plants under ABA and drought stress conditions, suggesting that TaABL1 might be a valuable genetic resource for transgenic molecular breeding.

  13. A wheat salinity-induced WRKY transcription factor TaWRKY93 confers multiple abiotic stress tolerance in Arabidopsis thaliana.

    PubMed

    Qin, Yuxiang; Tian, Yanchen; Liu, Xiuzhi

    2015-08-21

    Wheat is an important crop in the world. But most of the cultivars are salt sensitive, and often adversely affected by salt stress. WRKY transcription factors play a major role in plant responses to salt stress, but the effective salinity regulatory WRKYs identified in bread wheat are limited and the mechanism of salt stress tolerance is also not well explored. Here, we identified a salt (NaCl) induced class II WRKY transcription factor TaWRKY93. Its transcript level was strongly induced by salt (NaCl) and exogenous abscisic acid (ABA). Over-expression of TaWRKY93 in Arabidopsis thaliana enhanced salt (NaCl), drought, low temperature and osmotic (mannitol) stress tolerance, mainly demonstrated by transgenic plants forming longer primary roots or more lateral roots on MS plates supplemented with NaCl and mannitol individually, higher survival rate under drought and low temperature stress. Further, transgenic plants maintained a more proline content, higher relative water content and less electrolyte leakage than the wild type plants. The transcript abundance of a series of abiotic stress-related genes was up-regulated in the TaWRKY93 transgenic plants. In summary, TaWRKY93 is a new positive regulator of abiotic stress, it may increase salinity, drought and low temperature stress tolerance through enhancing osmotic adjustment, maintaining membrane stability and increasing transcription of stress related genes, and contribute to the superior agricultural traits of SR3 through promoting root development. It can be used as a candidate gene for wheat transgenic engineering breeding against abiotic stress. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Impact of biotic and abiotic factors on the expression of fungal effector-encoding genes in axenic growth conditions.

    PubMed

    Meyer, Michel; Bourras, Salim; Gervais, Julie; Labadie, Karine; Cruaud, Corinne; Balesdent, Marie-Hélène; Rouxel, Thierry

    2017-02-01

    In phytopathogenic fungi, the expression of hundreds of small secreted protein (SSP)-encoding genes is induced upon primary infection of plants while no or a low level of expression is observed during vegetative growth. In some species such as Leptosphaeria maculans, this coordinated in-planta upregulation of SSP-encoding genes expression relies on an epigenetic control but the signals triggering gene expression in-planta are unknown. In the present study, biotic and abiotic factors that may relieve suppression of SSP-encoding gene expression during axenic growth of L. maculans were investigated. Some abiotic factors (temperature, pH) could have a limited effect on SSP gene expression. In contrast, two types of cellular stresses induced by antibiotics (cycloheximide, phleomycin) activated strongly the transcription of SSP genes. A transcriptomic analysis to cycloheximide exposure revealed that biological processes such as ribosome biosynthesis and rRNA processing were induced whereas important metabolic pathways such as glycogen and nitrogen metabolism, glycolysis and tricarboxylic acid cycle activity were down-regulated. A quantitatively different expression of SSP-encoding genes compared to plant infection was also detected. Interestingly, the same physico-chemical parameters as those identified here for L. maculans effectors were identified to regulate positively or negatively the expression of bacterial effectors. This suggests that apoplastic phytopathogens may react to similar physiological parameters for regulation of their effector genes. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Abiotic and Biotic Factors Regulating Inter-Kingdom Engagement between Insects and Microbe Activity on Vertebrate Remains.

    PubMed

    Jordan, Heather R; Tomberlin, Jeffery K

    2017-05-24

    Abstract: A number of abiotic and biotic factors are known to regulate arthropod attraction, colonization, and utilization of decomposing vertebrate remains. Such information is critical when assessing arthropod evidence associated with said remains in terms of forensic relevance. Interactions are not limited to just between the resource and arthropods. There is another biotic factor that has been historically overlooked; however, with the advent of high-throughput sequencing, and other molecular techniques, the curtain has been pulled back to reveal a microscopic world that is playing a major role with regards to carrion decomposition patterns in association with arthropods. The objective of this publication is to review many of these factors and draw attention to their impact on microbial, specifically bacteria, activity associated with these remains as it is our contention that microbes serve as a primary mechanism regulating associated arthropod behavior.

  16. Abiotic and Biotic Factors Regulating Inter-Kingdom Engagement between Insects and Microbe Activity on Vertebrate Remains

    PubMed Central

    Jordan, Heather R.; Tomberlin, Jeffery K.

    2017-01-01

    A number of abiotic and biotic factors are known to regulate arthropod attraction, colonization, and utilization of decomposing vertebrate remains. Such information is critical when assessing arthropod evidence associated with said remains in terms of forensic relevance. Interactions are not limited to just between the resource and arthropods. There is another biotic factor that has been historically overlooked; however, with the advent of high-throughput sequencing, and other molecular techniques, the curtain has been pulled back to reveal a microscopic world that is playing a major role with regards to carrion decomposition patterns in association with arthropods. The objective of this publication is to review many of these factors and draw attention to their impact on microbial, specifically bacteria, activity associated with these remains as it is our contention that microbes serve as a primary mechanism regulating associated arthropod behavior. PMID:28538664

  17. Genome Wide Analysis of the Apple MYB Transcription Factor Family Allows the Identification of MdoMYB121 Gene Confering Abiotic Stress Tolerance in Plants

    PubMed Central

    Wang, Rong-Kai; Zhang, Rui-Fen; Hao, Yu-Jin

    2013-01-01

    The MYB proteins comprise one of the largest families of transcription factors (TFs) in plants. Although several MYB genes have been characterized to play roles in secondary metabolism, the MYB family has not yet been identified in apple. In this study, 229 apple MYB genes were identified through a genome-wide analysis and divided into 45 subgroups. A computational analysis was conducted using the apple genomic database to yield a complete overview of the MYB family, including the intron-exon organizations, the sequence features of the MYB DNA-binding domains, the carboxy-terminal motifs, and the chromosomal locations. Subsequently, the expression of 18 MYB genes, including 12 were chosen from stress-related subgroups, while another 6 ones from other subgroups, in response to various abiotic stresses was examined. It was found that several of these MYB genes, particularly MdoMYB121, were induced by multiple stresses. The MdoMYB121 was then further functionally characterized. Its predicted protein was found to be localized in the nucleus. A transgenic analysis indicated that the overexpression of the MdoMYB121 gene remarkably enhanced the tolerance to high salinity, drought, and cold stresses in transgenic tomato and apple plants. Our results indicate that the MYB genes are highly conserved in plant species and that MdoMYB121 can be used as a target gene in genetic engineering approaches to improve the tolerance of plants to multiple abiotic stresses. PMID:23950843

  18. Expression of the MYB transcription factor gene BplMYB46 affects abiotic stress tolerance and secondary cell wall deposition in Betula platyphylla.

    PubMed

    Guo, Huiyan; Wang, Yucheng; Wang, Liuqiang; Hu, Ping; Wang, Yanmin; Jia, Yuanyuan; Zhang, Chunrui; Zhang, Yu; Zhang, Yiming; Wang, Chao; Yang, Chuanping

    2017-01-01

    Plant MYB transcription factors control diverse biological processes, such as differentiation, development and abiotic stress responses. In this study, we characterized BplMYB46, an MYB gene from Betula platyphylla (birch) that is involved in both abiotic stress tolerance and secondary wall biosynthesis. BplMYB46 can act as a transcriptional activator in yeast and tobacco. We generated transgenic birch plants with overexpressing or silencing of BplMYB46 and subjected them to gain- or loss-of-function analysis. The results suggest that BplMYB46 improves salt and osmotic tolerance by affecting the expression of genes including SOD, POD and P5CS to increase both reactive oxygen species scavenging and proline levels. In addition, BplMYB46 appears to be involved in controlling stomatal aperture to reduce water loss. Overexpression of BplMYB46 increases lignin deposition, secondary cell wall thickness and the expression of genes in secondary cell wall formation. Further analysis indicated that BplMYB46 binds to MYBCORE and AC-box motifs and may directly activate the expression of genes involved in abiotic stress responses and secondary cell wall biosynthesis whose promoters contain these motifs. The transgenic BplMYB46-overexpressing birch plants, which have improved salt and osmotic stress tolerance, higher lignin and cellulose content and lower hemicellulose content than the control, have potential applications in the forestry industry. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  19. Abiotic factors control invasion by Argentine ants at the community scale.

    PubMed

    Menke, Sean B; Holway, David A

    2006-03-01

    1. A prominent and unresolved question in ecology concerns why communities differ in their susceptibility to invasion. While studies often emphasize biotic resistance, it is less widely appreciated how the physical environment affects community vulnerability to invasion. 2. In this study we performed field experiments to test how abiotic variation directly and indirectly influences the extent to which Linepithema humile Mayr (Argentine ants) invade seasonally dry environments in southern California. 3. In controlled and replicated experiments involving drip irrigation, we demonstrate (i) that elevated levels of soil moisture increased both the abundance of Argentine ants and their ability to invade native ant communities and (ii) that cessation of irrigation caused declines in the abundance of Argentine ants and led to their withdrawal from previously occupied areas. 4. Because drip irrigation stimulated plant growth, in an additional experiment we manipulated both soil moisture and plant cover to assess the direct vs. indirect effects of added water on the abundance of L. humile. 5. Local abundance of Argentine ants increased in irrigated plots but was 38% higher in irrigated plots with plants compared to irrigated plots where plant growth was suppressed. The results of this experiment thus argue for a direct role of soil moisture in influencing Argentine ant abundance but suggest that that the indirect effects of added water may also be important. 6. Our study illustrates more generally that fine-scale variation in the physical environment can control whether communities become invaded by non-native species and suggests that an understanding of community susceptibility to invasion will be improved by a better appreciation of interactions between the biotic and abiotic environment.

  20. The role of abiotic factors and pesticide levels on enzymatic activity in the freshwater mussel Anodonta cygnea at three different exposure sites.

    PubMed

    Robillard, Sophie; Beauchamp, Guy; Laulier, Marc

    2003-05-01

    Natural variation in abiotic factors, such as temperature and pH, probably influence the activity of enzymes used as potential biomarkers in bivalve mollusks to assess environmental contamination in the field. Changes in levels of an enzymatic biomarker may thus merely reflect natural variation in the annual physiological cycle of a species rather than exposure to contaminants. To investigate this issue, we documented the relationship between pesticide levels in water and three different enzymatic biomarkers over 1 year in enclosed populations of the freshwater unionid mussel Anodonta cygnea at three different sites of exposure. We considered the natural variation in temperature, pH and dissolved oxygen over the year and across the different sites as a potential correlate of enzymatic activity to disentangle the relative contribution of abiotic factors and pesticide levels. Pesticide levels varied among the three sites and over the course of the year. Catalase (CAT) and acetylcholinesterase activity (AChE) varied as a function of abiotic factors but showed no relation to pesticide levels. Glutathione S-transferase (GST) activity was also related to abiotic factors but also decreased with increases in total pesticide levels. The lack of activity induction or inhibition by pesticides and the natural variation in abiotic factors among sites and across time limits the use of CAT and AChE to assess environmental contamination in this species.

  1. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (Hymenoptera: Bethylidae).

    PubMed

    Wang, Xiaoyi; Wei, Ke; Yang, Zhongqi; Jennings, David E; Duan, Jian J

    2016-05-19

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. The percentage of winged female parasitoid progeny increased exponentially with temperature between 20 °C to 30 °C. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes. However, the percentage of male progeny increased significantly with the densities of maternal parasitoids. Our findings highlight the phenotypic partitioning of wing morphology and development in the parasitoid S. pupariae under varied environmental cues, and reveal the most favourable conditions for the production of winged females in this bethylid wasp. It is thus possible to increase winged female parasitoid production for the purposes of biological control by manipulation of biotic and abiotic conditions.

  2. Genome-wide characterization and analysis of bZIP transcription factor gene family related to abiotic stress in cassava

    PubMed Central

    Hu, Wei; Yang, Hubiao; Yan, Yan; Wei, Yunxie; Tie, Weiwei; Ding, Zehong; Zuo, Jiao; Peng, Ming; Li, Kaimian

    2016-01-01

    The basic leucine zipper (bZIP) transcription factor family plays crucial roles in various aspects of biological processes. Currently, no information is available regarding the bZIP family in the important tropical crop cassava. Herein, 77 bZIP genes were identified from cassava. Evolutionary analysis indicated that MebZIPs could be divided into 10 subfamilies, which was further supported by conserved motif and gene structure analyses. Global expression analysis suggested that MebZIPs showed similar or distinct expression patterns in different tissues between cultivated variety and wild subspecies. Transcriptome analysis of three cassava genotypes revealed that many MebZIP genes were activated by drought in the root of W14 subspecies, indicating the involvement of these genes in the strong resistance of cassava to drought. Expression analysis of selected MebZIP genes in response to osmotic, salt, cold, ABA, and H2O2 suggested that they might participate in distinct signaling pathways. Our systematic analysis of MebZIPs reveals constitutive, tissue-specific and abiotic stress-responsive candidate MebZIP genes for further functional characterization in planta, yields new insights into transcriptional regulation of MebZIP genes, and lays a foundation for understanding of bZIP-mediated abiotic stress response. PMID:26947924

  3. Effects of biotic and abiotic factors on phenotypic partitioning of wing morphology and development in Sclerodermus pupariae (Hymenoptera: Bethylidae)

    PubMed Central

    Wang, Xiaoyi; Wei, Ke; Yang, Zhongqi; Jennings, David E.; Duan, Jian J.

    2016-01-01

    Wing phenotype polymorphism is commonly observed in insects, yet little is known about the influence of environmental cues on the development or expression of the alternative phenotypes. Here, we report how both biotic and abiotic factors affect the wing morph differentiation of a bethylid parasitoid Sclerodermus pupariae. The percentage of winged female parasitoid progeny increased exponentially with temperature between 20 °C to 30 °C. Low intensity light and short-day photoperiod conditions also significantly induced the development of winged morphs. Interestingly, wingless maternal parasitoids produced more winged progeny. Furthermore, the degree of wing dimorphism was significantly influenced by the interactions between light intensity and maternal wing morphs. The percentage of winged female progeny was not significantly influenced by foundress densities, but increased significantly with parasitoid brood sizes. However, the percentage of male progeny increased significantly with the densities of maternal parasitoids. Our findings highlight the phenotypic partitioning of wing morphology and development in the parasitoid S. pupariae under varied environmental cues, and reveal the most favourable conditions for the production of winged females in this bethylid wasp. It is thus possible to increase winged female parasitoid production for the purposes of biological control by manipulation of biotic and abiotic conditions. PMID:27194095

  4. Heat shock factors in carrot: genome-wide identification, classification, and expression profiles response to abiotic stress.

    PubMed

    Huang, Ying; Li, Meng-Yao; Wang, Feng; Xu, Zhi-Sheng; Huang, Wei; Wang, Guang-Long; Ma, Jing; Xiong, Ai-Sheng

    2015-05-01

    Heat shock factors (HSFs) play key roles in the response to abiotic stress in eukaryotes. In this study, 35 DcHSFs were identified from carrot (Daucus carota L.) based on the carrot genome database. All 35 DcHSFs were divided into three classes (A, B, and C) according to the structure and phylogenetic relationships of four different plants, namely, Arabidopsis thaliana, Vitis vinifera, Brassica rapa, and Oryza sativa. Comparative analysis of algae, gymnosperms, and angiosperms indicated that the numbers of HSF transcription factors were related to the plant's evolution. The expression profiles of five DcHsf genes (DcHsf 01, DcHsf 02, DcHsf 09, DcHsf 10, and DcHsf 16), which selected from each subfamily (A, B, and C), were detected by quantitative real-time PCR under abiotic stresses (cold, heat, high salinity, and drought) in two carrot cultivars, D. carota L. cvs. Kurodagosun and Junchuanhong. The expression levels of DcHsfs were markedly increased by heat stress, except that of DcHsf 10, which was down regulated. The expression profiles of different DcHsfs in the same class also differed under various stress treatments. The expression profiles of these DcHsfs were also different in tissues of two carrot cultivars. This study is the first to identify and characterize the DcHSF family transcription factors in plants of Apiaceae using whole-genome analysis. The results of this study provide an in-depth understanding of the DcHSF family transcription factors' structure, function, and evolution in carrot.

  5. The Translation Initiation Factor 1A (TheIF1A) from Tamarix hispida Is Regulated by a Dof Transcription Factor and Increased Abiotic Stress Tolerance

    PubMed Central

    Yang, Guiyan; Yu, Lili; Wang, Yucheng; Wang, Chao; Gao, Caiqiu

    2017-01-01

    Eukaryotic translation initiation factor 1A (eIF1A) functions as an mRNA scanner and AUG initiation codon locator. However, few studies have clarified the role of eIF1A in abiotic stress. In this study, we cloned eIF1A (TheIF1A) from Tamarix hispida and found its expression to be induced by NaCl and polyethylene glycol (PEG) in roots, stems, and leaves. Compared to control, TheIF1A root expression was increased 187.63-fold when exposed to NaCl for 6 h, suggesting a potential abiotic stress response for this gene. Furthermore, transgenic tobacco plants overexpressing TheIF1A exhibited enhanced seed germination and a higher total chlorophyll content under salt and mannitol stresses. Increased superoxide dismutase, peroxidase, glutathione transferase and glutathione peroxidase activities, as well as decreased electrolyte leakage rates and malondialdehyde contents, were observed in TheIF1A-transgenic tobacco and T. hispida seedlings under salt and mannitol stresses. Histochemical staining suggested that TheIF1A improves reactive oxygen species (ROS) scavenging in plants. Moreover, TheIF1A may regulate expression of stress-related genes, including TOBLTP, GST, MnSOD, NtMPK9, poxN1, and CDPK15. Moreover, a 1352-bp promoter fragment of TheIF1A was isolated, and cis-elements were identified. Yeast one-hybrid assays showed that ThDof can specifically bind to the Dof motif present in the promoter. In addition, ThDof showed expression patterns similar to those of TheIF1A under NaCl and PEG stresses. These findings suggest the potential mechanism and physiological roles of TheIF1A. ThDof may be an upstream regulator of TheIF1A, and TheIF1A may function as a stress response regulator to improve plant salt and osmotic stress tolerance via regulation of associated enzymes and ROS scavenging, thereby reducing cell damage under stress conditions. PMID:28439284

  6. Effect of biotic and abiotic factors on diversity patterns of anthophyllous insect communities in a tropical mountain forest.

    PubMed

    Cuartas-Hernández, S E; Gómez-Murillo, L

    2015-06-01

    The determinants of diversity are a central issue in ecology, particularly in Andean forests that are known to be a major diversity hotspot for several taxa. We examined the effect of abiotic (elevation and precipitation) and biotic (flowering plant diversity) factors considered to be decisive causal factors of diversity patterns on anthophyllous insect communities on mountain forest. Sampling was carried out in 100-m transects at eight elevational levels and during a period of 8 months. All flowering plants in the understory and their flowering visitors were recorded. Species richness and diversity were estimated for each elevation and month. Diversity of flowering plants, elevation, and precipitation were used as independent variables in multiple regressions against insect diversity. The evaluated abiotic and biotic factors had contrasting effects on insect diversity: a significant decrease on insect diversity occurred at high elevation and dry months (i.e., threshold effect), while it showed a positive relationship with flowering plant diversity through time (i.e., linear effect), but not along elevation. Rapid turnover of species of both interacting guilds was observed every 100-m altitude and month. Local insect communities were also divided functionally depending on the plant family they visit. These results indicate that each insect community is distinctive among elevations and months and that diversity of flowering plants, precipitation, and elevation influence their structure and composition. Thus, conservation strategies should involve protection of forest cover at the whole elevation gradient, in order to preserve common and exclusive components of diversity and consequently, the mosaic of plant-pollinator interactions.

  7. Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

    PubMed Central

    Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

    2015-01-01

    Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (RA) and heterotrophic (RH) in total soil (RT) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.–Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of RH and RA to RT for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to RT, accounted for over 63% of RH. 3) AT and ST were significantly positively correlated with RT and its components (p<0.05), and were major factors affecting soil respiration. 4) Components of soil respiration were significantly different between two forest stands (p<0.05), indicating that vegetation types played a role in soil respiration and its components. PMID:25680112

  8. Quantifying components of soil respiration and their response to abiotic factors in two typical subtropical forest stands, southwest China.

    PubMed

    Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

    2015-01-01

    Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (RA) and heterotrophic (RH) in total soil (RT) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.-Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6 cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of RH and RA to RT for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to RT, accounted for over 63% of RH. 3) AT and ST were significantly positively correlated with RT and its components (p<0.05), and were major factors affecting soil respiration. 4) Components of soil respiration were significantly different between two forest stands (p<0.05), indicating that vegetation types played a role in soil respiration and its components.

  9. Factors influencing the abundance of Japanese encephalitis vectors in ricefields in India--I. Abiotic.

    PubMed

    Sunish, I P; Reuben, R

    2001-12-01

    Mosquitoes of the Culex vishnui subgroup (Diptera: Culicidae) are the most important vectors of Japanese encephalitis (JE) and ricefields are their most productive breeding sites in south India, where predominant species of this subgroup are Culex tritaeniorhynchus Giles, Cx. pseudovishnui Colless and Cx. vishnui Theobald sensu stricto. The relationship of 13 abiotic variables with the abundance of Cx. vishnui subgroup immatures was investigated in transplanted rice fields for 3 years (1991-94) covering three different crop seasons. The results from the multiple regression model suggested paddy height (- ve), water temperature (+ ve), dissolved oxygen (- ve), ammonia nitrogen (- ve) and nitrate nitrogen (+ ve) to be the best predictor variables associated with the immature abundance, nearly always consistent in their effects within and between seasons. Application of synthetic nitrogenous fertilizers to the rice fields was followed by a rise in concentration of ammonia nitrogen and a subsequent increase in nitrate nitrogen level in the rice field water, during which an increase in the density of larval instars was observed.

  10. Improved abiotic stress tolerance of bermudagrass by exogenous small molecules.

    PubMed

    Chan, Zhulong; Shi, Haitao

    2015-01-01

    As a widely used warm-season turfgrass in landscapes and golf courses, bermudagrass encounters multiple abiotic stresses during the growth and development. Physiology analysis indicated that abiotic stresses induced the accumulation of ROS and decline of photosynthesis, resulting in increased cell damage and inhibited growth. Proteomic and metabolomic approaches showed that antioxidant enzymes and osmoprotectant contents (sugar, sucrose, dehydrin, proline) were extensively changed under abiotic stress conditions. Exogenous application of small molecules, such as ABA, NO, CaCl2, H2S, polyamine and melatonin, could effectively alleviate damages caused by multiple abiotic stresses, including drought, salt, heat and cold. Based on high through-put RNA seq analysis, genes involved in ROS, transcription factors, hormones, and carbohydrate metabolisms were largely enriched. The data indicated that small molecules induced the accumulation of osmoprotectants and antioxidants, kept cell membrane integrity, increased photosynthesis and kept ion homeostasis, which protected bermudagrass from damages caused by abiotic stresses.

  11. Influence of biotic and abiotic factors on the allelopathic activity of the cyanobacterium Cylindrospermopsis raciborskii strain LEGE 99043.

    PubMed

    Antunes, Jorge T; Leão, Pedro N; Vasconcelos, Vítor M

    2012-10-01

    Allelopathy is considered to be one of the factors underlying the global expansion of the toxic cyanobacterium Cylindrospermopsis raciborskii. Although the production and release of allelopathic compounds by cyanobacteria is acknowledged to be influenced by environmental parameters, the response of C. raciborskii remains generally unrecognized. Here, the growth and allelopathic potential of C. raciborskii strain LEGE 99043 towards the ubiquitous microalga Ankistrodesmus falcatus were analyzed under different biotic and abiotic conditions. Filtrates from C. raciborskii cultures growing at different cell densities displayed broad inhibitory activity. Moreover, higher temperature, higher light intensity as well phosphate limitation further enhanced this activity. The distinct and comprehensive patterns of inhibition verified during the growth phase, and under the tested parameters, suggest the action of several, still unidentified allelopathic compounds. It is expectable that the observed increase in allelopathic activity can result in distinct ecological advantages to C. raciborskii.

  12. Identification of 30 MYB transcription factor genes and analysis of their expression during abiotic stress in peanut (Arachis hypogaea L.).

    PubMed

    Chen, Na; Yang, Qingli; Pan, Lijuan; Chi, Xiaoyuan; Chen, Mingna; Hu, Dongqing; Yang, Zhen; Wang, Tong; Wang, Mian; Yu, Shanlin

    2014-01-01

    The MYB superfamily constitutes one of the most abundant groups of transcription factors and plays central roles in developmental processes and defense responses in plants. In the work described in this article, 30 unique peanut MYB genes that contained full-length cDNA sequences were isolated. The 30 genes were grouped into three categories: one R1R2R3-MYB, nine R2R3-MYBs and 20 MYB-related members. The sequence composition of the R2 and R3 repeats was conserved among the nine peanut R2R3-MYB proteins. Phylogenetic comparison of the members of this superfamily between peanut and Arabidopsis revealed that the putative functions of some peanut MYB proteins were clustered into the Arabidopsis functional groups. Expression analysis during abiotic stress identified a group of MYB genes that responded to at least one stress treatment. This is the first comprehensive study of the MYB gene family in peanut. © 2013.

  13. Abiotic factors influencing biomass accumulation of green tide causing Ulva spp. on Pyropia culture rafts in the Yellow Sea, China.

    PubMed

    Keesing, John K; Liu, Dongyan; Shi, Yajun; Wang, Yujue

    2016-04-15

    Annually recurrent green-tides in the Yellow Sea have been shown to result from direct disposal into the sea of fouling Ulva from Pyropia aquaculture. The role abiotic factors play in Ulva biomass accumulation on rafts was studied to find ways to mitigate this problem. Dissolved inorganic nitrogen (DIN) was very high at all sites, but the highest Ulva biomass was associated with the lowest DIN and anthropogenic N. Under luxuriant background nutrient conditions, variability in temperature and periods of emersion, rather than pH, light and salinity determined Ulva biomass. Two dominant species of Ulva displayed differing tolerances to temperature and desiccation which helped explain why Ulva prolifera dominates floating green-tides. Rather than trying to mitigate green-tides only by reducing nutrient pollution, an earlier harvest of Pyropia in southern Jiangsu Province especially before temperatures increase greatly above 10°C during April, could reduce the biomass of U. prolifera disposed from rafts.

  14. EsDREB2B, a novel truncated DREB2-type transcription factor in the desert legume Eremosparton songoricum, enhances tolerance to multiple abiotic stresses in yeast and transgenic tobacco

    PubMed Central

    2014-01-01

    Background Dehydration-Responsive Element-Binding Protein2 (DREB2) is a transcriptional factor which regulates the expression of several stress-inducible genes. DREB2-type proteins are particularly important in plant responses to drought, salt and heat. DREB2 genes have been identified and characterized in a variety of plants, and DREB2 genes are promising candidate genes for the improvement of stress tolerance in plants. However, little is known about these genes in plants adapted to water-limiting environments. Results In this study, we describe the characterization of EsDREB2B, a novel DREB2B gene identified from the desert plant Eremosparton songoricum. Phylogenetic analysis and motif prediction indicate that EsDREB2B encodes a truncated DREB2 polypeptide that belongs to a legume-specific DREB2 group. In E. songoricum, EsDREB2B transcript accumulation was induced by a variety of abiotic stresses, including drought, salinity, cold, heat, heavy metal, mechanical wounding, oxidative stress and exogenous abscisic acid (ABA) treatment. Consistent with the predicted role as a transcription factor, EsDREB2B was targeted to the nucleus of onion epidermal cells and exhibited transactivation activity of a GAL4-containing reporter gene in yeast. In transgenic yeast, overexpression of EsDREB2B increased tolerance to multiple abiotic stresses. Our findings indicate that EsDREB2B can enhance stress tolerance in other plant species. Heterologous expression of EsDREB2B in tobacco showed improved tolerance to multiple abiotic stresses, and the transgenic plants exhibited no reduction in foliar growth. We observed that EsDREB2B is a functional DREB2-orthologue able to influence the physiological and biochemical response of transgenic tobacco to stress. Conclusions Based upon these findings, EsDREB2B encodes an abiotic stress-inducible, transcription factor which confers abiotic stress-tolerance in yeast and transgenic tobacco. PMID:24506952

  15. Three ERF transcription factors from Chinese wild grapevine Vitis pseudoreticulata participate in different biotic and abiotic stress-responsive pathways.

    PubMed

    Zhu, Ziguo; Shi, Jiangli; Xu, Weirong; Li, Huie; He, Mingyang; Xu, Yan; Xu, Tengfei; Yang, Yazhou; Cao, Jiangling; Wang, Yuejin

    2013-07-01

    Ethylene response factor (ERF) functions as an important plant-specific transcription factor in regulating biotic and abiotic stress response through interaction with various stress pathways. We previously obtained three ERF members, VpERF1, VpERF2, and VpERF3 from a highly powdery mildew (PM)-resistant Chinese wild Vitis pseudoreticulata cDNA full-length library. To explore their functions associated with plant disease resistance or biotic stress, we report here to characterize three ERF members from this library. PM-inoculation analysis on three different resistant grapevine genotypes revealed that three VpERFs displayed significant responses, but a different expression pattern. Over-expression of VpERF1, VpERF2, and VpERF3 in transgenic tobacco plants demonstrated that VpERF2 and VpERF3 enhanced resistance to both bacterial pathogen Ralstonia solanacearum and fungal pathogen Phytophtora parasitica var. nicotianae Tucker. Importantly, VpERF1-overexpressing transgenic Arabidopsis plants increased susceptibility toward these pathogens. Investigation on drought, cold, and heat treatments suggested, VpERF2 was distinctly induced, whereas VpERF3 displayed a very weak response and VpERF1 was distinctly induced by drought and heat. Concurrently, VpERF3 was significantly induced by salicylic acid (SA), methyl jasmonate (MeJA), and ET. Our results showed that the three VpERFs from Chinese wild V. pseudoreticulata play different roles in either preventing disease progression via regulating the expression of relevant defense genes, or directly involving abiotic stress responsive pathways.

  16. Characterization of a eukaryotic translation initiation factor 5A homolog from Tamarix androssowii involved in plant abiotic stress tolerance.

    PubMed

    Wang, Liuqiang; Xu, Chenxi; Wang, Chao; Wang, Yucheng

    2012-07-26

    The eukaryotic translation initiation factor 5A (eIF5A) promotes formation of the first peptide bond at the onset of protein synthesis. However, the function of eIF5A in plants is not well understood. In this study, we characterized the function of eIF5A (TaeIF5A1) from Tamarix androssowii. The promoter of TaeIF5A1 with 1,486 bp in length was isolated, and the cis-elements in the promoter were identified. A WRKY (TaWRKY) and RAV (TaRAV) protein can specifically bind to a W-box motif in the promoter of TaeIF5A1 and activate the expression of TaeIF5A1. Furthermore, TaeIF5A1, TaWRKY and TaRAV share very similar expression pattern and are all stress-responsive gene that functions in the abscisic acid (ABA) signaling pathway, indicating that they are components of a single regulatory pathway. Transgenic yeast and poplar expressing TaeIF5A1 showed elevated protein levels combined with improved abiotic stresses tolerance. Furthermore, TaeIF5A1-transformed plants exhibited enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, lower electrolyte leakage and higher chlorophyll content under salt stress. These results suggested that TaeIF5A1 is involved in abiotic stress tolerance, and is likely regulated by transcription factors TaWRKY and TaRAV both of which can bind to the W-box motif. In addition, TaeIF5A1 may mediate stress tolerance by increasing protein synthesis, enhancing ROS scavenging by improving SOD and POD activities, and preventing chlorophyll loss and membrane damage. Therefore, eIF5A may play an important role in plant adaptation to changing environmental conditions.

  17. Characterization of a eukaryotic translation initiation factor 5A homolog from Tamarix androssowii involved in plant abiotic stress tolerance

    PubMed Central

    2012-01-01

    Background The eukaryotic translation initiation factor 5A (eIF5A) promotes formation of the first peptide bond at the onset of protein synthesis. However, the function of eIF5A in plants is not well understood. Results In this study, we characterized the function of eIF5A (TaeIF5A1) from Tamarix androssowii. The promoter of TaeIF5A1 with 1,486 bp in length was isolated, and the cis-elements in the promoter were identified. A WRKY (TaWRKY) and RAV (TaRAV) protein can specifically bind to a W-box motif in the promoter of TaeIF5A1 and activate the expression of TaeIF5A1. Furthermore, TaeIF5A1, TaWRKY and TaRAV share very similar expression pattern and are all stress-responsive gene that functions in the abscisic acid (ABA) signaling pathway, indicating that they are components of a single regulatory pathway. Transgenic yeast and poplar expressing TaeIF5A1 showed elevated protein levels combined with improved abiotic stresses tolerance. Furthermore, TaeIF5A1-transformed plants exhibited enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, lower electrolyte leakage and higher chlorophyll content under salt stress. Conclusions These results suggested that TaeIF5A1 is involved in abiotic stress tolerance, and is likely regulated by transcription factors TaWRKY and TaRAV both of which can bind to the W-box motif. In addition, TaeIF5A1 may mediate stress tolerance by increasing protein synthesis, enhancing ROS scavenging by improving SOD and POD activities, and preventing chlorophyll loss and membrane damage. Therefore, eIF5A may play an important role in plant adaptation to changing environmental conditions. PMID:22834699

  18. Biotic and abiotic factors influencing zooplankton vertical distribution in Lake Huron

    USGS Publications Warehouse

    Nowicki, Carly J.; Bunnell, David B.; Armenio, Patricia M.; Warner, David M.; Vanderploeg, Henry A.; Cavaletto, Joann F.; Mayer, Christine M.; Adams, Jean V.

    2017-01-01

    The vertical distribution of zooplankton can have substantial influence on trophic structure in freshwater systems, particularly by determining spatial overlap for predator/prey dynamics and influencing energy transfer. The zooplankton community in some of the Laurentian Great Lakes has undergone changes in composition and declines in total biomass, especially after 2003. Mechanisms underlying these zooplankton changes remain poorly understood, in part, because few studies have described their vertical distributions during daytime and nighttime conditions or evaluated the extent to which predation, resources, or environmental conditions could explain their distribution patterns. Within multiple 24-h periods during July through October 2012 in Lake Huron, we conducted daytime and nighttime sampling of zooplankton, and measured food (chlorophyll-a), temperature, light (Secchi disk depth), and planktivory (biomass of Bythotrephes longimanus and Mysis diluviana). We used linear mixed models to determine whether the densities for 22 zooplankton taxa varied between day and night in the epi-, meta-, and hypolimnion. For eight taxa, higher epilimnetic densities were observed at night than during the day; general linear models revealed these patterns were best explained by Mysis diluviana (four taxa), Secchi disk depth (three taxa), epilimnetic water temperature (three taxa), chlorophyll (one taxon), and biomass of Bythotrephes longimanus (one taxon). By investigating the potential effects of both biotic and abiotic variables on the vertical distribution of crustacean zooplankton and rotifers, we provide descriptions of the Lake Huron zooplankton community and discuss how future changes in food web dynamics or climate change may alter zooplankton distribution in freshwater environments.

  19. Effects of biotic and abiotic factors on the oxygen content of green sea turtle nests during embryogenesis.

    PubMed

    Chen, Chiu-Lin; Wang, Chun-Chun; Cheng, I-Jiunn

    2010-10-01

    Several biotic and abiotic factors can influence nest oxygen content during embryogenesis. Several of these factors were determined during each developmental stage of green sea turtle embryos on Wan-an Island, Penghu Archipelago, Taiwan. We examined oxygen content in 7 nests in 2007 and 11 in 2008. Oxygen in the adjacent sand, total and viable clutch sizes, air, sand and nest temperatures, and sand characters of each nest were also determined. Oxygen content was lower in late stages than in the early and middle stages. It was also lower in the middle layer than in the upper and bottom layers. Nest temperature showed opposite trends, reaching its maximum value in late stages of development. Nest oxygen content was influenced by fraction of viable eggs, total clutch sizes, sand temperatures, maximum nest temperature and maximum change in the nest temperature during incubation. Clutch size during embryogenesis was the most influential factor overall. However, the major influential factors were different for different developmental stages. In the first half of the incubation, the development rate was low, and the change in the nest oxygen content was influenced mainly by the clutch size. During the second half, the rapid embryonic development rate became the dominant factor, and hatchling activities caused even greater oxygen consumption during the last stage of development.

  20. Biotic and abiotic factors investigated in two Drosophila species - evidence of both negative and positive effects of interactions on performance.

    PubMed

    Ørsted, Michael; Schou, Mads Fristrup; Kristensen, Torsten Nygaard

    2017-01-06

    Multiple environmental factors acting in concert can interact and strongly influence population fitness and ecosystem composition. Studies investigating interactions usually involve only two environmental factors; most frequently a chemical and another abiotic factor such as a stressful temperature. Here we investigate the effects of three environmental factors: temperature, an insecticide (dimethoate) and interspecific co-occurrence. We expose two naturally co-occurring species of Drosophila (D. hydei and D. melanogaster) to the different environments during development and examine the consequences on several performance measures. Results are highly species and trait specific with evidence of two- and three-way interactions in approximately 30% of all cases, suggesting that additive effects of combined environmental factors are most common, and that interactions are not universal. To provide more informative descriptions of complex interactions we implemented re-conceptualised definitions of synergism and antagonism. We found approximately equal proportions of synergistic and antagonistic interactions in both species, however the effects of interactions on performance differed between the two. Furthermore, we found negative impacts on performance in only 60% of interactions, thus our study also reveals a high proportion of cases with positive effects of interactions.

  1. Novel DREB A-5 subgroup transcription factors from desert moss (Syntrichia caninervis) confers multiple abiotic stress tolerance to yeast.

    PubMed

    Li, Haiyan; Zhang, Daoyuan; Li, Xiaoshuang; Guan, Kaiyun; Yang, Honglan

    2016-05-01

    Syntrichia caninervis Mitt. is a typical desiccation tolerant moss from a temperate desert which has been a good resource for stress tolerant gene isolation. Dehydration responsive element binding proteins (DREBs) was proven to play an important role in responding to abiotic stress, which has been identified in many plants, and were rarely reported in moss. In this study, we cloned ten DREB genes from S. caninervis, and investigated their abiotic stress response and stress tolerance. The results showed that ten ScDREB proteins belonged to the A-5 sub-group of the DREB sub-family. Six genes, ScDREB1, ScDREB2, ScDREB4, ScDREB6, ScDREB7, and ScDREB8 were involved in the ABA-dependent signal pathway and the desiccation, salt, and cold stress response. ScDREB3 also responded to desiccation, salt, and cold stresses, but was insensitive to ABA treatment. Another gene, ScDREB5, was involved in an ABA-independent cold stress-responsive signal pathway. Two genes, ScDREB9 and ScDREB10, responded slightly or had no response to neither stress factor or ABA treatment. We transformed four typical genes into yeast cells and the stress tolerance ability of transgenic yeast was evaluated. The results showed that ScDREB3 and ScDREB5 enhanced the yeast's cold and salt tolerance. ScDREB8 and ScDREB10 conferred the osmotic, salt, cold, and high temperature stresses tolerance, especially for osmotic and salt stresses. Our results indicated that A-5 sub-group DREB genes in S. caninervis played important roles in abiotic stresses response and enhanced stress tolerance to transgenic yeast. To our knowledge, this is the first report on DREB genes characterization from desiccation tolerant moss, and this study will not only provide insight into the molecular mechanisms of S. caninervis adaptation to environmental stresses, but also provides valuable gene candidates for plant molecular breeding.

  2. Comparisons of stemflow and its bio-/abiotic influential factors between two xerophytic shrub species

    NASA Astrophysics Data System (ADS)

    Yuan, Chuan; Gao, Guangyao; Fu, Bojie

    2017-03-01

    Stemflow transports nutrient-enriched precipitation to the rhizosphere and functions as an efficient terrestrial flux in water-stressed ecosystems. However, its ecological significance has generally been underestimated because it is relatively limited in amount, and the biotic mechanisms that affect it have not been thoroughly studied at the leaf scale. This study was conducted during the 2014 and 2015 rainy seasons at the northern Loess Plateau of China. We measured the branch stemflow volume (SFb), shrub stemflow equivalent water depth (SFd), stemflow percentage of incident precipitation (SF %), stemflow productivity (SFP), funnelling ratio (FR), the meteorological characteristics and the plant traits of branches and leaves of C. korshinskii and S. psammophila. This study evaluated stemflow efficiency for the first time with the combined results of SFP and FR, and sought to determine the inter- and intra-specific differences of stemflow yield and efficiency between the two species, as well as the specific bio-/abiotic mechanisms that affected stemflow. The results indicated that C. korshinskii had a greater stemflow yield and efficiency at all precipitation levels than that of S. psammophila. The largest inter-specific difference generally occurred at the 5-10 mm branches during rains of ≤ 2 mm. Precipitation amount was the most influential meteorological characteristic that affected stemflow yield and efficiency in these two endemic shrub species. Branch angle was the most influential plant trait on FR. For SFb, stem biomass and leaf biomass were the most influential plant traits for C. korshinskii and S. psammophila, respectively. For SFP of these two shrub species, leaf traits (the individual leaf area) and branch traits (branch size and biomass allocation pattern) had a great influence during lighter rains ≤ 10 mm and heavier rains > 15 mm, respectively. The lower precipitation threshold to start stemflow allowed C. korshinskii (0.9 mm vs. 2

  3. Identification and expression of the WRKY transcription factors of Carica papaya in response to abiotic and biotic stresses.

    PubMed

    Pan, Lin-Jie; Jiang, Ling

    2014-03-01

    The WRKY transcription factor (TF) plays a very important role in the response of plants to various abiotic and biotic stresses. A local papaya database was built according to the GenBank expressed sequence tag database using the BioEdit software. Fifty-two coding sequences of Carica papaya WRKY TFs were predicted using the tBLASTn tool. The phylogenetic tree of the WRKY proteins was classified. The expression profiles of 13 selected C. papaya WRKY TF genes under stress induction were constructed by quantitative real-time polymerase chain reaction. The expression levels of these WRKY genes in response to 3 abiotic and 2 biotic stresses were evaluated. TF807.3 and TF72.14 are upregulated by low temperature; TF807.3, TF43.76, TF12.199 and TF12.62 are involved in the response to drought stress; TF9.35, TF18.51, TF72.14 and TF12.199 is involved in response to wound; TF12.199, TF807.3, TF21.156 and TF18.51 was induced by PRSV pathogen; TF72.14 and TF43.76 are upregulated by SA. The regulated expression levels of above eight genes normalized against housekeeping gene actin were significant at probability of 0.01 levels. These WRKY TFs could be related to corresponding stress resistance and selected as the candidate genes, especially, the two genes TF807.3 and TF12.199, which were regulated notably by four stresses respectively. This study may provide useful information and candidate genes for the development of transgenic stress tolerant papaya varieties.

  4. Plant distribution and stand characteristics in brackish marshes: Unravelling the roles of abiotic factors and interspecific competition

    NASA Astrophysics Data System (ADS)

    Carus, Jana; Heuner, Maike; Paul, Maike; Schröder, Boris

    2017-09-01

    Due to increasing pressure on estuarine marshes from sea level rise and river training, there is a growing need to understand how species-environment relationships influence the zonation and growth of tidal marsh vegetation. In the present study, we investigated the distribution and stand characteristics of the two key brackish marsh species Bolboschoenus maritimus and Phragmites australis in the Elbe estuary together with several abiotic habitat factors. We then tested the effect of these habitat factors on plant growth and zonation with generalised linear models (GLMs). Our study provides detailed information on the importance of single habitat factors and their interactions for controlling the distribution patterns and stand characteristics of two key marsh species. Our results suggest that flow velocity is the main factor influencing species distribution and stand characteristics and together with soil-water salinity even affects the inundation tolerance of the two specie investigated here. Additionally, inundation height and duration as well as interspecific competition helped explain the distribution patterns and stand characteristics. By identifying the drivers of marsh zonation and stand characteristics and quantifying their effects, this study provides useful information for evaluating a future contribution of tidal marsh vegetation to ecosystem-based shore protection.

  5. The SsDREB Transcription Factor from the Succulent Halophyte Suaeda salsa Enhances Abiotic Stress Tolerance in Transgenic Tobacco.

    PubMed

    Zhang, Xu; Liu, Xiaoxue; Wu, Lei; Yu, Guihong; Wang, Xiue; Ma, Hongxiang

    2015-01-01

    Dehydration-responsive element-binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. In this study, a novel cDNA encoding DREB transcription factor, designated SsDREB, was isolated from succulent halophyte Suaeda salsa. This protein was classified in the A-6 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Yeast one-hybrid assays showed that SsDREB protein specifically binds to the DRE sequence and could activate the expression of reporter genes in yeast, suggesting that the SsDREB protein was a CBF/DREB transcription factor. Real-time RT-PCR showed that SsDREB was significantly induced under salinity and drought stress. Overexpression of SsDREB cDNA in transgenic tobacco plants exhibited an improved salt and drought stress tolerance in comparison to the nontransformed controls. The transgenic plants revealed better growth, higher chlorophyll content, and net photosynthesis rate, as well as higher level of proline and soluble sugars. The semiquantitative PCR of transgenics showed higher expression of stress-responsive genes. These data suggest that the SsDREB transcription factor is involved in the regulation of salt stress tolerance in tobacco by the activation of different downstream gene expression.

  6. The SsDREB Transcription Factor from the Succulent Halophyte Suaeda salsa Enhances Abiotic Stress Tolerance in Transgenic Tobacco

    PubMed Central

    Zhang, Xu; Liu, Xiaoxue; Wu, Lei; Yu, Guihong; Wang, Xiue; Ma, Hongxiang

    2015-01-01

    Dehydration-responsive element-binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. In this study, a novel cDNA encoding DREB transcription factor, designated SsDREB, was isolated from succulent halophyte Suaeda salsa. This protein was classified in the A-6 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Yeast one-hybrid assays showed that SsDREB protein specifically binds to the DRE sequence and could activate the expression of reporter genes in yeast, suggesting that the SsDREB protein was a CBF/DREB transcription factor. Real-time RT-PCR showed that SsDREB was significantly induced under salinity and drought stress. Overexpression of SsDREB cDNA in transgenic tobacco plants exhibited an improved salt and drought stress tolerance in comparison to the nontransformed controls. The transgenic plants revealed better growth, higher chlorophyll content, and net photosynthesis rate, as well as higher level of proline and soluble sugars. The semiquantitative PCR of transgenics showed higher expression of stress-responsive genes. These data suggest that the SsDREB transcription factor is involved in the regulation of salt stress tolerance in tobacco by the activation of different downstream gene expression. PMID:26504772

  7. Disentangling the relative importance of host tree community, abiotic environment and spatial factors on ectomycorrhizal fungal assemblages along an elevation gradient.

    PubMed

    Matsuoka, Shunsuke; Mori, Akira S; Kawaguchi, Eri; Hobara, Satoru; Osono, Takashi

    2016-05-01

    Recent studies have shown that changes in community compositions of ectomycorrhizal (ECM) fungi along elevation gradients are mainly affected by changes in host tree communities and/or in abiotic environments. However, few studies have taken the effects of processes related to fungal dispersal (i.e. spatial processes) into account and distinguished the effects of host community, abiotic environment and spatial processes on community composition along elevation gradients. This has left unclear the relative importance of these factors in structuring the ECM community assemblages. To address this, we investigated the community composition of ECM fungi along an elevation gradient in northern Japan with 454 meta-barcoding. We found that the community composition of ECM fungi changed along the elevation and that all three factors jointly affected the compositional changes. We separated the magnitude of importance of the three factors in structuring ECM fungal communities and found that most of the spatial variation in ECM fungal community was explained by host communities and abiotic environments. Our results suggest that while biotic and/or abiotic environments can be important factors in determining the ECM fungal community composition along an elevation gradient, spatial processes may also be a primary determinant. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. A wheat WRKY transcription factor TaWRKY10 confers tolerance to multiple abiotic stresses in transgenic tobacco.

    PubMed

    Wang, Chen; Deng, Pengyi; Chen, Liulin; Wang, Xiatian; Ma, Hui; Hu, Wei; Yao, Ningcong; Feng, Ying; Chai, Ruihong; Yang, Guangxiao; He, Guangyuan

    2013-01-01

    WRKY transcription factors are reported to be involved in defense regulation, stress response and plant growth and development. However, the precise role of WRKY transcription factors in abiotic stress tolerance is not completely understood, especially in crops. In this study, we identified and cloned 10 WRKY genes from genome of wheat (Triticum aestivum L.). TaWRKY10, a gene induced by multiple stresses, was selected for further investigation. TaWRKY10 was upregulated by treatment with polyethylene glycol, NaCl, cold and H2O2. Result of Southern blot indicates that the wheat genome contains three copies of TaWRKY10. The TaWRKY10 protein is localized in the nucleus and functions as a transcriptional activator. Overexpression of TaWRKY10 in tobacco (Nicotiana tabacum L.) resulted in enhanced drought and salt stress tolerance, mainly demonstrated by the transgenic plants exhibiting of increased germination rate, root length, survival rate, and relative water content under these stress conditions. Further investigation showed that transgenic plants also retained higher proline and soluble sugar contents, and lower reactive oxygen species and malonaldehyde contents. Moreover, overexpression of the TaWRKY10 regulated the expression of a series of stress related genes. Taken together, our results indicate that TaWRKY10 functions as a positive factor under drought and salt stresses by regulating the osmotic balance, ROS scavenging and transcription of stress related genes.

  9. A Wheat WRKY Transcription Factor TaWRKY10 Confers Tolerance to Multiple Abiotic Stresses in Transgenic Tobacco

    PubMed Central

    Chen, Liulin; Wang, Xiatian; Ma, Hui; Hu, Wei; Yao, Ningcong; Feng, Ying; Chai, Ruihong; Yang, Guangxiao; He, Guangyuan

    2013-01-01

    WRKY transcription factors are reported to be involved in defense regulation, stress response and plant growth and development. However, the precise role of WRKY transcription factors in abiotic stress tolerance is not completely understood, especially in crops. In this study, we identified and cloned 10 WRKY genes from genome of wheat (Triticum aestivum L.). TaWRKY10, a gene induced by multiple stresses, was selected for further investigation. TaWRKY10 was upregulated by treatment with polyethylene glycol, NaCl, cold and H2O2. Result of Southern blot indicates that the wheat genome contains three copies of TaWRKY10. The TaWRKY10 protein is localized in the nucleus and functions as a transcriptional activator. Overexpression of TaWRKY10 in tobacco (Nicotiana tabacum L.) resulted in enhanced drought and salt stress tolerance, mainly demonstrated by the transgenic plants exhibiting of increased germination rate, root length, survival rate, and relative water content under these stress conditions. Further investigation showed that transgenic plants also retained higher proline and soluble sugar contents, and lower reactive oxygen species and malonaldehyde contents. Moreover, overexpression of the TaWRKY10 regulated the expression of a series of stress related genes. Taken together, our results indicate that TaWRKY10 functions as a positive factor under drought and salt stresses by regulating the osmotic balance, ROS scavenging and transcription of stress related genes. PMID:23762295

  10. Perception of Bradyrhizobium japonicum Nod factor by soybean [Glycine max (L.) Merr.] root hairs under abiotic stress conditions.

    PubMed

    Duzan, H M; Zhou, X; Souleimanov, A; Smith, D L

    2004-12-01

    Suboptimal growth conditions, such as low rhizosphere temperature, high salinity, and low pH can negatively affect the rhizobia-legume symbioses, resulting in poor nodulation and lower amounts of nitrogen fixed. Early stages of the Bradyrhizobium japonicum-soybean [Glycine max (L.) Merr.] symbiosis, such as excretion of genistein (the plant-to-bacteria signal) and infection initiation can be inhibited by abiotic stresses; however, the effect on early events modulated by Nod factors (bacteria-to-plant signalling), particularly root hair deformations is unknown. Thus, the objective of this study was to evaluate the perception of Nod factor by soybean root hairs under three stress conditions: low temperature, low pH, and high salinity. Three experiments were conducted using a 1:1 ratio of Nod Bj-V (C(18:1), MeFuc) and Nod Bj-V (Ac, C(16:0), MeFuc). Nod factor induced four types of root hair deformation (HAD), wiggling, bulging, curling, and branching. Under optimal experimental conditions root hair response to the three levels of Nod factor tested (10(-6), 10(-8), and 10(-10) M) was dose-dependent. The highest frequency of root hair deformations was elicited by the 10(-6) M level. Root hair deformation decreased with temperature (25, 17, and 15 degrees C), low pH, and high salinity. Nod factor concentration did not interact with either low temperature or pH. However, salinity strongly inhibited HAD responses to increases in Nod factor concentration. Thus, the addition of higher levels of Nod factor is able to overcome the effects of low pH and temperature stress, but not salinity.

  11. Elasticity of population growth with respect to the intensity of biotic or abiotic driving factors.

    PubMed

    Lee, Charlotte T

    2016-12-19

    Demographic analysis can elucidate how driving factors, such as climate or species interactions,affect populations. One important question is how growth would respond to future changes in the mean intensity of a driving factor or in its variability, such as might be expected in a fluctuating and shifting climate. Here I develop an approach to computing new stochastic elasticities to address this question. The linchpin of this novel approach is the multidimensional demographic difference that expresses how a population responds to change in the driving factor between two discrete levels of intensity. I use this difference to design a perturbation matrix that links data from common empirical sampling schemes with rigorous theory for stochastic elasticities. Although the starting point is a difference, the products of this synthesis are true derivatives: they are elasticity with respect to the mean intensity of a driving factor, and elasticity with respect to variability in a driving factor. Applying the methods to published data, I demonstrate how these new elasticities can shed light on growth rate response within and at the boundary of the previously observed range of the driving factor, thus helpfully indicating nonlinearity in the observed and in the potential future response. The stochastic approach simplifies in a fixed environment, yielding a compact formula for deterministic elasticity to a driving factor. This article is protected by copyright. All rights reserved.

  12. Invasion biology in non-free-living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda, Entocytheridae)

    PubMed Central

    Mestre, Alexandre; Aguilar-Alberola, Josep A; Baldry, David; Balkis, Husamettin; Ellis, Adam; Gil-Delgado, Jose A; Grabow, Karsten; Klobučar, Göran; Kouba, Antonín; Maguire, Ivana; Martens, Andreas; Mülayim, Ayşegül; Rueda, Juan; Scharf, Burkhard; Soes, Menno; S Monrós, Juan; Mesquita-Joanes, Francesc

    2013-01-01

    In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This

  13. Invasion biology in non-free-living species: interactions between abiotic (climatic) and biotic (host availability) factors in geographical space in crayfish commensals (Ostracoda, Entocytheridae).

    PubMed

    Mestre, Alexandre; Aguilar-Alberola, Josep A; Baldry, David; Balkis, Husamettin; Ellis, Adam; Gil-Delgado, Jose A; Grabow, Karsten; Klobučar, Göran; Kouba, Antonín; Maguire, Ivana; Martens, Andreas; Mülayim, Ayşegül; Rueda, Juan; Scharf, Burkhard; Soes, Menno; S Monrós, Juan; Mesquita-Joanes, Francesc

    2013-12-01

    In invasion processes, both abiotic and biotic factors are considered essential, but the latter are usually disregarded when modeling the potential spread of exotic species. In the framework of set theory, interactions between biotic (B), abiotic (A), and movement-related (M) factors in the geographical space can be hypothesized with BAM diagrams and tested using ecological niche models (ENMs) to estimate A and B areas. The main aim of our survey was to evaluate the interactions between abiotic (climatic) and biotic (host availability) factors in geographical space for exotic symbionts (i.e., non-free-living species), using ENM techniques combined with a BAM framework and using exotic Entocytheridae (Ostracoda) found in Europe as model organisms. We carried out an extensive survey to evaluate the distribution of entocytherids hosted by crayfish in Europe by checking 94 European localities and 12 crayfish species. Both exotic entocytherid species found, Ankylocythere sinuosa and Uncinocythere occidentalis, were widely distributed in W Europe living on the exotic crayfish species Procambarus clarkii and Pacifastacus leniusculus, respectively. No entocytherids were observed in the remaining crayfish species. The suitable area for A. sinuosa was mainly restricted by its own limitations to minimum temperatures in W and N Europe and precipitation seasonality in circum-Mediterranean areas. Uncinocythere occidentalis was mostly restricted by host availability in circum-Mediterranean regions due to limitations of P. leniusculus to higher precipitation seasonality and maximum temperatures. The combination of ENMs with set theory allows studying the invasive biology of symbionts and provides clues about biogeographic barriers due to abiotic or biotic factors limiting the expansion of the symbiont in different regions of the invasive range. The relative importance of abiotic and biotic factors on geographical space can then be assessed and applied in conservation plans. This

  14. The effect of abiotic factors on the toxicity of cypermethrin against the snail Lymnaea acuminata in the control of fascioliasis.

    PubMed

    Singh, V; Singh, D K

    2009-03-01

    Every month during the year 2006-2007, the 24, 48, 72 and 96 h LC50 values of a molluscicide, cypermethrin, were determined for a snail Lymnaea acuminata, with concomitant estimation of levels of temperature, pH, dissolved oxygen and carbon dioxide and electrical conductivity, both in control and test water. On the basis of a 24 h toxicity assay, it was noted that LC50 values of 10.39, 10.90 and 11.19 mg l- 1 during the months of May, June and July, respectively, were most effective in killing the snails, while the molluscicide was least effective in the month of January, when its 24 h LC50 was 65.84 mg l- 1.There was a significant positive correlation between LC50 of cypermethrin and levels of dissolved O2/pH of water in corresponding months. On the contrary, a negative correlation was observed between LC50 and dissolved CO2/temperature of test water in the same months. In order to ascertain that such a relationship between toxicity and abiotic factors is not coincidental, the nervous tissue of the snail was assayed for the activity of acetylcholinesterase (AChE), acid phosphatase (ACP) and alkaline phosphatase (ALP) to sublethal concentrations (40% and 80%) of 24 h LC50 during each of the 12 months of the same year. The findings confirmed that abiotic factors indeed influence toxicity of cypermethrin in the snail. A significant positive rank correlation between AChE, ACP and ALP activity did exist following exposure to the corresponding sublethal concentrations. Moreover, there was a maximum inhibition of 61.29 and 76.16% of AChE and ACP, respectively, in snails exposed to 80% of the 24 h LC50 in the month of May. A similar treatment caused a maximum inhibition of 70.53% of ALP activity in the month of June. This work shows conclusively that the best time to control the snail population with cypermethrin is during the months of May and June.

  15. Seasonal biotic and abiotic factors affecting hunting strategy in free-living Saharan sand vipers, Cerastes vipera.

    PubMed

    Horesh, Sefi J A; Sivan, Jaim; Rosenstrauch, Avi; Tesler, Itay; Degen, A Allan; Kam, Michael

    2017-02-01

    Sit-and-wait ambushing and active hunting are two strategies used by predators to capture prey. In snakes, hunting strategy is conserved phylogenetically; most species employ only one strategy. Active hunters encounter and capture more prey but invest more energy in hunting and have higher risks of being predated. This trade-off is important to small predators. The small Cerastes vipera employs both modes of hunting, which is unlike most viperids which use only sit-and wait ambushing. This species hibernates in October and emerges in April. Energy intake should be high prior to hibernation to overcome the non-feeding hibernation period and for reproduction on their emergence. We predicted that more individuals would hunt actively towards hibernation and an abiotic factor would trigger this response. Furthermore, since more energy is required for active hunting, we predicted that snakes in good body condition would use active hunting to a greater extent than snakes in poor body condition. To test our predictions, we tracked free-living snakes year round and determined their hunting strategy, estimated their body condition index (BCI), and calculated circannual parameters of day length as environmental cues known to affect animal behaviour. Two novel findings emerged in this study, namely, hunting strategy was affected significantly by 1) the circannual change in day length and 2) by BCI. The proportion of active hunters increased from 5% in April to over 30% in October and BCI of active foragers was higher than that of sit-and-wait foragers and, therefore, our predictions were supported. The entrainment between the proportion of active hunting and the abiotic factor is indicative of an adaptive function for choosing a hunting strategy. A trend was evident among life stages. When all life stages were present (September-October), the proportion of active foragers increased with age: 0.0% among neonates, 18.2% among juveniles and 31.4% among adults. We concluded that

  16. A special member of the rice SRO family, OsSRO1c, mediates responses to multiple abiotic stresses through interaction with various transcription factors.

    PubMed

    You, Jun; Zong, Wei; Du, Hao; Hu, Honghong; Xiong, Lizhong

    2014-04-01

    SIMILAR TO RCD ONE (SRO) is a plant-specific gene family involved in development and abiotic stress responses. SRO proteins are characterized by containing poly (ADP-ribose) polymerase catalytic (PARP) and C-terminal RCD1-SRO-TAF4 domains, and can be classified into two groups and five subgroups on the basis of their PARP domain. Expression analysis of rice SRO genes in response to various abiotic stresses showed that OsSRO1c, a rice SRO gene which functions downstream of the stress-responsive transcription factor SNAC1, is the major stress-responsive gene in the rice SRO family. The ossro1c-1 mutant showed resistance not only to chloroplastic oxidative stress, but also to apoplastic oxidative stress. However, the ossro1c-1 mutant and artificial microRNA-OsSRO1c transgenic rice were significantly impaired in cold tolerance. When compared with the well-characterized Arabidopsis SRO protein radical-induced cell death 1 (RCD1), OsSRO1c has considerable variation in the protein sequence, and the two genes exhibit different expression profiles under abiotic stresses. Furthermore, ossro1c-1 and rcd1 showed different responses to multiple abiotic stresses. By screening an Arabidopsis transcription factor library, 29 transcription factors interacted with OsSRO1c in yeast, but only two of these transcription factors were reported to interact with RCD1, which may partly explain the different responses of the two mutants under various stresses. The data presented in this report provide important clues for further elucidating the molecular and biochemical mechanisms of OsSRO1c in mediating responses to multiple abiotic stresses.

  17. Abiotic stresses and endophyte effects

    USDA-ARS?s Scientific Manuscript database

    Abiotic stresses consist of nonorganismal, nonpathogenic factors that inhibit plant function. Tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] is widely symbiotic with a naturally occurring endophytic fungus [Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon, and Hanlin], which con...

  18. Effect of abiotic factors on initiation of red flour beetle (Coleoptera: Tenebrionidae) flight

    USDA-ARS?s Scientific Manuscript database

    Traps baited with pheromones are used to monitor the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), populations in flour mills to aid in making pest management decisions, but the factors that influence T. castaneum flight aren’t fully understood. We investigated the impa...

  19. Influence of different abiotic and biotic factors on the metalaxyl and carbofuran dissipation.

    PubMed

    Bermúdez-Couso, Alipio; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel; Fernández-Calviño, David

    2013-03-01

    Metalaxyl and carbofuran dissipation was studied in response to different factors (soil bacterial communities, light irradiation, presence of an inorganic culture medium and presence of soil) and combinations of these factors in short-term experiments (48 h). The soil microbial communities have no effect on metalaxyl or carbofuran dissipation in the time scale employed. Light irradiation and soil promote metalaxyl and carbofuran dissipation by photodegradation and adsorption, respectively. However, photodegradation has a stronger effect on metalaxyl and carbofuran dissipation than the adsorption of the pesticides in the soil. The addition of the culture medium have no direct effect on pesticide dissipation, degradation by microbial communities or adsorption but its presence greatly increased photodegradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Herbivory and abiotic factors affect population dynamics of Arabidopsis thaliana in a sand dune area.

    PubMed

    Arany, A Mosleh; de Jong, T J; van der Meijden, E

    2005-09-01

    Population dynamics of the annual plant Arabidopsis thaliana (L.) Heynh. were studied in a natural habitat of this species on the coastal dunes of the Netherlands. The main objective was to elucidate factors controlling population dynamics and the relative importance of factors affecting final population density. Permanent plots were established and plants were mapped to obtain data on survival and reproductive performance of each individual, with special attention to herbivore damage. In experimental plots we studied how watering, addition of nutrients, artificial disturbance, and natural herbivores affected survival and growth. Mortality was low during autumn and early winter and high at the time of stem elongation, between February and April. A key factor analysis showed a high correlation between mortality from February to April and total mortality. The specialist weevils Ceutorhyncus atomus and C. contractus (Curculionidae) were identified as the major insect herbivores on A. thaliana, reducing seed production by more than 40 %. These herbivores acted in a plant size-dependent manner, attacking a greater fraction of the fruits on large plants. While mortality rates were not affected by density, fecundity decreased with density, although the effect was small. Adding water reduced mortality in rosette and flowering plant stages. Soil disturbance did not increase seed germination, but did have a significant positive effect on survival of rosette and flowering plants. Seed production of A. thaliana populations varied greatly between years, leading to population fluctuations, with a small role for density-dependent fecundity and plant size-dependent herbivory.

  1. Identification and expression of C2H2 transcription factor genes in Carica papaya under abiotic and biotic stresses.

    PubMed

    Jiang, Ling; Pan, Lin-jie

    2012-06-01

    C2H2 proteins belong to a group of transcription factors (TFs) existing as a superfamily that plays important roles in defense responses and various other physiological processes in plants. The present study aimed to screen for and identify C2H2 proteins associated with defense responses to abiotic and biotic stresses in Carica papaya L. Data were collected for 47,483 papaya-expressed sequence tags (ESTs). The full-length cDNA nucleotide sequences of 87 C2H2 proteins were predicated by BioEdit. All 91 C2H2 proteins were aligned, and a phylogenetic tree was constructed using DNAman. The expression levels of 42 C2H2 were analyzed under conditions of salt stress by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Methyl jasmonate treatment rapidly upregulated ZF(23.4) and ZF(30,912.1) by 18.6- and 21.7-fold, respectively. ZF(1.3), ZF(138.44), ZF(94.49), ZF(29.160), and ZF(20.206) were found to be downregulated after low temperature treatment at very significant levels (p < 0.01). ZF(23.4), ZF(161.1), and ZF(30,912.1) were upregulated while ZF1.3, ZF(158.1), ZF(249.5), ZF(138.44), ZF(94.49), ZF(29.160), and ZF(20.206) were significantly downregulated by Spermine treatment. ZF(23.4) was upregulated while ZF(1.3), ZF(249.5), ZF(94.94), ZF(29.160), ZF(138.44), and ZF(20.206) were significantly repressed after SA treatment. ZF(23.4) and ZF(30,912.1) were significantly upregulated after sap inoculation with papaya ringspot virus pathogen. ZF(30,912.1) was subcellularly localized in the nucleus by a transgenic fusion of pBS-ZF(30,912.1)-GFP into the protoplast of papaya. The results of the present study showed that ZF(30,912.1) could be an important TF that mediates responses to abiotic and biotic stresses in papaya.

  2. Heat shock factors in rice (Oryza sativa L.): genome-wide expression analysis during reproductive development and abiotic stress.

    PubMed

    Chauhan, Harsh; Khurana, Neetika; Agarwal, Pinky; Khurana, Paramjit

    2011-08-01

    Plants respond to heat stress by enhancing the expression of genes encoding heat shock protein (HSPs) genes through activation of heat shock factors (HSFs) which interact with heat shock elements present in the promoter of HSP genes. Plant HSFs have been divided into three conserved classes viz A, B and C. In the present study, a detailed analysis has been done of all rice HSFs, along with their spliced variants. Their chromosomal localization reveals that six HSFs are segmentally duplicated and four pairs of these segmentally duplicated HSF encoding genes show pseudo-functionalization. Expression profiling through microarray and quantitative real-time PCR showed that eight OsHsfs express at a higher level during seed development, while six HSFs are up-regulated in all the abiotic stresses studied. The expression of OsHsfA2a gene in particular was greatly stimulated by heat stress in both root and shoot tissues and also during panicle and seed development. OsHsfA3 was found more responsive to cold and drought stress, while OsHsfA7 and OsHsfA9 showed developing seed-specific expression. This study also revealed that spliced variants generally accumulated at a higher level in all the tissues examined. Different hormones/elicitors like ABA, brassinosteroids and salicylic acid also alter OsHsf gene expression. Calcium in combination with heat stress elevated further the level of HSF transcripts. Expression analysis by both microarray and real-time RT-PCR revealed a unique stable constitutive expression of OsHsfA1 across all the tissues and stresses. A detailed in silico analysis involving identification of unidentified domains has been done by MEME-motif tool in their full-length proteins as well as in DNA-binding domains. Analysis of 1 kb putative promoter region revealed presence of tissue-specific, abiotic stress and hormone-related cis-acting elements, correlating with expression under stress conditions.

  3. Divergent Responses of Ecosystem Water and Carbon Fluxes to Meteorological Drought are Controlled by Both Abiotic and Biotic Factors

    NASA Astrophysics Data System (ADS)

    Wang, M.; Chen, Y.

    2016-12-01

    Drought is one of the dominant disturbances to the ecosystems, which might be more pervasive and severe in the future. Even though several studies have been focused on the impacts of water stress on the water and carbon cycles, our understanding of ecosystem responses to drought is still limited, especially for inter-annual droughts. By using 24 Ameriflux sites across the continent, covering 6 different plant functional types and more than six year observations for each site, this study indicated that both abiotic and biotic factors contribute to the ecosystem responses to droughts. Results showed that deciduous broadleaf forest seems more sensitive to the inter-annual drought and its variability of evapotranspiration could be as high as 14.5 mm while non-forest lands (e.g. grasslands and shrubs) are less sensitive, with standard deviation about 3 mm. As for the gross primary products, the ecosystems have similar responses during the growing season but some sites are more influenced by the dryness / wetness in the previous seasons, which seems independent of plant functional types. Impacts of pre-season conditions could be as much as 43% by using partial correlations. The study implies that both plant functional types and climate conditions could affect the responses of ecosystem to the inter-annual meteorological droughts.

  4. Combined effects of Corexit EC 9500A with secondary abiotic and biotic factors in the rotifer Brachionus plicatilis.

    PubMed

    Williams, Michael B; Powell, Mickie L; Watts, Stephen A

    2016-10-01

    We examined lethality and behavioral effects of Corexit EC 9500A (C-9500A) exposure on the model marine zooplankton Brachionus plicatilis singularly and in combination with abiotic and biotic factors. C-9500A exposure at standard husbandry conditions (17.5ppt, 24°C, 200 rotifer*mL(-1) density) identified the 24h median lethal concentration, by Probit analysis, to be 107ppm for cultured B. plicatilis. Rotifers surviving exposure to higher concentrations (100 and 150ppm) exhibited a decreased swimming velocity and a reduced net to gross movement ratio. Significant interaction between C-9500A exposure and temperature or salinity was observed. Upper thermal range was reduced and maximal salinity stress was seen as ca. 25ppt. Increased or decreased nutritional availability over the exposure period did not significantly alter mortality of B. plicatilis populations at the concentrations tested. Results from this study may be useful for predicting possible outcomes on marine zooplankton following dispersant application under diverse natural conditions.

  5. Wind as an abiotic factor of Colorado potato beetle (Coleoptera: Chrysomelidae) flight take-off activity under field conditions.

    PubMed

    Boiteau, G; Mccarthy, P C; MacKinley, P D

    2010-10-01

    The flight take-off activity of Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), was significantly higher at a landscape-protected than at semiexposed and exposed sites in a 2-yr field study. In both years, mean daylight temperature, solar radiation, and relative humidity were generally similar at all sites, but wind speed was lower at the protected site than at the exposed sites. Results suggest that wind was the limiting abiotic factor for flight take-off at the exposed site. Caged beetles exposed to constant wind speeds of 3.4, 4.7, and 7.0 m/s showed a significant corresponding decrease in number of flight take-off. There was no cumulative effect of wind exposure on the readiness of the beetles to fly, suggesting that wind acts as a physical barrier to flight take-off. It should be possible to reduce Colorado potato beetle flight dispersal by selecting fields most exposed to wind over landscape-protected fields when rotating potato, Solanum tuberosum L., crops.

  6. Dominant repression by Arabidopsis transcription factor MYB44 causes oxidative damage and hypersensitivity to abiotic stress.

    PubMed

    Persak, Helene; Pitzschke, Andrea

    2014-02-13

    In any living species, stress adaptation is closely linked with major changes of the gene expression profile. As a substrate protein of the rapidly stress-induced mitogen-activated protein kinase MPK3, Arabidopsis transcription factor MYB44 likely acts at the front line of stress-induced re-programming. We recently characterized MYB44 as phosphorylation-dependent positive regulator of salt stress signaling. Molecular events downstream of MYB44 are largely unknown. Although MYB44 binds to the MBSII element in vitro, it has no discernible effect on MBSII-driven reporter gene expression in plant co-transfection assays. This may suggest limited abundance of a synergistic co-regulator. MYB44 carries a putative transcriptional repression (Ethylene responsive element binding factor-associated Amphiphilic Repression, EAR) motif. We employed a dominant repressor strategy to gain insights into MYB44-conferred stress resistance. Overexpression of a MYB44-REP fusion markedly compromised salt and drought stress tolerance--the opposite was seen in MYB44 overexpression lines. MYB44-mediated resistance likely results from induction of tolerance-enhancing, rather than from repression of tolerance-diminishing factors. Salt stress-induced accumulation of destructive reactive oxygen species is efficiently prevented in transgenic MYB44, but accelerated in MYB44-REP lines. Furthermore, heterologous overexpression of MYB44-REP caused tissue collapse in Nicotiana. A mechanistic model of MAPK-MYB-mediated enhancement in the antioxidative capacity and stress tolerance is proposed. Genetic engineering of MYB44 variants with higher trans-activating capacity may be a means to further raise stress resistance in crops.

  7. [Variation characteristic in soil respiration of apple orchard and its biotic and abiotic influencing factors].

    PubMed

    Wang, Rui; Guo, Sheng-Li; Liu, Qing-Fang; Zhang, Yan-Jun; Jiang, Ji-Shao; Guo, Hui-Min; Li, Ru-Jian

    2014-05-01

    To evaluate the orchard variability of soil respiration and the response of soil respiration to its influencing factors is helpful for a deep understanding about the effects of converting cropland to apple orchard. A field experiment was conducted in the Changwu State Key Agro-Ecological Station. Soil respiration, soil temperature, soil moisture and roots biomasses were periodically measured in a mature apple orchard during 2011 and 2012. Soil respiration decreased as the distance from the trunk increased. The cumulative soil respiration in the 0.5 m-distance from the trunk was 20% and 31% higher than that in the 2 m-distance from the trunk, respectively in 2011 and 2012. The temperature sensitivity of soil respiration (Q10) was relatively lower in the 2 m-distance than that in the 0. 5 m-distance in both years. Soil temperature and soil moisture were slightly higher in the 2 m-distance, but there was no significant difference between the 2 m-distance and the 0. 5 m-distance. Soil respiration and soil temperature showed a significant exponential relationship, but there was no positive correlation between soil moisture and soil respiration. Soil temperature changes can explain seasonal variation of soil respiration well, but it could not explain its spatial variability. Root density was an important factor for the spatial variability of soil respiration and Q15. Variation of soil respiration coefficient was 23% -31%. Therefore, the distance from the trunk should be considered when estimating orchards soil respiration.

  8. Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland.

    PubMed

    He, Wei; Choi, Ilhwan; Lee, Jung-Joon; Hur, Jin

    2016-02-15

    In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-CL(-1), respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS+BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands.

  9. Overexpression of PgDREB2A transcription factor enhances abiotic stress tolerance and activates downstream stress-responsive genes.

    PubMed

    Agarwal, Parinita; Agarwal, Pradeep K; Joshi, Arvind J; Sopory, Sudhir K; Reddy, Malireddy K

    2010-02-01

    The DREB transcription factors comprise conserved ERF/AP2 DNA-binding domain, bind specifically to DRE/CRT motif and regulate abiotic stress mediated gene expression. In this study we show that PgDREB2A from Pennisetum glaucum is a powerful transcription factor to engineer multiple stress tolerance in tobacco plants. The PgDREB2A protein lacks any potential PEST sequence, which is known to act as a signal peptide for protein degradation. Therefore, the transgenic tobacco plants were raised using full-length cDNA without modification. The transgenics exhibited enhanced tolerance to both hyperionic and hyperosmotic stresses. At lower concentration of NaCl and mannitol, seed germination and seedling growth was similar in WT and transgenic, however at higher concentration germination in WT decreased significantly. D15 and D46 lines showed 4-fold higher germination percent at 200 mM NaCl. At 400 mM mannitol seed germination in WT was completely arrested, whereas in transgenic line it was more than 50%. Seedlings of D15 and D46 lines showed better growth like leaf area, root number, root length and fresh weight compared to wild type for both the stresses. The quantitative Real time PCR of transgenic showed higher expression of downstream genes NtERD10B, HSP70-3, Hsp18p, PLC3, AP2 domain TF, THT1, LTP1 and heat shock (NtHSF2) and pathogen-regulated (NtERF5) factors with different stress treatments.

  10. Influence of abiotic factors on cathemeral activity: the case of Eulemur fulvus collaris in the littoral forest of Madagascar.

    PubMed

    Donati, Giuseppe; Borgognini-Tarli, Silvana M

    2006-01-01

    The role environmental factors play in influencing circadian rhythms in natural habitats is still poorly described in primates, especially for those taxa with an activity cycle extended over the 24-hour cycle. In this paper, we elucidate the importance of abiotic factors in entraining the activity of cathemeral primates, focussing on results from a long-term study of Eulemur fulvus collaris (collared brown lemur) in south-eastern Malagasy littoral forest. Two groups of lemurs were followed for 60 whole-day and 59 whole-night observation periods over 14 months. Diurnal and nocturnal observations were equally distributed among moon phases and seasons. Temperature and humidity were recorded hourly by automatic data loggers. The littoral forest has a climatic environment where rainfall and humidity are uncorrelated with temperature and photoperiod. Diurnal and nocturnal activity varied seasonally, with the former increasing significantly with extended day length and the latter increasing significantly with shortened day length. Dusk seemed to act as a primary zeitgeber for these lemurs, coordinating the onset of evening activity throughout the entire year. Lunar phase and the nocturnal luminosity index correlated positively with the duration of nocturnal activity and negatively with the length of diurnal activity. Temperature was positively associated with diurnal activity but did not seem to influence lemur rhythms at night. Finally, lemur nocturnal activity significantly decreased when levels of humidity and rainfall were high. Cathemeral biorhythm is triggered by zeitgebers and influenced by masking factors. The activity of collared brown lemurs appears to be seasonally influenced by photoperiod and directly modulated by nocturnal ambient luminosity. These results are discussed by comparing data from other cathemeral species living in various climatic situations.

  11. Cork oak vulnerability to fire: the role of bark harvesting, tree characteristics and abiotic factors.

    PubMed

    Catry, Filipe X; Moreira, Francisco; Pausas, Juli G; Fernandes, Paulo M; Rego, Francisco; Cardillo, Enrique; Curt, Thomas

    2012-01-01

    Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently debarked individuals) and decreased with increasing bark thickness until cork was 3-4 cm thick. This bark thickness corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help estimating the impact of fire and to support management decisions. The results suggested that an appropriate management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak ecosystems.

  12. Cork Oak Vulnerability to Fire: The Role of Bark Harvesting, Tree Characteristics and Abiotic Factors

    PubMed Central

    Catry, Filipe X.; Moreira, Francisco; Pausas, Juli G.; Fernandes, Paulo M.; Rego, Francisco; Cardillo, Enrique; Curt, Thomas

    2012-01-01

    Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently debarked individuals) and decreased with increasing bark thickness until cork was 3–4 cm thick. This bark thickness corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help estimating the impact of fire and to support management decisions. The results suggested that an appropriate management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak ecosystems. PMID:22787521

  13. Controls of evapotranspiration and CO2 fluxes from scots pine by surface conductance and abiotic factors.

    PubMed

    Zha, Tianshan; Li, Chunyi; Kellomäki, Seppo; Peltola, Heli; Wang, Kai-Yun; Zhang, Yuqing

    2013-01-01

    Evapotranspiration (E) and CO2 flux (Fc ) in the growing season of an unusual dry year were measured continuously over a Scots pine forest in eastern Finland, by eddy covariance techniques. The aims were to gain an understanding of their biological and environmental control processes. As a result, there were obvious diurnal and seasonal changes in E, Fc , surface conductance (gc ), and decoupling coefficient (Ω), showing similar trends to those in radiation (PAR) and vapour pressure deficit (δ). The maximum mean daily values (24-h average) for E, Fc , gc , and Ω were 1.78 mmol m(-2) s(-1), -11.18 µmol m(-2) s(-1), 6.27 mm s(-1), and 0.31, respectively, with seasonal averages of 0.71 mmol m(-2) s(-1), -4.61 µmol m(-2) s(-1), 3.3 mm s(-1), and 0.16. E and Fc were controlled by combined biological and environmental variables. There was curvilinear dependence of E on gc and Fc on gc . Among the environmental variables, PAR was the most important factor having a positive linear relationship to E and curvilinear relationship to Fc , while vapour pressure deficit was the most important environmental factor affecting gc . Water use efficiency was slightly higher in the dry season, with mean monthly values ranging from 6.67 to 7.48 μmol CO2 (mmol H2O)(-1) and a seasonal average of 7.06 μmol CO2 (μmol H2O)(-1). Low Ω and its close positive relationship with gc indicate that evapotranspiration was sensitive to surface conductance. Mid summer drought reduced surface conductance and decoupling coefficient, suggesting a more biotic control of evapotranspiration and a physiological acclimation to dry air. Surface conductance remained low and constant under dry condition, supporting that a constant value of surface constant can be used for modelling transpiration under drought condition.

  14. Controls of Evapotranspiration and CO2 Fluxes from Scots Pine by Surface Conductance and Abiotic Factors

    PubMed Central

    Zha, Tianshan; Li, Chunyi; Kellomäki, Seppo; Peltola, Heli; Wang, Kai-Yun; Zhang, Yuqing

    2013-01-01

    Evapotranspiration (E) and CO2 flux (Fc) in the growing season of an unusual dry year were measured continuously over a Scots pine forest in eastern Finland, by eddy covariance techniques. The aims were to gain an understanding of their biological and environmental control processes. As a result, there were obvious diurnal and seasonal changes in E, Fc, surface conductance (gc), and decoupling coefficient (Ω), showing similar trends to those in radiation (PAR) and vapour pressure deficit (δ). The maximum mean daily values (24-h average) for E, Fc, gc, and Ω were 1.78 mmol m−2 s−1, −11.18 µmol m−2 s−1, 6.27 mm s−1, and 0.31, respectively, with seasonal averages of 0.71 mmol m−2 s−1, −4.61 µmol m−2 s−1, 3.3 mm s−1, and 0.16. E and Fc were controlled by combined biological and environmental variables. There was curvilinear dependence of E on gc and Fc on gc. Among the environmental variables, PAR was the most important factor having a positive linear relationship to E and curvilinear relationship to Fc, while vapour pressure deficit was the most important environmental factor affecting gc. Water use efficiency was slightly higher in the dry season, with mean monthly values ranging from 6.67 to 7.48 μmol CO2 (mmol H2O)−1 and a seasonal average of 7.06 μmol CO2 (μmol H2O)−1. Low Ω and its close positive relationship with gc indicate that evapotranspiration was sensitive to surface conductance. Mid summer drought reduced surface conductance and decoupling coefficient, suggesting a more biotic control of evapotranspiration and a physiological acclimation to dry air. Surface conductance remained low and constant under dry condition, supporting that a constant value of surface constant can be used for modelling transpiration under drought condition. PMID:23894401

  15. ENAC1, a NAC transcription factor, is an early and transient response regulator induced by abiotic stress in rice (Oryza sativa L.).

    PubMed

    Sun, Hui; Huang, Xi; Xu, Xingjun; Lan, Hongxia; Huang, Ji; Zhang, Hong-Sheng

    2012-10-01

    The plant-specific NAC (NAM, ATAF, and CUC)-domain proteins play important roles in plant development and stress responses. In this research, a full-length cDNA named ENAC1 (early NAC-domain protein induced by abiotic stress 1) was isolated from rice. ENAC1 possess one NAC domain in the N-terminus. Comparative time-course expression analysis indicated that ENAC1 expression, similar with OsDREB1A, was induced very quickly by various abiotic stresses including salt, drought, cold, and exogenous abscisic acid. However, the induction of ENAC1 by abiotic stress was transient and lasted up to 3 h, whereas that of OsDREB1A maintained longer. The promoter sequence of ENAC1 harbors several cis-elements including ABA response elements, but the well-known dehydration responsive element/C-repeat element is absent. The ENAC1-GFP (green fluorescent protein) fusion protein was localized in the nucleus of rice protoplast cell. Yeast hybrid assays revealed that ENAC1 was a transcription activator and bound to NAC recognition sequence (NACRS). Co-expression analysis suggested that ENAC1 co-expressed with a number of stress-related genes. Taken together, ENAC1 may be an early transcription activator of stress responses and function in the regulation of NACRS-mediated gene expression under abiotic stress.

  16. Ostreopsis cf. ovata dynamics in the NW Mediterranean Sea in relation to biotic and abiotic factors.

    PubMed

    Carnicer, Olga; Guallar, Carles; Andree, Karl B; Diogène, Jorge; Fernández-Tejedor, Margarita

    2015-11-01

    An expansion of the distribution of Ostreopsis cf. ovata, a dinoflagellate which produces palytoxin-like compounds, has been reported in recent years. Economical and social interests are affected by blooms, as they are responsible for respiratory and skin problems in humans and may cause damage to marine organisms. In order to identify the most influential environmental factors that trigger proliferations of O. cf. ovata in the area of the adjacent shallow rocky coast of the Ebro Delta (NW Mediterranean Sea) a three-year survey was performed on the metaphytic microalgae community growing on the macrophytes Jania rubens and Corallina elongata. Small-size diatoms were more abundant than dinoflagellates; O. cf. ovata was identified as the only species present from the genus. Seawater temperature was the primary driver defining the ecological niche of O. cf. ovata. Freshwater and groundwater fluxes were more pronounced in southern than in northern sites, which may have resulted in a distinct O. cf. ovata spatial distribution, with the highest records of abundance and more frequent blooms in the north. In consequence, negative correlations between the abundance of O. cf. ovata and nitrate concentrations and significant positive correlation with salinity were observed. The temporal pattern of O. cf. ovata dynamics from mid-July to early-November is probably due to the fact that this species is observed only above a certain threshold temperature of seawater. Metaphytic cells of O. cf. ovata were smaller in the northern site than in the south, possibly as a result of an increase in cell division, coinciding with higher abundance, and this could be an indicator of favorable conditions. Toxicity in planktonic cells was negatively correlated with cell abundance in the water column, achieving maximum concentrations of 25pg. PLTX eqcell(-1).

  17. The impact of abiotic factors (temperature and glucose) on physicochemical properties of lipids from Yersinia pseudotuberculosis.

    PubMed

    Bakholdina, S I; Sanina, N M; Krasikova, I N; Popova, O B; Solov'eva, T F

    2004-12-01

    The impact of the availability of glucose in nutrition medium and growth temperature on the composition and thermotropic behavior of lipids from Yersinia pseudotuberculosis (Enterobacteriaceae) was studied. Y. pseudotuberculosis was grown in nutrition broth (NB) with/without glucose at 8 and 37 degrees C, corresponding to the temperatures of saprophytic and parasitic phases of this bacterium life. The decrease of phosphatidylethanolamine, phosphatidylglycerol and unsaturated fatty acids and the parallel increase of lysophosphatidylethanolamine and diphosphatidylglycerol and saturated and cyclopropane acids were the most significant changes with temperature in bacterial phospholipid (PL) classes and fatty acids, respectively. Glucose did not effect the direction of temperature-induced changes in the contents of PLs, fatty acids, however it enhanced (for PLs) or diminished (for fatty acids) intensity of these changes. The thermally induced transitions of lipids were studied by differential scanning calorimetry (DSC). It was revealed that the addition of glucose to NB induced a sharp shift of DSC thermograms to lower temperatures in the "warm" variants of bacteria. The peak maximum temperature (Tmax) of thermal transitions dropped from 50 to 26 degrees C that is the optimal growth temperature of Y. pseudotuberculosis. Tmax of total lipids of the cells grown at 8 degrees C without glucose in NB was equal to growth temperature that corresponded to the classical mechanism of homeoviscous adaptation of bacteria. An addition of glucose to NB at this growth temperature caused the subsequent reduction of Tmax to -8 degrees C, while the temperature ranges of thermograms were not substantially changed. So, not only the temperature growth of bacteria, but also the presence of glucose in NB can modify the physical state of lipids from Y. pseudotuberculosis. In this case, both factors affect additively. It is suggested that glucose influences some membrane-associated proteins and

  18. Effect of biotic and abiotic factors on in vitro proliferation, encystment, and excystment of Pfiesteria piscicida.

    PubMed

    Saito, Keiko; Drgon, Tomás; Krupatkina, Danara N; Drgonova, Jana; Terlizzi, Daniel E; Mercer, Natalia; Vasta, Gerardo R

    2007-10-01

    Pfiesteria spp. are mixotrophic armored dinoflagellates populating the Atlantic coastal waters of the United States. They have been a focus of intense research due to their reported association with several fish mortality events. We have now used a clonal culture of Pfiesteria piscicida and several new environmental isolates to describe growth characteristics, feeding, and factors contributing to the encystment and germination of the organism in both laboratory and environmental samples. We also discuss applied methods of detection of the different morphological forms of Pfiesteria in environmental samples. In summary, Pfiesteria, when grown with its algal prey, Rhodomonas sp., presents a typical growth curve with lag, exponential, and stationary phases, followed by encystment. The doubling time in exponential phase is about 12 h. The profiles of proliferation under a standard light cycle and in the dark were similar, although the peak cell densities were markedly lower when cells were grown in the dark. The addition of urea, chicken manure, and soil extracts did not enhance Pfiesteria proliferation, but crude unfiltered spent aquarium water did. Under conditions of food deprivation or cold (4 degrees C), Pfiesteria readily formed harvestable cysts that were further analyzed by PCR and scanning electron microscopy. The germination of Pfiesteria cysts in environmental sediment was enhanced by the presence of live fish: dinospores could be detected 13 to 15 days earlier and reached 5- to 10-times-higher peak cell densities with live fish than with artificial seawater or f/2 medium alone. The addition of ammonia, urea, nitrate, phosphate, or surprisingly, spent fish aquarium water had no effect.

  19. Distribution and Diversity of Soil Microfauna from East Antarctica: Assessing the Link between Biotic and Abiotic Factors

    PubMed Central

    Velasco-Castrillón, Alejandro; Schultz, Mark B.; Colombo, Federica; Gibson, John A. E.; Davies, Kerrie A.; Austin, Andrew D.; Stevens, Mark I.

    2014-01-01

    Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw), with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw). Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3− and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity. PMID:24498126

  20. Distribution and diversity of soil microfauna from East Antarctica: assessing the link between biotic and abiotic factors.

    PubMed

    Velasco-Castrillón, Alejandro; Schultz, Mark B; Colombo, Federica; Gibson, John A E; Davies, Kerrie A; Austin, Andrew D; Stevens, Mark I

    2014-01-01

    Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw), with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw). Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3 (-) and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity.

  1. Abiotic and biotic factors affect efficacy of chlorfenapyr for control of stored-product insect pests.

    PubMed

    Kavallieratos, Nickolas G; Athanassiou, Christos G; Hatzikonstantinou, Ann N; Kavallieratou, Helen N

    2011-08-01

    Laboratory bioassays were conducted to assess pyrole chlorfenapyr as a potential grain protectant against adults of Rhyzopertha dominica, Sitophilus oryzae, Prostephanus truncatus, Tribolium confusum, and Liposcelis bostrychophila. Factors such as dose (0.01, 0.1, 0.5, 1, 5, and 10 ppm), exposure interval (7 and 14 days), temperature (20, 25, and 30°C), relative humidity (RH; 55 and 75%), and commodity (wheat, maize, barley, and paddy rice) were evaluated. Progeny production was assessed after 74 days of exposure. For L. bostrychophila and T. confusum the increase of dose increased mortality. After 7 or 14 days of exposure, mortality was low at doses of ≤ 1 ppm and did not exceed 23 or 36%, respectively, for L. bostrychophila or 13 or 58%, respectively, for T. confusum. After 14 days of exposure, mortality of S. oryzae at 30°C and 75% RH was 82.2%. Mortality of P. truncatus was considerably higher than that of the other species. At 0.5 ppm, mortality exceeded 81% after 7 days of exposure and 91% after 14 days of exposure. Progeny production of L. bostrychophila was extremely high. Very few progeny were found for T. confusum. For S. oryzae, offspring emergence was high, except at 20°C and 55% RH. For P. truncatus, progeny production in the treated maize was not avoided, even at 10 ppm. In the case of S. oryzae, at 0.1 ppm and after 14 days of exposure, mortality in wheat was higher than in the other three commodities. For R. dominica, mortality was low at 0.1 and 1 ppm for paddy rice but reached 74.4% in barley after 14 days of exposure. For T. confusum, mortality was low at 0.1 and 1 ppm in all commodities. For progeny production counts, for S. oryzae or R. dominica, adult emergence was higher in paddy rice than in the other three commodities. Finally, overall T. confusum progeny was low. Chlorfenapyr efficacy varied remarkably among the combinations tested, and it may be a viable grain protectant in combination with other insecticides.

  2. The effects of biotic and abiotic factors on the spatial heterogeneity of alpine grassland vegetation at a small scale on the Qinghai-Tibet Plateau (QTP), China.

    PubMed

    Wen, Lu; Dong, Shi Kui; Li, Yuan Yuan; Sherman, Ruth; Shi, Jian Jun; Liu, De Mei; Wang, Yan Long; Ma, Yu Shou; Zhu, Lei

    2013-10-01

    Understanding the complex effects of biotic and abiotic factors on the composition of vegetation is very important for developing and implementing strategies for promoting sustainable grassland development. The vegetation-disturbance-environment relationship was examined in degraded alpine grasslands in the headwater areas of three rivers on the Qinghai-Tibet Plateau in this study. The investigated hypotheses were that (1) the heterogeneity of the vegetation of the alpine grassland is due to a combination of biotic and abiotic factors and that (2) at a small scale, biotic factors are more important for the distribution of alpine vegetation. On this basis, four transects were set along altitudinal gradients from 3,770 to 3,890 m on a sunny slope, and four parallel transects were set along altitudinal gradients on a shady slope in alpine grasslands in Guoluo Prefecture of Qinghai Province, China. It was found that biological disturbances were the major forces driving the spatial heterogeneity of the alpine grassland vegetation and abiotic factors were of secondary importance. Heavy grazing and intensive rat activity resulted in increases in unpalatable and poisonous weeds and decreased fine forages in the form of sedges, forbs, and grasses in the vegetation composition. Habitat degradation associated with biological disturbances significantly affected the spatial variation of the alpine grassland vegetation, i.e., more pioneer plants of poisonous or unpalatable weed species, such as Ligularia virgaurea and Euphorbia fischeriana, were found in bare patches. Environmental/abiotic factors were less important than biological disturbances in affecting the spatial distribution of the alpine grassland vegetation at a small scale. It was concluded that rat control and light grazing should be applied first in implementing restoration strategies. The primary vegetation in lightly grazed and less rat-damaged sites should be regarded as a reference for devising vegetation

  3. Effects of pH on the hydrolysis of lignocellulosic wastes and volatile fatty acids accumulation: the contribution of biotic and abiotic factors.

    PubMed

    Chen, Yi; Wen, Yue; Zhou, Junwei; Xu, Chao; Zhou, Qi

    2012-04-01

    In this study, a combination of micro-scale structure and extracellular enzyme activity (EEA) analysis was successfully used to explore the effect of pH (from 6.0 to 12.0) on wetland plant litter (WPL) hydrolysis and VFAs accumulation. During 30days of fermentation, the maximum VFAs production and abiotic release of carbohydrate, combined with the minimum EEAs were observed at pH 12.0, suggesting that abiotic factors were most important for hydrolysis and VFAs accumulation at pH 12.0. As the pH decreased, the factors most important to carbohydrate hydrolysis shifted from abiotic factors to biotic factors with the maximum bio-release of carbohydrate occurring at pH 9.0. Further investigation showed that pH 9.0 could significantly enhance the bio-release of carbohydrate through the increase in the mesoporous surface area, surface cellulose accessibility and cellulase activity. Alkaline fermentation at ambient temperature can be considered as a sustainable technology for VFAs recovery and WPL management.

  4. CkDREB gene in Caragana korshinskii is involved in the regulation of stress response to multiple abiotic stresses as an AP2/EREBP transcription factor.

    PubMed

    Wang, Xuemin; Chen, Xiaofang; Liu, Yun; Gao, Hongwen; Wang, Zan; Sun, Guizhi

    2011-04-01

    Using RACE method, a DREB-like gene-CkDREB, which contains a conserved AP2/ERF domain, was isolated from Caragana korshinskii. Full length of CkDREB cDNA was 1743 bp, including an ORF of 1038 bp and encoding a polypeptide of 345 amino acids. CkDREB protein shared high identification with other homologs from other plants. The KR-rich motif at the N-terminal region played an essential role in nuclear localization of CkDREB. Yeast one-hybrid experiments testified that CkDREB possess specific DRE element-binding activity and transcriptional activation. A variety of abiotic stress, including high salt, dehydration, low temperature all significantly induced the expression of CkDREB gene. Exogenous phytohormone ABA also slightly up-regulated the mRNA accumulation of CkDREB. Overexpression of CkDREB in transgenic tobacco plants resulted in enhanced tolerance to high salinity and osmotic stresses and induction of downstream target genes under normal conditions. These results suggested that CkDREB may play an essential role as a DREB transcription factor in regulation of stress-responsive signaling in C. korshinskii.

  5. Global analysis of WRKY transcription factor superfamily in Setaria identifies potential candidates involved in abiotic stress signaling.

    PubMed

    Muthamilarasan, Mehanathan; Bonthala, Venkata S; Khandelwal, Rohit; Jaishankar, Jananee; Shweta, Shweta; Nawaz, Kashif; Prasad, Manoj

    2015-01-01

    Transcription factors (TFs) are major players in stress signaling and constitute an integral part of signaling networks. Among the major TFs, WRKY proteins play pivotal roles in regulation of transcriptional reprogramming associated with stress responses. In view of this, genome- and transcriptome-wide identification of WRKY TF family was performed in the C4model plants, Setaria italica (SiWRKY) and S. viridis (SvWRKY), respectively. The study identified 105 SiWRKY and 44 SvWRKY proteins that were computationally analyzed for their physicochemical properties. Sequence alignment and phylogenetic analysis classified these proteins into three major groups, namely I, II, and III with majority of WRKY proteins belonging to group II (53 SiWRKY and 23 SvWRKY), followed by group III (39 SiWRKY and 11 SvWRKY) and group I (10 SiWRKY and 6 SvWRKY). Group II proteins were further classified into 5 subgroups (IIa to IIe) based on their phylogeny. Domain analysis showed the presence of WRKY motif and zinc finger-like structures in these proteins along with additional domains in a few proteins. All SiWRKY genes were physically mapped on the S. italica genome and their duplication analysis revealed that 10 and 8 gene pairs underwent tandem and segmental duplications, respectively. Comparative mapping of SiWRKY and SvWRKY genes in related C4 panicoid genomes demonstrated the orthologous relationships between these genomes. In silico expression analysis of SiWRKY and SvWRKY genes showed their differential expression patterns in different tissues and stress conditions. Expression profiling of candidate SiWRKY genes in response to stress (dehydration and salinity) and hormone treatments (abscisic acid, salicylic acid, and methyl jasmonate) suggested the putative involvement of SiWRKY066 and SiWRKY082 in stress and hormone signaling. These genes could be potential candidates for further characterization to delineate their functional roles in abiotic stress signaling.

  6. Global analysis of WRKY transcription factor superfamily in Setaria identifies potential candidates involved in abiotic stress signaling

    PubMed Central

    Muthamilarasan, Mehanathan; Bonthala, Venkata S.; Khandelwal, Rohit; Jaishankar, Jananee; Shweta, Shweta; Nawaz, Kashif; Prasad, Manoj

    2015-01-01

    Transcription factors (TFs) are major players in stress signaling and constitute an integral part of signaling networks. Among the major TFs, WRKY proteins play pivotal roles in regulation of transcriptional reprogramming associated with stress responses. In view of this, genome- and transcriptome-wide identification of WRKY TF family was performed in the C4model plants, Setaria italica (SiWRKY) and S. viridis (SvWRKY), respectively. The study identified 105 SiWRKY and 44 SvWRKY proteins that were computationally analyzed for their physicochemical properties. Sequence alignment and phylogenetic analysis classified these proteins into three major groups, namely I, II, and III with majority of WRKY proteins belonging to group II (53 SiWRKY and 23 SvWRKY), followed by group III (39 SiWRKY and 11 SvWRKY) and group I (10 SiWRKY and 6 SvWRKY). Group II proteins were further classified into 5 subgroups (IIa to IIe) based on their phylogeny. Domain analysis showed the presence of WRKY motif and zinc finger-like structures in these proteins along with additional domains in a few proteins. All SiWRKY genes were physically mapped on the S. italica genome and their duplication analysis revealed that 10 and 8 gene pairs underwent tandem and segmental duplications, respectively. Comparative mapping of SiWRKY and SvWRKY genes in related C4 panicoid genomes demonstrated the orthologous relationships between these genomes. In silico expression analysis of SiWRKY and SvWRKY genes showed their differential expression patterns in different tissues and stress conditions. Expression profiling of candidate SiWRKY genes in response to stress (dehydration and salinity) and hormone treatments (abscisic acid, salicylic acid, and methyl jasmonate) suggested the putative involvement of SiWRKY066 and SiWRKY082 in stress and hormone signaling. These genes could be potential candidates for further characterization to delineate their functional roles in abiotic stress signaling. PMID:26635818

  7. Habitat fragmentation as a result of biotic and abiotic factors controls pathogen transmission throughout a host population.

    PubMed

    Greer, Amy L; Collins, James P

    2008-03-01

    1. The hypothesis that habitat fragmentation (biotic or abiotic) alters the transmission of disease within a population is explored using field data from a well-studied amphibian-pathogen system. 2. We used the Ambystoma tigrinum-A. tigrinum virus (ATV) model system to show how habitat fragmentation as a result of emergent vegetation and habitat management affects disease transmission dynamics in ponds across a landscape. 3. We quantified variation in ATV infection over time and across the landscape. ATV infection was significantly higher in ponds modified for livestock use (P = 0.032). Disease incidence decreased with increased amounts of emergent vegetation (P < 0.001). These factors appear to control disease transmission by altering the host contact rate and with it disease transmission. 4. A field experiment to test the effect of emergent vegetation on the distribution of larvae in ponds demonstrated a behavioural change in larvae found in sparsely vegetated ponds. Microhabitat choices resulted in larvae being concentrated at the pond edge resulting in a 'halo effect' in sparsely vegetated ponds, whereas larvae in heavily vegetated ponds were distributed more evenly throughout. Microhabitat choice affects the effective density that larvae experience. This 'halo effect' increases contact rates in the shallows of sparsely vegetated ponds and increases the transmission of a directly transmitted pathogen. 5. Despite recurrent epidemics of a lethal Ranavirus in tiger salamanders on the Kaibab Plateau, Arizona, USA, these populations persist. We discuss the implications of our results in the context of density-dependent transmission and homogeneous mixing, two increases key assumptions of epidemiological theory.

  8. Influence of plant ontogeny and abiotic factors on resistance of glandular-haired alfalfa to potato leafhopper (Hemiptera: Cicadellidae).

    PubMed

    Casteel, Clare L; Ranger, Christopher M; Backus, Elaine A; Ellersieck, Mark R; Johnson, David W

    2006-04-01

    Laboratory experiments were conducted to characterize the trichome-based defense of glandular-haired alfalfa, Medicago sativa L., against the potato leafhopper, Empoasca fabae (Harris). Within-plant variability in leafhopper resistance was examined by caging adult leafhoppers to either basal or apical stem internodes of the leafhopper-resistant, glandular-haired M. sativa genotype G98A or the susceptible, nonglandular-haired M. sativa 'Ranger'. Young, actively secreting glandular trichomes are located on apical internodes of G98A, whereas senesced gland heads are found on older, basal internodes of G98A. After 96 h, the highest cumulative leafhopper mortality and lowest number of excretory droplets were associated with apical internodes of G98A. No difference was detected in mortality and feeding levels among insects caged to basal internodes of G98A and basal and apical internodes of Ranger. The influence of abiotic factors on leafhopper resistance was evaluated by caging adult leafhoppers to either G98A or Ranger under four combinations of low and high light (250 and 1,000 micromol s(-1) m(-2)) and temperature regimes (17 and 30 degrees C). After 96 h, the highest cumulative mortality was associated with leafhoppers confined to G98A under high light and high temperature conditions. Temperature level and plant type also had an effect on the production of excretory droplets, resulting in the highest number of excretory droplets being associated with Ranger under the high temperature regime. These results indicate that certain regions of M. sativa G98A are better protected against the potato leafhopper than others and that temperature influences resistance levels of glandular-haired alfalfa.

  9. C2H2 type of zinc finger transcription factors in foxtail millet define response to abiotic stresses.

    PubMed

    Muthamilarasan, Mehanathan; Bonthala, Venkata Suresh; Mishra, Awdhesh Kumar; Khandelwal, Rohit; Khan, Yusuf; Roy, Riti; Prasad, Manoj

    2014-09-01

    C2H2 type of zinc finger transcription factors (TFs) play crucial roles in plant stress response and hormone signal transduction. Hence considering its importance, genome-wide investigation and characterization of C2H2 zinc finger proteins were performed in Arabidopsis, rice and poplar but no such study was conducted in foxtail millet which is a C4 Panicoid model crop well known for its abiotic stress tolerance. The present study identified 124 C2H2-type zinc finger TFs in foxtail millet (SiC2H2) and physically mapped them onto the genome. The gene duplication analysis revealed that SiC2H2s primarily expanded in the genome through tandem duplication. The phylogenetic tree classified these TFs into five groups (I-V). Further, miRNAs targeting SiC2H2 transcripts in foxtail millet were identified. Heat map demonstrated differential and tissue-specific expression patterns of these SiC2H2 genes. Comparative physical mapping between foxtail millet SiC2H2 genes and its orthologs of sorghum, maize and rice revealed the evolutionary relationships of C2H2 type of zinc finger TFs. The duplication and divergence data provided novel insight into the evolutionary aspects of these TFs in foxtail millet and related grass species. Expression profiling of candidate SiC2H2 genes in response to salinity, dehydration and cold stress showed differential expression pattern of these genes at different time points of stresses.

  10. Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

    PubMed Central

    Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C.

    2016-01-01

    High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments. PMID:27032533

  11. A seed preferential heat shock transcription factor from wheat provides abiotic stress tolerance and yield enhancement in transgenic Arabidopsis under heat stress environment.

    PubMed

    Chauhan, Harsh; Khurana, Neetika; Agarwal, Preeti; Khurana, Jitendra P; Khurana, Paramjit

    2013-01-01

    Reduction in crop yield and quality due to various abiotic stresses is a worldwide phenomenon. In the present investigation, a heat shock factor (HSF) gene expressing preferentially in developing seed tissues of wheat grown under high temperatures was cloned. This newly identified heat shock factor possesses the characteristic domains of class A type plant HSFs and shows high similarity to rice OsHsfA2d, hence named as TaHsfA2d. The transcription factor activity of TaHsfA2d was confirmed through transactivation assay in yeast. Transgenic Arabidopsis plants overexpressing TaHsfA2d not only possess higher tolerance towards high temperature but also showed considerable tolerance to salinity and drought stresses, they also showed higher yield and biomass accumulation under constant heat stress conditions. Analysis of putative target genes of AtHSFA2 through quantitative RT-PCR showed higher and constitutive expression of several abiotic stress responsive genes in transgenic Arabidopsis plants over-expressing TaHsfA2d. Under stress conditions, TaHsfA2d can also functionally complement the T-DNA insertion mutants of AtHsfA2, although partially. These observations suggest that TaHsfA2d may be useful in molecular breeding of crop plants, especially wheat, to improve yield under abiotic stress conditions.

  12. Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles

    NASA Astrophysics Data System (ADS)

    Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C.

    2016-04-01

    High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

  13. Disentangling effects of abiotic factors and biotic interactions on cross-taxon congruence in species turnover patterns of plants, moths and beetles.

    PubMed

    Duan, Meichun; Liu, Yunhui; Yu, Zhenrong; Baudry, Jacques; Li, Liangtao; Wang, Changliu; Axmacher, Jan C

    2016-04-01

    High cross-taxon congruence in species diversity patterns is essential for the use of surrogate taxa in biodiversity conservation, but presence and strength of congruence in species turnover patterns, and the relative contributions of abiotic environmental factors and biotic interaction towards this congruence, remain poorly understood. In our study, we used variation partitioning in multiple regressions to quantify cross-taxon congruence in community dissimilarities of vascular plants, geometrid and arciinid moths and carabid beetles, subsequently investigating their respective underpinning by abiotic factors and biotic interactions. Significant cross-taxon congruence observed across all taxon pairs was linked to their similar responses towards elevation change. Changes in the vegetation composition were closely linked to carabid turnover, with vegetation structure and associated microclimatic conditions proposed causes of this link. In contrast, moth assemblages appeared to be dominated by generalist species whose turnover was weakly associated with vegetation changes. Overall, abiotic factors exerted a stronger influence on cross-taxon congruence across our study sites than biotic interactions. The weak congruence in turnover observed particularly between plants and moths highlights the importance of multi-taxon approaches based on groupings of taxa with similar turnovers, rather than the use of single surrogate taxa or environmental proxies, in biodiversity assessments.

  14. Plant available silicon in South-east Asian rice paddy soils - relevance of agricultural practice and of abiotic factors

    NASA Astrophysics Data System (ADS)

    Marxen, A.; Klotzbücher, T.; Vetterlein, D.; Jahn, R.

    2012-12-01

    Background Silicon (Si) plays a crucial role in rice production. Si content of rice plants exceeds the content of other major nutrients such as nitrogen, phosphorous or potassium. Recent studies showed that in some environments external supply of Si can enhance the growth of rice plants. Rice plants express specific Si transporters to absorb Si from soil solutions in form of silicic acid, which precipitates in tissue cells forming amorphous silica bodies, called phytoliths. The phytoliths are returned to soils with plant residues. They might be a main source of plant available silicic acid in soils. Aims In this study we assess the effects of rice paddy cultivation on the stocks of `reactive` Si fractions in mineral topsoils of rice paddy fields in contrasting landscapes. The `reactive` Si fractions are presumed to determine the release of plant-available silicic acid in soils. We consider the relevance of abiotic factors (mineral assemblage; soil weathering status) and agricultural practice for these fractions. Agricultural practices, which were assumed to affect the stocks of `reactive` Si were (i) the usage of different rice varieties (which might differ in Si demand), (ii) straw residue management (i.e., whether straw residues are returned to the fields or removed and used e.g. as fodder), and (iii) yield level and number of crops per year. Material and methods Soils (top horizon of about 0-20 cm depth) were sampled from rice paddy fields in 2 mountainous and 5 lowland landscapes of contrasting geologic conditions in Vietnam and the Philippines. Ten paddy fields were sampled per landscape. The rice paddy management within landscapes differed when different farmers and/or communities managed the fields. We analysed the following fractions of `reactive` Si in the soils: acetate-extractable Si (dissolved and easily exchangeable Si), phosphate-extractable Si (adsorbed Si), oxalate extractable Si (Si associated with poorly-ordered sesquioxides), NaOH extractable Si

  15. Abiotic origin of biopolymers

    NASA Technical Reports Server (NTRS)

    Oro, J.; Stephen-Sherwood, E.

    1976-01-01

    A variety of methods have been investigated in different laboratories for the polymerization of amino acids and nucleotides under abiotic conditions. They include (1) thermal polymerization; (2) direct polymerization of certain amino acid nitriles, amides, or esters; (3) polymerization using polyphosphate esters; (4) polymerization under aqueous or drying conditions at moderate temperatures using a variety of simple catalysts or condensing agents like cyanamide, dicyandiamide, or imidazole; and (5) polymerization under similar mild conditions but employing activated monomers or abiotically synthesized high-energy compounds such as adenosine 5'-triphosphate (ATP). The role and significance of these methods for the synthesis of oligopeptides and oligonucleotides under possible primitive-earth conditions is evaluated. It is concluded that the more recent approach involving chemical processes similar to those used by contemporary living organisms appears to offer a reasonable solution to the prebiotic synthesis of these biopolymers.

  16. The heat shock factor gene family in Salix suchowensis: a genome-wide survey and expression profiling during development and abiotic stresses

    PubMed Central

    Zhang, Jin; Li, Yu; Jia, Hui-Xia; Li, Jian-Bo; Huang, Juan; Lu, Meng-Zhu; Hu, Jian-Jun

    2015-01-01

    Heat shock transcription factors (Hsfs), which act as important transcriptional regulatory proteins, play crucial roles in plant developmental processes, and stress responses. Recently, the genome of the shrub willow Salix suchowensis was fully sequenced. In this study, a total of 27 non-redundant Hsf genes were identified from the S. suchowensis genome. Phylogenetic analysis revealed that the members of the SsuHsf family can be divided into three groups (class A, B, and C) based on their structural characteristics. Promoter analysis indicated that the SsuHsfs promoters included various cis-acting elements related to hormone and/or stress responses. Furthermore, the expression profiles of 27 SsuHsfs were analyzed in different tissues and under various stresses (heat, drought, salt, and ABA treatment) using RT-PCR. The results demonstrated that the SsuHsfs were involved in abiotic stress responses. Our results contribute to a better understanding of the complexity of the SsuHsf gene family, and will facilitate functional characterization in future studies. PMID:26442061

  17. The NAC-type transcription factor OsNAC2 regulates ABA-dependent genes and abiotic stress tolerance in rice

    PubMed Central

    Shen, Jiabin; Lv, Bo; Luo, Liqiong; He, Jianmei; Mao, Chanjuan; Xi, Dandan; Ming, Feng

    2017-01-01

    Plants can perceive environmental changes and respond to external stressors. Here, we show that OsNAC2, a member of the NAC transcription factor family, was strongly induced by ABA and osmotic stressors such as drought and high salt. With reduced yields under drought conditions at the flowering stage, OsNAC2 overexpression lines had lower resistance to high salt and drought conditions. RNAi plants showed enhanced tolerance to high salinity and drought stress at both the vegetative and flowering stages. Furthermore, RNAi plants had improved yields after drought stress. A microarray assay indicated that many ABA-dependent stress-related genes were down-regulated in OsNAC2 overexpression lines. We further confirmed that OsNAC2 directly binds the promoters of LATE EMBRYOGENESIS ABUNDANT 3 (OsLEA3) and Stress-Activated Protein Kinases 1 (OsSAPK1), two marker genes in the abiotic stress and ABA response pathways, respectively. Our results suggest that in rice OsNAC2 regulates both abiotic stress responses and ABA-mediated responses, and acts at the junction between the ABA and abiotic stress pathways. PMID:28074873

  18. A stress-associated NAC transcription factor (SlNAC35) from tomato plays a positive role in biotic and abiotic stresses.

    PubMed

    Wang, Guodong; Zhang, Song; Ma, Xiaocui; Wang, Yong; Kong, Fanying; Meng, Qingwei

    2016-09-01

    The NAC transcription factor family participates in responses to various kinds of environmental stimuli in plants. Responses of NAC genes to abiotic stresses have been widely studied, but their functions in response to biotic stress are little reported in plants, especially in crops. In the present study, we examined the functions of a novel tomato (Solanum lycopersicum) NAC protein (SlNAC35) in abiotic and biotic stress resistance by using transgenic tobacco. Expression analysis found that SlNAC35 expression was induced by drought stress, salt stress, bacterial pathogen, and signaling molecules, suggesting its involvement in plant responses to biotic and abiotic stimuli. Moreover, transgenic lines exhibited a greater number of lateral roots and longer root length compared with Vec lines (empty vector lines) after drought and salt treatment. These results indicate that overexpression of SlNAC35 promoted root growth and development under drought and salt stresses. Higher expressions of NtARF1, NtARF2 and NtARF8 were observed under drought and salt stresses in transgenic lines, suggesting that overexpression of SlNAC35 promoted growth and development of roots in transgenic lines possibly by involving auxin signaling and by regulating NtARF expression. In addition, SlNAC35 overexpression improved resistance to bacterial pathogen in transgenic tobacco, and reactive oxygen species may be in the upstream of salicylic acid (SA) signaling in transgenic tobacco during defense response. © 2016 Scandinavian Plant Physiology Society.

  19. Risk factors for breast cancer, including occupational exposures.

    PubMed

    Weiderpass, Elisabete; Meo, Margrethe; Vainio, Harri

    2011-03-01

    The knowledge on the etiology of breast cancer has advanced substantially in recent years, and several etiological factors are now firmly established. However, very few new discoveries have been made in relation to occupational risk factors. The International Agency for Research on Cancer has evaluated over 900 different exposures or agents to-date to determine whether they are carcinogenic to humans. These evaluations are published as a series of Monographs (www.iarc.fr). For breast cancer the following substances have been classified as "carcinogenic to humans" (Group 1): alcoholic beverages, exposure to diethylstilbestrol, estrogen-progestogen contraceptives, estrogen-progestogen hormone replacement therapy and exposure to X-radiation and gamma-radiation (in special populations such as atomic bomb survivors, medical patients, and in-utero exposure). Ethylene oxide is also classified as a Group 1 carcinogen, although the evidence for carcinogenicity in epidemiologic studies, and specifically for the human breast, is limited. The classification "probably carcinogenic to humans" (Group 2A) includes estrogen hormone replacement therapy, tobacco smoking, and shift work involving circadian disruption, including work as a flight attendant. If the association between shift work and breast cancer, the most common female cancer, is confirmed, shift work could become the leading cause of occupational cancer in women.

  20. Risk Factors for Breast Cancer, Including Occupational Exposures

    PubMed Central

    Meo, Margrethe; Vainio, Harri

    2011-01-01

    The knowledge on the etiology of breast cancer has advanced substantially in recent years, and several etiological factors are now firmly established. However, very few new discoveries have been made in relation to occupational risk factors. The International Agency for Research on Cancer has evaluated over 900 different exposures or agents to-date to determine whether they are carcinogenic to humans. These evaluations are published as a series of Monographs (www.iarc.fr). For breast cancer the following substances have been classified as "carcinogenic to humans" (Group 1): alcoholic beverages, exposure to diethylstilbestrol, estrogen-progestogen contraceptives, estrogen-progestogen hormone replacement therapy and exposure to X-radiation and gamma-radiation (in special populations such as atomic bomb survivors, medical patients, and in-utero exposure). Ethylene oxide is also classified as a Group 1 carcinogen, although the evidence for carcinogenicity in epidemiologic studies, and specifically for the human breast, is limited. The classification "probably carcinogenic to humans" (Group 2A) includes estrogen hormone replacement therapy, tobacco smoking, and shift work involving circadian disruption, including work as a flight attendant. If the association between shift work and breast cancer, the most common female cancer, is confirmed, shift work could become the leading cause of occupational cancer in women. PMID:22953181

  1. The Alfin-like homeodomain finger protein AL5 suppresses multiple negative factors to confer abiotic stress tolerance in Arabidopsis.

    PubMed

    Wei, Wei; Zhang, Yu-Qin; Tao, Jian-Jun; Chen, Hao-Wei; Li, Qing-Tian; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-03-01

    Plant homeodomain (PHD) finger proteins affect processes of growth and development by changing transcription and reading epigenetic histone modifications, but their functions in abiotic stress responses remain largely unclear. Here we characterized seven Arabidopsis thaliana Alfin1-like PHD finger proteins (ALs) in terms of the responses to abiotic stresses. ALs localized to the nucleus and repressed transcription. Except AL6, all the ALs bound to G-rich elements. Mutations of the amino acids at positions 34 and 35 in AL6 caused loss of ability to bind to G-rich elements. Expression of the AL genes responded differentially to osmotic stress, salt, cold and abscisic acid treatments. AL5-over-expressing plants showed higher tolerance to salt, drought and freezing stress than Col-0. Consistently, al5 mutants showed reduced stress tolerance. We used ChIP-Seq assays to identify eight direct targets of AL5, and found that AL5 binds to the promoter regions of these genes. Knockout mutants of five of these target genes exhibited varying tolerances to stresses. These results indicate that AL5 inhibits multiple signaling pathways to confer stress tolerance. Our study sheds light on mechanisms of AL5-mediated signaling in abiotic stress responses, and provides tools for improvement of stress tolerance in crop plants.

  2. Basic leucine zipper (bZIP) transcription factors involved in abiotic stresses: A molecular model of a wheat bZIP factor and implications of its structure in function.

    PubMed

    Sornaraj, Pradeep; Luang, Sukanya; Lopato, Sergiy; Hrmova, Maria

    2016-01-01

    Basic leucine zipper (bZIP) genes encode transcription factors (TFs) that control important biochemical and physiological processes in plants and all other eukaryotic organisms. Here we present (i) the homo-dimeric structural model of bZIP consisting of basic leucine zipper and DNA binding regions, in complex with the synthetic Abscisic Acid-Responsive Element (ABREsyn); (ii) discuss homo- and hetero-dimerisation patterns of bZIP TFs; (iii) summarise the current progress in understanding the molecular mechanisms of function of bZIP TFs, including features determining the specificity of their binding to DNA cis-elements, and (iv) review information on interaction partners of bZIPs during plant development and stress response, as well as on types and roles of post-translational modifications, and regulatory aspects of protein-degradation mediated turn-over. Finally, we (v) recapitulate on the recent advances regarding functional roles of bZIP factors in major agricultural crops, and discuss the potential significance of bZIP-based genetic engineering in improving crop yield and tolerance to abiotic stresses. An accurate analysis and understanding of roles of plant bZIP TFs in different biological processes requires the knowledge of interacting partners, time and location of expression in plant organs, and the information on mechanisms of homo- and hetero-dimerisation of bZIP TFs. Studies on molecular mechanisms of plant bZIP TFs at the atomic levels will provide novel insights into the regulatory processes during plant development, and responses to abiotic and biotic stresses. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  3. Genome-wide characterization and expression analysis enables identification of abiotic stress-responsive MYB transcription factors in cassava (Manihot esculenta).

    PubMed

    Ruan, Meng-Bin; Guo, Xin; Wang, Bin; Yang, Yi-Ling; Li, Wen-Qi; Yu, Xiao-Ling; Zhang, Peng; Peng, Ming

    2017-06-15

    The myeloblastosis (MYB) transcription factor superfamily is the largest transcription factor family in plants, playing different roles during stress response. However, abiotic stress-responsive MYB transcription factors have not been systematically studied in cassava (Manihot esculenta), an important tropical tuber root crop. In this study, we used a genome-wide transcriptome analysis to predict 299 putative MeMYB genes in the cassava genome. Under drought and cold stresses, many MeMYB genes exhibited different expression patterns in cassava leaves, indicating that these genes might play a role in abiotic stress responses. We found that several stress-responsive MeMYB genes responded to abscisic acid (ABA) in cassava leaves. We characterize four MeMYBs, namely MeMYB1, MeMYB2, MeMYB4, and MeMYB9, as R2R3-MYB transcription factors. Furthermore, RNAi-driven repression of MeMYB2 resulted in drought and cold tolerance in transgenic cassava. Gene expression assays in wild-type and MeMYB2-RNAi cassava plants revealed that MeMYB2 may affect other MeMYBs as well as MeWRKYs under drought and cold stress, suggesting crosstalk between MYB and WRKY family genes under stress conditions in cassava. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  4. Review of recent transgenic studies on abiotic stress tolerance and future molecular breeding in potato.

    PubMed

    Kikuchi, Akira; Huynh, Huu Duc; Endo, Tsukasa; Watanabe, Kazuo

    2015-03-01

    Global warming has become a major issue within the last decade. Traditional breeding programs for potato have focused on increasing productivity and quality and disease resistance, thus, modern cultivars have limited tolerance of abiotic stresses. The introgression of abiotic stress tolerance into modern cultivars is essential work for the future. Recently, many studies have investigated abiotic stress using transgenic techniques. This manuscript focuses on the study of abiotic stress, in particular drought, salinity and low temperature, during this century. Dividing studies into these three stress categories for this review was difficult. Thus, based on the study title and the transgene property, transgenic studies were classified into five categories in this review; oxidative scavengers, transcriptional factors, and above three abiotic categories. The review focuses on studies that investigate confer of stress tolerance and the identification of responsible factors, including wild relatives. From a practical application perspective, further evaluation of transgenic potato with abiotic stress tolerance is required. Although potato plants, including wild species, have a large potential for abiotic stress tolerance, exploration of the factors responsible for conferring this tolerance is still developing. Molecular breeding, including genetic engineering and conventional breeding using DNA markers, is expected to develop in the future.

  5. Review of recent transgenic studies on abiotic stress tolerance and future molecular breeding in potato

    PubMed Central

    Kikuchi, Akira; Huynh, Huu Duc; Endo, Tsukasa; Watanabe, Kazuo

    2015-01-01

    Global warming has become a major issue within the last decade. Traditional breeding programs for potato have focused on increasing productivity and quality and disease resistance, thus, modern cultivars have limited tolerance of abiotic stresses. The introgression of abiotic stress tolerance into modern cultivars is essential work for the future. Recently, many studies have investigated abiotic stress using transgenic techniques. This manuscript focuses on the study of abiotic stress, in particular drought, salinity and low temperature, during this century. Dividing studies into these three stress categories for this review was difficult. Thus, based on the study title and the transgene property, transgenic studies were classified into five categories in this review; oxidative scavengers, transcriptional factors, and above three abiotic categories. The review focuses on studies that investigate confer of stress tolerance and the identification of responsible factors, including wild relatives. From a practical application perspective, further evaluation of transgenic potato with abiotic stress tolerance is required. Although potato plants, including wild species, have a large potential for abiotic stress tolerance, exploration of the factors responsible for conferring this tolerance is still developing. Molecular breeding, including genetic engineering and conventional breeding using DNA markers, is expected to develop in the future. PMID:25931983

  6. Common and distinct functions of Arabidopsis class A1 and A2 heat shock factors in diverse abiotic stress responses and development.

    PubMed

    Liu, Hsiang-chin; Charng, Yee-yung

    2013-09-01

    There are 21 heat shock factor (HSF) homologs in Arabidopsis (Arabidopsis thaliana), of which members of class A1 (HSFA1a/HSFA1b/HSFA1d/HSFA1e) play the major role in activating the transcription of heat-induced genes, including HSFA2. Once induced, HSFA2 becomes the dominant HSF and is able to form heterooligomeric complexes with HSFA1. However, whether HSFA2 could function independently as a transcription regulator in the absence of the HSFA1s was undetermined. To address this question, we introduced a Cauliflower mosaic virus 35S promoter:HSFA2 construct into hsfa1a/hsfa1b/hsfa1d/hsfa1e quadruple knockout (QK) and wild-type (Wt) backgrounds to yield transgenic lines A2QK and A2Wt, respectively. Constitutive expression of HSFA2 rescued the developmental defects of the QK mutant and promoted callus formation in A2QK, but not in A2Wt, after heat treatment. Transcriptome analysis showed that heat stress response genes are differentially regulated by the HSFA1s and HSFA2; the genes involved in metabolism and redox homeostasis are preferentially regulated by HSFA2, while HSFA1-preferring genes are enriched in transcription function. Ectopic expression of HSFA2 complemented the defects of QK in tolerance to different heat stress regimes, and to hydrogen peroxide, but not to salt and osmotic stresses. Furthermore, we showed that HSFA1a/HSFA1b/HSFA1d are involved in thermotolerance to mild heat stress at temperatures as low as 27°C. We also noticed subfunctionalization of the four Arabidopsis A1-type HSFs in diverse abiotic stress responses. Overall, this study reveals the overlapping and distinct functions of class A1 and A2 HSFs and may enable more precise use of HSFs in engineering stress tolerance in the future.

  7. Plant community, geographic distance and abiotic factors play different roles in predicting AMF biogeography at the regional scale in northern China.

    PubMed

    Xu, Tianle; Veresoglou, Stavros D; Chen, Yongliang; Rillig, Matthias C; Xiang, Dan; Ondřej, Daniel; Hao, Zhipeng; Liu, Lei; Deng, Ye; Hu, Yajun; Chen, Weiping; Wang, Juntao; He, Jizheng; Chen, Baodong

    2016-12-01

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous mutualists of terrestrial plants and play key roles in regulating various ecosystem processes, but little is known about AMF biogeography at regional scale. This study aims at exploring the key predictors of AMF communities across a 5000-km transect in northern China. We determined the soil AMF species richness and community composition at 47 sites representative of four vegetation types (meadow steppe, typical steppe, desert steppe and desert) and related them to plant community characteristics, abiotic factors and geographic distance. The results showed that soil pH was the strongest predictor of AMF richness and phylogenetic diversity. However, abiotic factors only have a low predictive effect on AMF community composition or phylogenetic patterns. By contrast, we found a significant relationship between community composition of AMF and plants, which was a surprising result given the extent of heterogeneity in the plant community across this transect. Moreover, the geographic distance predominantly explained the AMF phylogenetic structure, implying that history evolutionary may play a role in shaping AMF biogeographic patterns. This study highlighted the different roles of main factors in predicting AMF biogeography, and bridge landscape-scale studies to more recent global-scale efforts. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Four potato (Solanum tuberosum) ABCG transporters and their expression in response to abiotic factors and Phytophthora infestans infection.

    PubMed

    Ruocco, Michelina; Ambrosino, Patrizia; Lanzuise, Stefania; Woo, Sheridan Lois; Lorito, Matteo; Scala, Felice

    2011-12-15

    Pleiotropic drug resistant (PDR/ABCG) genes are involved in plant response to biotic and abiotic stresses. In this work, we cloned, from Solanum tuberosum, four PDR/ABCG transporter genes named StPDR1, StPDR2, StPDR3 and StPDR4, which were differentially expressed in plant tissues and cell cultures. A number of different chemically unrelated compounds were found to regulate the transcript levels of the four genes in cultured cells. In particular, StPDR2 was highly up-regulated in the presence of Botrytis cinerea cell walls, NaCl, 2,4-dichlorophenol, sclareol and α-solanin and biological compounds. The expression of the genes was also investigated by real time RT-PCR during infection by Phytophthora infestans. StPDR1 and StPDR2 were up-regulated about 13- and 37-fold at 48 h post-infection (hpi), StPDR3 was expressed (4-5-fold) at 24 and 48 hpi and then rapidly decreased, while StPDR4 RNA accumulation was stimulated (about 4-fold) at 12 and 24 hpi, decreased at 48 hpi and increased again at 96 hpi. We discuss the role of StPDR1-4 genes in response to pathogens and abiotic stresses.

  9. The role of receptor-like protein kinases (RLKs) in abiotic stress response in plants.

    PubMed

    Ye, Yaoyao; Ding, Yanfei; Jiang, Qiong; Wang, Feijuan; Sun, Junwei; Zhu, Cheng

    2017-02-01

    We review and introduce recent studies on RLK s involved in the abiotic stress response and provide insights into potential regulatory mechanisms for alleviating abiotic stress. Abiotic stresses are important factors affecting plant growth and development, resulting in crop production reduction and even plant death. To survive, plants utilize different mechanisms to respond and adapt to continuously changing environmental factors. Understanding of the molecular mechanisms of plant response to various stresses will aid in improving tolerance of plants to abiotic stress through genetic engineering, which would greatly promote the development of modern agriculture. RLKs, the largest gene family in plants, play critical roles in the regulation of plant developmental processes, signaling networks and disease resistance. Many RLKs have been shown to be involved in abiotic stress responses, including the abscisic acid response, calcium signaling and antioxidant defense. This review summarizes recent studies on RLKs involved in plant responses to abiotic stress, including drought, salt, cold, toxic metals/metalloids and other stresses, and emphasizes the upstream and downstream factors in RLK signal transduction pathways under abiotic stress.

  10. Characterization of tomato Cycling Dof Factors reveals conserved and new functions in the control of flowering time and abiotic stress responses.

    PubMed

    Corrales, Alba-Rocío; Nebauer, Sergio G; Carrillo, Laura; Fernández-Nohales, Pedro; Marqués, Jorge; Renau-Morata, Begoña; Granell, Antonio; Pollmann, Stephan; Vicente-Carbajosa, Jesús; Molina, Rosa-Victoria; Medina, Joaquín

    2014-03-01

    DNA binding with One Finger (DOF) transcription factors are involved in multiple aspects of plant growth and development but their precise roles in abiotic stress tolerance are largely unknown. Here we report a group of five tomato DOF genes, homologous to Arabidopsis Cycling DOF Factors (CDFs), that function as transcriptional regulators involved in responses to drought and salt stress and flowering-time control in a gene-specific manner. SlCDF1-5 are nuclear proteins that display specific binding with different affinities to canonical DNA target sequences and present diverse transcriptional activation capacities in vivo. SlCDF1-5 genes exhibited distinct diurnal expression patterns and were differentially induced in response to osmotic, salt, heat, and low-temperature stresses. Arabidopsis plants overexpressing SlCDF1 or SlCDF3 showed increased drought and salt tolerance. In addition, the expression of various stress-responsive genes, such as COR15, RD29A, and RD10, were differentially activated in the overexpressing lines. Interestingly, overexpression in Arabidopsis of SlCDF3 but not SlCDF1 promotes late flowering through modulation of the expression of flowering control genes such as CO and FT. Overall, our data connect SlCDFs to undescribed functions related to abiotic stress tolerance and flowering time through the regulation of specific target genes and an increase in particular metabolites.

  11. Influence of abiotic and environmental factors on the density and infection prevalence of Ixodes pacificus (Acari:Ixodidae) with Borrelia burgdorferi.

    PubMed

    Swei, A; Meentemeyer, R; Briggs, C J

    2011-01-01

    The abiotic and biotic factors that govern the spatial distribution of Lyme disease vectors are poorly understood. This study addressed the influence of abiotic and biotic environmental variables on Ixodes pacificus Cooley & Kohls (Acari:Ixodidae) nymphs, because it is the primary vector of Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner in the far-western United States. Three metrics of Lyme disease risk were evaluated: the density of nymphs, the density of infected nymphs, and the nymphal infection prevalence. This study sampled randomly located plots in oak (Quercus spp.) woodland habitat in Sonoma County, CA. Each plot was drag-sampled for nymphal ticks and tested for B. burgdorferi infection. Path analysis was used to evaluate the direct and indirect relationship between topographic, forest structure and microclimatic variables on ticks. Significant negative correlations were found between maximum temperature in the dry season and the density of infected ticks in 2006 and tick density in 2007, but we did not find a significant relationship with nymphal infection prevalence in either year. Tick density and infected tick density had an indirect, positive correlation with elevation, mediated through temperature. This study found that in certain years but not others, temperature maxima in the dry season may constrain the density and density of infected I. pacificus nymphs. In other years, biotic or stochastic factors may play a more important role in determining tick density.

  12. Stress inducible expression of the DREB1A transcription factor from xeric, Hordeum spontaneum L. in turf and forage grass (Paspalum notatum Flugge) enhances abiotic stress tolerance.

    PubMed

    James, Victoria A; Neibaur, Isaac; Altpeter, Fredy

    2008-02-01

    The dehydration-responsive element binding proteins (DREB1)/C-repeat (CRT) binding factors (CBF) function as transcription activators and bind to the DRE/CRT cis-acting element commonly present in the promoters of abiotic stress-regulated genes. A DREB1A transcription factor ortholog was isolated from a xeric, wild barley (Hordeum spontaneum L.) accession, originating from the Negev desert. Sequence comparison revealed a very high degree of sequence conservation of HsDREB1A to the published barley (Hordeum vulgare L.) DREB1A. Constitutive expression of the HsDREB1A gene was able to trans-activate a reporter gene under transcriptional control of the stress-inducible HVA1s and Dhn8 promoters. HsDREB1A was subcloned under transcriptional control of the stress-inducible barley HVA1s promoter and introduced into the apomictic bahiagrass (Paspalum notatum Flugge) cultivar 'Argentine'. HsDREB1A integration and stress inducible expression was detected in primary transgenic bahiagrass plants and apomictic seed progeny by Southern blot, RT-PCR and northern blot analysis respectively. Transgenic bahiagrass plants with stress-inducible expression of HsDREB1A survived severe salt stress and repeated cycles of severe dehydration stress under controlled environment conditions, in contrast to non-transgenic plants. The observed abiotic stress tolerance is very desirable in turf and forage grasses like bahiagrass, where seasonal droughts and irrigation restrictions affect establishment, persistence or productivity of this perennial crop.

  13. Individual Cell Based Traits Obtained by Scanning Flow-Cytometry Show Selection by Biotic and Abiotic Environmental Factors during a Phytoplankton Spring Bloom

    PubMed Central

    Pomati, Francesco; Kraft, Nathan J. B.; Posch, Thomas; Eugster, Bettina; Jokela, Jukka; Ibelings, Bas W.

    2013-01-01

    In ecology and evolution, the primary challenge in understanding the processes that shape biodiversity is to assess the relationship between the phenotypic traits of organisms and the environment. Here we tested for selection on physio-morphological traits measured by scanning flow-cytometry at the individual level in phytoplankton communities under a temporally changing biotic and abiotic environment. Our aim was to study how high-frequency temporal changes in the environment influence biodiversity dynamics in a natural community. We focused on a spring bloom in Lake Zurich (Switzerland), characterized by rapid changes in phytoplankton, water conditions, nutrients and grazing (mainly mediated by herbivore ciliates). We described bloom dynamics in terms of taxonomic and trait-based diversity and found that diversity dynamics of trait-based groups were more pronounced than those of identified phytoplankton taxa. We characterized the linkage between measured phytoplankton traits, abiotic environmental factors and abundance of the main grazers and observed weak but significant correlations between changing abiotic and biotic conditions and measured size-related and fluorescence-related traits. We tested for deviations in observed community-wide distributions of focal traits from random patterns and found evidence for both clustering and even spacing of traits, occurring sporadically over the time series. Patterns were consistent with environmental filtering and phenotypic divergence under herbivore pressure, respectively. Size-related traits showed significant even spacing during the peak of herbivore abundance, suggesting that morphology-related traits were under selection from grazing. Pigment distribution within cells and colonies appeared instead to be associated with acclimation to temperature and water chemistry. We found support for trade-offs among grazing resistance and environmental tolerance traits, as well as for substantial periods of dynamics in which

  14. Abiotic and biotic factors associated with tick population dynamics on a mammalian host: Ixodes hexagonus infesting otters, Lutra lutra.

    PubMed

    Sherrard-Smith, Ellie; Chadwick, Elizabeth; Cable, Joanne

    2012-01-01

    The Eurasian otter, Lutra lutra, hosts several parasites with zoonotic potential. As this semiaquatic mammal has large ranges across terrestrial, freshwater and marine habitats, it has the capacity for wide dispersion of pathogens. Despite this, parasites of otters have received relatively little attention. Here, we examine their ectoparasite load and assess whether this is influenced by abiotic or biotic variables. Climatic phenomena such as the North Atlantic Oscillation (NAO) affect weather conditions in northern Europe. Consequently parasite distributions, particularly species with life stages exposed to the external environment, can be affected. We assessed the extent to which inter-annual variations in large-scale weather patterns (specifically the NAO and Central England (CE) temperatures) and host characteristics influenced tick prevalence and intensity. Ectoparasites consisted of a single species, the nidiculous tick Ixodes hexagonus (prevalence = 24.3%; mean intensity = 7.2; range = 1-122; on n = 820 otter hosts). The prevalence, but not intensity of infestation, was associated with high CE temperatures, while both prevalence and intensity were associated with positive phases of the NAO. Such associations indicate that I. hexagonus are most abundant when weather conditions are warmer and wetter. Ticks were more prevalent on juvenile than sub-adult or adult otters, which probably reflects the length of time the hosts spend in the holt where these ticks quest. High tick number was associated with poor host condition, so either poor condition hosts are more susceptible to ticks, or tick infestations negatively impact on host condition. Otters are clearly an important and common host for I. hexagonus, which has implications for vector-borne diseases. This work is the first to consider the impacts of long-term weather patterns on I. hexagonus and uses wild-animal cadavers to illustrate the importance of abiotic and biotic pressures impacting parasitic

  15. PsAP2 an AP2/ERF family transcription factor from Papaver somniferum enhances abiotic and biotic stress tolerance in transgenic tobacco.

    PubMed

    Mishra, Sonal; Phukan, Ujjal J; Tripathi, Vineeta; Singh, Dhananjay K; Luqman, Suaib; Shukla, Rakesh Kumar

    2015-09-01

    The AP2/ERFs are one of the most important family of transcription factors which regulate multiple responses like stress, metabolism and development in plants. We isolated PsAP2 a novel AP2/ERF from Papaver somniferum which was highly upregulated in response to wounding followed by ethylene, methyl jasmonate and ABA treatment. PsAP2 showed specific binding with both DRE and GCC box elements and it was able to transactivate the reporter genes in yeast. PsAP2 overexpressing transgenic tobacco plants exhibited enhanced tolerance towards both abiotic and biotic stresses . Real time transcript expression analysis showed constitutive upregulation of tobacco Alternative oxidase1a and Myo-inositol-1-phosphate synthase in PsAP2 overexpressing tobacco plants. Further, PsAP2 showed interaction with NtAOX1a promoter in vitro, it also specifically activated the NtAOX1a promoter in yeast and tobacco BY2 cells. The silencing of PsAP2 using VIGS lead to significant reduction in the AOX1 level in P. somniferum. Taken together PsAP2 can directly bind and transcriptionally activate NtAOX1a and its overexpression in tobacco imparted increased tolerance towards both abiotic and biotic stress.

  16. A dehydration-responsive element binding (DREB) transcription factor from the succulent halophyte Salicornia brachiata enhances abiotic stress tolerance in transgenic tobacco.

    PubMed

    Gupta, Kapil; Jha, Bhavanath; Agarwal, Pradeep K

    2014-12-01

    Dehydration-responsive element binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. Earlier, we have published the isolation and characterisation of an A-2-type SbDREB2A TF from an extreme halophyte Salicornia brachiata. The SbDREB2A protein lacks potential proline (P), glutamic acid (E), serine (S) and threonine (T) (PEST) sequence which is known to act as signal peptide for protein degradation. In this study, SbDREB2A TF was over-expressed in tobacco plants without any modification in polypeptide sequence. Transgenic plants showed better seed germination and growth characteristics in both hyperionic and hyperosmotic stresses. Transgenic plants exhibited higher water content, membrane stability and less electrolyte leakage in stress conditions. The transgenic plants accumulated less Na(+) and higher K(+) than wildtype (WT) plants. The transgenic plants revealed higher chlorophyll content, water use efficiency (WUE) and net photosynthesis rate. Transgenics exhibited higher level of proline and low amount of MDA and H2O2 under stress conditions. The real-time PCR of transgenics showed higher expression of downstream heat shock genes (Hsp18, Hsp26 and Hsp70), TFs (AP2 domain containing TF, HSF2 and ZFP), signalling components (PLC3 and Ca (2+) /calmodulin) and dehydrins (ERD10B, ERD10D and LEA5) under different abiotic stress treatments.

  17. Plant Responses to Simultaneous Biotic and Abiotic Stress: Molecular Mechanisms

    PubMed Central

    Ben Rejeb, Ines; Pastor, Victoria; Mauch-Mani, Brigitte

    2014-01-01

    Plants are constantly confronted to both abiotic and biotic stresses that seriously reduce their productivity. Plant responses to these stresses are complex and involve numerous physiological, molecular, and cellular adaptations. Recent evidence shows that a combination of abiotic and biotic stress can have a positive effect on plant performance by reducing the susceptibility to biotic stress. Such an interaction between both types of stress points to a crosstalk between their respective signaling pathways. This crosstalk may be synergistic and/or antagonistic and include among others the involvement of phytohormones, transcription factors, kinase cascades, and reactive oxygen species (ROS). In certain cases, such crosstalk can lead to a cross-tolerance and enhancement of a plant’s resistance against pathogens. This review aims at giving an insight into cross-tolerance between abiotic and biotic stress, focusing on the molecular level and regulatory pathways. PMID:27135514

  18. Plant Responses to Simultaneous Biotic and Abiotic Stress: Molecular Mechanisms.

    PubMed

    Rejeb, Ines Ben; Pastor, Victoria; Mauch-Mani, Brigitte

    2014-10-15

    Plants are constantly confronted to both abiotic and biotic stresses that seriously reduce their productivity. Plant responses to these stresses are complex and involve numerous physiological, molecular, and cellular adaptations. Recent evidence shows that a combination of abiotic and biotic stress can have a positive effect on plant performance by reducing the susceptibility to biotic stress. Such an interaction between both types of stress points to a crosstalk between their respective signaling pathways. This crosstalk may be synergistic and/or antagonistic and include among others the involvement of phytohormones, transcription factors, kinase cascades, and reactive oxygen species (ROS). In certain cases, such crosstalk can lead to a cross-tolerance and enhancement of a plant's resistance against pathogens. This review aims at giving an insight into cross-tolerance between abiotic and biotic stress, focusing on the molecular level and regulatory pathways.

  19. The transcription factor SlAREB1 confers drought, salt stress tolerance and regulates biotic and abiotic stress-related genes in tomato.

    PubMed

    Orellana, Sandra; Yañez, Mónica; Espinoza, Analía; Verdugo, Isabel; González, Enrique; Ruiz-Lara, Simón; Casaretto, José A

    2010-12-01

    Members of the abscisic acid-responsive element binding protein (AREB)/abscisic acid-responsive element binding factor (ABF) subfamily of basic leucine zipper (bZIP) transcription factors have been implicated in abscisic acid (ABA) and abiotic stress responses in plants. Here we describe two members identified in cultivated tomato (Solanum lycopersicum), named SlAREB1 and SlAREB2. Expression of SlAREB1 and SlAREB2 is induced by drought and salinity in both leaves and root tissues, although that of SlAREB1 was more affected. In stress assays, SlAREB1-overexpressing transgenic tomato plants showed increased tolerance to salt and water stress compared to wild-type and SlAREB1-down-regulating transgenic plants, as assessed by physiological parameters such as relative water content (RWC), chlorophyll fluorescence and damage by lipoperoxidation. In order to identify SlAREB1 target genes responsible for the enhanced tolerance, microarray and cDNA-amplified fragment length polymorphism (AFLP) analyses were performed. Genes encoding oxidative stress-related proteins, lipid transfer proteins (LTPs), transcription regulators and late embryogenesis abundant proteins were found among the up-regulated genes in SlAREB1-overexpressing lines, especially in aerial tissue. Notably, several genes encoding defence proteins associated with responses to biotic stress (e.g. pathogenesis-related proteins, protease inhibitors, and catabolic enzymes) were also up-regulated by SlAREB1 overexpression, suggesting that this bZIP transcription factor is involved in ABA signals that participate in abiotic stress and possibly in response to pathogens.

  20. Toward understanding transcriptional regulatory networks in abiotic stress responses and tolerance in rice

    PubMed Central

    2012-01-01

    Abiotic stress causes loss of crop production. Under abiotic stress conditions, expression of many genes is induced, and their products have important roles in stress responses and tolerance. Progress has been made in understanding the biological roles of regulons in abiotic stress responses in rice. A number of transcription factors (TFs) regulate stress-responsive gene expression. OsDREB1s and OsDREB2s were identified as abiotic-stress responsive TFs that belong to the AP2/ERF family. Similar to Arabidopsis, these DREB regulons were most likely not involved in the abscisic acid (ABA) pathway. OsAREBs such as OsAREB1 were identified as key components in ABA-dependent transcriptional networks in rice. OsNAC/SNACs including OsNAC6 were characterized as factors that regulate expression of genes important for abiotic stress responses in rice. Here, we review on the rice abiotic-stress responses mediated by transcriptional networks, with the main focus on TFs that function in abiotic stress responses and confer stress tolerance in rice. PMID:24764506

  1. Using vegetation model-to-data comparisons to test the role of abiotic factors in the Neogene and Quaternary origins of modern C4 grasslands

    NASA Astrophysics Data System (ADS)

    Fox, D. L.; Strömberg, C.; Pau, S.; Taylor, L.; Lehmann, C.; Osborne, C.; Beerling, D. J.; Still, C. J.

    2014-12-01

    ) of multiple plant functional types (C3 and C4 grasses, evergreen and deciduous trees). Statistical comparisons of the isotopic and paleobotanical databases with the paleoclimate and vegetation model outputs allows us to assess the possible role of abiotic factors in the evolution of modern C4 grasslands during the late Neogene.

  2. Biotic and abiotic factors influencing the long-term stability of covers on waste rock piles in the uranium mining district of Saxony and Thuringia (Germany)

    SciTech Connect

    Heinze, M.; Koehler, M.; Saenger, H.

    1999-07-01

    This report presents the results of basic investigations of root penetration on various partially covered excavation discard material mounds of the Saxonian-Thuringian uranium mining region (Germany) in comparison to root penetration in autochthonous (native) soils. Bioturbation is an essential, unavoidable impact to consider in addition to root penetration. With increasing age, the functionality of each layer of a cover system becomes diminished through the workings of the local flora and fauna. Pedological cover layers can only temporarily maintain their initial positions and technical functionality. Considering actual prevailing biotic and abiotic influences (e.g., site-specific transpiration rates), the planning and installation of cover systems should take into account (within acceptable balances) factors which are able to at least partially compensate for eventual diminishing of technical functionality.

  3. Recovery of white sturgeon populations through natural production: Understanding the influence of abiotic and biotic factors on spawning and subsequent recruitment

    USGS Publications Warehouse

    Parsley, M.J.; Anders, P.J.; Miller, Allen I.; Beckman, L.G.; McCabe, G.T.

    2002-01-01

    Recovery or maintenance of sturgeon populations through natural production in perturbed rivers requires adequate knowledge of the abiotic and biotic factors that influence spawning and cause mortality of embryonic, larval, and juvenile life stages. Although it is known that year-class strength of white sturgeon Acipenser transmontanus is determined within 2-3 months after spawning, little is known about specific causes of mortality to early life stages during this period. Initial spawning success is critical in the development of a strong year-class, and maximized recruitment may be dependent upon water temperature and the availability of optimal in-river habitat. Analyses have shown that increased river discharge combined with suitable water temperatures during spawning, egg incubation, yolk sac larvae dispersal, and first exogenous feeding result in greater recruitment. However, little is known about the importance of other variables, such as food availability or losses due to predation that influence year-class strength. ?? 2002 by the American Fisheries Society.

  4. Overexpression of an AP2/ERF Type Transcription Factor OsEREBP1 Confers Biotic and Abiotic Stress Tolerance in Rice

    PubMed Central

    Jisha, V.; Ramanan, Rajeshwari

    2015-01-01

    AP2/ERF–type transcription factors regulate important functions of plant growth and development as well as responses to environmental stimuli. A rice AP2/ERF transcription factor, OsEREBP1 is a downstream component of a signal transduction pathway in a specific interaction between rice (Oryza sativa) and its bacterial pathogen, Xoo (Xanthomonas oryzae pv. oryzae). Constitutive expression of OsEREBP1 in rice driven by maize ubiquitin promoter did not affect normal plant growth. Microarray analysis revealed that over expression of OsEREBP1 caused increased expression of lipid metabolism related genes such as lipase and chloroplastic lipoxygenase as well as several genes related to jasmonate and abscisic acid biosynthesis. PR genes, transcription regulators and Aldhs (alcohol dehydrogenases) implicated in abiotic stress and submergence tolerance were also upregulated in transgenic plants. Transgenic plants showed increase in endogenous levels of α-linolenate, several jasmonate derivatives and abscisic acid but not salicylic acid. Soluble modified GFP (SmGFP)-tagged OsEREBP1 was localized to plastid nucleoids. Comparative analysis of non-transgenic and OsEREBP1 overexpressing genotypes revealed that OsEREBP1 attenuates disease caused by Xoo and confers drought and submergence tolerance in transgenic rice. Our results suggest that constitutive expression of OsEREBP1 activates the jasmonate and abscisic acid signalling pathways thereby priming the rice plants for enhanced survival under abiotic or biotic stress conditions. OsEREBP1 is thus, a good candidate gene for engineering plants for multiple stress tolerance. PMID:26035591

  5. Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata.

    PubMed

    Agrahari, P; Singh, D K

    2013-11-01

    Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September.

  6. The CarERF genes in chickpea (Cicer arietinum L.) and the identification of CarERF116 as abiotic stress responsive transcription factor.

    PubMed

    Deokar, Amit A; Kondawar, Vishwajith; Kohli, Deshika; Aslam, Mohammad; Jain, Pradeep K; Karuppayil, S Mohan; Varshney, Rajeev K; Srinivasan, Ramamurthy

    2015-01-01

    The AP2/ERF family is one of the largest transcription factor gene families that are involved in various plant processes, especially in response to biotic and abiotic stresses. Complete genome sequences of one of the world's most important pulse crops chickpea (Cicer arietinum L.), has provided an important opportunity to identify and characterize genome-wide ERF genes. In this study, we identified 120 putative ERF genes from chickpea. The genomic organization of the chickpea ERF genes suggested that the gene family might have been expanded through the segmental duplications. The 120 member ERF family was classified into eleven distinct groups (I-X and VI-L). Transcriptional factor CarERF116, which is differentially expressed between drought tolerant and susceptible chickpea cultivar under terminal drought stress has been identified and functionally characterized. The CarERF116 encodes a putative protein of 241 amino acids and classified into group IX of ERF family. An in vitro CarERF116 protein-DNA binding assay demonstrated that CarERF116 protein specifically interacts with GCC box. We demonstrate that CarERF116 is capable of transactivation activity of and show that the functional transcriptional domain lies at the C-terminal region of the CarERF116. In transgenic Arabidopsis plants overexpressing CarERF116, significant up-regulation of several stress related genes were observed. These plants also exhibit resistance to osmotic stress and reduced sensitivity to ABA during seed germination. Based on these findings, we conclude that CarERF116 is an abiotic stress responsive gene, which plays an important role in stress tolerance. In addition, the present study leads to genome-wide identification and evolutionary analyses of chickpea ERF gene family, which will facilitate further research on this important group of genes and provides valuable resources for comparative genomics among the grain legumes.

  7. The auxin response factor gene family in banana: genome-wide identification and expression analyses during development, ripening, and abiotic stress

    PubMed Central

    Hu, Wei; Zuo, Jiao; Hou, Xiaowan; Yan, Yan; Wei, Yunxie; Liu, Juhua; Li, Meiying; Xu, Biyu; Jin, Zhiqiang

    2015-01-01

    Auxin signaling regulates various auxin-responsive genes via two types of transcriptional regulators, Auxin Response Factors (ARF) and Aux/IAA. ARF transcription factors act as critical components of auxin signaling that play important roles in modulating various biological processes. However, limited information about this gene family in fruit crops is currently available. Herein, 47 ARF genes were identified in banana based on its genome sequence. Phylogenetic analysis of the ARFs from banana, rice, and Arabidopsis suggested that the ARFs could be divided into four subgroups, among which most ARFs from the banana showed a closer relationship with those from rice than those from Arabidopsis. Conserved motif analysis showed that all identified MaARFs had typical DNA-binding and ARF domains, but 12 members lacked the dimerization domain. Gene structure analysis showed that the number of exons in MaARF genes ranged from 5 to 21, suggesting large variation amongst banana ARF genes. The comprehensive expression profiles of MaARF genes yielded useful information about their involvement in diverse tissues, different stages of fruit development and ripening, and responses to abiotic stresses in different varieties. Interaction networks and co-expression assays indicated the strong transcriptional response of banana ARFs and ARF-mediated networks in early fruit development for different varieties. Our systematic analysis of MaARFs revealed robust tissue-specific, development-dependent, and abiotic stress-responsive candidate MaARF genes for further functional assays in planta. These findings could lead to potential applications in the genetic improvement of banana cultivars, and yield new insights into the complexity of the control of MaARF gene expression at the transcriptional level. Finally, they support the hypothesis that ARFs are a crucial component of the auxin signaling pathway, which regulates a wide range of physiological processes. PMID:26442055

  8. Effects of biotic and abiotic factors on grape root borer (Lepidoptera: Sesiidae) infestations in commercial vineyards in Virginia.

    PubMed

    Rijal, Jhalendra P; Brewster, C C; Bergh, J C

    2014-10-01

    Larval grape root borer, Vitacea polistiformis (Harris) (Lepidoptera: Sesiidae), feed on roots of wild Vitis and commercially important Vitis species and rootstocks in portions of the eastern United States. Grape root borer pupal exuviae sampling in Virginia vineyards from 2008 to 2012 revealed that infestation levels varied substantially among 48 vineyard blocks. Data on horticultural (cultivar, rootstock, vine age, and planting area), cultural (insecticide use, ground cover, weed control, and irrigation), and environmental variables (proximity to forest, soil composition, soil moisture holding capacity, pH, organic matter, bulk density, and cation exchange capacity) from each block were subjected to optimal quantification using categorical principal component analysis (CATPCA). Variables with component loading values ≥0.70 from the CATPCA were used as predictors and pupal exuviae density as the dependent variable in binary logistic regression. A prediction model was developed by including statistically significant variables in the logistic regression. CATPCA showed that seven vineyard factors (ground cover, soil texture, soil mass moisture, soil pH, clay/sand ratio, clay/silt ratio, and sand/silt ratio) based on three selected principal components were significant for subsequent regression analysis. Binary logistic regression showed that soil mass moisture and clay/sand ratio were statistically significant factors contributing to differences in infestation among vineyard blocks. Based on these two factors, a risk prediction model for calculating the probability of grape root borer infestation in vineyards was developed and validated using receiver operating characteristic curve. Results are discussed in relation to the practical implications of a predictive, risk assessment model for grape root borer management.

  9. Biotic and abiotic factors related to rainbow smelt recruitment in the Wisconsin waters of Lake Superior, 1978-1997

    USGS Publications Warehouse

    Hoff, Michael H.

    2004-01-01

    Lake Superior rainbow smelt (Osmerus mordax) recruitment to 12-13 months of age in the Wisconsin waters of Lake Superior varied by a factor of 9.3 during 1978-1997. Management agencies have sought models that accurately predict recruitment, but no satisfactory models had previously been developed. In this study, modeling was conducted to determine which factors best explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data accounted for 63% of the variability in recruitment data. The functional relationship that accounted for the greatest amount of recruitment variation (81%) included rainbow smelt stock size, May rainfall, and bloater (Coregonus hoyi) biomass. Model results were interpreted to mean that recruitment was affected negatively by increased river flows from increased rainfall, and affected positively by the biomass of bloater, and those results were interpreted to mean that bloater mediated the effects of lake trout predation on rainbow smelt recruits. Model results were also interpreted to mean that stock size caused compensatory, density-dependent mortality on rainbow smelt recruits. Correlations observed here may be of value to managers seeking approaches to either enhance or control populations of this species, which is not indigenous to the Great Lakes.

  10. Biotic and abiotic factors investigated in two Drosophila species – evidence of both negative and positive effects of interactions on performance

    PubMed Central

    Ørsted, Michael; Schou, Mads Fristrup; Kristensen, Torsten Nygaard

    2017-01-01

    Multiple environmental factors acting in concert can interact and strongly influence population fitness and ecosystem composition. Studies investigating interactions usually involve only two environmental factors; most frequently a chemical and another abiotic factor such as a stressful temperature. Here we investigate the effects of three environmental factors: temperature, an insecticide (dimethoate) and interspecific co-occurrence. We expose two naturally co-occurring species of Drosophila (D. hydei and D. melanogaster) to the different environments during development and examine the consequences on several performance measures. Results are highly species and trait specific with evidence of two- and three-way interactions in approximately 30% of all cases, suggesting that additive effects of combined environmental factors are most common, and that interactions are not universal. To provide more informative descriptions of complex interactions we implemented re-conceptualised definitions of synergism and antagonism. We found approximately equal proportions of synergistic and antagonistic interactions in both species, however the effects of interactions on performance differed between the two. Furthermore, we found negative impacts on performance in only 60% of interactions, thus our study also reveals a high proportion of cases with positive effects of interactions. PMID:28059144

  11. Biotic and abiotic factors related to lake herring recruitment in the Wisconsin waters of Lake Superior, 1984-1998

    USGS Publications Warehouse

    Hoff, Michael H.

    2004-01-01

    Lake Superior lake herring (Coregonus artedi) recruitment to 13-14 months of age in the Wisconsin waters of Lake Superior varied by a factor of 5,233 during 1984-1998. Management agencies have sought models that accurately predict recruitment, but no satisfactory model had previously been developed. Lake herring recruitment was modeled to determine which factors most explained recruitment variability. The Ricker stock-recruitment model derived from only the paired stock and recruit data explained 35% of the variability in the recruitment data. The functional relationship that explained the greatest amount of recruitment variation (93%) included lake herring stock size, lake trout (Salvelinus namaycush) population size, slimy sculpin (Cottus cognatus) biomass, the interaction of mean daily wind speed in April (month of hatch) and lake herring stock size, and mean air temperature in April (when lake herring are 12-months old). Model results were interpreted to mean that lake herring recruitment was affected negatively by: slimy sculpin predation on lake herring ova; predation on age-0 lake herring by lake trout; and adult cannibalism on lake herring larvae, which was reduced by increased wind speed. April temperature was the variable that explained the least amount of variability in recruitment, but lake herring recruitment was positively affected by a warm April, which shortened winter and apparently reduced first-winter mortality. Stock size caused compensatory, density-dependent mortality on lake herring recruits. Management efforts appear best targeted at stock size protection, and empirical data implies that stock size in the Wisconsin waters of the lake should be maintained at 2.1-15.0 adults/ha in spring, bottom-trawl surveys.

  12. Spatial patterns of distribution and the influence of seasonal and abiotic factors on demersal ichthyofauna in an estuarine tropical bay.

    PubMed

    da Silva, D R; Paranhos, R; Vianna, M

    2016-07-01

    This study focused on the influence of local-scale environmental factors on key metrics of fish community structure and function at Guanabara Bay, an estuarine system that differs from all other south-western Atlantic estuaries due to the influence of an annual low-intensity upwelling event during late spring and summer, between November and March, when a warm rainy climate prevails. The spatial patterns of the bottom temperature and salinity were more heterogeneous during the rainy season than the dry season, being linked to total precipitation and seasonal oceanographic events. The study identified 130 species and 45 families, placing Guanabara Bay as one of the most species-rich tropical estuarine ecosystems, far exceeding 22 other Brazilian estuaries. These results, in addition to characteristics such as a relatively well-preserved mangrove forest, high productivity and favourable conditions for the growth and reproduction of estuarine species, indicate that Guanabara Bay plays a central role in supporting large populations of fishes, including commercially important species. © 2016 The Fisheries Society of the British Isles.

  13. Genome-wide analysis of AP2/ERF transcription factors in carrot (Daucus carota L.) reveals evolution and expression profiles under abiotic stress.

    PubMed

    Li, Meng-Yao; Xu, Zhi-Sheng; Huang, Ying; Tian, Chang; Wang, Feng; Xiong, Ai-Sheng

    2015-12-01

    AP2/ERF is a large transcription factor family that regulates plant physiological processes, such as plant development and stress response. Carrot (Daucus carota L.) is an important economical crop with a genome size of 480 Mb; the draft genome sequencing of this crop has been completed by our group. However, little is known about the AP2/ERF factors in carrot. In this study, a total of 267 putative AP2/ERF factors were identified from the whole-genome sequence of carrot. These AP2/ERF proteins were phylogenetically clustered into five subfamilies based on their similarity to the amino acid sequences from Arabidopsis. The distribution and comparative genome analysis of the AP2/ERF factors among plants showed the AP2/ERF factors had expansion during the evolutionary process, and the AP2 domain was highly conserved during evolution. The number of AP2/ERF factors in land plants expanded during their evolution. A total of 60 orthologous and 145 coorthologous AP2/ERF gene pairs between carrot and Arabidopsis were identified, and the interaction network of orthologous genes was constructed. The expression patterns of eight AP2/ERF family genes from each subfamily (DREB, ERF, AP2, and RAV) were related to abiotic stresses. Yeast one-hybrid and β-galactosidase activity assays confirmed the DRE and GCC box-binding activities of DREB subfamily genes. This study is the first to identify and characterize the AP2/ERF transcription factors in carrot using whole-genome analysis, and the findings may serve as references for future functional research on the transcription factors in carrot.

  14. Genome-wide identification and characterization of the Populus WRKY transcription factor family and analysis of their expression in response to biotic and abiotic stresses.

    PubMed

    Jiang, Yuanzhong; Duan, Yanjiao; Yin, Jia; Ye, Shenglong; Zhu, Jingru; Zhang, Faqi; Lu, Wanxiang; Fan, Di; Luo, Keming

    2014-12-01

    WRKY proteins are a large family of regulators involved in various developmental and physiological processes, especially in coping with diverse biotic and abiotic stresses. In this study, 100 putative PtrWRKY genes encoded the proteins contained in the complete WRKY domain in Populus. Phylogenetic analysis revealed that the members of this superfamily among poplar, Arabidopsis, and other species were divided into three groups with several subgroups based on the structures of the WRKY protein sequences. Various cis-acting elements related to stress and defence responses were found in the promoter regions of PtrWRKY genes by promoter analysis. High-throughput transcriptomic analyses identified that 61 of the PtrWRKY genes were induced by biotic and abiotic treatments, such as Marssonina brunnea, salicylic acid (SA), methyl jasmonate (MeJA), wounding, cold, and salinity. Among these PtrWRKY genes, transcripts of 46 selected genes were observed in different tissues, including roots, stems, and leaves. Quantitative RT-PCR analysis further confirmed the induced expression of 18 PtrWRKY genes by one or more stress treatments. The overexpression of an SA-inducible gene, PtrWRKY89, accelerated expression of PR protein genes and improved resistance to pathogens in transgenic poplar, suggesting that PtrWRKY89 is a regulator of an SA-dependent defence-signalling pathway in poplar. Taken together, our results provided significant information for improving the resistance and stress tolerance of woody plants. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  15. Abiotic and biotic factors associated with the presence of Anopheles arabiensis immatures and their abundance in naturally occurring and man-made aquatic habitats

    PubMed Central

    2012-01-01

    Background Anopheles arabiensis (Diptera: Culicidae) is a potential malaria vector commonly present at low altitudes in remote areas in Reunion Island. Little attention has been paid to the environmental conditions driving larval development and abundance patterns in potential habitats. Two field surveys were designed to determine whether factors that discriminate between aquatic habitats with and without An. arabiensis larvae also drive larval abundance, comparatively in man-made and naturally occurring habitats. Methods In an initial preliminary survey, a representative sample of aquatic habitats that would be amenable to an intensive long-term study were selected and divided into positive and negative sites based on the presence or absence of Anopheles arabiensis larvae. Subsequently, a second survey was prompted to gain a better understanding of biotic and abiotic drivers of larval abundance, comparatively in man-made and naturally occurring habitats in the two studied locations. In both surveys, weekly sampling was performed to record mosquito species composition and larval density within individual habitats, as well as in situ biological characteristics and physico-chemical properties. Results Whilst virtually any stagnant water body could be a potential breeding ground for An. arabiensis, habitats occupied by their immatures had different structural and biological characteristics when compared to those where larvae were absent. Larval occurrence seemed to be influenced by flow velocity, macrofauna diversity and predation pressure. Interestingly, the relative abundance of larvae in man-made habitats (average: 0.55 larvae per dip, 95%CI [0.3–0.7]) was significantly lower than that recorded in naturally occurring ones (0.74, 95%CI [0.5–0.8]). Such differences may be accounted for in part by varying pressures that could be linked to a specific habitat. Conclusions If the larval ecology of An. arabiensis is in general very complex and factors affecting

  16. Abiotic and biotic factors associated with the presence of Anopheles arabiensis immatures and their abundance in naturally occurring and man-made aquatic habitats.

    PubMed

    Gouagna, Louis Clément; Rakotondranary, Manpionona; Boyer, Sebastien; Lempérière, Guy; Dehecq, Jean-Sébastien; Fontenille, Didier

    2012-05-19

    Anopheles arabiensis (Diptera: Culicidae) is a potential malaria vector commonly present at low altitudes in remote areas in Reunion Island. Little attention has been paid to the environmental conditions driving larval development and abundance patterns in potential habitats. Two field surveys were designed to determine whether factors that discriminate between aquatic habitats with and without An. arabiensis larvae also drive larval abundance, comparatively in man-made and naturally occurring habitats. In an initial preliminary survey, a representative sample of aquatic habitats that would be amenable to an intensive long-term study were selected and divided into positive and negative sites based on the presence or absence of Anopheles arabiensis larvae. Subsequently, a second survey was prompted to gain a better understanding of biotic and abiotic drivers of larval abundance, comparatively in man-made and naturally occurring habitats in the two studied locations. In both surveys, weekly sampling was performed to record mosquito species composition and larval density within individual habitats, as well as in situ biological characteristics and physico-chemical properties. Whilst virtually any stagnant water body could be a potential breeding ground for An. arabiensis, habitats occupied by their immatures had different structural and biological characteristics when compared to those where larvae were absent. Larval occurrence seemed to be influenced by flow velocity, macrofauna diversity and predation pressure. Interestingly, the relative abundance of larvae in man-made habitats (average: 0.55 larvae per dip, 95%CI [0.3-0.7]) was significantly lower than that recorded in naturally occurring ones (0.74, 95%CI [0.5-0.8]). Such differences may be accounted for in part by varying pressures that could be linked to a specific habitat. If the larval ecology of An. arabiensis is in general very complex and factors affecting breeding site productivity sometimes not easy to

  17. Use of a Generalized Additive Model to Investigate Key Abiotic Factors Affecting Microcystin Cellular Quotas in Heavy Bloom Areas of Lake Taihu

    PubMed Central

    Tao, Min; Xie, Ping; Chen, Jun; Qin, Boqiang; Zhang, Dawen; Niu, Yuan; Zhang, Meng; Wang, Qing; Wu, Laiyan

    2012-01-01

    Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation. PMID:22384128

  18. Use of a generalized additive model to investigate key abiotic factors affecting microcystin cellular quotas in heavy bloom areas of Lake Taihu.

    PubMed

    Tao, Min; Xie, Ping; Chen, Jun; Qin, Boqiang; Zhang, Dawen; Niu, Yuan; Zhang, Meng; Wang, Qing; Wu, Laiyan

    2012-01-01

    Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation.

  19. Biotic and abiotic factors affecting the genetic structure and diversity of butternut in the southern Appalachian Mountains, USA

    Treesearch

    Amanda Parks; Michael Jenkins; Michael Ostry; Peng Zhao; Keith. Woeste

    2014-01-01

    The abundance of butternut (Juglans cinerea L.) trees has severely declined rangewide over the past 50 years. An important factor in the decline is butternut canker, a disease caused by the fungus Ophiognomonia clavigigentijuglandacearum, which has left the remaining butternuts isolated and sparsely distributed. To manage the...

  20. A novel ethylene-responsive factor from Tamarix hispida, ThERF1, is a GCC-box- and DRE-motif binding protein that negatively modulates abiotic stress tolerance in Arabidopsis.

    PubMed

    Wang, Liuqiang; Qin, Liping; Liu, Wenjin; Zhang, Daoyuan; Wang, Yucheng

    2014-09-01

    Ethylene-responsive factor (ERF) family is one of the largest families of plant-specific transcription factor that can positively or negatively regulate abiotic stress tolerance. However, their functions in regulating abiotic stress tolerance are still not fully understood. In this study, we characterized the functions of an ERF gene from Tamarix hispida, ThERF1, which can negatively regulate abiotic stress tolerance. The expression of ThERF1 was induced by salinity, PEG-simulated drought and abscisic acid (ABA) treatments. ThERF1 can specifically bind to GCC-box and DRE motifs. Overexpression of ThERF1 in transgenic Arabidopsis plants showed inhibited seed germination, and decreased fresh weight gain and root growth compared with wild-type (WT) plants. In addition, the transcript levels of several superoxide dismutase (SOD) and peroxidase (POD) genes in transgenic plants were significantly inhibited compared with in WT plants, resulting in decreased SOD and POD activities in transgenic plants under salt and drought stress conditions. Furthermore, the reactive oxygen species (ROS) levels, malondialdehyde (MDA) contents and cell membrane damage in ThERF1-transformed plants were all highly increased relative to WT plants. Our results suggest that ThERF1 negatively regulates abiotic stress tolerance by strongly inhibiting the expression of SOD and POD genes, leading to decreased ROS-scavenging ability.

  1. Oxylipins and plant abiotic stress resistance.

    PubMed

    Savchenko, T V; Zastrijnaja, O M; Klimov, V V

    2014-04-01

    Oxylipins are signaling molecules formed enzymatically or spontaneously from unsaturated fatty acids in all aerobic organisms. Oxylipins regulate growth, development, and responses to environmental stimuli of organisms. The oxylipin biosynthesis pathway in plants includes a few parallel branches named after first enzyme of the corresponding branch as allene oxide synthase, hydroperoxide lyase, divinyl ether synthase, peroxygenase, epoxy alcohol synthase, and others in which various biologically active metabolites are produced. Oxylipins can be formed non-enzymatically as a result of oxygenation of fatty acids by free radicals and reactive oxygen species. Spontaneously formed oxylipins are called phytoprostanes. The role of oxylipins in biotic stress responses has been described in many published works. The role of oxylipins in plant adaptation to abiotic stress conditions is less studied; there is also obvious lack of available data compilation and analysis in this area of research. In this work we analyze data on oxylipins functions in plant adaptation to abiotic stress conditions, such as wounding, suboptimal light and temperature, dehydration and osmotic stress, and effects of ozone and heavy metals. Modern research articles elucidating the molecular mechanisms of oxylipins action by the methods of biochemistry, molecular biology, and genetics are reviewed here. Data on the role of oxylipins in stress signal transduction, stress-inducible gene expression regulation, and interaction of these metabolites with other signal transduction pathways in cells are described. In this review the general oxylipin-mediated mechanisms that help plants to adjust to a broad spectrum of stress factors are considered, followed by analysis of more specific responses regulated by oxylipins only under certain stress conditions. New approaches to improvement of plant resistance to abiotic stresses based on the induction of oxylipin-mediated processes are discussed.

  2. Temporal dynamics of abiotic and biotic factors on leaf litter of three plant species in relation to decomposition rate along a subalpine elevation gradient.

    PubMed

    Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

    2013-01-01

    Relationships between abiotic (soil temperature and number of freeze-thaw cycles) or biotic factors (chemical elements, microbial biomass, extracellular enzymes, and decomposer communities in litter) and litter decomposition rates were investigated over two years in subalpine forests close to the Qinghai-Tibet Plateau in China. Litterbags with senescent birch, fir, and spruce leaves were placed on the forest floor at 2,704 m, 3,023 m, 3,298 m, and 3,582 m elevation. Results showed that the decomposition rate positively correlated with soil mean temperature during the plant growing season, and with the number of soil freeze-thaw cycles during the winter. Concentrations of soluble nitrogen (N), phosphorus (P) and potassium (K) had positive effects but C:N and lignin:N ratios had negative effects on the decomposition rate (k), especially during the winter. Meanwhile, microbial biomass carbon (MBC), N (MBN), and P (MBP) were positively correlated with k values during the first growing season. These biotic factors accounted for 60.0% and 56.4% of the variation in decomposition rate during the winter and the growing season in the first year, respectively. Specifically, litter chemistry (C, N, P, K, lignin, C:N and lignin:N ratio) independently explained 29.6% and 13.3%, and the microbe-related factors (MBC, MBN, MBP, bacterial and fungal biomass, sucrase and ACP activity) explained 22.9% and 34.9% during the first winter and the first growing season, respectively. We conclude that frequent freeze-thaw cycles and litter chemical properties determine the winter decomposition while microbe-related factors play more important roles in determining decomposition in the subsequent growing season.

  3. Temporal Dynamics of Abiotic and Biotic Factors on Leaf Litter of Three Plant Species in Relation to Decomposition Rate along a Subalpine Elevation Gradient

    PubMed Central

    Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

    2013-01-01

    Relationships between abiotic (soil temperature and number of freeze-thaw cycles) or biotic factors (chemical elements, microbial biomass, extracellular enzymes, and decomposer communities in litter) and litter decomposition rates were investigated over two years in subalpine forests close to the Qinghai-Tibet Plateau in China. Litterbags with senescent birch, fir, and spruce leaves were placed on the forest floor at 2,704 m, 3,023 m, 3,298 m, and 3,582 m elevation. Results showed that the decomposition rate positively correlated with soil mean temperature during the plant growing season, and with the number of soil freeze-thaw cycles during the winter. Concentrations of soluble nitrogen (N), phosphorus (P) and potassium (K) had positive effects but C:N and lignin:N ratios had negative effects on the decomposition rate (k), especially during the winter. Meanwhile, microbial biomass carbon (MBC), N (MBN), and P (MBP) were positively correlated with k values during the first growing season. These biotic factors accounted for 60.0% and 56.4% of the variation in decomposition rate during the winter and the growing season in the first year, respectively. Specifically, litter chemistry (C, N, P, K, lignin, C:N and lignin:N ratio) independently explained 29.6% and 13.3%, and the microbe-related factors (MBC, MBN, MBP, bacterial and fungal biomass, sucrase and ACP activity) explained 22.9% and 34.9% during the first winter and the first growing season, respectively. We conclude that frequent freeze-thaw cycles and litter chemical properties determine the winter decomposition while microbe-related factors play more important roles in determining decomposition in the subsequent growing season. PMID:23620803

  4. No Silver Bullet - Canonical Poly(ADP-Ribose) Polymerases (PARPs) Are No Universal Factors of Abiotic and Biotic Stress Resistance of Arabidopsis thaliana.

    PubMed

    Rissel, Dagmar; Heym, Peter P; Thor, Kathrin; Brandt, Wolfgang; Wessjohann, Ludger A; Peiter, Edgar

    2017-01-01

    Abiotic and biotic stress can have a detrimental impact on plant growth and productivity. Hence, there is a substantial demand for key factors of stress responses to improve yield stability of crops. Members of the poly(ADP-ribose)polymerase (PARP) protein family, which post-translationally modify (PARylate) nuclear proteins, have been suggested as such universal determinants of plant stress responses. A role under abiotic stress has been inferred from studies in which a genetic or, more commonly, pharmacological inhibition of PARP activity improved the performance of stressed plants. To further elucidate the role of PARP proteins under stress, T-DNA knockout mutants for the three Arabidopsis thaliana PARP genes were subjected to drought, osmotic, salt, and oxidative stress. To exclude a functional redundancy, which was indicated by a transcriptional upregulation of the remaining parp genes, a parp triple mutant was generated. Surprisingly, parp mutant plants did not differ from wild type plants in any of these stress experiments, independent from the number of PARP genes mutated. The parp triple mutant was also analyzed for callose formation in response to the pathogenassociated molecular pattern flg22. Unexpectedly, callose formation was unaltered in the mutant, albeit pharmacological PARP inhibition robustly blocked this immune response, confirming previous reports. Evidently, pharmacological inhibition appears to be more robust than the abolition of all PARP genes, indicating the presence of so-far undescribed proteins with PARP activity. This was supported by the finding that protein PARylation was not absent, but even increased in the parp triple mutant. Candidates for novel PARP-inhibitor targets may be found in the SRO protein family. These proteins harbor a catalytic PARP-like domain and are centrally involved in stress responses. Molecular modeling analyses, employing animal PARPs as templates, indeed indicated a capability of the SRO proteins RCD1 and

  5. Genome-wide survey of heat shock factors and heat shock protein 70s and their regulatory network under abiotic stresses in Brachypodium distachyon.

    PubMed

    Wen, Feng; Wu, Xiaozhu; Li, Tongjian; Jia, Mingliang; Liu, Xinshen; Li, Peng; Zhou, Xiaojian; Ji, Xinxin; Yue, Xiaomin

    2017-01-01

    The heat shock protein 70s (Hsp70s) and heat shock factors (Hsfs) play key roles in protecting plant cells or tissues from various abiotic stresses. Brachypodium distachyon, recently developed an excellent model organism for functional genomics research, is related to the major cereal grain species. Although B. distachyon genome has been fully sequenced, the information of Hsf and Hsp70 genes and especially the regulatory network between Hsfs and Hsp70s remains incomplete. Here, a total of 24 BdHsfs and 29 BdHsp70s were identified in the genome by bioinformatics analysis and the regulatory network between Hsfs and Hsp70s were performed in this study. Based on highly conserved domain and motif analysis, BdHsfs were grouped into three classes, and BdHsp70s divided into six groups, respectively. Most of Hsf proteins contain five conserved domains: DBD, HR-A/B region, NLS and NES motifs and AHA domain, while Hsp70 proteins have three conserved domains: N-terminal nucleotide binding domain, peptide binding domain and a variable C-terminal lid region. Expression data revealed a large number of BdHsfs and BdHsp70s were induced by HS challenge, and a previous heat acclimation could induce the acquired thermotolerance to help seedling suffer the severe HS challenge, suggesting that the BdHsfs and BdHsp70s played a role in alleviating the damage by HS. The comparison revealed that, most BdHsfs and BdHsp70s genes responded to multiple abiotic stresses in an overlapping relationship, while some of them were stress specific response genes. Moreover, co-expression relationships and predicted protein-protein interaction network implied that class A and B Hsfs played as activator and repressors, respectively, suggesting that BdHsp70s might be regulated by both the activation and the repression mechanisms under stress condition. Our genomics analysis of BdHsfs and BdHsp70s provides important evolutionary and functional characterization for further investigation of the accurate

  6. No Silver Bullet – Canonical Poly(ADP-Ribose) Polymerases (PARPs) Are No Universal Factors of Abiotic and Biotic Stress Resistance of Arabidopsis thaliana

    PubMed Central

    Rissel, Dagmar; Heym, Peter P.; Thor, Kathrin; Brandt, Wolfgang; Wessjohann, Ludger A.; Peiter, Edgar

    2017-01-01

    Abiotic and biotic stress can have a detrimental impact on plant growth and productivity. Hence, there is a substantial demand for key factors of stress responses to improve yield stability of crops. Members of the poly(ADP-ribose)polymerase (PARP) protein family, which post-translationally modify (PARylate) nuclear proteins, have been suggested as such universal determinants of plant stress responses. A role under abiotic stress has been inferred from studies in which a genetic or, more commonly, pharmacological inhibition of PARP activity improved the performance of stressed plants. To further elucidate the role of PARP proteins under stress, T-DNA knockout mutants for the three Arabidopsis thaliana PARP genes were subjected to drought, osmotic, salt, and oxidative stress. To exclude a functional redundancy, which was indicated by a transcriptional upregulation of the remaining parp genes, a parp triple mutant was generated. Surprisingly, parp mutant plants did not differ from wild type plants in any of these stress experiments, independent from the number of PARP genes mutated. The parp triple mutant was also analyzed for callose formation in response to the pathogenassociated molecular pattern flg22. Unexpectedly, callose formation was unaltered in the mutant, albeit pharmacological PARP inhibition robustly blocked this immune response, confirming previous reports. Evidently, pharmacological inhibition appears to be more robust than the abolition of all PARP genes, indicating the presence of so-far undescribed proteins with PARP activity. This was supported by the finding that protein PARylation was not absent, but even increased in the parp triple mutant. Candidates for novel PARP-inhibitor targets may be found in the SRO protein family. These proteins harbor a catalytic PARP-like domain and are centrally involved in stress responses. Molecular modeling analyses, employing animal PARPs as templates, indeed indicated a capability of the SRO proteins RCD1 and

  7. Changes in biotic and abiotic processes following mangrove clearing

    NASA Astrophysics Data System (ADS)

    Granek, Elise; Ruttenberg, Benjamin I.

    2008-12-01

    Mangrove forests, important tropical coastal habitats, are in decline worldwide primarily due to removal by humans. Changes to mangrove systems can alter ecosystem properties through direct effects on abiotic factors such as temperature, light and nutrient supply or through changes in biotic factors such as primary productivity or species composition. Despite the importance of mangroves as transitional habitats between land and sea, little research has examined changes that occur when they are cleared. We examined changes in a number of biotic and abiotic factors following the anthropogenic removal of red mangroves ( Rhizophora mangle) in the Panamanian Caribbean, including algal biomass, algal diversity, algal grazing rates, light penetration, temperature, sedimentation rates and sediment organic content. In this first study examining multiple ecosystem-level effects of mangrove disturbance, we found that areas cleared of mangroves had higher algal biomass and richness than intact mangrove areas. This increase in algal biomass and richness was likely due to changes in abiotic factors (e.g. light intensity, temperature), but not biotic factors (fish herbivory). Additionally the algal and cyanobacterial genera dominating mangrove-cleared areas were rare in intact mangroves and included a number of genera that compete with coral for space on reefs. Interestingly, sedimentation rates did not differ between intact and cleared areas, but the sediments that accumulated in intact mangroves had higher organic content. These findings are the first to demonstrate that anthropogenic clearing of mangroves changes multiple biotic and abiotic processes in mangrove forests and that some of these changes may influence adjacent habitats such as coral reefs and seagrass beds. Additional research is needed to further explore the community and ecosystem-level effects of mangrove clearing and their influence on adjacent habitats, but it is clear that mangrove conservation is an

  8. Interactions among biotic and abiotic factors affect the reliability of tungsten microneedles puncturing in vitro and in vivo peripheral nerves: A hybrid computational approach.

    PubMed

    Sergi, Pier Nicola; Jensen, Winnie; Yoshida, Ken

    2016-02-01

    Tungsten is an elective material to produce slender and stiff microneedles able to enter soft tissues and minimize puncture wounds. In particular, tungsten microneedles are used to puncture peripheral nerves and insert neural interfaces, bridging the gap between the nervous system and robotic devices (e.g., hand prostheses). Unfortunately, microneedles fail during the puncture process and this failure is not dependent on stiffness or fracture toughness of the constituent material. In addition, the microneedles' performances decrease during in vivo trials with respect to the in vitro ones. This further effect is independent on internal biotic effects, while it seems to be related to external biotic causes. Since the exact synergy of phenomena decreasing the in vivo reliability is still not known, this work explored the connection between in vitro and in vivo behavior of tungsten microneedles through the study of interactions between biotic and abiotic factors. A hybrid computational approach, simultaneously using theoretical relationships and in silico models of nerves, was implemented to model the change of reliability varying the microneedle diameter, and to predict in vivo performances by using in vitro reliability and local differences between in vivo and in vitro mechanical response of nerves. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Interactive Effects of UV-B Light with Abiotic Factors on Plant Growth and Chemistry, and Their Consequences for Defense against Arthropod Herbivores

    PubMed Central

    Escobar-Bravo, Rocio; Klinkhamer, Peter G. L.; Leiss, Kirsten A.

    2017-01-01

    Ultraviolet-B (UV-B) light plays a crucial role in plant–herbivorous arthropods interactions by inducing changes in constitutive and inducible plant defenses. In particular, constitutive defenses can be modulated by UV-B-induced photomorphogenic responses and changes in the plant metabolome. In accordance, the prospective use of UV-B light as a tool to increase plant protection in agricultural practice has gained increasing interest. Changes in the environmental conditions might, however, modulate the UV-B -induced plant responses. While in some cases plant responses to UV-B can increase adaptation to changes in certain abiotic factors, UV-B-induced responses might be also antagonized by the changing environment. The outcome of these interactions might have a great influence on how plants interact with their enemies, e.g., herbivorous arthropods. Here, we provide a review on the interactive effects of UV-B and light quantity and quality, increased temperature and drought stress on plant biochemistry, and we discuss the implications of the outcome of these interactions for plant resistance to arthropod pests. PMID:28303147

  10. Interactive Effects of UV-B Light with Abiotic Factors on Plant Growth and Chemistry, and Their Consequences for Defense against Arthropod Herbivores.

    PubMed

    Escobar-Bravo, Rocio; Klinkhamer, Peter G L; Leiss, Kirsten A

    2017-01-01

    Ultraviolet-B (UV-B) light plays a crucial role in plant-herbivorous arthropods interactions by inducing changes in constitutive and inducible plant defenses. In particular, constitutive defenses can be modulated by UV-B-induced photomorphogenic responses and changes in the plant metabolome. In accordance, the prospective use of UV-B light as a tool to increase plant protection in agricultural practice has gained increasing interest. Changes in the environmental conditions might, however, modulate the UV-B -induced plant responses. While in some cases plant responses to UV-B can increase adaptation to changes in certain abiotic factors, UV-B-induced responses might be also antagonized by the changing environment. The outcome of these interactions might have a great influence on how plants interact with their enemies, e.g., herbivorous arthropods. Here, we provide a review on the interactive effects of UV-B and light quantity and quality, increased temperature and drought stress on plant biochemistry, and we discuss the implications of the outcome of these interactions for plant resistance to arthropod pests.

  11. Aquatic macroinvertebrates associated with Eichhornia azurea (Swartz) Kunth and relationships with abiotic factors in marginal lentic ecosystems (São Paulo, Brazil).

    PubMed

    Silva, C V; Henry, R

    2013-02-01

    Marginal lakes are characterised by their having high biological diversity due to the presence of aquatic macrophytes in their coastal zones, providing habitats for refuge and food for animal community members. Among the fauna components associated with macrophytes, aquatic macroinvertebrates are important because they are an energy source for predators and fish. In six lakes and two different seasons (March and August 2009), the ecological attributes of aquatic macroinvertebrate community associated with Eichhornia azurea were compared and the controlling environmental factors were identified. Since the attributes of macroinvertebrate community are strictly associated with abiotic variables of each distinct habitat, our hypothesis was that each site associated with the same floating aquatic macrophyte (E. azurea) should have a typical composition and density of organisms. We identified 50 taxa of macroinvertebrates, with greater taxa richness for aquatic insects (37 taxa) divided into eight orders; the order Diptera being the most abundant in the two study periods. On the other hand, higher values of total taxa richness were recorded in August. Dissolved oxygen and pH presented the greatest number of significant positive correlations with the different taxa. The animals most frequently collected in the six lakes in March and August 2009 were Hirudinea, Oligochaeta, Hydrachnidae, Conchostraca, Ostracoda, Noteridae, Ceratopogonidae, Chironomidae, Culicidae, Caenidae, Pleidae, Aeshnidae, Libellulidae, Coenagrionidae and Nematoda. Only densities of Trichoptera, Ostracoda and Conchostraca presented the highest significant differences between lakes in both study periods and considering the composition of macroinvertebrates no significant differences were registered for macroinvertebrate composition.

  12. The influence of biotic and abiotic factors on (137)Cs accumulation in higher fungi after the accident at Chernobyl NPP.

    PubMed

    Zarubina, N

    2016-09-01

    Levels of soil contamination with (137)Cs, the belonging of fungi to a certain ecological group, the localization depth of the main part of mycelium in soil are the primary factors influencing the value of (137)Cs specific activity in higher fungi after the accident at Chernobyl NPP. It has been found that the value of (137)Cs specific activity in fungi of one species could vary by more than 10 times during a vegetation period. A correlation between the changes of (137)Cs content in fungi during the vegetation period and the amount of precipitates during various periods preceding the collection of samples has not been determined. An assumption has been proposed stating dependence between peculiarities of mycelium growth during the vegetation period and the changes of (137)Cs specific activity in fungi.

  13. Molecular cloning and expression profile of an abiotic stress and hormone responsive MYB transcription factor gene from Panax ginseng.

    PubMed

    Afrin, Sadia; Zhu, Jie; Cao, Hongzhe; Huang, Jingjia; Xiu, Hao; Luo, Tiao; Luo, Zhiyong

    2015-04-01

    The v-myb avian myeloblastosis viral oncogene homolog (MYB) family constitutes one of the most abundant groups of transcription factors and plays vital roles in developmental processes and defense responses in plants. A ginseng (Panax ginseng C.A. Meyer) MYB gene was cloned and designated as PgMYB1. The cDNA of PgMYB1 is 762 base pairs long and encodes the R2R3-type protein consisting 238 amino acids. Subcellular localization showed that PgMYB1-mGFP5 fusion protein was specifically localized in the nucleus. To understand the functional roles of PgMYB1, we investigated the expression patterns of PgMYB1 in different tissues and under various conditions. Quantitative real-time polymerase chain reaction and western blot analysis showed that PgMYB1 was expressed at higher level in roots, leaves, and lateral roots than in stems and seeds. The expression of PgMYB1 was up-regulated by abscisic acid, salicylic acid, NaCl, and cold (chilling), and down-regulated by methyl jasmonate. These results suggest that PgMYB1 might be involved in responding to environmental stresses and hormones.

  14. Biotic and abiotic factors affecting the flight activity of Fopius arisanus, an egg-pupal parasitoid of fruit fly pests.

    PubMed

    Rousse, P; Gourdon, F; Roubaud, M; Chiroleu, F; Quilici, S

    2009-06-01

    Climatic conditions and the physiological state of a parasitoid may alter its host selection behavior and thus its efficiency as a biological control agent. We studied the influence of these parameters on the behavior of Fopius arisanus (Sonan), an egg-pupal parasitoid of many Tephritidae. In the first experiment, we assessed in field cage assays the influence of temperature, humidity, light intensity, barometric pressure, and wind speed. Both flight and parasitism were mainly affected by temperature and humidity. However, because these two factors were strongly correlated in our experiments, the direct influence of each one cannot be specified. Flight activity was affected by variations in barometric pressure. In a second set of experiments, we conducted release and recapture assays with dyed insects to determine the influence of sex, mating status, egg load, age, and starvation on attraction toward infested fruit. Males were not attracted, suggesting that fruit are not a mating site. The egg load seemed to be a major parameter of foraging motivation. Finally, we showed that flight activity strongly decreased after 48 h of starvation. We observed a possible switch to food in the foraging motivation of starved females, but this result was impaired by poor recoveries: <10% of released females were recaptured after 96 h of starvation. We finally discuss the importance of these observations on the efficiency of F. arisanus as a biological control agent in tropical humid areas.

  15. Abiotic and biotic factors influencing nanoflagellate abundance and distribution in three different seasons in PRE, South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Xia; Shi, Zhen; Huang, Xiaoping; Li, Xiangfu

    2017-07-01

    Spatial distribution characteristics of two nanoflagellate groups, together with physico-chemical and biological factors, were studied in three seasons in the Pearl River Estuary (PRE), South China Sea. Nanoflagellates were more abundant in warm periods than that in winter. The average abundance in the three observations (spring, summer and winter) was as follow: 1.28 ± 1.17, 0.88 ± 1.02 and 0.28 ± 0.23 × 103 cells ml-1 of heterotrophic nanoflagellate (HNF), and 1.26 ± 0.85, 0.89 ± 0.77 and 0.65 ± 0.52 × 103 cells ml-1 of pigmented nanoflagellate (PNF). In our three studied seasons, NF density was generally higher in the inner estuary and decreasing to the lowest in the outer estuary. Our results suggested that PNF classes were more sensitive than HNF groups to freshwater discharge. The proportion of PNF gradually increased from spring (49.7%) to winter (67.7%), with the river flow was accordingly decreasing. Moreover, spatial distribution pattern in three seasons showed the response of PNF populations to freshwater input was similar to phytoplankton assemblages in the PRE. Total bacterial and live bacterial abundance (measured by LIVE/DEAD kit) were associated with both two NF components, which implied that NF was a potential predator controlling the bulk abundance of bacteria and proportion of active cells. These results revealed the seasonal and spatial variations of NF abundance in diverse conditions in the PRE and how their response to different ecological processes.

  16. Marine invasion in the Mediterranean Sea: the role of abiotic factors when there is no biological resistance.

    PubMed

    Cebrian, Emma; Rodríguez-Prieto, Conxi

    2012-01-01

    The tropical red alga Womersleyella setacea (Rhodomelaceae, Rhodophyta) is causing increasing concern in the Mediterranean Sea because of its invasive behavior. After its introduction it has colonized most Mediterranean areas, but the mechanism underlying its acclimatization and invasion process remains unknown. To understand this process, we decided i) to assess in situ the seasonal biomass and phenological patterns of populations inhabiting the Mediterranean Sea in relation to the main environmental factors, and ii) to experimentally determine if the tolerance of W. setacea to different light and temperature conditions can explain its colonization success, as well as its bathymetric distribution range. The bathymetric distribution, biomass, and phenology of W. setacea were studied at two localities, and related to irradiance and temperature values recorded in situ. Laboratory experiments were set up to study survival, growth and reproduction under contrasting light and temperature conditions in the short, mid, and long term. Results showed that, in the studied area, the bathymetric distribution of W. setacea is restricted to a depth belt between 25 and 40 m deep, reaching maximum biomass values (126 g dw m(-2)) at 30 m depth. In concordance, although in the short term W. setacea survived and grew in a large range of environmental conditions, its life requirements for the mid and long term were dim light levels and low temperatures. Biomass of Womersleyella setacea did not show any clear seasonal pattern, though minimum values were reported in spring. Reproductive structures were always absent. Bearing in mind that no herbivores feed on Womersleyella setacea and that its thermal preferences are more characteristic of temperate than of tropical seaweeds, low light (50 µmol photon m(-2) s(-1)) and low temperature (12°C) levels are critical for W. setacea survival and growth, thus probably determining its spread and bathymetric distribution across the Mediterranean

  17. Marine Invasion in the Mediterranean Sea: The Role of Abiotic Factors When There Is No Biological Resistance

    PubMed Central

    2012-01-01

    The tropical red alga Womersleyella setacea (Rhodomelaceae, Rhodophyta) is causing increasing concern in the Mediterranean Sea because of its invasive behavior. After its introduction it has colonized most Mediterranean areas, but the mechanism underlying its acclimatization and invasion process remains unknown. To understand this process, we decided i) to assess in situ the seasonal biomass and phenological patterns of populations inhabiting the Mediterranean Sea in relation to the main environmental factors, and ii) to experimentally determine if the tolerance of W. setacea to different light and temperature conditions can explain its colonization success, as well as its bathymetric distribution range. The bathymetric distribution, biomass, and phenology of W. setacea were studied at two localities, and related to irradiance and temperature values recorded in situ. Laboratory experiments were set up to study survival, growth and reproduction under contrasting light and temperature conditions in the short, mid, and long term.Results showed that, in the studied area, the bathymetric distribution of W. setacea is restricted to a depth belt between 25 and 40 m deep, reaching maximum biomass values (126 g dw m−2) at 30 m depth. In concordance, although in the short term W. setacea survived and grew in a large range of environmental conditions, its life requirements for the mid and long term were dim light levels and low temperatures. Biomass of Womersleyella setacea did not show any clear seasonal pattern, though minimum values were reported in spring. Reproductive structures were always absent. Bearing in mind that no herbivores feed on Womersleyella setacea and that its thermal preferences are more characteristic of temperate than of tropical seaweeds, low light (50 µmol photon m−2 s−1) and low temperature (12°C) levels are critical for W. setacea survival and growth, thus probably determining its spread and bathymetric distribution across the Mediterranean

  18. Major Biotic and Abiotic Factors that Influence Soil Carbon Dynamics in Forested Floodplains of the Eastern United States

    NASA Astrophysics Data System (ADS)

    Ricker, M. C.

    2016-12-01

    Alluvial soil organic carbon (SOC) storage and sequestration rates are extremely variable among the heterogeneous river systems of the eastern United States. Much of the variability observed in soil carbon can be attributed to the spatial and temporal complexity of fluvial landscapes. Floodplain soils form via two major pedogenic processes; alluviation (net sedimentation) and humification (incorporation of organic matter). The degree that these processes impact SOC dynamics depends on many modern and antecedent factors within a watershed. Although a great deal of complexity exists in floodplain soil formation, commonalities among studies have indicated some key carbon storage processes to focus our research attention on. For example, in poorly drained hydric soils the mineralization of organic matter is slow and we consistently measure greater SOC storage in floodplain landscapes that have a high water table during the growing season (meander scars, backswamps) compared to drier areas, such as natural levees and flats. Alluvial soils with buried surfaces (humus-rich A or O horizons) also have significantly greater carbon storage than soils lacking this morphology, regardless of drainage class. Rapid burial of carbon-rich surfaces likely protects SOC from microbial mineralization and promotes long-term storage. Removal of vegetation during land use change has also increased regional erosion rates, resulting in a common sequence of soil morphologies. In the field we frequently observe a pre-colonial surface buried by thick deposits of agricultural or industrial "legacy sediments" with modern urban alluvium deposited at the surface. By using relative and absolute dating methodologies it is possible to discern changes in floodplain sedimentation over time and link this process with SOC dynamics. Our findings indicate that as sedimentation rates have historically increased, there are also greater carbon sequestration rates in floodplains. The exact mechanisms for this

  19. The Arabidopsis Transcription Factor ANAC032 Represses Anthocyanin Biosynthesis in Response to High Sucrose and Oxidative and Abiotic Stresses

    PubMed Central

    Mahmood, Kashif; Xu, Zhenhua; El-Kereamy, Ashraf; Casaretto, José A.; Rothstein, Steven J.

    2016-01-01

    Production of anthocyanins is one of the adaptive responses employed by plants during stress conditions. During stress, anthocyanin biosynthesis is mainly regulated at the transcriptional level via a complex interplay between activators and repressors of anthocyanin biosynthesis genes. In this study, we investigated the role of a NAC transcription factor, ANAC032, in the regulation of anthocyanin biosynthesis during stress conditions. ANAC032 expression was found to be induced by exogenous sucrose as well as high light (HL) stress. Using biochemical, molecular and transgenic approaches, we show that ANAC032 represses anthocyanin biosynthesis in response to sucrose treatment, HL and oxidative stress. ANAC032 was found to negatively affect anthocyanin accumulation and the expression of anthocyanin biosynthesis (DFR, ANS/LDOX) and positive regulatory (TT8) genes as demonstrated in overexpression line (35S:ANAC032) compared to wild-type under HL stress. The chimeric repressor line (35S:ANAC032-SRDX) exhibited the opposite expression patterns for these genes. The negative impact of ANAC032 on the expression of DFR, ANS/LDOX and TT8 was found to be correlated with the altered expression of negative regulators of anthocyanin biosynthesis, AtMYBL2 and SPL9. In addition to this, ANAC032 also repressed the MeJA- and ABA-induced anthocyanin biosynthesis. As a result, transgenic lines overexpressing ANAC032 (35S:ANAC032) produced drastically reduced levels of anthocyanin pigment compared to wild-type when challenged with salinity stress. However, transgenic chimeric repressor lines (35S:ANAC032-SRDX) exhibited the opposite phenotype. Our results suggest that ANAC032 functions as a negative regulator of anthocyanin biosynthesis in Arabidopsis thaliana during stress conditions. PMID:27790239

  20. Reactive oxygen species signaling in plants under abiotic stress.

    PubMed

    Choudhury, Shuvasish; Panda, Piyalee; Sahoo, Lingaraj; Panda, Sanjib Kumar

    2013-04-01

    Abiotic stresses like heavy metals, drought, salt, low temperature, etc. are the major factors that limit crop productivity and yield. These stresses are associated with production of certain deleterious chemical entities called reactive oxygen species (ROS), which include hydrogen peroxide (H₂O₂), superoxide radical (O₂(-)), hydroxyl radical (OH(-)), etc. ROS are capable of inducing cellular damage by degradation of proteins, inactivation of enzymes, alterations in the gene and interfere in various pathways of metabolic importance. Our understanding on ROS in response to abiotic stress is revolutionized with the advancements in plant molecular biology, where the basic understanding on chemical behavior of ROS is better understood. Understanding the molecular mechanisms involved in ROS generation and its potential role during abiotic stress is important to identify means by which plant growth and metabolism can be regulated under acute stress conditions. ROS mediated oxidative stress, which is the key to understand stress related toxicity have been widely studied in many plants and the results in those studies clearly revealed that oxidative stress is the main symptom of toxicity. Plants have their own antioxidant defense mechanisms to encounter ROS that is of enzymic and non-enzymic nature . Coordinated activities of these antioxidants regulate ROS detoxification and reduces oxidative load in plants. Though ROS are always regarded to impart negative impact on plants, some reports consider them to be important in regulating key cellular functions; however, such reports in plant are limited. Molecular approaches to understand ROS metabolism and signaling have opened new avenues to comprehend its critical role in abiotic stress. ROS also acts as secondary messenger that signals key cellular functions like cell proliferation, apoptosis and necrosis. In higher eukaryotes, ROS signaling is not fully understood. In this review we summarize our understanding on ROS

  1. Abiotic tooth enamel.

    PubMed

    Yeom, Bongjun; Sain, Trisha; Lacevic, Naida; Bukharina, Daria; Cha, Sang-Ho; Waas, Anthony M; Arruda, Ellen M; Kotov, Nicholas A

    2017-03-01

    Tooth enamel comprises parallel microscale and nanoscale ceramic columns or prisms interlaced with a soft protein matrix. This structural motif is unusually consistent across all species from all geological eras. Such invariability-especially when juxtaposed with the diversity of other tissues-suggests the existence of a functional basis. Here we performed ex vivo replication of enamel-inspired columnar nanocomposites by sequential growth of zinc oxide nanowire carpets followed by layer-by-layer deposition of a polymeric matrix around these. We show that the mechanical properties of these nanocomposites, including hardness, are comparable to those of enamel despite the nanocomposites having a smaller hard-phase content. Our abiotic enamels have viscoelastic figures of merit (VFOM) and weight-adjusted VFOM that are similar to, or higher than, those of natural tooth enamels-we achieve values that exceed the traditional materials limits of 0.6 and 0.8, respectively. VFOM values describe resistance to vibrational damage, and our columnar composites demonstrate that light-weight materials of unusually high resistance to structural damage from shocks, environmental vibrations and oscillatory stress can be made using biomimetic design. The previously inaccessible combinations of high stiffness, damping and light weight that we achieve in these layer-by-layer composites are attributed to efficient energy dissipation in the interfacial portion of the organic phase. The in vivo contribution of this interfacial portion to macroscale deformations along the tooth's normal is maximized when the architecture is columnar, suggesting an evolutionary advantage of the columnar motif in the enamel of living species. We expect our findings to apply to all columnar composites and to lead to the development of high-performance load-bearing materials.

  2. Abiotic tooth enamel

    NASA Astrophysics Data System (ADS)

    Yeom, Bongjun; Sain, Trisha; Lacevic, Naida; Bukharina, Daria; Cha, Sang-Ho; Waas, Anthony M.; Arruda, Ellen M.; Kotov, Nicholas A.

    2017-03-01

    Tooth enamel comprises parallel microscale and nanoscale ceramic columns or prisms interlaced with a soft protein matrix. This structural motif is unusually consistent across all species from all geological eras. Such invariability—especially when juxtaposed with the diversity of other tissues—suggests the existence of a functional basis. Here we performed ex vivo replication of enamel-inspired columnar nanocomposites by sequential growth of zinc oxide nanowire carpets followed by layer-by-layer deposition of a polymeric matrix around these. We show that the mechanical properties of these nanocomposites, including hardness, are comparable to those of enamel despite the nanocomposites having a smaller hard-phase content. Our abiotic enamels have viscoelastic figures of merit (VFOM) and weight-adjusted VFOM that are similar to, or higher than, those of natural tooth enamels—we achieve values that exceed the traditional materials limits of 0.6 and 0.8, respectively. VFOM values describe resistance to vibrational damage, and our columnar composites demonstrate that light-weight materials of unusually high resistance to structural damage from shocks, environmental vibrations and oscillatory stress can be made using biomimetic design. The previously inaccessible combinations of high stiffness, damping and light weight that we achieve in these layer-by-layer composites are attributed to efficient energy dissipation in the interfacial portion of the organic phase. The in vivo contribution of this interfacial portion to macroscale deformations along the tooth’s normal is maximized when the architecture is columnar, suggesting an evolutionary advantage of the columnar motif in the enamel of living species. We expect our findings to apply to all columnar composites and to lead to the development of high-performance load-bearing materials.

  3. Diagnosing Abiotic Degradation

    EPA Science Inventory

    The abiotic degradation of chlorinated solvents in ground water can be difficult to diagnose. Under current practice, most of the “evidence” is negative; specifically the apparent disappearance of chlorinated solvents with an accumulation of vinyl chloride, ethane, ethylene, or ...

  4. Diagnosing Abiotic Degradation

    EPA Science Inventory

    The abiotic degradation of chlorinated solvents in ground water can be difficult to diagnose. Under current practice, most of the “evidence” is negative; specifically the apparent disappearance of chlorinated solvents with an accumulation of vinyl chloride, ethane, ethylene, or ...

  5. Direct and Indirect Effects of Climate on Demography and Early Growth of Pinus sylvestris at the Rear Edge: Changing Roles of Biotic and Abiotic Factors

    PubMed Central

    Benavides, Raquel; Rabasa, Sonia G.; Granda, Elena; Escudero, Adrián; Hódar, José A.; Martínez-Vilalta, Jordi; Rincón, Ana M.; Zamora, Regino; Valladares, Fernando

    2013-01-01

    Global change triggers shifts in forest composition, with warming and aridification being particularly threatening for the populations located at the rear edge of the species distributions. This is the case of Scots pine (Pinus sylvestris) in the Mediterranean Basin where uncertainties in relation to its dynamics under these changing scenarios are still high. We analysed the relative effect of climate on the recruitment patterns of Scots pine and its interactions with local biotic and abiotic variables at different spatial scales. Number of seedlings and saplings was surveyed, and their annual shoot growth measured in 96 plots located across altitudinal gradients in three different regions in the Iberian Peninsula. We found a significant influence of climate on demography and performance of recruits, with a non-linear effect of temperature on the presence of juveniles, and a positive effect of precipitation on their survival. Abundance of juveniles of P. sylvestris that underwent their first summer drought was skewed towards higher altitudes than the altitudinal mean range of the conspecific adults and the optimum elevation for seedlings' emergence. At local level, light availability did not influence juveniles' density, but it enhanced their growth. Biotic interactions were found between juveniles and the herb cover (competition) and between the number of newly emerged seedlings and shrubs (facilitation). Results also highlighted the indirect effect that climate exerts over the local factors, modulating the interactions with the pre-existing vegetation that were more evident at more stressful sites. This multiscale approach improves our understanding of the dynamics of these marginal populations and some management criteria can be inferred to boost their conservation under the current global warming. PMID:23555794

  6. Abiotic factors and their interactions influence on the co-production of aflatoxin B(1) and cyclopiazonic acid by Aspergillus flavus isolated from corn.

    PubMed

    Astoreca, Andrea; Vaamonde, Graciela; Dalcero, Ana; Marin, Sonia; Ramos, Antonio

    2014-04-01

    The objectives of this study were i) to determine the effects of the interactions of water activity, temperature and incubation time on the co-production of AFB1 and CPA by isolates of Aspergillus flavus with different profile of mycotoxin production and ii) to identify the aW and temperature limiting conditions for the production of both mycotoxins. Fungi used in this study were selected because they belonged to different chemotypes: chemotype I (AFB1+/CPA+), III (AFB1+/CPA-) and IV (AFB1-/CPA+), respectively. Two culture media were used; Czapek yeast agar (CYA) and corn extract agar (CEM), at different incubated temperatures (10-40 °C) and aW levels (0.80-0.98). AFB1 and CPA production were analyzed after 7, 14, 21 and 28 days of incubation. Significant differences were observed with respect to mycotoxin production depending on the media evaluated. The AFB1 production occurred more favorably on CYA while the highest CPA concentrations were recorded on CEM. Within the range of aW evaluated in this study, 0.83 was the limiting level for both toxins production. The optimum conditions for AFB1 production occurred at 0.96 aW and 30 °C after 21 days of incubation, regardless of the media and isolate. Although different amounts of toxins were produced in each medium, the limiting and optimum conditions for their production were similar in both. No differences in the response of the three isolates to the abiotic factors discussed were observed despite belonging to different chemotypes. The determination of the thresholds of mycotoxins co-production, especially in the case of data obtained with the corn extract medium can be useful to avoid the conditions conducive to co-occurrence of these mycotoxins in corn.

  7. Direct and indirect effects of climate on demography and early growth of Pinus sylvestris at the rear edge: changing roles of biotic and abiotic factors.

    PubMed

    Benavides, Raquel; Rabasa, Sonia G; Granda, Elena; Escudero, Adrián; Hódar, José A; Martínez-Vilalta, Jordi; Rincón, Ana M; Zamora, Regino; Valladares, Fernando

    2013-01-01

    Global change triggers shifts in forest composition, with warming and aridification being particularly threatening for the populations located at the rear edge of the species distributions. This is the case of Scots pine (Pinus sylvestris) in the Mediterranean Basin where uncertainties in relation to its dynamics under these changing scenarios are still high. We analysed the relative effect of climate on the recruitment patterns of Scots pine and its interactions with local biotic and abiotic variables at different spatial scales. Number of seedlings and saplings was surveyed, and their annual shoot growth measured in 96 plots located across altitudinal gradients in three different regions in the Iberian Peninsula. We found a significant influence of climate on demography and performance of recruits, with a non-linear effect of temperature on the presence of juveniles, and a positive effect of precipitation on their survival. Abundance of juveniles of P. sylvestris that underwent their first summer drought was skewed towards higher altitudes than the altitudinal mean range of the conspecific adults and the optimum elevation for seedlings' emergence. At local level, light availability did not influence juveniles' density, but it enhanced their growth. Biotic interactions were found between juveniles and the herb cover (competition) and between the number of newly emerged seedlings and shrubs (facilitation). Results also highlighted the indirect effect that climate exerts over the local factors, modulating the interactions with the pre-existing vegetation that were more evident at more stressful sites. This multiscale approach improves our understanding of the dynamics of these marginal populations and some management criteria can be inferred to boost their conservation under the current global warming.

  8. Spatial and temporal structuring of arbuscular mycorrhizal communities is differentially influenced by abiotic factors and host crop in a semi-arid prairie agroecosystem.

    PubMed

    Bainard, Luke D; Bainard, Jillian D; Hamel, Chantal; Gan, Yantai

    2014-05-01

    Agroecosystems are dynamic systems that experience frequent chemical inputs and changes in plant cover. The objective of this study was to test whether abiotic (soil chemical properties and climate) and biotic (plant host identity) factors influence the spatial and temporal structuring of arbuscular mycorrhizal fungal (AMF) communities in a semi-arid prairie agroecosystem. 454 GS FLX+ high-throughput sequencing technology was successfully utilized to characterize the AMF communities based on long reads (mean length: 751.7 bp) and generated high-resolution data with excellent taxonomic coverage. The composition of the AMF community colonizing roots of the three crops (pea, lentil, and wheat) significantly differed, but plant host identity had a minimal effect on the composition of the AMF community in the soil. We observed a temporal shift in the composition of AMF communities in the roots and surrounding soil of the crops during the growing season. This temporal shift was particularly evident in the root-associated AMF community and was correlated with soil phosphate flux and climatic variables. In contrast, the spatial structuring of the AMF community in the site was correlated with soil pH and electrical conductivity. Individual AMF taxa were significantly correlated with pH, electrical conductivity, and phosphate flux, and these relationships were phylogenetically conserved at the genus level within the Glomeromycota. © 2014 Her Majesty the Queen in Right of Canada. FEMS Microbiology Ecology © 2014 Published by John Wiley & Sons Ltd on behalf of the Federation of European Microbiological Societies. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

  9. Transcriptional networks-crops, clocks, and abiotic stress.

    PubMed

    Gehan, Malia A; Greenham, Kathleen; Mockler, Todd C; McClung, C Robertson

    2015-04-01

    Several factors affect the yield potential and geographical range of crops including the circadian clock, water availability, and seasonal temperature changes. In order to sustain and increase plant productivity on marginal land in the face of both biotic and abiotic stresses, we need to more efficiently generate stress-resistant crops through marker-assisted breeding, genetic modification, and new genome-editing technologies. To leverage these strategies for producing the next generation of crops, future transcriptomic data acquisition should be pursued with an appropriate temporal design and analyzed with a network-centric approach. The following review focuses on recent developments in abiotic stress transcriptional networks in economically important crops and will highlight the utility of correlation-based network analysis and applications.

  10. Biotic and abiotic factors regulating forest floor CO2 flux across a range of forest age classes in the southern Appalachians

    Treesearch

    James M. Vose; Paul V. Bolstad

    2007-01-01

    We measured forest floor CO2 flux in three age classes of forest in the southern Appalachians: 20-year-old, 85-year-old, and old-growth. Our objectives were to quantify differences in forest floor CO2 flux among age classes, and determine the relative importance of abiotic and biotic driving variables. Forest floor CO

  11. Transgenic expression of TaMYB2A confers enhanced tolerance to multiple abiotic stresses in Arabidopsis.

    PubMed

    Mao, Xinguo; Jia, Dongsheng; Li, Ang; Zhang, Hongying; Tian, Shanjun; Zhang, Xiaoke; Jia, Jizeng; Jing, Ruilian

    2011-09-01

    Osmotic stresses such as drought, salinity, and cold are major environmental factors that limit agricultural productivity. Transcription factors play essential roles in abiotic stress signaling in plants. Three TaMYB2 members were identified and designated TaMYB2A, TaMYB2B, and TaMYB2D based on their genomic origins. The cis-regulatory elements in the promoter regions were compared, and their diverse expression patterns under different abiotic stress conditions were identified. TaMYB2A was further characterized because of its earlier response to stresses. Subcellular localization revealed that TaMYB2A localized in the nucleus. To examine the role of TaMYB2A under various environmental stresses, transgenic Arabidopsis plants carrying TaMYB2A controlled by the CaMV 35S promoter were generated and subjected to severe abiotic stress. TaMYB2A transgenics had enhanced tolerance to drought, salt, and freezing stresses, which were confirmed by the enhanced expressions of abiotic stress-responsive genes and several physiological indices, including decreased rate of water loss, enhanced cell membrane stability, improved photosynthetic potential, and reduced osmotic potential. TaMYB2A is a multifunctional regulatory factor. Its overexpression confers enhanced tolerance to multiple abiotic stresses while having no obvious negative effects on phenotype under well-watered and stressed conditions; thus, TaMYB2A has the potential for utilization in transgenic breeding to improve abiotic stress tolerances in crops.

  12. Abiotic drivers of Chihuahuan Desert plant communities

    Treesearch

    Laura Marie Ladwig

    2014-01-01

    Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural...

  13. Polyamines and abiotic stress tolerance in plants

    PubMed Central

    Gill, Sarvajeet Singh

    2010-01-01

    Environmental stresses including climate change, especially global warming, are severely affecting plant growth and productivity worldwide. It has been estimated that two-thirds of the yield potential of major crops are routinely lost due to the unfavorable environmental factors. On the other hand, the world population is estimated to reach about 10 billion by 2050, which will witness serious food shortages. Therefore, crops with enhanced vigour and high tolerance to various environmental factors should be developed to feed the increasing world population. Maintaining crop yields under adverse environmental stresses is probably the major challenge facing modern agriculture where polyamines can play important role. Polyamines (PAs)(putrescine, spermidine and spermine) are group of phytohormone-like aliphatic amine natural compounds with aliphatic nitrogen structure and present in almost all living organisms including plants. Evidences showed that polyamines are involved in many physiological processes, such as cell growth and development and respond to stress tolerance to various environmental factors. In many cases the relationship of plant stress tolerance was noted with the production of conjugated and bound polyamines as well as stimulation of polyamine oxidation. Therefore, genetic manipulation of crop plants with genes encoding enzymes of polyamine biosynthetic pathways may provide better stress tolerance to crop plants. Furthermore, the exogenous application of PAs is also another option for increasing the stress tolerance potential in plants. Here, we have described the synthesis and role of various polyamines in abiotic stress tolerance in plants. PMID:20592804

  14. Transcriptomic Profiling of the Maize (Zea mays L.) Leaf Response to Abiotic Stresses at the Seedling Stage

    PubMed Central

    Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng

    2017-01-01

    Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize (Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses. PMID:28298920

  15. Transcriptomic Profiling of the Maize (Zea mays L.) Leaf Response to Abiotic Stresses at the Seedling Stage.

    PubMed

    Li, Pengcheng; Cao, Wei; Fang, Huimin; Xu, Shuhui; Yin, Shuangyi; Zhang, Yingying; Lin, Dezhou; Wang, Jianan; Chen, Yufei; Xu, Chenwu; Yang, Zefeng

    2017-01-01

    Abiotic stresses, including drought, salinity, heat, and cold, negatively affect maize (Zea mays L.) development and productivity. To elucidate the molecular mechanisms of resistance to abiotic stresses in maize, RNA-seq was used for global transcriptome profiling of B73 seedling leaves exposed to drought, salinity, heat, and cold stress. A total of 5,330 differentially expressed genes (DEGs) were detected in differential comparisons between the control and each stressed sample, with 1,661, 2,019, 2,346, and 1,841 DEGs being identified in comparisons of the control with salinity, drought, heat, and cold stress, respectively. Functional annotations of DEGs suggested that the stress response was mediated by pathways involving hormone metabolism and signaling, transcription factors (TFs), very-long-chain fatty acid biosynthesis and lipid signaling, among others. Of the obtained DEGs (5,330), 167 genes are common to these four abiotic stresses, including 10 up-regulated TFs (five ERFs, two NACs, one ARF, one MYB, and one HD-ZIP) and two down-regulated TFs (one b-ZIP and one MYB-related), which suggested that common mechanisms may be initiated in response to different abiotic stresses in maize. This study contributes to a better understanding of the molecular mechanisms of maize leaf responses to abiotic stresses and could be useful for developing maize cultivars resistant to abiotic stresses.

  16. Environment Is Life (EIL): a new local structure to study the influence of abiotic factors on agro-systems functional behavior

    NASA Astrophysics Data System (ADS)

    Longdoz, Bernard; Leemans, Vincent; Heinesch, Bernard; Delaplace, Pierre; Dumont, Benjamin; Jacques, Philippe

    2017-04-01

    , to simulate the biogeochemical cycles of an outdoor agro-system plots. The objectives of the model runs will be to translate for natural conditions (real agro-system), the impact of the studied perturbation, with possibilities of divergences in terms of intensity and timing compared to the Ecotron situations Finally, the structure is completed with an eddy covariance tower site named Lonzée installed in a traditional European temperate agro-system plot and presently part of the ICOS labeling process. The Lonzee site is a cropland (cultivated for more than 75 years) with a 4-year rotation: sugar beet (Beta vulgaris L.), winter wheat (Triticum aestivum L.), potato (Solanum tuberosum L.), winter wheat. The experimental device collect some data similar to those obtained in the Ecotron chambers and will give the opportunity to (i) quantify the actual and real the influence of abiotic factors on ecosystemic services and (ii) validate the model used for the spatio-temporal extrapolation of the Ecotron results.

  17. The Importance of Biotic vs. Abiotic Drivers of Local Plant Community Composition Along Regional Bioclimatic Gradients

    PubMed Central

    Klanderud, Kari; Vandvik, Vigdis; Goldberg, Deborah

    2015-01-01

    We assessed if the relative importance of biotic and abiotic factors for plant community composition differs along environmental gradients and between functional groups, and asked which implications this may have in a warmer and wetter future. The study location is a unique grid of sites spanning regional-scale temperature and precipitation gradients in boreal and alpine grasslands in southern Norway. Within each site we sampled vegetation and associated biotic and abiotic factors, and combined broad- and fine-scale ordination analyses to assess the relative explanatory power of these factors for species composition. Although the community responses to biotic and abiotic factors did not consistently change as predicted along the bioclimatic gradients, abiotic variables tended to explain a larger proportion of the variation in species composition towards colder sites, whereas biotic variables explained more towards warmer sites, supporting the stress gradient hypothesis. Significant interactions with precipitation suggest that biotic variables explained more towards wetter climates in the sub alpine and boreal sites, but more towards drier climates in the colder alpine. Thus, we predict that biotic interactions may become more important in alpine and boreal grasslands in a warmer future, although more winter precipitation may counteract this trend in oceanic alpine climates. Our results show that both local and regional scales analyses are needed to disentangle the local vegetation-environment relationships and their regional-scale drivers, and biotic interactions and precipitation must be included when predicting future species assemblages. PMID:26091266

  18. The Importance of Biotic vs. Abiotic Drivers of Local Plant Community Composition Along Regional Bioclimatic Gradients.

    PubMed

    Klanderud, Kari; Vandvik, Vigdis; Goldberg, Deborah

    2015-01-01

    We assessed if the relative importance of biotic and abiotic factors for plant community composition differs along environmental gradients and between functional groups, and asked which implications this may have in a warmer and wetter future. The study location is a unique grid of sites spanning regional-scale temperature and precipitation gradients in boreal and alpine grasslands in southern Norway. Within each site we sampled vegetation and associated biotic and abiotic factors, and combined broad- and fine-scale ordination analyses to assess the relative explanatory power of these factors for species composition. Although the community responses to biotic and abiotic factors did not consistently change as predicted along the bioclimatic gradients, abiotic variables tended to explain a larger proportion of the variation in species composition towards colder sites, whereas biotic variables explained more towards warmer sites, supporting the stress gradient hypothesis. Significant interactions with precipitation suggest that biotic variables explained more towards wetter climates in the sub alpine and boreal sites, but more towards drier climates in the colder alpine. Thus, we predict that biotic interactions may become more important in alpine and boreal grasslands in a warmer future, although more winter precipitation may counteract this trend in oceanic alpine climates. Our results show that both local and regional scales analyses are needed to disentangle the local vegetation-environment relationships and their regional-scale drivers, and biotic interactions and precipitation must be included when predicting future species assemblages.

  19. Monthly Distribution of Phlebotomine Sand Flies, and Biotic and Abiotic Factors Related to Their Abundance, in an Urban Area to Which Visceral Leishmaniasis Is Endemic in Corumbá, Brazil

    PubMed Central

    Casaril, Aline Etelvina; Fernandes, Wagner Souza; Ravanelli, Michelle de Saboya; Paranhos Filho, Antônio Conceição; Oshiro, Elisa Teruya; de Oliveira, Alessandra Gutierrez

    2016-01-01

    The monthly distribution and abundance of sand flies are influenced by both biotic and abiotic factors. The present study aimed to evaluate the seasonal distribution of sand flies and the relation between their abundance and environmental parameters, including vegetation and climate. This study was conducted over a 2-year period (April 2012 to March 2014). Monthly distribution was evaluated through the weekly deployment of CDC light traps in the peridomicile area of 5 residences in an urban area of the municipality of Corumbá in the State of Mato Grosso do Sul, Brazil. Meteorological data were obtained from the Mato Grosso do Sul Center for Weather, Climate, and Water Resources. The spectral indices were calculated based on spatial resolution images (GeoEye) and the percentage of vegetal coverage. Differences in the abundance of sand flies among the collection sites were assessed using the Kruskal-Wallis test, and the strength of correlations between environmental variables was determined by calculating Spearman’s correlation coefficients. Lutzomyia cruzi, Lu. forattinii, and Evandromyia corumbaensis were the most frequently found species. Although no significant association was found among these sand fly species and the tested environmental variables (vegetation and climate), high population peaks were found during the rainy season, whereas low peaks were observed in the dry season. The monthly distribution of sand flies was primarily determined by Lu. cruzi, which accounted for 93.94% of the specimens collected each month throughout the experimental period. The fact that sand flies were detected year-round indicates a continuous risk of infection to humans, demonstrating the need for targeted management and education programs. PMID:27783667

  20. Monthly Distribution of Phlebotomine Sand Flies, and Biotic and Abiotic Factors Related to Their Abundance, in an Urban Area to Which Visceral Leishmaniasis Is Endemic in Corumbá, Brazil.

    PubMed

    Falcão de Oliveira, Everton; Casaril, Aline Etelvina; Fernandes, Wagner Souza; Ravanelli, Michelle de Saboya; Medeiros, Márcio José de; Gamarra, Roberto Macedo; Paranhos Filho, Antônio Conceição; Oshiro, Elisa Teruya; Oliveira, Alessandra Gutierrez de; Galati, Eunice Aparecida Bianchi

    2016-01-01

    The monthly distribution and abundance of sand flies are influenced by both biotic and abiotic factors. The present study aimed to evaluate the seasonal distribution of sand flies and the relation between their abundance and environmental parameters, including vegetation and climate. This study was conducted over a 2-year period (April 2012 to March 2014). Monthly distribution was evaluated through the weekly deployment of CDC light traps in the peridomicile area of 5 residences in an urban area of the municipality of Corumbá in the State of Mato Grosso do Sul, Brazil. Meteorological data were obtained from the Mato Grosso do Sul Center for Weather, Climate, and Water Resources. The spectral indices were calculated based on spatial resolution images (GeoEye) and the percentage of vegetal coverage. Differences in the abundance of sand flies among the collection sites were assessed using the Kruskal-Wallis test, and the strength of correlations between environmental variables was determined by calculating Spearman's correlation coefficients. Lutzomyia cruzi, Lu. forattinii, and Evandromyia corumbaensis were the most frequently found species. Although no significant association was found among these sand fly species and the tested environmental variables (vegetation and climate), high population peaks were found during the rainy season, whereas low peaks were observed in the dry season. The monthly distribution of sand flies was primarily determined by Lu. cruzi, which accounted for 93.94% of the specimens collected each month throughout the experimental period. The fact that sand flies were detected year-round indicates a continuous risk of infection to humans, demonstrating the need for targeted management and education programs.

  1. RBM25 Mediates Abiotic Responses in Plants

    PubMed Central

    Cheng, Chunhong; Wang, Zhijuan; Yuan, Bingjian; Li, Xia

    2017-01-01

    Alternative splicing (AS) of pre-mRNAs is one of the most important post-transcriptional regulations that enable a single gene to code for multiple proteins resulting in the biodiversity of proteins in eukaryotes. Recently, we have shown that an Arabidopsis thaliana RNA recognition motif-containing protein RBM25 is a novel splicing factor to modulate plant response to ABA during seed germination and post-germination through regulating HAB1 pre-mRNA AS. Here, we show that RBM25 is preferentially expressed in stomata and vascular tissues in Arabidopsis and is induced by ABA and abiotic stresses. Loss-of-function mutant is highly tolerant to drought and sensitive to salt stress. Bioinformatic analysis and expression assays reveal that Arabidopsis RBM25 is induced by multiple abiotic stresses, suggesting a crucial role of RBM25 in Arabidopsis responses to adverse environmental conditions. Furthermore, we provide a comprehensive characterization of the homologous genes of Arabidopsis RBM25 based on the latest plant genome sequences and public microarray databases. Fourteen homologous genes are identified in different plant species which show similar structure in gene and protein. Notably, the promoter analysis reveals that RBM25 homologs are likely controlled by the regulators involved in multiple plant growth and abiotic stresses, such as drought and unfavorable temperature. The comparative analysis of general and unique cis regulatory elements of the RBM25 homologs highlights the conserved and unique molecular processes that modulate plant response to abiotic stresses through RBM25-mediated alternative splicing. PMID:28344583

  2. RBM25 Mediates Abiotic Responses in Plants.

    PubMed

    Cheng, Chunhong; Wang, Zhijuan; Yuan, Bingjian; Li, Xia

    2017-01-01

    Alternative splicing (AS) of pre-mRNAs is one of the most important post-transcriptional regulations that enable a single gene to code for multiple proteins resulting in the biodiversity of proteins in eukaryotes. Recently, we have shown that an Arabidopsis thaliana RNA recognition motif-containing protein RBM25 is a novel splicing factor to modulate plant response to ABA during seed germination and post-germination through regulating HAB1 pre-mRNA AS. Here, we show that RBM25 is preferentially expressed in stomata and vascular tissues in Arabidopsis and is induced by ABA and abiotic stresses. Loss-of-function mutant is highly tolerant to drought and sensitive to salt stress. Bioinformatic analysis and expression assays reveal that Arabidopsis RBM25 is induced by multiple abiotic stresses, suggesting a crucial role of RBM25 in Arabidopsis responses to adverse environmental conditions. Furthermore, we provide a comprehensive characterization of the homologous genes of Arabidopsis RBM25 based on the latest plant genome sequences and public microarray databases. Fourteen homologous genes are identified in different plant species which show similar structure in gene and protein. Notably, the promoter analysis reveals that RBM25 homologs are likely controlled by the regulators involved in multiple plant growth and abiotic stresses, such as drought and unfavorable temperature. The comparative analysis of general and unique cis regulatory elements of the RBM25 homologs highlights the conserved and unique molecular processes that modulate plant response to abiotic stresses through RBM25-mediated alternative splicing.

  3. Abiotic stresses induce different localizations of anthocyanins in Arabidopsis

    PubMed Central

    Kovinich, Nik; Kayanja, Gilbert; Chanoca, Alexandra; Otegui, Marisa S; Grotewold, Erich

    2015-01-01

    Anthocyanins are induced in plants in response to abiotic stresses such as drought, high salinity, excess light, and cold, where they often correlate with enhanced stress tolerance. Numerous roles have been proposed for anthocyanins induced during abiotic stresses including functioning as ROS scavengers, photoprotectants, and stress signals. We have recently found different profiles of anthocyanins in Arabidopsis (Arabidopsis thaliana) plants exposed to different abiotic stresses, suggesting that not all anthocyanins have the same function. Here, we discuss these findings in the context of other studies and show that anthocyanins induced in Arabidopsis in response to various abiotic stresses have different localizations at the organ and tissue levels. These studies provide a basis to clarify the role of particular anthocyanin species during abiotic stress. PMID:26179363

  4. Influence of abiotic stress signals on secondary metabolites in plants

    PubMed Central

    Ramakrishna, Akula; Ravishankar, Gokare Aswathanarayana

    2011-01-01

    Plant secondary metabolites are unique sources for pharmaceuticals, food additives, flavors, and industrially important biochemicals. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Secondary metabolites play a major role in the adaptation of plants to the environment and in overcoming stress conditions. Environmental factors viz. temperature, humidity, light intensity, the supply of water, minerals, and CO2 influence the growth of a plant and secondary metabolite production. Drought, high salinity, and freezing temperatures are environmental conditions that cause adverse effects on the growth of plants and the productivity of crops. Plant cell culture technologies have been effective tools for both studying and producing plant secondary metabolites under in vitro conditions and for plant improvement. This brief review summarizes the influence of different abiotic factors include salt, drought, light, heavy metals, frost etc. on secondary metabolites in plants. The focus of the present review is the influence of abiotic factors on secondary metabolite production and some of important plant pharmaceuticals. Also, we describe the results of in vitro cultures and production of some important secondary metabolites obtained in our laboratory. PMID:22041989

  5. Influence of abiotic stress signals on secondary metabolites in plants.

    PubMed

    Ramakrishna, Akula; Ravishankar, Gokare Aswathanarayana

    2011-11-01

    Plant secondary metabolites are unique sources for pharmaceuticals, food additives, flavors, and industrially important biochemicals. Accumulation of such metabolites often occurs in plants subjected to stresses including various elicitors or signal molecules. Secondary metabolites play a major role in the adaptation of plants to the environment and in overcoming stress conditions. Environmental factors viz. temperature, humidity, light intensity, the supply of water, minerals, and CO2 influence the growth of a plant and secondary metabolite production. Drought, high salinity, and freezing temperatures are environmental conditions that cause adverse effects on the growth of plants and the productivity of crops. Plant cell culture technologies have been effective tools for both studying and producing plant secondary metabolites under in vitro conditions and for plant improvement. This brief review summarizes the influence of different abiotic factors include salt, drought, light, heavy metals, frost etc. on secondary metabolites in plants. The focus of the present review is the influence of abiotic factors on secondary metabolite production and some of important plant pharmaceuticals. Also, we describe the results of in vitro cultures and production of some important secondary metabolites obtained in our laboratory.

  6. Robust Programming Problems Based on the Mean-Variance Model Including Uncertainty Factors

    NASA Astrophysics Data System (ADS)

    Hasuike, Takashi; Ishii, Hiroaki

    2009-01-01

    This paper considers robust programming problems based on the mean-variance model including uncertainty sets and fuzzy factors. Since these problems are not well-defined problems due to fuzzy factors, it is hard to solve them directly. Therefore, introducing chance constraints, fuzzy goals and possibility measures, the proposed models are transformed into the deterministic equivalent problems. Furthermore, in order to solve these equivalent problems efficiently, the solution method is constructed introducing the mean-absolute deviation and doing the equivalent transformations.

  7. The Arabidopsis ETHYLENE RESPONSE FACTOR1 Regulates Abiotic Stress-Responsive Gene Expression by Binding to Different cis-Acting Elements in Response to Different Stress Signals1[W][OA

    PubMed Central

    Cheng, Mei-Chun; Liao, Po-Ming; Kuo, Wei-Wen; Lin, Tsan-Piao

    2013-01-01

    ETHYLENE RESPONSE FACTOR1 (ERF1) is an upstream component in both jasmonate (JA) and ethylene (ET) signaling and is involved in pathogen resistance. Accumulating evidence suggests that ERF1 might be related to the salt stress response through ethylene signaling. However, the specific role of ERF1 in abiotic stress and the molecular mechanism underlying the signaling cross talk still need to be elucidated. Here, we report that ERF1 was highly induced by high salinity and drought stress in Arabidopsis (Arabidopsis thaliana). The salt stress induction required both JA and ET signaling but was inhibited by abscisic acid. ERF1-overexpressing lines (35S:ERF1) were more tolerant to drought and salt stress. They also displayed constitutively smaller stomatal aperture and less transpirational water loss. Surprisingly, 35S:ERF1 also showed enhanced heat tolerance and up-regulation of heat tolerance genes compared with the wild type. Several suites of genes activated by JA, drought, salt, and heat were found in microarray analysis of 35S:ERF1. Chromatin immunoprecipitation assays found that ERF1 up-regulates specific suites of genes in response to different abiotic stresses by stress-specific binding to GCC or DRE/CRT. In response to biotic stress, ERF1 bound to GCC boxes but not DRE elements; conversely, under abiotic stress, we observed specific binding of ERF1 to DRE elements. Furthermore, ERF1 bound preferentially to only one among several GCC box or DRE/CRT elements in the promoter region of its target genes. ERF1 plays a positive role in salt, drought, and heat stress tolerance by stress-specific gene regulation, which integrates JA, ET, and abscisic acid signals. PMID:23719892

  8. Abiotic Bromination of Soil Organic Matter.

    PubMed

    Leri, Alessandra C; Ravel, Bruce

    2015-11-17

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide and assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.

  9. Abiotic Bromination of Soil Organic Matter

    SciTech Connect

    Leri, Alessandra C.; Ravel, Bruce

    2015-11-17

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide and assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.

  10. Recent Molecular Advances on Downstream Plant Responses to Abiotic Stress

    PubMed Central

    dos Reis, Sávio Pinho; Lima, Aline Medeiros; de Souza, Cláudia Regina Batista

    2012-01-01

    Abiotic stresses such as extremes of temperature and pH, high salinity and drought, comprise some of the major factors causing extensive losses to crop production worldwide. Understanding how plants respond and adapt at cellular and molecular levels to continuous environmental changes is a pre-requisite for the generation of resistant or tolerant plants to abiotic stresses. In this review we aimed to present the recent advances on mechanisms of downstream plant responses to abiotic stresses and the use of stress-related genes in the development of genetically engineered crops. PMID:22942725

  11. Nuclear actin activates human transcription factor genes including the OCT4 gene.

    PubMed

    Yamazaki, Shota; Yamamoto, Koji; Tokunaga, Makio; Sakata-Sogawa, Kumiko; Harata, Masahiko

    2015-01-01

    RNA microarray analyses revealed that nuclear actin activated many human transcription factor genes including OCT4, which is required for gene reprogramming. Oct4 is known to be activated by nuclear actin in Xenopus oocytes. Our findings imply that this process of OCT4 activation is conserved in vertebrates and among cell types and could be used for gene reprogramming of human cells.

  12. A Study of Factors Promoting Success in Computer Science Including Gender Differences

    NASA Astrophysics Data System (ADS)

    Cantwell Wilson, Brenda

    2002-03-01

    This study was conducted to determine factors that promote success in an introductory college computer science course and to determine what, if any, differences appear between genders on those factors. The model included math background, attribution for success/failure, self-efficacy, encouragement, comfort level in the course, work style preference, previous programming experience, previous non-programming computer experience, and gender as possible predictive factors for success in the computer science course. Subjects included 105 students enrolled in an introductory computer science course. The study revealed three predictive factors in the following order of importance: comfort level (with a positive influence), math background (with a positive influence), and attribution to luck (with a negative influence). No significant gender differences were found in these three factors. The study also revealed that both a formal class in programming (which had a positive correlation) and game playing (which had a negative correlation) were predictive of success. The study revealed a significant gender difference in game playing with males reporting more experience with playing games on the computer than females reported.

  13. DNA Damage Response Factors from Diverse Pathways, Including DNA Crosslink Repair, Mediate Alternative End Joining

    PubMed Central

    Howard, Sean M.; Yanez, Diana A.; Stark, Jeremy M.

    2015-01-01

    Alternative end joining (Alt-EJ) chromosomal break repair involves bypassing classical non-homologous end joining (c-NHEJ), and such repair causes mutations often with microhomology at the repair junction. Since the mediators of Alt-EJ are not well understood, we have sought to identify DNA damage response (DDR) factors important for this repair event. Using chromosomal break reporter assays, we surveyed an RNAi library targeting known DDR factors for siRNAs that cause a specific decrease in Alt-EJ, relative to an EJ event that is a composite of Alt-EJ and c-NHEJ (Distal-EJ between two tandem breaks). From this analysis, we identified several DDR factors that are specifically important for Alt-EJ relative to Distal-EJ. While these factors are from diverse pathways, we also found that most of them also promote homologous recombination (HR), including factors important for DNA crosslink repair, such as the Fanconi Anemia factor, FANCA. Since bypass of c-NHEJ is likely important for both Alt-EJ and HR, we disrupted the c-NHEJ factor Ku70 in Fanca-deficient mouse cells and found that Ku70 loss significantly diminishes the influence of Fanca on Alt-EJ. In contrast, an inhibitor of poly ADP-ribose polymerase (PARP) causes a decrease in Alt-EJ that is enhanced by Ku70 loss. Additionally, the helicase/nuclease DNA2 appears to have distinct effects from FANCA and PARP on both Alt-EJ, as well as end resection. Finally, we found that the proteasome inhibitor Bortezomib, a cancer therapeutic that has been shown to disrupt FANC signaling, causes a significant reduction in both Alt-EJ and HR, relative to Distal-EJ, as well as a substantial loss of end resection. We suggest that several distinct DDR functions are important for Alt-EJ, which include promoting bypass of c-NHEJ and end resection. PMID:25629353

  14. The spindle-shaped cells in cutaneous Kaposi's sarcoma. Histologic simulators include factor XIIIa dermal dendrocytes.

    PubMed Central

    Nickoloff, B. J.; Griffiths, C. E.

    1989-01-01

    Kaposi's sarcoma is a neoplasm that develops as multifocal lesions, often involving the skin, characterized by a complex histologic picture including numerous vascular spaces, perivascular and interstitial spindle-shaped cells, and extravasated erythrocytes, lymphocytes, and plasma cells. Using an antibody against factor XIIIa, which identifies dermal dendrocytes, numerous factor XIIIa-positive dermal dendrocytes were detected among the spindle-shaped cells in 12 acquired immune deficiency syndrome (AIDS)-associated, and five non-AIDS-associated Kaposi's sarcoma lesions. The factor XIIIa-positive dermal dendrocytes were also increased in histologic simulators of Kaposi's sarcoma such as dermatofibroma, angiomatoid malignant fibrous histiocytoma, granuloma annulare, and early wound healing, but were absent in keloids. The increased number of dermal dendrocytes, which are often in an angiocentric configuration and which also express CD4, lymphocyte function associated antigen-1 (LFA-1), and Leu M3 in Kaposi's sarcoma, may be important to the angioproliferative response. The results suggested that the spindle-shaped cells that are present in a variety of cutaneous lesions are dermal dendrocytes and belong to the reticuloendothelial system, unlike other mesenchymal cell types such as the endothelial cell. Apparently a diverse array of stimuli, including human immunodeficiency virus type-1 (HIV-1) infection and trauma, can stimulate the accumulation of factor XIIIa expressing dermal dendrocytes in the skin. These cells can then participate in different stages of a variety of cutaneous alterations including Kaposi's sarcoma, dermatofibroma, granuloma annulare, and early wound healing. Thus, the factor XIIIa-positive dermal dendrocyte is a common cellular denominator among diverse clinical entities that share some histologic features. Images Figure 1 Figure 2 Figure 3 p797-a PMID:2573283

  15. Genome-wide analysis and expression patterns of ZF-HD transcription factors under different developmental tissues and abiotic stresses in Chinese cabbage.

    PubMed

    Wang, Wenli; Wu, Peng; Li, Ying; Hou, XiLin

    2016-06-01

    The ZF-HD gene family plays an important role in plant developmental processes and stress responses. However, the function of the ZF-HD genes in Chinese cabbage remains largely unknown. Chinese cabbage (Brassica rapa ssp. pekinensis) is a member of one of the most important leaf vegetables grown worldwide. The entire Chinese cabbage genome sequence has been determined, and more than forty thousand proteins have been identified to date. In this study, 31 ZF-HD genes were identified in Chinese cabbage. We show here that the BraZF-HD genes could be categorized into ZHD and MIF subfamilies. Among them, ZHD genes are plant-specific, nearly all intronless, and related to MINI ZINC FINGER genes that possess only the zinc finger. Phylogenetic analysis suggested that ZHDs have expanded considerably during angiosperm evolution. In addition, the ZHD group has 24 members, which is twice as much as the Arabidopsis ZHD group, indicating that the Chinese cabbage ZHD genes have been retained more frequently than other group genes. Real-time PCR analysis showed that most of BraZF-HD genes are preferentially expressed in flower. Furthermore, most of these genes are significantly induced under photoperiod or vernalization conditions, as well as abiotic stresses. Thereby implying that they may play important roles in these processes. This study provides insight into the evolution of ZF-HD genes in Chinese cabbage genome and may aid efforts to further characterize the function of these predicted ZF-HD genes in flowering and resistance.

  16. Biotic and Abiotic Stresses Activate Different Ca2+ Permeable Channels in Arabidopsis

    PubMed Central

    Cao, Xiao-Qiang; Jiang, Zhong-Hao; Yi, Yan-Yan; Yang, Yi; Ke, Li-Ping; Pei, Zhen-Ming; Zhu, Shan

    2017-01-01

    To survive, plants must respond rapidly and effectively to various stress factors, including biotic and abiotic stresses. Salinity stress triggers the increase of cytosolic free Ca2+ concentration ([Ca2+]i) via Ca2+ influx across the plasma membrane, as well as bacterial flg22 and plant endogenous peptide Pep1. However, the interaction between abiotic stress-induced [Ca2+]i increases and biotic stress-induced [Ca2+]i increases is still not clear. Employing an aequorin-based Ca2+ imaging assay, in this work, we investigated the [Ca2+]i changes in response to flg22, Pep1, and NaCl treatments in Arabidopsis thaliana. We observed an additive effect on the [Ca2+]i increase which induced by flg22, Pep1, and NaCl. Our results indicate that biotic and abiotic stresses may activate different Ca2+ permeable channels. Further, calcium signal induced by biotic and abiotic stresses was independent in terms of spatial and temporal patterning. PMID:28197161

  17. Biotic and Abiotic Stresses Activate Different Ca(2+) Permeable Channels in Arabidopsis.

    PubMed

    Cao, Xiao-Qiang; Jiang, Zhong-Hao; Yi, Yan-Yan; Yang, Yi; Ke, Li-Ping; Pei, Zhen-Ming; Zhu, Shan

    2017-01-01

    To survive, plants must respond rapidly and effectively to various stress factors, including biotic and abiotic stresses. Salinity stress triggers the increase of cytosolic free Ca(2+) concentration ([Ca(2+)]i) via Ca(2+) influx across the plasma membrane, as well as bacterial flg22 and plant endogenous peptide Pep1. However, the interaction between abiotic stress-induced [Ca(2+)]i increases and biotic stress-induced [Ca(2+)]i increases is still not clear. Employing an aequorin-based Ca(2+) imaging assay, in this work, we investigated the [Ca(2+)]i changes in response to flg22, Pep1, and NaCl treatments in Arabidopsis thaliana. We observed an additive effect on the [Ca(2+)]i increase which induced by flg22, Pep1, and NaCl. Our results indicate that biotic and abiotic stresses may activate different Ca(2+) permeable channels. Further, calcium signal induced by biotic and abiotic stresses was independent in terms of spatial and temporal patterning.

  18. Unraveling the role of fungal symbionts in plant abiotic stress tolerance

    PubMed Central

    Singh, Lamabam Peter

    2011-01-01

    Fungal symbionts have been found to be associated with every plant studied in the natural ecosystem, where they colonize and reside entirely or partially in the internal tissues of their host plant. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress and heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is an increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered. PMID:21512319

  19. Natural abiotic formation of oxalic acid in soils: results from aromatic model compounds and soil samples.

    PubMed

    Studenroth, Sabine; Huber, Stefan G; Kotte, Karsten; Schöler, Heinz F

    2013-02-05

    Oxalic acid is the smallest dicarboxylic acid and plays an important role in soil processes (e.g., mineral weathering and metal detoxification in plants). We have first proven its abiotic formation in soils and investigated natural abiotic degradation processes based on the oxidation of soil organic matter, enhanced by Fe(3+) and H(2)O(2) as hydroxyl radical suppliers. Experiments with the model compound catechol and further hydroxylated benzenes were performed to examine a common degradation pathway and to presume a general formation mechanism of oxalic acid. Two soil samples were tested for the release of oxalic acid and the potential effects of various soil parameters on oxalic acid formation. Additionally, the soil samples were treated with different soil sterilization methods to prove the oxalic acid formation under abiotic soil conditions. Different series of model experiments were conducted to determine a range of factors including Fe(3+), H(2)O(2), reaction time, pH, and chloride concentration on oxalic acid formation. Under certain conditions, catechol is degraded up to 65.6% to oxalic acid referring to carbon. In serial experiments with two soil samples, oxalic acid was produced, and the obtained results are suggestive of an abiotic degradation process. In conclusion, Fenton-like conditions with low Fe(3+) concentrations and an excess of H(2)O(2) as well as acidic conditions were required for an optimal oxalic acid formation. The presence of chloride reduced oxalic acid formation.

  20. Abiotic and biotic factors influencing the mobility of arsenic in groundwater of a through-flow island in the Okavango Delta, Botswana

    NASA Astrophysics Data System (ADS)

    Mladenov, Natalie; Wolski, Piotr; Hettiarachchi, Ganga M.; Murray-Hudson, Michael; Enriquez, Hersy; Damaraju, Sivaramakrishna; Galkaduwa, Madhubhashini B.; McKnight, Diane M.; Masamba, Wellington

    2014-10-01

    The Okavango Delta of Botswana is a large arid-zone wetland comprising 20,000 km2 of permanent and seasonal floodplains and over 100,000 islands. It has been shown that island groundwater can have very high dissolved arsenic (As) concentration, but the abiotic and biotic controls on As mobility are not well understood in this setting. At New Island, an island located in the seasonal swamp, dissolved As concentration increased from below detection limits in the surface water to 180 μg/L in groundwater, present as As(III) species. We investigated the relative importance of hydrologic, geochemical, and geomicrobial processes, as well as influences of recent extreme flooding events, in mobilizing and sequestering As in the shallow groundwater system under this island. Our results suggest that evapotranspiration and through-flow conditions control the location of the high arsenic zone. A combination of processes is hypothesized to control elevated As in the concentration zone of New Island: high evapotranspiration rates concentrate As and other solutes, more alkaline pH leads to desorption of arsenic or dissolution of arsenic sulfides, and formation of thioarsenic complexes acts to keep arsenic in solution. Evidence from X-ray absorption near-edge structure spectroscopy (XANES) and sulfate reducing bacteria (SRB) measurements further suggests that SRBs influence arsenic sequestration as orpiment (As2S3). Although dissolved organic matter (DOM) was not significantly correlated to dissolved As in the groundwater, our results suggest that DOM may serve as an electron donor for sulfate reduction or other microbial reactions that influence redox state and As mobility. These results have important implications for water management in the region and in other large wetland environments. The processes evaluated in this study are also relevant for arsenic removal in subsurface constructed wetland systems that may exhibit rapidly changing processes over small spatial scales.

  1. Simultaneous expression of abiotic stress responsive transcription factors, AtDREB2A, AtHB7 and AtABF3 improves salinity and drought tolerance in peanut (Arachis hypogaea L.).

    PubMed

    Pruthvi, Vittal; Narasimhan, Rama; Nataraja, Karaba N

    2014-01-01

    Drought, salinity and extreme temperatures are the most common abiotic stresses, adversely affecting plant growth and productivity. Exposure of plants to stress activates stress signalling pathways that induce biochemical and physiological changes essential for stress acclimation. Stress tolerance is governed by multiple traits, and importance of a few traits in imparting tolerance has been demonstrated. Under drought, traits linked to water mining and water conservation, water use efficiency and cellular tolerance (CT) to desiccation are considered to be relevant. In this study, an attempt has been made to improve CT in drought hardy crop, peanut (Arachis hypogaea L., cv. TMV2) by co-expressing stress-responsive transcription factors (TFs), AtDREB2A, AtHB7 and AtABF3, associated with downstream gene expression. Transgenic plants simultaneously expressing these TFs showed increased tolerance to drought, salinity and oxidative stresses compared to wild type, with an increase in total plant biomass. The transgenic plants exhibited improved membrane and chlorophyll stability due to enhanced reactive oxygen species scavenging and osmotic adjustment by proline synthesis under stress. The improvement in stress tolerance in transgenic lines were associated with induced expression of various CT related genes like AhGlutaredoxin, AhAldehyde reductase, AhSerine threonine kinase like protein, AhRbx1, AhProline amino peptidase, AhHSP70, AhDIP and AhLea4. Taken together the results indicate that co-expression of stress responsive TFs can activate multiple CT pathways, and this strategy can be employed to improve abiotic stress tolerance in crop plants.

  2. Simultaneous Expression of Abiotic Stress Responsive Transcription Factors, AtDREB2A, AtHB7 and AtABF3 Improves Salinity and Drought Tolerance in Peanut (Arachis hypogaea L.)

    PubMed Central

    Pruthvi, Vittal; Narasimhan, Rama; Nataraja, Karaba N.

    2014-01-01

    Drought, salinity and extreme temperatures are the most common abiotic stresses, adversely affecting plant growth and productivity. Exposure of plants to stress activates stress signalling pathways that induce biochemical and physiological changes essential for stress acclimation. Stress tolerance is governed by multiple traits, and importance of a few traits in imparting tolerance has been demonstrated. Under drought, traits linked to water mining and water conservation, water use efficiency and cellular tolerance (CT) to desiccation are considered to be relevant. In this study, an attempt has been made to improve CT in drought hardy crop, peanut (Arachis hypogaea L., cv. TMV2) by co-expressing stress-responsive transcription factors (TFs), AtDREB2A, AtHB7 and AtABF3, associated with downstream gene expression. Transgenic plants simultaneously expressing these TFs showed increased tolerance to drought, salinity and oxidative stresses compared to wild type, with an increase in total plant biomass. The transgenic plants exhibited improved membrane and chlorophyll stability due to enhanced reactive oxygen species scavenging and osmotic adjustment by proline synthesis under stress. The improvement in stress tolerance in transgenic lines were associated with induced expression of various CT related genes like AhGlutaredoxin, AhAldehyde reductase, AhSerine threonine kinase like protein, AhRbx1, AhProline amino peptidase, AhHSP70, AhDIP and AhLea4. Taken together the results indicate that co-expression of stress responsive TFs can activate multiple CT pathways, and this strategy can be employed to improve abiotic stress tolerance in crop plants. PMID:25474740

  3. Prognostic factors of infantile spasms: role of treatment options including a ketogenic diet.

    PubMed

    Lee, Jeehun; Lee, Jun Hwa; Yu, Hee Jun; Lee, Munhyang

    2013-09-01

    The aim of this study was to provide additional evidences on prognostic factors for infantile spasms and the possible role of a ketogenic diet. A retrospective analysis was performed for patients with infantile spasms who had been followed up for more than 6months between January 2000 and July 2012 at Samsung Medical Center (Seoul, Republic of Korea). We analyzed the association between possible prognostic factors and seizure/developmental outcomes. Sixty-nine patients were included in this study and their mean follow-up duration was 52.5 (9-147) months. In the patients who had been followed up for more than 2years, 53.6% (n=30/57) remained seizure-free at the last visit. Sixty patients (86.9%) showed developmental delay at last follow-up. Forty-two patients (60.9%) became spasm-free with one or two antiepileptic drugs, one patient with epilepsy surgery for a tumor, and seven patients with a ketogenic diet after the failure of two or more antiepileptic drugs. The etiology and age of seizure onset were the significant prognostic factors. In this study, about 60% of the patients became spasm-free with vigabatrin and topiramate. Ketogenic diet increased the rate by 10% in the remaining antiepileptic drug resistant patients. However, 86.9% of the patients showed developmental delay, mostly a severe degree. Early diagnosis and prompt application of treatment options such as antiepileptic drugs, a ketogenic diet or epilepsy surgery can improve outcomes in patients with infantile spasms. Copyright © 2013 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  4. Analysis of the lifted weight including height and frequency factors for workers in Colombia.

    PubMed

    Saavedra-Robinson, Luisa; Quintana, Leonardo A J; Fortunato Leal, Luis Díaz; Niño, María

    2012-01-01

    Factors related to the height of the load and the frequency of handling have become a way to predict the acceptable standard weight lifted for workers whose main task is the manual lifting of materials and measuring the conditions is important to determine a maximum weight lifted. This study was conducted to twenty (20) workers between eighteen (18) and forty (40) years old with a minimum six months experience and belonging to the warehouse and packaging area of a dairy products company. Consideration was given to three different heights such as knuckle, shoulder and total height as well as frequencies of 2, 4 and 6 times per minute. Average values for lifted weight were 17.9306 ± 2.37 kg. The conclusions and recommendations included a review of legislation related to Colombian maximum acceptable weight of lifting due to the current law does not match the acceptable weight handled in this research.

  5. Macroenvironmental factors including GDP per capita and physical activity in Europe.

    PubMed

    Cameron, Adrian J; Van Stralen, Maartje M; Kunst, Anton E; Te Velde, Saskia J; Van Lenthe, Frank J; Salmon, Jo; Brug, Johannes

    2013-02-01

    Socioeconomic inequalities in physical activity at the individual level are well reported. Whether inequalities in economic development and other macroenvironmental variables between countries are also related to physical activity at the country level is comparatively unstudied. We examined the relationship between country-level data on macroenvironmental factors (gross domestic product (GDP) per capita, public sector expenditure on health, percentage living in urban areas, and cars per 1000 population) with country-level physical activity prevalence obtained from previous pan-European studies. Studies that assessed leisuretime physical activity (n = 3 studies including 27 countries in adults, n = 2 studies including 28 countries in children) and total physical activity (n = 3 studies in adults including 16 countries) were analyzed separately as were studies among adults and children. Strong and consistent positive correlations were observed between country prevalence of leisure-time physical activity and country GDP per capita in adults (average r = 0.70; all studies, P G 0.05). In multivariate analysis, country prevalence of leisure-time physical activity among adults remained associated with country GDP per capita (two of three studies) but not urbanization or educational attainment. Among school-age populations, no association was found between country GDP per capita and country prevalence of leisure-time physical activity. In those studies that assessed total physical activity (which also includes occupational and transport physical activity), no association with country GDP per capita was observed. Clear differences in national leisure-time physical activity levels throughout Europe may be a consequence of economic development. Lack of economic development of some countries in Europe may make increasing leisure-time physical activity more difficult. Further examination of the link between country GDP per capita and national physical activity levels (across

  6. Influence of salinity and temperature on the physiology of Limia melanonotata (Cyprinodontiformes: Poeciliidae): A search for abiotic factors limiting insular distribution in Hispaniola

    USGS Publications Warehouse

    Haney, D.C.; Walsh, S.J.

    2003-01-01

    We investigated salinity and temperature effects on routine metabolic rate (RMR), temperature tolerance (CTMax, critical thermal maximum), and salinity tolerance of Limia melanonotata, a poecliid fish that occurs in west-central inland waters of Hispaniola. Routine metabolic rate and CTMax were measured in fish acclimated to three salinities (0, 30, and 60 ppt) and temperatures (25??, 30??, and 35??C) for nine temperature-salinity combinations. Salinity and temperature did not significantly interact in their effect on RMR. For combined salinity acclimations, adjusted RMR (ANCOVA) was significantly lower at 25??C than either 30?? or 35??C. For combined temperature acclimations, mean RMR was significantly lower at 60 ppt than either 0 or 30 ppt. Salinity and temperature had a significant interactive effect on temperature tolerance. Mean CTMax was significantly higher at 30?? than 25??C at all salinities, but at 35??C was significantly higher than at 25?? or 30??C only among fish acclimated in fresh water. Fish exposed to a chronic increase in salinity experienced most mortality in a salinity range of 70-107 ppt, with females exhibiting greater salinity tolerance than males. Limia melanonotata approaches the upper extreme in salinity and temperature tolerances known for poeciliids. Our results also suggest that L. melanonotata may reduce energy expenditures at environmental extremes to tolerate harsh conditions for extended periods. Despite its curythermal and euryhaline adaptations, L. melanonotata has a relatively restricted inland range in Hispaniola and is unknown from inshore brackish or marine habitats. The present distribution of this species and congeners may be the result of a combination of factors that include historical zoogeography and ecological requirements.

  7. The Arabidopsis PLAT domain protein1 is critically involved in abiotic stress tolerance.

    PubMed

    Hyun, Tae Kyung; van der Graaff, Eric; Albacete, Alfonso; Eom, Seung Hee; Großkinsky, Dominik K; Böhm, Hannah; Janschek, Ursula; Rim, Yeonggil; Ali, Walid Wahid; Kim, Soo Young; Roitsch, Thomas

    2014-01-01

    Despite the completion of the Arabidopsis genome sequence, for only a relatively low percentage of the encoded proteins experimental evidence concerning their function is available. Plant proteins that harbour a single PLAT (Polycystin, Lipoxygenase, Alpha-toxin and Triacylglycerol lipase) domain and belong to the PLAT-plant-stress protein family are ubiquitously present in monocot and dicots. However, the function of PLAT-plant-stress proteins is still poorly understood. Therefore, we have assessed the function of the uncharacterised Arabidopsis PLAT-plant-stress family members through a combination of functional genetic and physiological approaches. PLAT1 overexpression conferred increased abiotic stress tolerance, including cold, drought and salt stress, while loss-of-function resulted in opposite effects on abiotic stress tolerance. Strikingly, PLAT1 promoted growth under non-stressed conditions. Abiotic stress treatments induced PLAT1 expression and caused expansion of its expression domain. The ABF/ABRE transcription factors, which are positive mediators of abscisic acid signalling, activate PLAT1 promoter activity in transactivation assays and directly bind to the ABRE elements located in this promoter in electrophoretic mobility shift assays. This suggests that PLAT1 represents a novel downstream target of the abscisic acid signalling pathway. Thus, we showed that PLAT1 critically functions as positive regulator of abiotic stress tolerance, but also is involved in regulating plant growth, and thereby assigned a function to this previously uncharacterised PLAT domain protein. The functional data obtained for PLAT1 support that PLAT-plant-stress proteins in general could be promising targets for improving abiotic stress tolerance without yield penalty.

  8. An omics approach to understand the plant abiotic stress.

    PubMed

    Debnath, Mousumi; Pandey, Mukeshwar; Bisen, P S

    2011-11-01

    Abiotic stress can lead to changes in development, productivity, and severe stress and may even threaten survival of plants. Several environmental stresses cause drastic changes in the growth, physiology, and metabolism of plants leading to the increased accumulation of secondary metabolites. As medicinal plants are important sources of drugs, steps are taken to understand the effect of stress on the physiology, biochemistry, genomic, proteomic, and metabolic levels. The molecular responses of plants to abiotic stress are often considered as a complex process. They are mainly based on the modulation of transcriptional activity of stress-related genes. Many genes have been induced under stress conditions. The products of stress-inducible genes protecting against these stresses includes the enzymes responsible for the synthesis of various osmoprotectants. Genetic engineering of tolerance to abiotic stresses help in molecular understanding of pathways induced in response to one or more of the abiotic stresses. Systems biology and virtual experiments allow visualizing and understanding how plants work to overcome abiotic stress. This review discusses the omic approach to understand the plant response to abiotic stress with special emphasis on medicinal plant.

  9. Biological Networks Underlying Abiotic Stress Tolerance in Temperate Crops—A Proteomic Perspective

    PubMed Central

    Kosová, Klára; Vítámvás, Pavel; Urban, Milan Oldřich; Klíma, Miroslav; Roy, Amitava; Prášil, Ilja Tom

    2015-01-01

    Abiotic stress factors, especially low temperatures, drought, and salinity, represent the major constraints limiting agricultural production in temperate climate. Under the conditions of global climate change, the risk of damaging effects of abiotic stresses on crop production increases. Plant stress response represents an active process aimed at an establishment of novel homeostasis under altered environmental conditions. Proteins play a crucial role in plant stress response since they are directly involved in shaping the final phenotype. In the review, results of proteomic studies focused on stress response of major crops grown in temperate climate including cereals: common wheat (Triticum aestivum), durum wheat (Triticum durum), barley (Hordeum vulgare), maize (Zea mays); leguminous plants: alfalfa (Medicago sativa), soybean (Glycine max), common bean (Phaseolus vulgaris), pea (Pisum sativum); oilseed rape (Brassica napus); potato (Solanum tuberosum); tobacco (Nicotiana tabaccum); tomato (Lycopersicon esculentum); and others, to a wide range of abiotic stresses (cold, drought, salinity, heat, imbalances in mineral nutrition and heavy metals) are summarized. The dynamics of changes in various protein functional groups including signaling and regulatory proteins, transcription factors, proteins involved in protein metabolism, amino acid metabolism, metabolism of several stress-related compounds, proteins with chaperone and protective functions as well as structural proteins (cell wall components, cytoskeleton) are briefly overviewed. Attention is paid to the differences found between differentially tolerant genotypes. In addition, proteomic studies aimed at proteomic investigation of multiple stress factors are discussed. In conclusion, contribution of proteomic studies to understanding the complexity of crop response to abiotic stresses as well as possibilities to identify and utilize protein markers in crop breeding processes are discussed. PMID:26340626

  10. Biological Networks Underlying Abiotic Stress Tolerance in Temperate Crops--A Proteomic Perspective.

    PubMed

    Kosová, Klára; Vítámvás, Pavel; Urban, Milan Oldřich; Klíma, Miroslav; Roy, Amitava; Prášil, Ilja Tom

    2015-09-01

    Abiotic stress factors, especially low temperatures, drought, and salinity, represent the major constraints limiting agricultural production in temperate climate. Under the conditions of global climate change, the risk of damaging effects of abiotic stresses on crop production increases. Plant stress response represents an active process aimed at an establishment of novel homeostasis under altered environmental conditions. Proteins play a crucial role in plant stress response since they are directly involved in shaping the final phenotype. In the review, results of proteomic studies focused on stress response of major crops grown in temperate climate including cereals: common wheat (Triticum aestivum), durum wheat (Triticum durum), barley (Hordeum vulgare), maize (Zea mays); leguminous plants: alfalfa (Medicago sativa), soybean (Glycine max), common bean (Phaseolus vulgaris), pea (Pisum sativum); oilseed rape (Brassica napus); potato (Solanum tuberosum); tobacco (Nicotiana tabaccum); tomato (Lycopersicon esculentum); and others, to a wide range of abiotic stresses (cold, drought, salinity, heat, imbalances in mineral nutrition and heavy metals) are summarized. The dynamics of changes in various protein functional groups including signaling and regulatory proteins, transcription factors, proteins involved in protein metabolism, amino acid metabolism, metabolism of several stress-related compounds, proteins with chaperone and protective functions as well as structural proteins (cell wall components, cytoskeleton) are briefly overviewed. Attention is paid to the differences found between differentially tolerant genotypes. In addition, proteomic studies aimed at proteomic investigation of multiple stress factors are discussed. In conclusion, contribution of proteomic studies to understanding the complexity of crop response to abiotic stresses as well as possibilities to identify and utilize protein markers in crop breeding processes are discussed.

  11. Paternal postnatal depression in Japan: an investigation of correlated factors including relationship with a partner.

    PubMed

    Nishimura, Akiko; Fujita, Yuichi; Katsuta, Mayumi; Ishihara, Aya; Ohashi, Kazutomo

    2015-05-31

    A negative effect of paternal depression on child development has been revealed in several previous studies. The aims of this study were to examine the prevalence and relevant factors associated with paternal postnatal depression at four months postpartum, including age, part-time work or unemployment, experience of visiting a medical institution due to a mental health problem, economic anxiety, unexpected pregnancy, pregnancy with infertility treatment, first child, partner's depression, and lower marital relationship satisfaction. We distributed 2032 self-report questionnaires to couples (one mother and one father) with a 4-month old infant between January and April 2013. Data from 807 couples (39.7 %) were analyzed. Depressive symptoms were measured with the Edinburgh Postnatal Depression Scale (EPDS). In order to clarify the factors related with paternal depression, a logistic regression analysis was conducted. One hundred and ten fathers (13.6 %) and 83 mothers (10.3 %) were depressed. According to the logistic regression analysis, paternal depression was positively associated with partner's depression (adjusted odds ratio (AOR) 1.91, 95 % confidence interval (CI) 1.05-3.47), and negatively with marital relationship satisfaction (AOR 0.83, 95 % CI 0.77-0.89). History of infertility treatment (AOR 2.37, 95 % CI 1.32-4.24), experience of visiting a medical institution due to a mental health problem (AOR 4.56, 95 % CI 2.06-10.08), and economic anxiety (AOR 2.15, 95 % CI 1.34-3.45) were also correlated with paternal depression. This study showed that the prevalence of paternal depression at four months after childbirth was 13.6 % in Japan. The presence of partner's depression and low marital relationship satisfaction were significantly correlated with paternal postpartum depression, suggesting that health professionals need to pay attention to the mental status of both fathers and mothers, and to their relationship.

  12. Fever in trauma patients: evaluation of risk factors, including traumatic brain injury.

    PubMed

    Bengualid, Victoria; Talari, Goutham; Rubin, David; Albaeni, Aiham; Ciubotaru, Ronald L; Berger, Judith

    2015-03-01

    The role of fever in trauma patients remains unclear. Fever occurs as a response to release of cytokines and prostaglandins by white blood cells. Many factors, including trauma, can trigger release of these factors. To determine whether (1) fever in the first 48 hours is related to a favorable outcome in trauma patients and (2) fever is more common in patients with head trauma. Retrospective study of trauma patients admitted to the intensive care unit for at least 2 days. Data were analyzed by using multivariate analysis. Of 162 patients studied, 40% had fever during the first 48 hours. Febrile patients had higher mortality rates than did afebrile patients. When adjusted for severity of injuries, fever did not correlate with mortality. Neither the incidence of fever in the first 48 hours after admission to the intensive care unit nor the number of days febrile in the unit differed between patients with and patients without head trauma (traumatic brain injury). About 70% of febrile patients did not have a source found for their fever. Febrile patients without an identified source of infection had lower peak white blood cell counts, lower maximum body temperature, and higher minimum platelet counts than did febrile patients who had an infectious source identified. The most common infection was pneumonia. No relationship was found between the presence of fever during the first 48 hours and mortality. Patients with traumatic brain injury did not have a higher incidence of fever than did patients without traumatic brain injury. About 30% of febrile patients had an identifiable source of infection. Further studies are needed to understand the origin and role of fever in trauma patients. ©2015 American Association of Critical-Care Nurses.

  13. A decision support system prototype including human factors based on the TOGA meta-theory approach

    SciTech Connect

    Cappelli, M.; Memmi, F.; Gadomski, A. M.; Sepielli, M.

    2012-07-01

    The human contribution to the risk of operation of complex technological systems is often not negligible and sometimes tends to become significant, as shown by many reports on incidents and accidents occurred in the past inside Nuclear Power Plants (NPPs). An error of a human operator of a NPP can derive by both omission and commission. For instance, complex commission errors can also lead to significant catastrophic technological accidents, as for the case of the Three Mile Island accident. Typically, the problem is analyzed by focusing on the single event chain that has provoked the incident or accident. What is needed is a general framework able to include as many parameters as possible, i.e. both technological and human factors. Such a general model could allow to envisage an omission or commission error before it can happen or, alternatively, suggest preferred actions to do in order to take countermeasures to neutralize the effect of the error before it becomes critical. In this paper, a preliminary Decision Support System (DSS) based on the so-called (-) TOGA meta-theory approach is presented. The application of such a theory to the management of nuclear power plants has been presented in the previous ICAPP 2011. Here, a human factor simulator prototype is proposed in order to include the effect of human errors in the decision path. The DSS has been developed using a TRIGA research reactor as reference plant, and implemented using the LabVIEW programming environment and the Finite State Machine (FSM) model The proposed DSS shows how to apply the Universal Reasoning Paradigm (URP) and the Universal Management Paradigm (UMP) to a real plant context. The DSS receives inputs from instrumentation data and gives as output a suggested decision. It is obtained as the result of an internal elaborating process based on a performance function. The latter, describes the degree of satisfaction and efficiency, which are dependent on the level of responsibility related to

  14. The Cognitive Phenotype in Klinefelter Syndrome: A Review of the Literature Including Genetic and Hormonal Factors

    PubMed Central

    Boada, Richard; Janusz, Jennifer; Hutaff-Lee, Christa; Tartaglia, Nicole

    2011-01-01

    Klinefelter syndrome (KS) or 47,XXY occurs in ∼1 in 650 males. Individuals with KS often present with physical characteristics including tall stature, hypogonadism, and fertility problems. In addition to medical findings, the presence of the extra X chromosome can lead to characteristic cognitive and language deficits of varying severity. While a small, but significant downward shift in mean overall IQ has been reported, the general cognitive abilities of patients with KS are not typically in the intellectual disability range. Most studies support that males with KS have an increased risk of language disorders and reading disabilities. Results of other studies investigating the relationship between verbal and nonverbal/spatial cognitive abilities have been mixed, with differing results based on the age and ascertainment method of the cohort studied. Executive function deficits have been identified in children and adults with KS, however, the research in this area is limited and further investigation of the neuropsychological profile is needed. In this article, we review the strengths and weaknesses of previous cognitive and neuropsychological studies in males with KS in childhood and adulthood, provide historical perspective of these studies, and review what is known about how hormonal and genetic factors influence cognitive features in 47,XXY/KS. PMID:20014369

  15. Health Promotion Behavior of Chinese International Students in Korea Including Acculturation Factors: A Structural Equation Model.

    PubMed

    Kim, Sun Jung; Yoo, Il Young

    2016-03-01

    The purpose of this study was to explain the health promotion behavior of Chinese international students in Korea using a structural equation model including acculturation factors. A survey using self-administered questionnaires was employed. Data were collected from 272 Chinese students who have resided in Korea for longer than 6 months. The data were analyzed using structural equation modeling. The p value of final model is .31. The fitness parameters of the final model such as goodness of fit index, adjusted goodness of fit index, normed fit index, non-normed fit index, and comparative fit index were more than .95. Root mean square of residual and root mean square error of approximation also met the criteria. Self-esteem, perceived health status, acculturative stress and acculturation level had direct effects on health promotion behavior of the participants and the model explained 30.0% of variance. The Chinese students in Korea with higher self-esteem, perceived health status, acculturation level, and lower acculturative stress reported higher health promotion behavior. The findings can be applied to develop health promotion strategies for this population. Copyright © 2016. Published by Elsevier B.V.

  16. Analytical expressions for the gate utilization factors of passive multiplicity counters including signal build-up

    SciTech Connect

    Croft, Stephen; Evans, Louise G; Schear, Melissa A

    2010-01-01

    In the realm of nuclear safeguards, passive neutron multiplicity counting using shift register pulse train analysis to nondestructively quantify Pu in product materials is a familiar and widely applied technique. The approach most commonly taken is to construct a neutron detector consisting of {sup 3}He filled cylindrical proportional counters embedded in a high density polyethylene moderator. Fast neutrons from the item enter the moderator and are quickly slowed down, on timescales of the order of 1-2 {micro}s, creating a thermal population which then persists typically for several 10's {micro}s and is sampled by the {sup 3}He detectors. Because the initial transient is of comparatively short duration it has been traditional to treat it as instantaneous and furthermore to approximate the subsequent capture time distribution as exponential in shape. With these approximations simple expressions for the various Gate Utilization Factors (GUFs) can be obtained. These factors represent the proportion of time correlated events i.e. Doubles and Triples signal present in the pulse train that is detected by the coincidence gate structure chosen (predelay and gate width settings of the multiplicity shift register). More complicated expressions can be derived by generalizing the capture time distribution to multiple time components or harmonics typically present in real systems. When it comes to applying passive neutron multiplicity methods to extremely intense (i.e. high emission rate and highly multiplying) neutron sources there is a drive to use detector types with very fast response characteristics in order to cope with the high rates. In addition to short pulse width, detectors with a short capture time profile are also desirable so that a short coincidence gate width can be set in order to reduce the chance or Accidental coincidence signal. In extreme cases, such as might be realized using boron loaded scintillators, the dieaway time may be so short that the build

  17. Transcriptome analysis reveals crosstalk of responsive genes to multiple abiotic stresses in cotton (Gossypium hirsutum L.).

    PubMed

    Zhu, Ya-Na; Shi, Dong-Qiao; Ruan, Meng-Bin; Zhang, Li-Li; Meng, Zhao-Hong; Liu, Jie; Yang, Wei-Cai

    2013-01-01

    Abiotic stress is a major environmental factor that limits cotton growth and yield, moreover, this problem has become more and more serious recently, as multiple stresses often occur simultaneously due to the global climate change and environmental pollution. In this study, we sought to identify genes involved in diverse stresses including abscisic acid (ABA), cold, drought, salinity and alkalinity by comparative microarray analysis. Our result showed that 5790, 3067, 5608, 778 and 6148 transcripts, were differentially expressed in cotton seedlings under treatment of ABA (1 μM ABA), cold (4°C), drought (200 mM mannitol), salinity (200 mM NaCl) and alkalinity (pH=11) respectively. Among the induced or suppressed genes, 126 transcripts were shared by all of the five kinds of abiotic stresses, with 64 up-regulated and 62 down-regulated. These common members are grouped as stress signal transduction, transcription factors (TFs), stress response/defense proteins, metabolism, transport facilitation, as well as cell wall/structure, according to the function annotation. We also noticed that large proportion of significant differentially expressed genes specifically regulated in response to different stress. Nine of the common transcripts of multiple stresses were selected for further validation with quantitative real time RT-PCR (qRT-PCR). Furthermore, several well characterized TF families, for example, WRKY, MYB, NAC, AP2/ERF and zinc finger were shown to be involved in different stresses. As an original report using comparative microarray to analyze transcriptome of cotton under five abiotic stresses, valuable information about functional genes and related pathways of anti-stress, and/or stress tolerance in cotton seedlings was unveiled in our result. Besides this, some important common factors were focused for detailed identification and characterization. According to our analysis, it suggested that there was crosstalk of responsive genes or pathways to multiple

  18. ROS-mediated abiotic stress-induced programmed cell death in plants

    PubMed Central

    Petrov, Veselin; Hille, Jacques; Mueller-Roeber, Bernd; Gechev, Tsanko S.

    2015-01-01

    During the course of their ontogenesis plants are continuously exposed to a large variety of abiotic stress factors which can damage tissues and jeopardize the survival of the organism unless properly countered. While animals can simply escape and thus evade stressors, plants as sessile organisms have developed complex strategies to withstand them. When the intensity of a detrimental factor is high, one of the defense programs employed by plants is the induction of programmed cell death (PCD). This is an active, genetically controlled process which is initiated to isolate and remove damaged tissues thereby ensuring the survival of the organism. The mechanism of PCD induction usually includes an increase in the levels of reactive oxygen species (ROS) which are utilized as mediators of the stress signal. Abiotic stress-induced PCD is not only a process of fundamental biological importance, but also of considerable interest to agricultural practice as it has the potential to significantly influence crop yield. Therefore, numerous scientific enterprises have focused on elucidating the mechanisms leading to and controlling PCD in response to adverse conditions in plants. This knowledge may help develop novel strategies to obtain more resilient crop varieties with improved tolerance and enhanced productivity. The aim of the present review is to summarize the recent advances in research on ROS-induced PCD related to abiotic stress and the role of the organelles in the process. PMID:25741354

  19. Biotic and Abiotic Factors Controlling Respiration Rates of Above- and Belowground Woody Debris of Fagus crenata and Quercus crispula in Japan

    PubMed Central

    Jomura, Mayuko; Akashi, Yuhei; Itoh, Hiromu; Yuki, Risa; Sakai, Yoshimi; Maruyama, Yutaka

    2015-01-01

    As a large, long-term pool and source of carbon and nutrients, woody litter is an important component of forest ecosystems. The objective of this study was to estimate the effect of the factors that regulate the rate of decomposition of coarse and fine woody debris (CFWD) of dominant tree species in a cool-temperate forest in Japan. Respiration rates of dead stems, branches, and coarse and fine roots of Fagus crenata and Quercus crispula felled 4 years prior obtained in situ ranged from 20.9 to 500.1 mg CO2 [kg dry wood]–1 h–1 in a one-time measurement in summer. Respiration rate had a significant negative relationship with diameter; in particular, that of a sample of Q. crispula with a diameter of >15 cm and substantial heartwood was low. It also had a significant positive relationship with moisture content. The explanatory variables diameter, [N], wood density, and moisture content were interrelated. The most parsimonious path model showed 14 significant correlations among 8 factors and respiration. Diameter and [C] had large negative direct effects on CFWD respiration rate, and moisture content and species had medium positive direct effects. [N] and temperature did not have direct or indirect effects, and position and wood density had indirect effects. The model revealed some interrelationships between controlling factors. We discussed the influence of the direct effects of explanatory variables and the influence especially of species and position. We speculate that the small R2 value of the most parsimonious model was probably due to the omission of microbial biomass and activity. These direct and indirect effects and interrelationships between explanatory variables could be used to develop a process-based CFWD decomposition model. PMID:26658727

  20. Biotic and Abiotic Factors Controlling Respiration Rates of Above- and Belowground Woody Debris of Fagus crenata and Quercus crispula in Japan.

    PubMed

    Jomura, Mayuko; Akashi, Yuhei; Itoh, Hiromu; Yuki, Risa; Sakai, Yoshimi; Maruyama, Yutaka

    2015-01-01

    As a large, long-term pool and source of carbon and nutrients, woody litter is an important component of forest ecosystems. The objective of this study was to estimate the effect of the factors that regulate the rate of decomposition of coarse and fine woody debris (CFWD) of dominant tree species in a cool-temperate forest in Japan. Respiration rates of dead stems, branches, and coarse and fine roots of Fagus crenata and Quercus crispula felled 4 years prior obtained in situ ranged from 20.9 to 500.1 mg CO2 [kg dry wood](-1) h(-1) in a one-time measurement in summer. Respiration rate had a significant negative relationship with diameter; in particular, that of a sample of Q. crispula with a diameter of >15 cm and substantial heartwood was low. It also had a significant positive relationship with moisture content. The explanatory variables diameter, [N], wood density, and moisture content were interrelated. The most parsimonious path model showed 14 significant correlations among 8 factors and respiration. Diameter and [C] had large negative direct effects on CFWD respiration rate, and moisture content and species had medium positive direct effects. [N] and temperature did not have direct or indirect effects, and position and wood density had indirect effects. The model revealed some interrelationships between controlling factors. We discussed the influence of the direct effects of explanatory variables and the influence especially of species and position. We speculate that the small R2 value of the most parsimonious model was probably due to the omission of microbial biomass and activity. These direct and indirect effects and interrelationships between explanatory variables could be used to develop a process-based CFWD decomposition model.

  1. Assessing the influence of abiotic factors and leaf-level properties on the stability of growing-season canopy greenness in a deciduous forest

    NASA Astrophysics Data System (ADS)

    Cunningham, Vanessa Marie L.

    Maps depicting spatial pattern in the stability of summer greenness could advance understanding of how forest ecosystems will respond to global changes such as a longer growing season. Declining summer greenness, or "greendown", is spectrally related to declining near-infrared reflectance and is observed in most remote sensing time series to begin shortly after peak greenness at the end of spring and extend until the beginning of leaf coloration in autumn,. Understanding spatial patterns in the strength of greendown has recently become possible with the advancement of Landsat phenology products, which show that greendown patterns vary at scales appropriate for linking these patterns to proposed environmental forcing factors. This study tested two non-mutually exclusive hypotheses for how leaf measurements and environmental factors correlate with greendown and decreasing NIR reflectance across sites. At the landscape scale, we used linear regression to test the effects of maximum greenness, elevation, slope, aspect, solar irradiance and canopy rugosity on greendown. Secondly, we used leaf chemical traits and reflectance observations to test the effect of nitrogen availability and intrinsic water use efficiency on leaf-level greendown, and landscape-level greendown measured from Landsat. The study was conducted using Quercus alba canopies across 21 sites of an eastern deciduous forest in North America between June and August 2014. Our linear model explained greendown variance with an R 2=0.47 with maximum greenness as the greatest model effect. Subsequent models excluding one model effect revealed elevation and aspect were the two topographic factors that explained the greatest amount of greendown variance. Regression results also demonstrated important interactions between all three variables, with the greatest interaction showing that aspect had greater influence on greendown at sites with steeper slopes. Leaf-level reflectance was correlated with foliar delta13C

  2. The AaDREB1 Transcription Factor from the Cold-Tolerant Plant Adonis amurensis Enhances Abiotic Stress Tolerance in Transgenic Plant.

    PubMed

    Zong, Jun-Mei; Li, Xiao-Wei; Zhou, Yuan-Hang; Wang, Fa-Wei; Wang, Nan; Dong, Yuan-Yuan; Yuan, Yan-Xi; Chen, Huan; Liu, Xiu-Ming; Yao, Na; Li, Hai-Yan

    2016-04-22

    Dehydration-responsive element binding (DREB) transcription factors (TFs) play important roles in the regulation of plant resistance to environmental stresses and can specifically bind to dehydration-responsive element/C-repeat element (DRE/CRT) proteins (G/ACCGAC) and activate expression of many stress-inducible genes. Here, we cloned and characterized a novel gene (AaDREB1) encoding the DREB1 transcription factor from the cold-tolerant plant Adonis amurensis. Quantitative real-time (qRT)-PCR results indicated that AaDREB1 expression was induced by salt, drought, cold stress, and abscisic acid application. A yeast one-hybrid assay demonstrated that AaDREB1 encodes a transcription activator and specifically binds to DRE/CRT. Furthermore, transgenic Arabidopsis and rice harboring AaDREB1 showed enhanced tolerance to salt, drought, and low temperature. These results indicated that AaDREB1 might be useful in genetic engineering to improve plant stress tolerance.

  3. The AaDREB1 Transcription Factor from the Cold-Tolerant Plant Adonis amurensis Enhances Abiotic Stress Tolerance in Transgenic Plant

    PubMed Central

    Zong, Jun-Mei; Li, Xiao-Wei; Zhou, Yuan-Hang; Wang, Fa-Wei; Wang, Nan; Dong, Yuan-Yuan; Yuan, Yan-Xi; Chen, Huan; Liu, Xiu-Ming; Yao, Na; Li, Hai-Yan

    2016-01-01

    Dehydration-responsive element binding (DREB) transcription factors (TFs) play important roles in the regulation of plant resistance to environmental stresses and can specifically bind to dehydration-responsive element/C-repeat element (DRE/CRT) proteins (G/ACCGAC) and activate expression of many stress-inducible genes. Here, we cloned and characterized a novel gene (AaDREB1) encoding the DREB1 transcription factor from the cold-tolerant plant Adonis amurensis. Quantitative real-time (qRT)-PCR results indicated that AaDREB1 expression was induced by salt, drought, cold stress, and abscisic acid application. A yeast one-hybrid assay demonstrated that AaDREB1 encodes a transcription activator and specifically binds to DRE/CRT. Furthermore, transgenic Arabidopsis and rice harboring AaDREB1 showed enhanced tolerance to salt, drought, and low temperature. These results indicated that AaDREB1 might be useful in genetic engineering to improve plant stress tolerance. PMID:27110776

  4. Functional Analysis of the Maize C-Repeat/DRE Motif-Binding Transcription Factor CBF3 Promoter in Response to Abiotic Stress

    PubMed Central

    Liu, Jinliang; Wang, Fengting; Yu, Gang; Zhang, Xianghui; Jia, Chengguo; Qin, Jianchun; Pan, Hongyu

    2015-01-01

    The ZmCBF3 gene is a member of AP2/ERF transcription factor family, which is a large family of plant-specific transcription factors that share a well-conserved DNA-binding domain. To understand the regulatory mechanism of ZmCBF3 gene expression, we isolated and characterized the ZmCBF3 promoter (PZmCBF3). Three deletion fragments of PZmCBF3 were generated, C1–C3, from the translation start codon at position −1079, −638, and −234, and fused to the GUS reporter gene. Each deletion construct was analyzed by Agrobacterium-mediated stable transformation and expression in Arabidopsis thaliana. GUS expression assays indicated that the PZmCBF3 exhibited root-specific expression activity. A 234-bp fragment upstream of the ZmCBF3 gene conferred a high level of GUS activity in Arabidopsis. Some cis-acting elements involved in the down-regulation of gene expression were detected in the promoter, encompassing positions −1079 to −234. PZmCBF3 was activated by cold stress. The MYCCONSENSUSAT elements (CANNTG) were responsible for the ability of PZmCBF3 to respond to cold stress. The results of the present study suggest that PZmCBF3 might play a role in cold tolerance in maize. PMID:26030672

  5. Extension to the definition of quasistatic material coupling factor to include losses.

    PubMed

    Lamberti, Nicola; Sherrit, Stewart; Pappalardo, Massimo; Iula, Antonio

    2005-06-01

    In general the coupling factor is a dimensionless coefficient, defined as a particular combination of the dielectric, elastic, and piezoelectric coefficients that may be useful for the internal energy conversion description in piezoelectric materials. In order to extend the definition of the quasistatic coupling factor as ratio of energies to dynamic conditions and to lossy materials, its current definition and its derivation are reviewed. It is shown that this parameter can be computed as ratio of energies also in dynamic conditions, and the factors obtained in the static and the dynamic case are simply related by a proportionality coefficient. The coupling factor is computed as the square root of the ratio between the converted (from mechanical to electrical or vice versa) and the total energy involved in a transformation cycle for lossy materials in quasistatic conditions, obtaining a complex quantity related to the complex material parameters taking the losses into account. In order to apply this definition to the element vibrating around its resonance frequency, the kinetic is considered as the total energy and the electrical potential as the converted energy. The obtained result is a complex quantity related to the complex material coupling factor by means of the same proportionality coefficient of the case without losses. Finally, it is shown that both the material and the dynamic coupling factors still can be considered as real parameters for real lossy materials. It also is shown that the obtained results do not depend on the wave propagation direction (longitudinal or transverse).

  6. Establishment of non-native plant species after wildfires: Effects of fuel treatments, abiotic and biotic factors, and post-fire grass seeding treatments

    USGS Publications Warehouse

    Hunter, M.E.; Omi, Philip N.; Martinson, E.J.; Chong, G.W.

    2006-01-01

    Establishment and spread of non-native species following wildfires can pose threats to long-term native plant recovery. Factors such as disturbance severity, resource availability, and propagule pressure may influence where non-native species establish in burned areas. In addition, pre- and post-fire management activities may influence the likelihood of non-native species establishment. In the present study we examine the establishment of non-native species after wildfires in relation to native species richness, fire severity, dominant native plant cover, resource availability, and pre- and post-fire management actions (fuel treatments and post-fire rehabilitation treatments). We used an information-theoretic approach to compare alternative hypotheses. We analysed post-fire effects at multiple scales at three wildfires in Colorado and New Mexico. For large and small spatial scales at all fires, fire severity was the most consistent predictor of non-native species cover. Non-native species cover was also correlated with high native species richness, low native dominant species cover, and high seeded grass cover. There was a positive, but non-significant, association of non-native species with fuel-treated areas at one wildfire. While there may be some potential for fuels treatments to promote non-native species establishment, wildfire and post-fire seeding treatments seem to have a larger impact on non-native species. ?? IAWF 2006.

  7. Latina Resilience in Higher Education: Contributing Factors Including Seasonal Farmworker Experiences

    ERIC Educational Resources Information Center

    Graff, Cristina Santamaria; McCain, Terrence; Gomez-Vilchis, Veronica

    2013-01-01

    Many Latina students overcome multiple obstacles to earn university degrees. Five married Latina women with children and seasonal farmworker backgrounds are the focus of this study which is analyzed through resiliency theory to understand factors contributing to their academic resilience. Variables connected to academic success are explored and…

  8. Accurate expressions for solar cell fill factors including series and shunt resistances

    NASA Astrophysics Data System (ADS)

    Green, Martin A.

    2016-02-01

    Together with open-circuit voltage and short-circuit current, fill factor is a key solar cell parameter. In their classic paper on limiting efficiency, Shockley and Queisser first investigated this factor's analytical properties showing, for ideal cells, it could be expressed implicitly in terms of the maximum power point voltage. Subsequently, fill factors usually have been calculated iteratively from such implicit expressions or from analytical approximations. In the absence of detrimental series and shunt resistances, analytical fill factor expressions have recently been published in terms of the Lambert W function available in most mathematical computing software. Using a recently identified perturbative relationship, exact expressions in terms of this function are derived in technically interesting cases when both series and shunt resistances are present but have limited impact, allowing a better understanding of their effect individually and in combination. Approximate expressions for arbitrary shunt and series resistances are then deduced, which are significantly more accurate than any previously published. A method based on the insights developed is also reported for deducing one-diode fits to experimental data.

  9. School Factors Associated with Mainstream Progress in Secondary Education for Included Pupils with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Osborne, Lisa A.; Reed, Phil

    2011-01-01

    This research examined the factors promoting inclusion of young people with Autism Spectrum Disorders (ASD) in mainstream secondary schools, and noted high levels of behavioral difficulties in these pupils. The size of the secondary school, and the class size, impacted positively on the pupils with Autism, and the number of other pupils with…

  10. Latina Resilience in Higher Education: Contributing Factors Including Seasonal Farmworker Experiences

    ERIC Educational Resources Information Center

    Graff, Cristina Santamaria; McCain, Terrence; Gomez-Vilchis, Veronica

    2013-01-01

    Many Latina students overcome multiple obstacles to earn university degrees. Five married Latina women with children and seasonal farmworker backgrounds are the focus of this study which is analyzed through resiliency theory to understand factors contributing to their academic resilience. Variables connected to academic success are explored and…

  11. ROS Regulation During Abiotic Stress Responses in Crop Plants

    PubMed Central

    You, Jun; Chan, Zhulong

    2015-01-01

    Abiotic stresses such as drought, cold, salt and heat cause reduction of plant growth and loss of crop yield worldwide. Reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide anions (O2•-), hydroxyl radical (OH•) and singlet oxygen (1O2) are by-products of physiological metabolisms, and are precisely controlled by enzymatic and non-enzymatic antioxidant defense systems. ROS are significantly accumulated under abiotic stress conditions, which cause oxidative damage and eventually resulting in cell death. Recently, ROS have been also recognized as key players in the complex signaling network of plants stress responses. The involvement of ROS in signal transduction implies that there must be coordinated function of regulation networks to maintain ROS at non-toxic levels in a delicate balancing act between ROS production, involving ROS generating enzymes and the unavoidable production of ROS during basic cellular metabolism, and ROS-scavenging pathways. Increasing evidence showed that ROS play crucial roles in abiotic stress responses of crop plants for the activation of stress-response and defense pathways. More importantly, manipulating ROS levels provides an opportunity to enhance stress tolerances of crop plants under a variety of unfavorable environmental conditions. This review presents an overview of current knowledge about homeostasis regulation of ROS in crop plants. In particular, we summarize the essential proteins that are involved in abiotic stress tolerance of crop plants through ROS regulation. Finally, the challenges toward the improvement of abiotic stress tolerance through ROS regulation in crops are discussed. PMID:26697045

  12. ROS Regulation During Abiotic Stress Responses in Crop Plants.

    PubMed

    You, Jun; Chan, Zhulong

    2015-01-01

    Abiotic stresses such as drought, cold, salt and heat cause reduction of plant growth and loss of crop yield worldwide. Reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide anions (O2 (•-)), hydroxyl radical (OH•) and singlet oxygen ((1)O2) are by-products of physiological metabolisms, and are precisely controlled by enzymatic and non-enzymatic antioxidant defense systems. ROS are significantly accumulated under abiotic stress conditions, which cause oxidative damage and eventually resulting in cell death. Recently, ROS have been also recognized as key players in the complex signaling network of plants stress responses. The involvement of ROS in signal transduction implies that there must be coordinated function of regulation networks to maintain ROS at non-toxic levels in a delicate balancing act between ROS production, involving ROS generating enzymes and the unavoidable production of ROS during basic cellular metabolism, and ROS-scavenging pathways. Increasing evidence showed that ROS play crucial roles in abiotic stress responses of crop plants for the activation of stress-response and defense pathways. More importantly, manipulating ROS levels provides an opportunity to enhance stress tolerances of crop plants under a variety of unfavorable environmental conditions. This review presents an overview of current knowledge about homeostasis regulation of ROS in crop plants. In particular, we summarize the essential proteins that are involved in abiotic stress tolerance of crop plants through ROS regulation. Finally, the challenges toward the improvement of abiotic stress tolerance through ROS regulation in crops are discussed.

  13. Abiotic regulation: a common way for proteins to modulate their functions.

    PubMed

    Zou, Zhi; Fu, Xinmiao

    2015-01-01

    Modulation of protein intrinsic activity in cells is generally carried out via a combination of four common ways, i.e., allosteric regulation, covalent modification, proteolytic cleavage and association of other regulatory proteins. Accumulated evidence indicate that changes of certain abiotic factors (e.g., temperature, pH, light and mechanical force) within or outside the cells directly influence protein structure and thus profoundly modulate the functions of a wide range of proteins, termed as abiotic regulatory proteins (e.g., heat shock factor, small heat shock protein, hemoglobin, zymogen, integrin, rhodopsin). Such abiotic regulation apparently differs from the four classic ways in perceiving and response to the signals. Importantly, it enables cells to directly and also immediately response to extracellular stimuli, thus facilitating the ability of organisms to resist against and adapt to the abiotic stress and thereby playing crucial roles in life evolution. Altogether, abiotic regulation may be considered as a common way for proteins to modulate their functions.

  14. Transcription factors relevant to auxin signalling coordinate broad-spectrum metabolic shifts including sulphur metabolism

    PubMed Central

    Falkenberg, Bettina; Witt, Isabell; Zanor, Maria Inés; Steinhauser, Dirk; Mueller-Roeber, Bernd; Hesse, Holger; Hoefgen, Rainer

    2008-01-01

    A systems approach has previously been used to follow the response behaviour of Arabidopsis thaliana plants upon sulphur limitation. A response network was reconstructed from a time series of transcript and metabolite profiles, integrating complex metabolic and transcript data in order to investigate a potential causal relationship. The resulting scale-free network allowed potential transcriptional regulators of sulphur metabolism to be identified. Here, three sulphur-starvation responsive transcription factors, IAA13, IAA28, and ARF-2 (ARF1-Binding Protein), all of which are related to auxin signalling, were selected for further investigation. IAA28 overexpressing and knock-down lines showed no major morphological changes, whereas IAA13- and ARF1-BP-overexpressing plants grew more slowly than the wild type. Steady-state metabolite levels and expression of pathway-relevant genes were monitored under normal and sulphate-depleted conditions. For all lines, changes in transcript and metabolite levels were observed, yet none of these changes could exclusively be linked to sulphur stress. Instead, up- or down-regulation of the transcription factors caused metabolic changes which in turn affected sulphur metabolism. Auxin-relevant transcription factors are thus part of a complex response pattern to nutrient starvation that serve as coordinators of the metabolic shifts driving sulphur homeostasis rather then as direct effectors of the sulphate assimilation pathway. This study provides the first evidence ever presented that correlates auxin-related transcriptional regulators with primary plant metabolism. PMID:18596113

  15. Experiences with new European standards for calculation of flanged joints including necessary gasket factors

    SciTech Connect

    Bartonicek, J.; Kockelmann, H.; Schoeckle, F.

    1996-12-01

    The correct function of a flanged joint in a given construction (flanges, bolts) and with given loads (pressure, temperature, additional forces) depends on the following: (1) choice of the gasket for the operation environment; (2) determination of the gasket stress for assembly conditions; and (3) gasket stress in operation, i.e., the conditions when leakage has to be minimized. For the correct choice of a gasket it is necessary to have gasket factors available, as given by DIN 28090 (Sept. 95) together with the test procedures. These gasket factors determine the tightening characteristics as well as the deformation capability of the gaskets. Furthermore, these gasket factors must be available for use in calculations. On the basis of calculations a stress analysis (i.e. a limitation of the stresses in flanges and bolts) must be possible as well as the determination of the bolt forces for the assembly state and of the gasket stress for operating conditions. This is one of the goals of the standard pr DIN EN 1591. The paper first introduces the actual European standards. Calculations are reviewed using test data from special test rigs and from real flanged joints. The calculations were made according to DIN 2505 (initial German standard for flanged joints) and pr DIN EN 1591. Additionally, 2D and 3D Finite Element analysis calculations were performed.

  16. Multivariable modeling of radiotherapy outcomes, including dose-volume and clinical factors

    SciTech Connect

    El Naqa, Issam; Bradley, Jeffrey; Blanco, Angel I.; Lindsay, Patricia E.; Vicic, Milos; Hope, Andrew; Deasy, Joseph O. . E-mail: deasy@wustl.edu

    2006-03-15

    Purpose: The probability of a specific radiotherapy outcome is typically a complex, unknown function of dosimetric and clinical factors. Current models are usually oversimplified. We describe alternative methods for building multivariable dose-response models. Methods: Representative data sets of esophagitis and xerostomia are used. We use a logistic regression framework to approximate the treatment-response function. Bootstrap replications are performed to explore variable selection stability. To guard against under/overfitting, we compare several analytical and data-driven methods for model-order estimation. Spearman's coefficient is used to evaluate performance robustness. Novel graphical displays of variable cross correlations and bootstrap selection are demonstrated. Results: Bootstrap variable selection techniques improve model building by reducing sample size effects and unveiling variable cross correlations. Inference by resampling and Bayesian approaches produced generally consistent guidance for model order estimation. The optimal esophagitis model consisted of 5 dosimetric/clinical variables. Although the xerostomia model could be improved by combining clinical and dose-volume factors, the improvement would be small. Conclusions: Prediction of treatment response can be improved by mixing clinical and dose-volume factors. Graphical tools can mitigate the inherent complexity of multivariable modeling. Bootstrap-based variable selection analysis increases the reliability of reported models. Statistical inference methods combined with Spearman's coefficient provide an efficient approach to estimating optimal model order.

  17. Transcription factors relevant to auxin signalling coordinate broad-spectrum metabolic shifts including sulphur metabolism.

    PubMed

    Falkenberg, Bettina; Witt, Isabell; Zanor, Maria Inés; Steinhauser, Dirk; Mueller-Roeber, Bernd; Hesse, Holger; Hoefgen, Rainer

    2008-01-01

    A systems approach has previously been used to follow the response behaviour of Arabidopsis thaliana plants upon sulphur limitation. A response network was reconstructed from a time series of transcript and metabolite profiles, integrating complex metabolic and transcript data in order to investigate a potential causal relationship. The resulting scale-free network allowed potential transcriptional regulators of sulphur metabolism to be identified. Here, three sulphur-starvation responsive transcription factors, IAA13, IAA28, and ARF-2 (ARF1-Binding Protein), all of which are related to auxin signalling, were selected for further investigation. IAA28 overexpressing and knock-down lines showed no major morphological changes, whereas IAA13- and ARF1-BP-overexpressing plants grew more slowly than the wild type. Steady-state metabolite levels and expression of pathway-relevant genes were monitored under normal and sulphate-depleted conditions. For all lines, changes in transcript and metabolite levels were observed, yet none of these changes could exclusively be linked to sulphur stress. Instead, up- or down-regulation of the transcription factors caused metabolic changes which in turn affected sulphur metabolism. Auxin-relevant transcription factors are thus part of a complex response pattern to nutrient starvation that serve as coordinators of the metabolic shifts driving sulphur homeostasis rather then as direct effectors of the sulphate assimilation pathway. This study provides the first evidence ever presented that correlates auxin-related transcriptional regulators with primary plant metabolism.

  18. Starch as a determinant of plant fitness under abiotic stress.

    PubMed

    Thalmann, Matthias; Santelia, Diana

    2017-03-09

    I. II. III. IV. V. VI. References SUMMARY: Abiotic stresses, such as drought, high salinity and extreme temperatures, pose one of the most important constraints to plant growth and productivity in many regions of the world. A number of investigations have shown that plants, including several important crops, remobilize their starch reserve to release energy, sugars and derived metabolites to help mitigate the stress. This is an essential process for plant fitness with important implications for plant productivity under challenging environmental conditions. In this Tansley insight, we evaluate the current literature on starch metabolism in response to abiotic stresses, and discuss the key enzymes involved and how they are regulated.

  19. Antibiotic Susceptibility of Staphylococci Isolates from Patients with Chronic Conjunctivitis: Including Associated Factors and Clinical Evaluation

    PubMed Central

    Núñez, María Ximena

    2013-01-01

    Abstract Purpose To determine species of staphylococci in chronic conjunctivitis, their antibiotic susceptibility pattern, patient treatments, clinical course, and clinical conditions. Methods In this prospective study, 243 conjunctival cultures were taken from 191 patients with chronic conjunctivitis, we obtained staphylococci susceptibility patterns with E-test, and they were analyzed in coagulase-positive and negative. The minimum inhibitory concentration for 90% of isolates (MIC90) was determined for Staphylococcus aureus and Staphylococcus epidermidis. Additionally, clinical follow-up and associated factors of all patients were analyzed depending on methicillin resistance (MR) or susceptibility (MS) bacterial state. Results One hundred and eight (44%) cultures were positive; 81 positive cultures were Gram-positive of which, 77 were staphylococci, 29 coagulase-positive with S. aureus as the most prevalent, 89% MS, and 11% MR. And 48 were coagulase-negative with S. epidermidis as the most isolated with 36% of MS and 64% of MR. Poor susceptibility was found in the staphylococcus coagulase-negative/MR group. Moxifloxacin and vancomycin show the best in vitro activity for all isolates. The MIC90 of moxifloxacin and vancomycin were 0.064/1.5, 0.64/3.0, and 1/3.0 for S. aureus-MS, S. epidermidis-MS, and S. epidermidis-MR, respectively. The most frequently associated factors found in patients with positive culture for staphylococcus were exposure to the health care system 23 (29.87%) of 77 patients and dry eye 23 (29.87%) of 77 patients. Both with a proportion of 3 in 10. Conclusion Coagulase-negative staphylococci were the most frequently isolated from the conjunctiva with 58.33% of MR; even though multiresistance was detected, their susceptibility to a fourth-generation fluoroquinolone, commonly used, such as moxifloxacin, was preserved. PMID:23944906

  20. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants

    PubMed Central

    Hasanuzzaman, Mirza; Nahar, Kamrun; Hossain, Md. Shahadat; Mahmud, Jubayer Al; Rahman, Anisur; Inafuku, Masashi; Oku, Hirosuke; Fujita, Masayuki

    2017-01-01

    Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS). Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG), which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I) and glyoxalase II (Gly II), and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III), has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH) acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated action of

  1. Coordinated Actions of Glyoxalase and Antioxidant Defense Systems in Conferring Abiotic Stress Tolerance in Plants.

    PubMed

    Hasanuzzaman, Mirza; Nahar, Kamrun; Hossain, Md Shahadat; Mahmud, Jubayer Al; Rahman, Anisur; Inafuku, Masashi; Oku, Hirosuke; Fujita, Masayuki

    2017-01-20

    Being sessile organisms, plants are frequently exposed to various environmental stresses that cause several physiological disorders and even death. Oxidative stress is one of the common consequences of abiotic stress in plants, which is caused by excess generation of reactive oxygen species (ROS). Sometimes ROS production exceeds the capacity of antioxidant defense systems, which leads to oxidative stress. In line with ROS, plants also produce a high amount of methylglyoxal (MG), which is an α-oxoaldehyde compound, highly reactive, cytotoxic, and produced via different enzymatic and non-enzymatic reactions. This MG can impair cells or cell components and can even destroy DNA or cause mutation. Under stress conditions, MG concentration in plants can be increased 2- to 6-fold compared with normal conditions depending on the plant species. However, plants have a system developed to detoxify this MG consisting of two major enzymes: glyoxalase I (Gly I) and glyoxalase II (Gly II), and hence known as the glyoxalase system. Recently, a novel glyoxalase enzyme, named glyoxalase III (Gly III), has been detected in plants, providing a shorter pathway for MG detoxification, which is also a signpost in the research of abiotic stress tolerance. Glutathione (GSH) acts as a co-factor for this system. Therefore, this system not only detoxifies MG but also plays a role in maintaining GSH homeostasis and subsequent ROS detoxification. Upregulation of both Gly I and Gly II as well as their overexpression in plant species showed enhanced tolerance to various abiotic stresses including salinity, drought, metal toxicity, and extreme temperature. In the past few decades, a considerable amount of reports have indicated that both antioxidant defense and glyoxalase systems have strong interactions in conferring abiotic stress tolerance in plants through the detoxification of ROS and MG. In this review, we will focus on the mechanisms of these interactions and the coordinated action of

  2. Including social factors in the analysis of reminiscence in elderly individuals.

    PubMed

    Lamme, S; Baars, J

    1993-01-01

    Developmental psychologists have studied reminiscence in elderly individuals using widely varied conceptions of adult development. Determinist psychologists conceived of reminiscent behavior in elderly individuals as constituting the last phase in normal development. Contextualist psychologists have pointed to the historical and cultural relativity of adult development, and highlighted the variation in elderly persons with respect to reminiscent behavior. However, they do not fully acknowledge the role the environment plays in establishing reminiscent behavior in elderly people. Therefore, sociological life course theory should be included in the analyses and interpretation of this behavior.

  3. Lifestyle factors including diet and leukemia development: a case-control study from Mumbai, India.

    PubMed

    Balasubramaniam, Ganesh; Saoba, Sushama Laxman; Sarhade, Monika Nilesh; Kolekar, Suvarna Anand

    2013-01-01

    In India, among males, leukemia rates vary across the country. The present unmatched hospital-based case- control study conducted at Tata Memorial Hospital included subjects registered between the years 1997-99. There were 246 leukemia cases and 1,383 normal controls. Data on demographics, lifestyle, diet and occupation history were recorded. Cigarette (OR=2.1) and bidi smoking (OR=3.4) showed excess risk for leukemia. Odds ratios were 3.9 for fish-eaters, 0.40 for chilli eaters, 1.5 for milk drinkers and 0.60 for coffee drinkers, compared to non-drinkers/eaters. However, neither exposure to use of pesticides nor cotton dust showed any excess risk for leukemia.

  4. ‘LONESOME TOWN’? IS LONELINESS ASSOCIATED WITH THE RESIDENTIAL ENVIRONMENT, INCLUDING HOUSING AND NEIGHBORHOOD FACTORS?

    PubMed Central

    Whitley, Elise; Tannahill, Carol; Ellaway, Anne

    2015-01-01

    This article considers whether feelings of loneliness are associated with aspects of the home and neighborhood of residence. Multinominal logistic regression models were used to explore associations between residential environment and loneliness in 4,000 residents across deprived areas of Glasgow. People who rated their neighborhood environment of higher quality and who used more local amenities were less likely to report loneliness. Respondents who knew more people within the local area were less likely to report loneliness. Those who reported more antisocial behavior problems, who had a weak perception of collective efficacy, and who felt unsafe walking alone at nighttime were more likely to report loneliness. Length of residence and dwelling type were not associated with reported loneliness. The findings indicate the potential importance of several dimensions of the neighborhood physical, service, and social environment, including aspects of both quality and trust, in protecting against or reducing loneliness in deprived areas. PMID:26740728

  5. Abiotic stresses affect Trichoderma harzianum T39-induced resistance to downy mildew in grapevine.

    PubMed

    Roatti, Benedetta; Perazzolli, Michele; Gessler, Cesare; Pertot, Ilaria

    2013-12-01

    Enhancement of plant defense through the application of resistance inducers seems a promising alternative to chemical fungicides for controlling crop diseases but the efficacy can be affected by abiotic factors in the field. Plants respond to abiotic stresses with hormonal signals that may interfere with the mechanisms of induced systemic resistance (ISR) to pathogens. In this study, we exposed grapevines to heat, drought, or both to investigate the effects of abiotic stresses on grapevine resistance induced by Trichoderma harzianum T39 (T39) to downy mildew. Whereas the efficacy of T39-induced resistance was not affected by exposure to heat or drought, it was significantly reduced by combined abiotic stresses. Decrease of leaf water potential and upregulation of heat-stress markers confirmed that plants reacted to abiotic stresses. Basal expression of defense-related genes and their upregulation during T39-induced resistance were attenuated by abiotic stresses, in agreement with the reduced efficacy of T39. The evidence reported here suggests that exposure of crops to abiotic stress should be carefully considered to optimize the use of resistance inducers, especially in view of future global climate changes. Expression analysis of ISR marker genes could be helpful to identify when plants are responding to abiotic stresses, in order to optimize treatments with resistance inducers in field.

  6. Simultaneous optimization of monolayer formation factors, including temperature, to significantly improve nucleic acid hybridization efficiency on gold substrates.

    PubMed

    Pris, Andrew D; Ostrowski, Sara G; Garaas, Sarah D

    2010-04-20

    Past literature investigations have optimized various single factors used in the formation of thiolated, single stranded DNA (ss-DNA) monolayers on gold. In this study a more comprehensive approach is taken, where a design of experiment (DOE) is employed to simultaneously optimize all of the factors involved in construction of the capture monolayer used in a fluorescence-based hybridization assay. Statistical analysis of the fluorescent intensities resulting from the DOE provides empirical evidence for the importance and the optimal levels of traditional and novel factors included in this investigation. We report on the statistical importance of a novel factor, temperature of the system during monolayer formation of the capture molecule and lateral spacer molecule, and how proper usage of this temperature factor increased the hybridization signal 50%. An initial theory of how the physical factor of heat is mechanistically supplementing the function of the lateral spacer molecule is provided.

  7. Integrating omic approaches for abiotic stress tolerance in soybean

    PubMed Central

    Deshmukh, Rupesh; Sonah, Humira; Patil, Gunvant; Chen, Wei; Prince, Silvas; Mutava, Raymond; Vuong, Tri; Valliyodan, Babu; Nguyen, Henry T.

    2014-01-01

    Soybean production is greatly influenced by abiotic stresses imposed by environmental factors such as drought, water submergence, salt, and heavy metals. A thorough understanding of plant response to abiotic stress at the molecular level is a prerequisite for its effective management. The molecular mechanism of stress tolerance is complex and requires information at the omic level to understand it effectively. In this regard, enormous progress has been made in the omics field in the areas of genomics, transcriptomics, and proteomics. The emerging field of ionomics is also being employed for investigating abiotic stress tolerance in soybean. Omic approaches generate a huge amount of data, and adequate advancements in computational tools have been achieved for effective analysis. However, the integration of omic-scale information to address complex genetics and physiological questions is still a challenge. In this review, we have described advances in omic tools in the view of conventional and modern approaches being used to dissect abiotic stress tolerance in soybean. Emphasis was given to approaches such as quantitative trait loci (QTL) mapping, genome-wide association studies (GWAS), and genomic selection (GS). Comparative genomics and candidate gene approaches are also discussed considering identification of potential genomic loci, genes, and biochemical pathways involved in stress tolerance mechanism in soybean. This review also provides a comprehensive catalog of available online omic resources for soybean and its effective utilization. We have also addressed the significance of phenomics in the integrated approaches and recognized high-throughput multi-dimensional phenotyping as a major limiting factor for the improvement of abiotic stress tolerance in soybean. PMID:24917870

  8. Abiotic degradation of plastic films

    NASA Astrophysics Data System (ADS)

    Ángeles-López, Y. G.; Gutiérrez-Mayen, A. M.; Velasco-Pérez, M.; Beltrán-Villavicencio, M.; Vázquez-Morillas, A.; Cano-Blanco, M.

    2017-01-01

    Degradable plastics have been promoted as an option to mitigate the environmental impacts of plastic waste. However, there is no certainty about its degradability under different environmental conditions. The effect of accelerated weathering (AW), natural weathering (NW) and thermal oxidation (TO) on different plastics (high density polyethylene, HDPE; oxodegradable high density polyethylene, HDPE-oxo; compostable plastic, Ecovio ® metalized polypropylene, PP; and oxodegradable metalized polypropylene, PP-oxo) was studied. Plastics films were exposed to AW per 110 hours; to NW per 90 days; and to TO per 30 days. Plastic films exposed to AW and NW showed a general loss on mechanical properties. The highest reduction in elongation at break on AW occurred to HDPE-oxo (from 400.4% to 20.9%) and was higher than 90% for HDPE, HDPE-oxo, Ecovio ® and PP-oxo in NW. No substantial evidence of degradation was found on plastics exposed to TO. Oxo-plastics showed higher degradation rates than their conventional counterparts, and the compostable plastic was resistant to degradation in the studied abiotic conditions. This study shows that degradation of plastics in real life conditions will vary depending in both, their composition and the environment.

  9. Abiotic and biotic controls over biogeochemical cycles in drylands: Insights from climate change and nitrogen deposition experiments on the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Reed, S.; Ferrenberg, S.; Tucker, C.; Rutherford, W. A.; Wertin, T. M.; McHugh, T. A.; Morrissey, E.; Kuske, C.; Mueller, R.; Belnap, J.

    2016-12-01

    As for all ecosystems, biogeochemical cycling in drylands represents numerous intricate connections between biotic and abiotic controls. However, patterns of many fundamental ecosystem processes that generally hold across global gradients fall apart at the arid and semiarid end of the spectrum, and data point to an exceptionally strong role for abiotic controls in explaining these patterns. Further, there are multiple dryland characteristics - such as extreme aridity and high UV radiation, as well as specialized biological communities - which can point to a conclusion that "drylands are different". Indeed, drylands are often characterized by their harsh environment, by the diverse classes of biota representing a range of traits aimed at surviving such harsh conditions, and, more recently, by the suggestion of dramatic biotic responses to seemingly subtle changes in abiotic factors. In this talk, we will explore a range of biotic and abiotic controls over fundamental biogeochemical cycling in drylands using data from a suite of manipulation experiments on the Colorado Plateau, USA. We will present results from field treatments that speak to the effects of increasing temperature, altered precipitation regimes, increased nitrogen availability via deposition, and the effects of altered litterfall inputs. Biogeochemical processes we explore will include plant photosynthesis, soil photosynthesis and respiration (with a focus on biological soil crusts), litter decomposition, and nutrient cycling. In addition, we will assess how treatments alter dryland community composition, as well as the resultant feedbacks of community shifts to environmental change. Taken together we will use these diverse datasets to ask questions about what makes drylands different or, instead, if a holistic joining of biotic and abiotic perspectives suggests they are not so different after all. These data will not only lend insight into the partitioning of and balance between biotic and abiotic

  10. Abiotic stress in crops: candidate genes, osmolytes, polyamines and biotechnological intervention

    USDA-ARS?s Scientific Manuscript database

    Agricultural production and quality are adversely affected by various abiotic stresses including water deficit conditions (drought), salinity, extreme temperatures (heat, cold), light intensities beyond those saturating for photosynthesis and radiation (UVB,C). This is exacerbated when such exposure...

  11. Antagonistic, overlapping and distinct responses to biotic stress in rice (Oryza sativa) and interactions with abiotic stress.

    PubMed

    Narsai, Reena; Wang, Chuang; Chen, Jie; Wu, Jianli; Shou, Huixia; Whelan, James

    2013-02-12

    Every year, substantial crop loss occurs globally, as a result of bacterial, fungal, parasite and viral infections in rice. Here, we present an in-depth investigation of the transcriptomic response to infection with the destructive bacterial pathogen Xanthomonas oryzae pv. oryzae(Xoo) in both resistant and susceptible varieties of Oryza sativa. A comparative analysis to fungal, parasite and viral infection in rice is also presented. Within 24 h of Xoo inoculation, significant reduction of cell wall components and induction of several signalling components, membrane bound receptor kinases and specific WRKY and NAC transcription factors was prominent, providing a framework for how the presence of this pathogen was signalled and response mounted. Extensive comparative analyses of various other pathogen responses, including in response to infection with another bacterium (Xoc), resistant and susceptible parasite infection, fungal, and viral infections, led to a proposed model for the rice biotic stress response. In this way, a conserved induction of calcium signalling functions, and specific WRKY and NAC transcription factors, was identified in response to all biotic stresses. Comparison of these responses to abiotic stress (cold, drought, salt, heat), enabled the identification of unique genes responsive only to bacterial infection, 240 genes responsive to both abiotic and biotic stress, and 135 genes responsive to biotic, but not abiotic stresses. Functional significance of a number of these genes, using genetic inactivation or over-expression, has revealed significant stress-associated phenotypes. While only a few antagonistic responses were observed between biotic and abiotic stresses, e.g. for a number of endochitinases and kinase encoding genes, some of these may be crucial in explaining greater pathogen infection and damage under abiotic stresses. The analyses presented here provides a global view of the responses to multiple stresses, further validates known

  12. Antagonistic, overlapping and distinct responses to biotic stress in rice (Oryza sativa) and interactions with abiotic stress

    PubMed Central

    2013-01-01

    Background Every year, substantial crop loss occurs globally, as a result of bacterial, fungal, parasite and viral infections in rice. Here, we present an in-depth investigation of the transcriptomic response to infection with the destructive bacterial pathogen Xanthomonas oryzae pv. oryzae(Xoo) in both resistant and susceptible varieties of Oryza sativa. A comparative analysis to fungal, parasite and viral infection in rice is also presented. Results Within 24 h of Xoo inoculation, significant reduction of cell wall components and induction of several signalling components, membrane bound receptor kinases and specific WRKY and NAC transcription factors was prominent, providing a framework for how the presence of this pathogen was signalled and response mounted. Extensive comparative analyses of various other pathogen responses, including in response to infection with another bacterium (Xoc), resistant and susceptible parasite infection, fungal, and viral infections, led to a proposed model for the rice biotic stress response. In this way, a conserved induction of calcium signalling functions, and specific WRKY and NAC transcription factors, was identified in response to all biotic stresses. Comparison of these responses to abiotic stress (cold, drought, salt, heat), enabled the identification of unique genes responsive only to bacterial infection, 240 genes responsive to both abiotic and biotic stress, and 135 genes responsive to biotic, but not abiotic stresses. Functional significance of a number of these genes, using genetic inactivation or over-expression, has revealed significant stress-associated phenotypes. While only a few antagonistic responses were observed between biotic and abiotic stresses, e.g. for a number of endochitinases and kinase encoding genes, some of these may be crucial in explaining greater pathogen infection and damage under abiotic stresses. Conclusions The analyses presented here provides a global view of the responses to multiple

  13. Hydrologic, abiotic and biotic interactions: plant density, windspeed, leaf size and groundwater all affect oak water use efficiency

    Treesearch

    Darin J. Law; Deborah M. Finch

    2011-01-01

    Plant water use in drylands can be complex due to variation in hydrologic, abiotic and biotic factors, particularly near ephemeral or intermittent streams. Plant use of groundwater may be important but is usually uncertain. Disturbances like fire contribute to complex spatiotemporal heterogeneity. Improved understanding of how such hydrologic, abiotic, and biotic...

  14. The Benefits of Including Clinical Factors in Rectal Normal Tissue Complication Probability Modeling After Radiotherapy for Prostate Cancer

    SciTech Connect

    Defraene, Gilles; Van den Bergh, Laura; Al-Mamgani, Abrahim; Haustermans, Karin; Heemsbergen, Wilma; Van den Heuvel, Frank; Lebesque, Joos V.

    2012-03-01

    Purpose: To study the impact of clinical predisposing factors on rectal normal tissue complication probability modeling using the updated results of the Dutch prostate dose-escalation trial. Methods and Materials: Toxicity data of 512 patients (conformally treated to 68 Gy [n = 284] and 78 Gy [n = 228]) with complete follow-up at 3 years after radiotherapy were studied. Scored end points were rectal bleeding, high stool frequency, and fecal incontinence. Two traditional dose-based models (Lyman-Kutcher-Burman (LKB) and Relative Seriality (RS) and a logistic model were fitted using a maximum likelihood approach. Furthermore, these model fits were improved by including the most significant clinical factors. The area under the receiver operating characteristic curve (AUC) was used to compare the discriminating ability of all fits. Results: Including clinical factors significantly increased the predictive power of the models for all end points. In the optimal LKB, RS, and logistic models for rectal bleeding and fecal incontinence, the first significant (p = 0.011-0.013) clinical factor was 'previous abdominal surgery.' As second significant (p = 0.012-0.016) factor, 'cardiac history' was included in all three rectal bleeding fits, whereas including 'diabetes' was significant (p = 0.039-0.048) in fecal incontinence modeling but only in the LKB and logistic models. High stool frequency fits only benefitted significantly (p = 0.003-0.006) from the inclusion of the baseline toxicity score. For all models rectal bleeding fits had the highest AUC (0.77) where it was 0.63 and 0.68 for high stool frequency and fecal incontinence, respectively. LKB and logistic model fits resulted in similar values for the volume parameter. The steepness parameter was somewhat higher in the logistic model, also resulting in a slightly lower D{sub 50}. Anal wall DVHs were used for fecal incontinence, whereas anorectal wall dose best described the other two endpoints. Conclusions: Comparable

  15. Demonstration of significant abiotic iron isotope fractionation in nature

    USGS Publications Warehouse

    Bullen, T.D.; White, A.F.; Childs, C.W.; Vivit, D.V.; Schultz, M.S.

    2001-01-01

    Field and laboratory studies reveal that the mineral ferrihydrite, formed as a result of abiotic oxidation of aqueous ferrous to ferric Fe, contains Fe that is isotopically heavy relative to coexisting aqueous Fe. Because the electron transfer step of the oxidation process at pH >5 is essentially irreversible and should favor the lighter Fe isotopes in the ferric iron product, this result suggests that relatively heavy Fe isotopes are preferentially partitioned into the readily oxidized Fe(II)(OH)x(aq) species or their transition complexes prior to oxidation. The apparent Fe isotope fractionation factor, ??ferrihydrite-water, depends primarily on the relative abundances of the Fe(II)(aq) species. This study demonstrates that abiotic processes can fractionate the Fe isotopes to the same extent as biotic processes, and thus Fe isotopes on their own do not provide an effective biosignature.

  16. Abiotic pyrite formation produces a large Fe isotope fractionation.

    PubMed

    Guilbaud, Romain; Butler, Ian B; Ellam, Rob M

    2011-06-24

    The iron isotope composition of sedimentary pyrite has been proposed as a potential proxy to trace microbial metabolism and the redox evolution of the oceans. We demonstrate that Fe isotope fractionation accompanies abiotic pyrite formation in the absence of Fe(II) redox change. Combined fractionation factors between Fe(II)(aq), mackinawite, and pyrite permit the generation of pyrite with Fe isotope signatures that nearly encapsulate the full range of sedimentary δ(56)Fe(pyrite) recorded in Archean to modern sediments. We propose that Archean negative Fe isotope excursions reflect partial Fe(II)(aq) utilization during abiotic pyrite formation rather than microbial dissimilatory Fe(III) reduction. Late Proterozoic to modern sediments may reflect greater Fe(II)(aq) utilization and variations in source composition.

  17. Reverse Engineering: A Key Component of Systems Biology to Unravel Global Abiotic Stress Cross-Talk

    PubMed Central

    Friedel, Swetlana; Usadel, Björn; von Wirén, Nicolaus; Sreenivasulu, Nese

    2012-01-01

    Understanding the global abiotic stress response is an important stepping stone for the development of universal stress tolerance in plants in the era of climate change. Although co-occurrence of several stress factors (abiotic and biotic) in nature is found to be frequent, current attempts are poor to understand the complex physiological processes impacting plant growth under combinatory factors. In this review article, we discuss the recent advances of reverse engineering approaches that led to seminal discoveries of key candidate regulatory genes involved in cross-talk of abiotic stress responses and summarized the available tools of reverse engineering and its relevant application. Among the universally induced regulators involved in various abiotic stress responses, we highlight the importance of (i) abscisic acid (ABA) and jasmonic acid (JA) hormonal cross-talks and (ii) the central role of WRKY transcription factors (TF), potentially mediating both abiotic and biotic stress responses. Such interactome networks help not only to derive hypotheses but also play a vital role in identifying key regulatory targets and interconnected hormonal responses. To explore the full potential of gene network inference in the area of abiotic stress tolerance, we need to validate hypotheses by implementing time-dependent gene expression data from genetically engineered plants with modulated expression of target genes. We further propose to combine information on gene-by-gene interactions with data from physical interaction platforms such as protein–protein or TF-gene networks. PMID:23293646

  18. Reverse engineering: a key component of systems biology to unravel global abiotic stress cross-talk.

    PubMed

    Friedel, Swetlana; Usadel, Björn; von Wirén, Nicolaus; Sreenivasulu, Nese

    2012-01-01

    Understanding the global abiotic stress response is an important stepping stone for the development of universal stress tolerance in plants in the era of climate change. Although co-occurrence of several stress factors (abiotic and biotic) in nature is found to be frequent, current attempts are poor to understand the complex physiological processes impacting plant growth under combinatory factors. In this review article, we discuss the recent advances of reverse engineering approaches that led to seminal discoveries of key candidate regulatory genes involved in cross-talk of abiotic stress responses and summarized the available tools of reverse engineering and its relevant application. Among the universally induced regulators involved in various abiotic stress responses, we highlight the importance of (i) abscisic acid (ABA) and jasmonic acid (JA) hormonal cross-talks and (ii) the central role of WRKY transcription factors (TF), potentially mediating both abiotic and biotic stress responses. Such interactome networks help not only to derive hypotheses but also play a vital role in identifying key regulatory targets and interconnected hormonal responses. To explore the full potential of gene network inference in the area of abiotic stress tolerance, we need to validate hypotheses by implementing time-dependent gene expression data from genetically engineered plants with modulated expression of target genes. We further propose to combine information on gene-by-gene interactions with data from physical interaction platforms such as protein-protein or TF-gene networks.

  19. Long-term dynamics of biotic and abiotic resistance to exotic species invasion in restored vernal pool plant communities.

    PubMed

    Collinge, Sharon K; Ray, Chris; Gerhardt, Fritz

    2011-09-01

    Invasion of native ecosystems by exotic species can seriously threaten native biodiversity, alter ecosystem function, and inhibit conservation. Moreover, restoration of native plant communities is often impeded by competition from exotic species. Exotic species invasion may be limited by unfavorable abiotic conditions and by competition with native species, but the relative importance of biotic and abiotic factors remains controversial and may vary during the invasion process. We used a long-term experiment involving restored vernal pool plant communities to characterize the temporal dynamics of exotic species invasion, and to evaluate the relative support for biotic and abiotic factors affecting invasion resistance. Experimental pools (n=256) were divided among controls and several seeding treatments. In most treatments, native vernal pool species were initially more abundant than exotic species, and pools that initially received more native seeds exhibited lower frequencies of exotic species over time. However, even densely seeded pools were eventually dominated by exotic species, following extreme climatic events that reduced both native and exotic plant densities across the study site. By the sixth year of the experiment, most pools supported more exotics than native vernal pool species, regardless of seeding treatment or pool depth. Although deeper pools were less invaded by exotic species, two exotics (Hordeum marinum and Lolium multiflorum) were able to colonize deeper pools as soon as the cover of native species was reduced by climatic extremes. Based on an information-theoretic analysis, the best model of invasion resistance included a nonlinear effect of seeding treatment and both linear and nonlinear effects of pool depth. Pool depth received more support as a predictor of invasion resistance, but seeding intensity was also strongly supported in multivariate models of invasion, and was the best predictor of resistance to invasion by H. marinum and L

  20. Biotic and abiotic constraints that facilitate host exclusivity of Gondwanamyces and Ophiostoma on Protea.

    PubMed

    Roets, Francois; Theron, Natalie; Wingfield, Michael J; Dreyer, Léanne L

    2012-01-01

    Estimations of global fungal diversity are hampered by a limited understanding of the forces that dictate host exclusivity in saprobic microfungi. To consider this problem for Gondwanamyces and Ophiostoma found in the flower heads of Protea in South Africa, we determined the role of various factors thought to influence their host exclusivity. Results showed that various biotic and abiotic factors influence the growth and survival of these fungi in vitro. Monitoring temperature and relative humidity (RH) fluctuations within infructescences in vivo revealed considerable microclimatic differences between different Protea spp. Fungal growth and survival at different RH levels experienced in the field suggested that this factor does not play a major role in host exclusivity of these fungi. Maximum temperatures within infructescences and host preferences of the vectors of Gondwanamyces and Ophiostoma appear to play a substantial part in determining colonisation of Protea in general. However, these factors did not explain host exclusivity of specific fungal species towards particular Protea hosts. In contrast, differential growth of fungal species on media containing macerated tissue of Protea showed that Gondwanamyces and Ophiostoma grow best on tissue from their natural hosts. Thus, host chemistry plays a role in host exclusivity of these fungi, although some species grew vigorously on tissue of Protea spp. with which they are not naturally associated. A combination of host chemistry and temperature partially explains host exclusivity, but the relationship for these factors on the tested saprobic microfungi and their hosts is clearly complex and most likely includes combinations of various biotic and abiotic factors including those emerging from this study.

  1. [Risk factors of nasogastric tube placement after elective colorectal surgery included in a rehabilitation programme: a multivariate analysis].

    PubMed

    Aveline, C; Le Roux, A; Le Hetet, H; Vautier, P; Cognet, F; Bonnet, F

    2013-01-01

    Nasogastric tube placement (NTP) is no more systematically recommended in patients scheduled for elective colorectal surgery but could be necessary in case of postoperative vomiting. The aim of this study was to determine independent risk factors for NTP after colorectal surgery. We performed an observational study including 290 patients scheduled for elective colorectal surgery included in an enhanced recovery programme: immunonutrition, thoracic epidural analgesia, antiemetic prophylaxis, respiratory physiotherapy, absence of NT and drainage, forced mobilization and oral nutrition. The main outcome was the occurrence of vomiting requiring NTP. Univariate analysis included: age, sex, BMI, American Society of Anesthesiologist Physical Status Classification System (ASA), duration of surgery, epidural analgesia, and mobilization, intraoperative fluid, temperature, laparotomy, use of droperidol, parenteral nutrition, stoma, diabetes, hypertension or coronary disease, COPD, type of surgery. A logistic regression was performed to determine independent risk factors of NTP. Among the 290 patients included, 277 were analyzed. The incidence of NTP was 10.5% (95%CI [7.4-14.6%]). Univariate analysis documented BMI, low temperature in PACU (<35°C), ASA scores, duration of surgery and epidural analgesia, rectal and sigmoid resections, diabetes, transfusion, no use of droperidol, duration of mobilization, conversion to laparotomy. Three independent risk factors were associated with NTP: temperature in SSPI<35.5°C (OR: 14.49; IC95% [4.52-45.45], P<0.0001), BMI<21kg/m(2) (8.40; [1.99-35.71], P=0.0038) and lack of postoperative droperidol administration (3.37 [1.02-11.39], P=0.04). After colorectal surgery tolerance to rapid oral feeding is impaired by denutrition and postoperative hypothermia. The combined used of postoperative droperidol should also be considered to avoid postoperative NTP. Copyright © 2012. Published by Elsevier SAS.

  2. Genetic engineering strategies for biotic and abiotic stress tolerance and quality enhancement in horticultural crops: a comprehensive review.

    PubMed

    Parmar, Nehanjali; Singh, Kunwar Harendra; Sharma, Deepika; Singh, Lal; Kumar, Pankaj; Nanjundan, J; Khan, Yasin Jeshima; Chauhan, Devendra Kumar; Thakur, Ajay Kumar

    2017-08-01

    Genetic engineering technique offers myriads of applications in improvement of horticultural crops for biotic and abiotic stress tolerance, and produce quality enhancement. During last two decades, a large number of transgenic horticultural crops has been developed and more are underway. A number of genes including natural and synthetic Cry genes, protease inhibitors, trypsin inhibitors and cystatin genes have been used to incorporate insect and nematode resistance. For providing protection against fungal and bacterial diseases, various genes like chitinase, glucanase, osmotin, defensin and pathogenesis-related genes are being transferred to many horticultural crops world over. RNAi technique has been found quite successful in inducing virus resistance in horticultural crops in addition to coat protein genes. Abiotic stresses such as drought, heat and salinity adversely affect production and productivity of horticultural crops and a number of genes encoding for biosynthesis of stress protecting compounds including mannitol, glycine betaine and heat shock proteins have been employed for abiotic stress tolerance besides various transcription factors like DREB1, MAPK, WRKY, etc. Antisense gene and RNAi technologies have revolutionized the pace of improvement of horticultural crops, particularly ornamentals for color modification, increasing shelf-life and reducing post-harvest losses. Precise genome editing tools, particularly CRISPR/Cas9, have been efficiently applied in tomato, petunia, citrus, grape, potato and apple for gene mutation, repression, activation and epigenome editing. This review provides comprehensive overview to draw the attention of researchers for better understanding of genetic engineering advancements in imparting biotic and abiotic stress tolerance as well as on improving various traits related to quality, texture, plant architecture modification, increasing shelf-life, etc. in different horticultural crops.

  3. Mesenchymal stem cell therapy ameliorates diabetic nephropathy via the paracrine effect of renal trophic factors including exosomes

    PubMed Central

    Nagaishi, Kanna; Mizue, Yuka; Chikenji, Takako; Otani, Miho; Nakano, Masako; Konari, Naoto; Fujimiya, Mineko

    2016-01-01

    Bone marrow-derived mesenchymal stem cells (MSCs) have contributed to the improvement of diabetic nephropathy (DN); however, the actual mediator of this effect and its role has not been characterized thoroughly. We investigated the effects of MSC therapy on DN, focusing on the paracrine effect of renal trophic factors, including exosomes secreted by MSCs. MSCs and MSC-conditioned medium (MSC-CM) as renal trophic factors were administered in parallel to high-fat diet (HFD)-induced type 2 diabetic mice and streptozotocin (STZ)-induced insulin-deficient diabetic mice. Both therapies showed approximately equivalent curative effects, as each inhibited the exacerbation of albuminuria. They also suppressed the excessive infiltration of BMDCs into the kidney by regulating the expression of the adhesion molecule ICAM-1. Proinflammatory cytokine expression (e.g., TNF-α) and fibrosis in tubular interstitium were inhibited. TGF-β1 expression was down-regulated and tight junction protein expression (e.g., ZO-1) was maintained, which sequentially suppressed the epithelial-to-mesenchymal transition of tubular epithelial cells (TECs). Exosomes purified from MSC-CM exerted an anti-apoptotic effect and protected tight junction structure in TECs. The increase of glomerular mesangium substrate was inhibited in HFD-diabetic mice. MSC therapy is a promising tool to prevent DN via the paracrine effect of renal trophic factors including exosomes due to its multifactorial action. PMID:27721418

  4. Abiotic mediation of a mutualism drives herbivore abundance.

    PubMed

    Mooney, Emily H; Phillips, Joseph S; Tillberg, Chadwick V; Sandrow, Cheryl; Nelson, Annika S; Mooney, Kailen A

    2016-01-01

    Species abundance is typically determined by the abiotic environment, but the extent to which such effects occur through the mediation of biotic interactions, including mutualisms, is unknown. We explored how light environment (open meadow vs. shaded understory) mediates the abundance and ant tending of the aphid Aphis helianthi feeding on the herb Ligusticum porteri. Yearly surveys consistently found aphids to be more than 17-fold more abundant on open meadow plants than on shaded understory plants. Manipulations demonstrated that this abundance pattern was not due to the direct effects of light environment on aphid performance, or indirectly through host plant quality or the effects of predators. Instead, open meadows had higher ant abundance and per capita rates of aphid tending and, accordingly, ants increased aphid population growth in meadow but not understory environments. The abiotic environment thus drives the abundance of this herbivore exclusively through the mediation of a protection mutualism.

  5. Abiotic stress and the plant circadian clock

    PubMed Central

    Sanchez, Alfredo; Shin, Jieun

    2011-01-01

    In this review, we focus on the interaction between the circadian clock of higher plants to that of metabolic and physiological processes that coordinate growth and performance under a predictable, albeit changing environment. In this, the phytochrome and cryptochrome photoreceptors have shown to be important, but not essential for oscillator control under diurnal cycles of light and dark. From this foundation, we will examine how emerging findings have firmly linked the circadian clock, as a central mediator in the coordination of metabolism, to maintain homeostasis. This occurs by oscillator synchronization of global transcription, which leads to a dynamic control of a host of physiological processes. These include the determination of the levels of primary and secondary metabolites, and the anticipation of future environmental stresses, such as mid-day drought and midnight coldness. Interestingly, metabolic and stress cues themselves appear to feedback on oscillator function. In such a way, the circadian clock of plants and abiotic-stress tolerance appear to be firmly interconnected processes. PMID:21325898

  6. Abiotic reductive immobilization of U(VI) by biogenic mackinawite.

    PubMed

    Veeramani, Harish; Scheinost, Andreas C; Monsegue, Niven; Qafoku, Nikolla P; Kukkadapu, Ravi; Newville, Matt; Lanzirotti, Antonio; Pruden, Amy; Murayama, Mitsuhiro; Hochella, Michael F

    2013-03-05

    During subsurface bioremediation of uranium-contaminated sites, indigenous metal and sulfate-reducing bacteria may utilize a variety of electron acceptors, including ferric iron and sulfate that could lead to the formation of various biogenic minerals in situ. Sulfides, as well as structural and adsorbed Fe(II) associated with biogenic Fe(II)-sulfide phases, can potentially catalyze abiotic U(VI) reduction via direct electron transfer processes. In the present work, the propensity of biogenic mackinawite (Fe 1+x S, x = 0 to 0.11) to reduce U(VI) abiotically was investigated. The biogenic mackinawite produced by Shewanella putrefaciens strain CN32 was characterized by employing a suite of analytical techniques including TEM, SEM, XAS, and Mössbauer analyses. Nanoscale and bulk analyses (microscopic and spectroscopic techniques, respectively) of biogenic mackinawite after exposure to U(VI) indicate the formation of nanoparticulate UO2. This study suggests the relevance of sulfide-bearing biogenic minerals in mediating abiotic U(VI) reduction, an alternative pathway in addition to direct enzymatic U(VI) reduction.

  7. Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite

    SciTech Connect

    Veeramani, Harish; Scheinost, Andreas; Monsegue, Niven; Qafoku, Nikolla; Kukkadapu, Ravi K.; Newville, Mathew; Lanzirotti, Anthony; Pruden, Amy; Murayama, Mitsuhiro; Hochella, Michael F.

    2013-03-01

    During subsurface bioremediation of uranium-contaminated sites, indigenous metal and sulfate-reducing bacteria may utilize a variety of electron acceptors, including ferric iron and sulfate that could lead to the formation of various biogenic minerals in-situ. Sulfides, as well as structural and adsorbed Fe(II) associated with biogenic Fe(II)-sulfide phases, can potentially catalyze abiotic U6+ reduction via direct electron transfer processes. In the present work, the propensity of biogenic mackinawite (Fe1+xS, x = 0 to 0.11) to reduce U6+ abiotically was investigated. The biogenic mackinawite produced by Shewanella putrefaciens strain CN32 was characterized by employing a suite of analytical techniques including TEM, SEM, XAS and Mössbauer analyses. Nanoscale and bulk analyses (microscopic and spectroscopic techniques, respectively) of biogenic mackinawite after exposure to U6+ indicate the formation of nanoparticulate UO2. This study suggests the relevance of Fe(II) and sulfide bearing biogenic minerals in mediating abiotic U6+ reduction, an alternative pathway in addition to direct enzymatic U6+ reduction.

  8. A bHLH gene from Tamarix hispida improves abiotic stress tolerance by enhancing osmotic potential and decreasing reactive oxygen species accumulation.

    PubMed

    Ji, Xiaoyu; Nie, Xianguang; Liu, Yujia; Zheng, Lei; Zhao, Huimin; Zhang, Bing; Huo, Lin; Wang, Yucheng

    2016-02-01

    Basic helix-loop-helix (bHLH) leucine-zipper transcription factors play important roles in abiotic stress responses. However, their specific roles in abiotic stress tolerance are not fully known. Here, we functionally characterized a bHLH gene, ThbHLH1, from Tamarix hispida in abiotic stress tolerance. ThbHLH1 specifically binds to G-box motif with the sequence of 'CACGTG'. Transiently transfected T. hispida plantlets with transiently overexpressed ThbHLH1 and RNAi-silenced ThbHLH1 were generated for gain- and loss-of-function analysis. Transgenic Arabidopsis thaliana lines overexpressing ThbHLH1 were generated to confirm the gain- and loss-of-function analysis. Overexpression of ThbHLH1 significantly elevates glycine betaine and proline levels, increases Ca(2+) concentration and enhances peroxidase (POD) and superoxide dismutase (SOD) activities to decrease reactive oxygen species (ROS) accumulation. Additionally, ThbHLH1 regulates the expression of the genes including P5CS, BADH, CaM, POD and SOD, to activate the above physiological changes, and also induces the expression of stress tolerance-related genes LEAs and HSPs. These data suggest that ThbHLH1 induces the expression of stress tolerance-related genes to improve abiotic stress tolerance by increasing osmotic potential, improving ROS scavenging capability and enhancing second messenger in stress signaling cascades.

  9. Genome-wide characterization of the WRKY gene family in radish (Raphanus sativus L.) reveals its critical functions under different abiotic stresses.

    PubMed

    Karanja, Bernard Kinuthia; Fan, Lianxue; Xu, Liang; Wang, Yan; Zhu, Xianwen; Tang, Mingjia; Wang, Ronghua; Zhang, Fei; Muleke, Everlyne M'mbone; Liu, Liwang

    2017-08-17

    The radish WRKY gene family was genome-widely identified and played critical roles in response to multiple abiotic stresses. The WRKY is among the largest transcription factors (TFs) associated with multiple biological activities for plant survival, including control response mechanisms against abiotic stresses such as heat, salinity, and heavy metals. Radish is an important root vegetable crop and therefore characterization and expression pattern investigation of WRKY transcription factors in radish is imperative. In the present study, 126 putative WRKY genes were retrieved from radish genome database. Protein sequence and annotation scrutiny confirmed that RsWRKY proteins possessed highly conserved domains and zinc finger motif. Based on phylogenetic analysis results, RsWRKYs candidate genes were divided into three groups (Group I, II and III) with the number 31, 74, and 20, respectively. Additionally, gene structure analysis revealed that intron-exon patterns of the WRKY genes are highly conserved in radish. Linkage map analysis indicated that RsWRKY genes were distributed with varying densities over nine linkage groups. Further, RT-qPCR analysis illustrated the significant variation of 36 RsWRKY genes under one or more abiotic stress treatments, implicating that they might be stress-responsive genes. In total, 126 WRKY TFs were identified from the R. sativus genome wherein, 35 of them showed abiotic stress-induced expression patterns. These results provide a genome-wide characterization of RsWRKY TFs and baseline for further functional dissection and molecular evolution investigation, specifically for improving abiotic stress resistances with an ultimate goal of increasing yield and quality of radish.

  10. Using thermodynamics to assess biotic and abiotic impediments to root water uptake

    NASA Astrophysics Data System (ADS)

    Bechmann, Marcel; Hildebrandt, Anke; Kleidon, Axel

    2016-04-01

    Root water uptake has been the subject of extensive research, dealing with understanding the processes limiting transpiration and understanding strategies of plants to avoid water stress. Many of those studies use models of water flow from the soil through the plant into the atmosphere to learn about biotic and abiotic factors affecting plant water relations. One important question in this context is to identify those processes that are most limiting to water transport, and specifically whether these processes lie within the plant or the soil? Here, we propose to use a thermodynamic formulation of root water uptake to answer this question. The method allows us to separate the energy exported at the root collar into a sum of energy fluxes related to all processes along the flow path, notably including the effect of increasing water retention in drier soils. Evaluation of the several contributions allows us to identify and rank the processes by how much these impede water flow from the soil to the atmosphere. The application of this approach to a complex 3-dimensional root water uptake model reveals insights on the role of root versus soil resistances to limit water flow. We investigate the efficiency of root water uptake in an ensemble of root systems with varying root hydraulic properties. While root morphology is kept the same, root radial and axial resistances are artificially varied. Starting with entirely young systems (uptake roots, high radial, low axial conductance) we increasingly add older roots (transport roots, high axial, low radial conductance) to improve transport within root systems. This yields a range of root hydraulic architectures, where the extremes are limited either by radial uptake capacity or low capacity to transport water along the root system. We model root water uptake in this range of root systems with a 3-dimensional root water uptake model in two different soils, applying constant flux boundary conditions in a dry down experiment and

  11. Selection of Reliable Reference Genes for Gene Expression Analysis under Abiotic Stresses in the Desert Biomass Willow, Salix psammophila.

    PubMed

    Li, Jianbo; Jia, Huixia; Han, Xiaojiao; Zhang, Jin; Sun, Pei; Lu, Mengzhu; Hu, Jianjun

    2016-01-01

    Salix psammophila is a desert shrub willow that has extraordinary adaptation to abiotic stresses and plays an important role in maintaining local ecosystems. Moreover, S. psammophila is regarded as a promising biomass feedstock because of its high biomass yields and short rotation coppice cycle. However, few suitable reference genes (RGs) for quantitative real-time polymerase chain reaction (qRT-PCR) constrain the study on normalization of gene expression in S. psammophila until now. Here, we investigated the expression stabilities of 14 candidate RGs across tissue types and under four abiotic stress treatments, including heat, cold, salt, and drought treatments. After calculation of PCR efficiencies, three different software, NormFinder, geNorm, and BestKeeper were employed to analyze systematically the qRT-PCR data, and the outputs were merged by RankAggreg software. The optimal RGs selected for gene expression analysis were EF1α (Elongation factor-1 alpha) and OTU (OTU-like cysteine protease family protein) for different tissue types, UBC (Ubiquitin-conjugating enzyme E2) and LTA4H (Leukotriene A-4 hydrolase homolog) for heat treatment, HIS (Histone superfamily protein H3) and ARF2 (ADP-ribosylation factor 2) for cold treatment, OTU and ACT7 (Actin 7) for salt treatment, UBC and LTA4H for drought treatment. The expression of UBC, ARF2, and VHAC (V-type proton ATPase subunit C) varied the least across tissue types and under abiotic stresses. Furthermore, the relative genes expression profiles of one tissue-specific gene WOX1a (WUSCHEL-related homeobox 1a), and four stress-inducible genes, including Hsf-A2 (Heat shock transcription factors A2), CBF3 (C-repeat binding factor 3), HKT1 (High-Affinity K(+) Transporter 1), and GST (Glutathione S-transferase), were conducted to confirm the validity of the RGs in this study. These results provided an important RGs application guideline for gene expression characterization in S. psammophila.

  12. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions

    NASA Astrophysics Data System (ADS)

    Coari, Kristin M.; Martin, Rebecca C.; Jain, Kopal; McGown, Linda B.

    2017-02-01

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  13. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions

    NASA Astrophysics Data System (ADS)

    Coari, Kristin M.; Martin, Rebecca C.; Jain, Kopal; McGown, Linda B.

    2017-09-01

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  14. Nucleotide Selectivity in Abiotic RNA Polymerization Reactions.

    PubMed

    Coari, Kristin M; Martin, Rebecca C; Jain, Kopal; McGown, Linda B

    2017-02-03

    In order to establish an RNA world on early Earth, the nucleotides must form polymers through chemical rather than biochemical reactions. The polymerization products must be long enough to perform catalytic functions, including self-replication, and to preserve genetic information. These functions depend not only on the length of the polymers, but also on their sequences. To date, studies of abiotic RNA polymerization generally have focused on routes to polymerization of a single nucleotide and lengths of the homopolymer products. Less work has been done the selectivity of the reaction toward incorporation of some nucleotides over others in nucleotide mixtures. Such information is an essential step toward understanding the chemical evolution of RNA. To address this question, in the present work RNA polymerization reactions were performed in the presence of montmorillonite clay catalyst. The nucleotides included the monophosphates of adenosine, cytosine, guanosine, uridine and inosine. Experiments included reactions of mixtures of an imidazole-activated nucleotide (ImpX) with one or more unactivated nucleotides (XMP), of two or more ImpX, and of XMP that were activated in situ in the polymerization reaction itself. The reaction products were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the lengths and nucleotide compositions of the polymerization products. The results show that the extent of polymerization, the degree of heteropolymerization vs. homopolymerization, and the composition of the polymeric products all vary among the different nucleotides and depend upon which nucleotides and how many different nucleotides are present in the mixture.

  15. Mechanisms of silicon-mediated alleviation of abiotic stresses in higher plants: a review.

    PubMed

    Liang, Yongchao; Sun, Wanchun; Zhu, Yong-Guan; Christie, Peter

    2007-05-01

    Although silicon (Si) is the second most abundant element both on the surface of the Earth's crust and in soils, it has not yet been listed among the essential elements for higher plants. However, the beneficial role of Si in stimulating the growth and development of many plant species has been generally recognized. Silicon is known to effectively mitigate various abiotic stresses such as manganese, aluminum and heavy metal toxicities, and salinity, drought, chilling and freezing stresses. However, mechanisms of Si-mediated alleviation of abiotic stresses remain poorly understood. The key mechanisms of Si-mediated alleviation of abiotic stresses in higher plants include: (1) stimulation of antioxidant systems in plants, (2) complexation or co-precipitation of toxic metal ions with Si, (3) immobilization of toxic metal ions in growth media, (4) uptake processes, and (5) compartmentation of metal ions within plants. Future research needs for Si-mediated alleviation of abiotic stresses are also discussed.

  16. Cell Wall Metabolism in Response to Abiotic Stress

    PubMed Central

    Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

    2015-01-01

    This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

  17. Lipid signalling in plant responses to abiotic stress.

    PubMed

    Hou, Quancan; Ufer, Guido; Bartels, Dorothea

    2016-05-01

    Lipids are one of the major components of biological membranes including the plasma membrane, which is the interface between the cell and the environment. It has become clear that membrane lipids also serve as substrates for the generation of numerous signalling lipids such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, N-acylethanolamines, free fatty acids and others. The enzymatic production and metabolism of these signalling molecules are tightly regulated and can rapidly be activated upon abiotic stress signals. Abiotic stress like water deficit and temperature stress triggers lipid-dependent signalling cascades, which control the expression of gene clusters and activate plant adaptation processes. Signalling lipids are able to recruit protein targets transiently to the membrane and thus affect conformation and activity of intracellular proteins and metabolites. In plants, knowledge is still scarce of lipid signalling targets and their physiological consequences. This review focuses on the generation of signalling lipids and their involvement in response to abiotic stress. We describe lipid-binding proteins in the context of changing environmental conditions and compare different approaches to determine lipid-protein interactions, crucial for deciphering the signalling cascades. © 2016 JohnWiley & Sons Ltd.

  18. Cell Wall Metabolism in Response to Abiotic Stress.

    PubMed

    Le Gall, Hyacinthe; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

    2015-02-16

    This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

  19. Abiotic and biotic drivers of aboveground biomass in semi-steppe rangelands.

    PubMed

    Sanaei, Anvar; Chahouki, Mohammad Ali Zare; Ali, Arshad; Jafari, Mohammad; Azarnivand, Hossein

    2017-10-07

    Rangelands play an important role in the biodiversity conservation and ecosystem functions. Yet, few studies have assessed the effects of biotic and abiotic factors on aboveground biomass across plant growth forms and at whole-community level in rangelands. Here, we hypothesized that aboveground biomass is driven by both biotic (plant coverage, species richness and evenness) and abiotic factors (soil textural properties and topographic factors) but biotic factors may best predict aboveground biomass, probably due to small spatial scale. To test this hypothesis, we performed multiple linear mixed model by including biotic and biotic factors as fixed effects while sites aspects and plant community types across sites, and disturbance intensities as random effects, using data from 735 quadrats across 35 sites in semi-steppe rangelands in Iran. The optimal model for shrubs showed that aboveground biomass was positively related to plant coverage, species richness, elevation, sand, silt and clay. Aboveground biomass of forbs and grasses was positively related to plant coverage, species richness, elevation and slope. Whole-community aboveground biomass was positively related to plant coverage, species richness and elevation, but negatively to species evenness and slope. We conclude that higher aboveground biomass is related to high species richness and plant coverage, and located on high elevation and/or slope across plant growth forms while having medium-coarse-textured to fine-textured soils for adaptation of shrubs only. Few dominant species or niche overlap in whole-community may also drive high aboveground biomass, and located on high elevation with gentle slope. Therefore, we found support for both the niche complementarity and selection effects across plant growth forms and at whole-community. In addition, this study shows that plant coverage is the best proxy for aboveground biomass in the studied rangelands. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A review of selection-based tests of abiotic surrogates for species representation.

    PubMed

    Beier, Paul; Sutcliffe, Patricia; Hjort, Jan; Faith, Daniel P; Pressey, Robert L; Albuquerque, Fabio

    2015-06-01

    Because conservation planners typically lack data on where species occur, environmental surrogates--including geophysical settings and climate types--have been used to prioritize sites within a planning area. We reviewed 622 evaluations of the effectiveness of abiotic surrogates in representing species in 19 study areas. Sites selected using abiotic surrogates represented more species than an equal number of randomly selected sites in 43% of tests (55% for plants) and on average improved on random selection of sites by about 8% (21% for plants). Environmental diversity (ED) (42% median improvement on random selection) and biotically informed clusters showed promising results and merit additional testing. We suggest 4 ways to improve performance of abiotic surrogates. First, analysts should consider a broad spectrum of candidate variables to define surrogates, including rarely used variables related to geographic separation, distance from coast, hydrology, and within-site abiotic diversity. Second, abiotic surrogates should be defined at fine thematic resolution. Third, sites (the landscape units prioritized within a planning area) should be small enough to ensure that surrogates reflect species' environments and to produce prioritizations that match the spatial resolution of conservation decisions. Fourth, if species inventories are available for some planning units, planners should define surrogates based on the abiotic variables that most influence species turnover in the planning area. Although species inventories increase the cost of using abiotic surrogates, a modest number of inventories could provide the data needed to select variables and evaluate surrogates. Additional tests of nonclimate abiotic surrogates are needed to evaluate the utility of conserving nature's stage as a strategy for conservation planning in the face of climate change.

  1. Abiotic controls on N2O emissions from soils and wetlands

    NASA Astrophysics Data System (ADS)

    Horwath, W. R.

    2016-12-01

    The increase in atmospheric nitrous oxide (N2O) is a critical climate change issue contributing to global warming. Most studies on N2O production attribute microbial processes and their associated enzymatic reactions to be the main driver affecting emissions. The role of redox capable iron, manganese and organic compounds that can react with intermediates in the nitrogen cycle has also been shown to produce N2O abiotically. The importance of the abiotic pathways, however, is highly debated. The abiotic production of N2O is related to biophysiochemical controls and unique isotopic signatures of nitrogen cycle intermediates (hydroxylamine, nitric oxide, and nitrite), redox-active metals (iron and manganese) and organic matter (humic and fulvic acids). In a range of soils, we find that the iron directly associated with organic compounds is the strongest variable relating to N2O emissions. In addition to these factors, management is also assumed to affect abiotic N2O production through its impact on nitrogen cycle intermediates, but the environmental and physiochemical conditions that are changed by management are rarely considered in the abiotic production of N2O. We find that the amount and quality of organic compounds in soils directly determines the fate of soil N2O production (i.e. be emitted or consumed). Water depth in rice paddies and wetlands also plays a significant role in partitioning production and consumption of N2O. What is evident from studies on N2O emission is that abiotic reactions are coupled to biotic processes and they cannot be easily separated. The biotic/abiotic interactions have important ecological outcomes that influence abiotic production mechanisms and should be recognized as important controllers of N2O production and consumption processes in soils and sediments.

  2. Molecular responses of genetically modified maize to abiotic stresses as determined through proteomic and metabolomic analyses

    PubMed Central

    Benevenuto, Rafael Fonseca; Agapito-Tenfen, Sarah Zanon; Vilperte, Vinicius; Wikmark, Odd-Gunnar; van Rensburg, Peet Jansen; Nodari, Rubens Onofre

    2017-01-01

    Some genetically modified (GM) plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA) analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses. PMID:28245233

  3. Molecular responses of genetically modified maize to abiotic stresses as determined through proteomic and metabolomic analyses.

    PubMed

    Benevenuto, Rafael Fonseca; Agapito-Tenfen, Sarah Zanon; Vilperte, Vinicius; Wikmark, Odd-Gunnar; van Rensburg, Peet Jansen; Nodari, Rubens Onofre

    2017-01-01

    Some genetically modified (GM) plants have transgenes that confer tolerance to abiotic stressors. Meanwhile, other transgenes may interact with abiotic stressors, causing pleiotropic effects that will affect the plant physiology. Thus, physiological alteration might have an impact on the product safety. However, routine risk assessment (RA) analyses do not evaluate the response of GM plants exposed to different environmental conditions. Therefore, we here present a proteome profile of herbicide-tolerant maize, including the levels of phytohormones and related compounds, compared to its near-isogenic non-GM variety under drought and herbicide stresses. Twenty differentially abundant proteins were detected between GM and non-GM hybrids under different water deficiency conditions and herbicide sprays. Pathway enrichment analysis showed that most of these proteins are assigned to energetic/carbohydrate metabolic processes. Among phytohormones and related compounds, different levels of ABA, CA, JA, MeJA and SA were detected in the maize varieties and stress conditions analysed. In pathway and proteome analyses, environment was found to be the major source of variation followed by the genetic transformation factor. Nonetheless, differences were detected in the levels of JA, MeJA and CA and in the abundance of 11 proteins when comparing the GM plant and its non-GM near-isogenic variety under the same environmental conditions. Thus, these findings do support molecular studies in GM plants Risk Assessment analyses.

  4. Parental concern about vaccine safety in Canadian children partially immunized at age 2: A multivariable model including system level factors

    PubMed Central

    MacDonald, Shannon E; Schopflocher, Donald P; Vaudry, Wendy

    2014-01-01

    Children who begin but do not fully complete the recommended series of childhood vaccines by 2 y of age are a much larger group than those who receive no vaccines. While parents who refuse all vaccines typically express concern about vaccine safety, it is critical to determine what influences parents of ‘partially’ immunized children. This case-control study examined whether parental concern about vaccine safety was responsible for partial immunization, and whether other personal or system-level factors played an important role. A random sample of parents of partially and completely immunized 2 y old children were selected from a Canadian regional immunization registry and completed a postal survey assessing various personal and system-level factors. Unadjusted odds ratios (OR) and adjusted ORs (aOR) were calculated with logistic regression. While vaccine safety concern was associated with partial immunization (OR 7.338, 95% CI 4.138– 13.012), other variables were more strongly associated and reduced the strength of the relationship between concern and partial immunization in multivariable analysis (aOR 2.829, 95% CI 1.151 – 6.957). Other important factors included perceived disease susceptibility and severity (aOR 4.629, 95% CI 2.017 – 10.625), residential mobility (aOR 3.908, 95% CI 2.075 – 7.358), daycare use (aOR 0.310, 95% CI 0.144 - 0.671), number of needles administered at each visit (aOR 7.734, 95% CI 2.598 – 23.025) and access to a regular physician (aOR 0.219, 95% CI 0.057 – 0.846). While concern about vaccine safety may be addressed through educational strategies, this study suggests that additional program and policy-level strategies may positively impact immunization uptake. PMID:25483477

  5. Parental concern about vaccine safety in Canadian children partially immunized at age 2: a multivariable model including system level factors.

    PubMed

    MacDonald, Shannon E; Schopflocher, Donald P; Vaudry, Wendy

    2014-01-01

    Children who begin but do not fully complete the recommended series of childhood vaccines by 2 y of age are a much larger group than those who receive no vaccines. While parents who refuse all vaccines typically express concern about vaccine safety, it is critical to determine what influences parents of 'partially' immunized children. This case-control study examined whether parental concern about vaccine safety was responsible for partial immunization, and whether other personal or system-level factors played an important role. A random sample of parents of partially and completely immunized 2 y old children were selected from a Canadian regional immunization registry and completed a postal survey assessing various personal and system-level factors. Unadjusted odds ratios (OR) and adjusted ORs (aOR) were calculated with logistic regression. While vaccine safety concern was associated with partial immunization (OR 7.338, 95% CI 4.138-13.012), other variables were more strongly associated and reduced the strength of the relationship between concern and partial immunization in multivariable analysis (aOR 2.829, 95% CI 1.151-6.957). Other important factors included perceived disease susceptibility and severity (aOR 4.629, 95% CI 2.017-10.625), residential mobility (aOR 3.908, 95% CI 2.075-7.358), daycare use (aOR 0.310, 95% CI 0.144-0.671), number of needles administered at each visit (aOR 7.734, 95% CI 2.598-23.025) and access to a regular physician (aOR 0.219, 95% CI 0.057-0.846). While concern about vaccine safety may be addressed through educational strategies, this study suggests that additional program and policy-level strategies may positively impact immunization uptake.

  6. Risk factors for exposure to influenza a viruses, including subtype H5 viruses, in Thai free-grazing ducks.

    PubMed

    Beaudoin, A L; Kitikoon, P; Schreiner, P J; Singer, R S; Sasipreeyajan, J; Amonsin, A; Gramer, M R; Pakinsee, S; Bender, J B

    2014-08-01

    Free-grazing ducks (FGD) have been associated with highly pathogenic avian influenza (HPAI) H5N1 outbreaks and may be a viral reservoir. In July-August 2010, we assessed influenza exposure of Thai FGD and risk factors thereof. Serum from 6254 ducks was analysed with enzyme-linked immunosorbent assay (ELISA) to detect antibodies to influenza A nucleoprotein (NP), and haemagglutinin H5 protein. Eighty-five per cent (5305 ducks) were seropositive for influenza A. Of the NP-seropositive sera tested with H5 assays (n = 1423), 553 (39%) were H5 ELISA positive and 57 (4%) suspect. Twelve per cent (74 of 610) of H5 ELISA-positive/suspect ducks had H5 titres ≥ 1 : 20 by haemagglutination inhibition. Risk factors for influenza A seropositivity include older age, poultry contact, flock visitors and older purchase age. Study flocks had H5 virus exposure as recently as March 2010, but no HPAI H5N1 outbreaks have been identified in Thailand since 2008, highlighting a need for rigorous FGD surveillance. © 2012 Blackwell Verlag GmbH.

  7. Prognostic factors of successful on-purpose tumor biopsies in metastatic cancer patients included in the SHIVA prospective clinical trial

    PubMed Central

    Desportes, Emilie; Wagner, Mathilde; Kamal, Maud; Salomon, Anne Vincent; Deniziaut, Gabrielle; Pierron, Gaëlle; Rouleau, Etienne; Jouffroy, Thomas; Le Tourneau, Christophe; Paoletti, Xavier; Servois, Vincent

    2017-01-01

    PURPOSE To identify patient/tumor characteristics associated with success of biopsy in patients who received multiple lines of chemotherapy. METHODS Patients with refractory cancer from our center, who were included in a prospective randomized phase II trial comparing targeted therapies based on molecular profile of tumors versus conventional chemotherapy, were retrospectively included in this IRB-approved study. All patients had a biopsy of a tumor lesion performed during surgery, or using CT/palpation/endoscopic guidance. A biopsy was considered successful if the neoplastic cellularity was greater than 30%. Primary lesion, size and location of biopsied lesion, on-going chemotherapy and the differential attenuation between non-enhanced and venous phase (HU) for CT-guided biopsied lesions were recorded. RESULTS 228 patients (age=59±15yo; M/F=1.9) were included. One hundred and sixty biopsies (72%) of the 221 biopsies performed were successful. Prognostic factors of biopsy success were: no ongoing chemotherapy, surgical or palpation-guided biopsy, lymph nodes/soft tissue location(P <0.01). Among the 221 performed biopsies, 122 (55%) were performed using CT guidance and 82 (67%) were successful. In this subgroup, biopsied lesions located in lymph nodes/soft tissue were associated with a higher success rate while lung location was associated with failure (P <0.01). The mean differential attenuation was significantly higher in lesions with a successful biopsy (P <0.001). CONCLUSION Success of biopsy was less frequent with CT guidance than with surgical or palpation-guided biopsy and was higher in soft tissues and lymph nodes than that in visceral metastasis. Ongoing chemotherapy decreased tumor cell content and consequently the success of the biopsy samples for molecular profiling. PMID:27655703

  8. Research advances in major cereal crops for adaptation to abiotic stresses

    PubMed Central

    Maiti, RK; Satya, Pratik

    2014-01-01

    With devastating increase in population there is a great necessity to increase crop productivity of staple crops but the productivity is greatly affected by various abiotic stress factors such as drought, salinity. An attempt has been made a brief account on abiotic stress resistance of major cereal crops viz. In spite of good successes obtained on physiological and use molecular biology, the benefits of this high cost technology are beyond the reach of developing countries. This review discusses several morphological, anatomical, physiological, biochemical and molecular mechanisms of major cereal crops related to the adaptation of these crop to abiotic stress factors. It discusses the effect of abiotic stresses on physiological processes such as flowering, grain filling and maturation and plant metabolisms viz. photosynthesis, enzyme activity, mineral nutrition, and respiration. Though significant progress has been attained on the physiological, biochemical basis of resistance to abiotic stress factors, very little progress has been achieved to increase productivity under sustainable agriculture. Therefore, there is a great necessity of inter-disciplinary research to address this issue and to evolve efficient technology and its transfer to the farmers’ fields. PMID:25523172

  9. Research advances in major cereal crops for adaptation to abiotic stresses.

    PubMed

    Maiti, R K; Satya, Pratik

    2014-01-01

    With devastating increase in population there is a great necessity to increase crop productivity of staple crops but the productivity is greatly affected by various abiotic stress factors such as drought, salinity. An attempt has been made a brief account on abiotic stress resistance of major cereal crops viz. In spite of good successes obtained on physiological and use molecular biology, the benefits of this high cost technology are beyond the reach of developing countries. This review discusses several morphological, anatomical, physiological, biochemical and molecular mechanisms of major cereal crops related to the adaptation of these crop to abiotic stress factors. It discusses the effect of abiotic stresses on physiological processes such as flowering, grain filling and maturation and plant metabolisms viz. photosynthesis, enzyme activity, mineral nutrition, and respiration. Though significant progress has been attained on the physiological, biochemical basis of resistance to abiotic stress factors, very little progress has been achieved to increase productivity under sustainable agriculture. Therefore, there is a great necessity of inter-disciplinary research to address this issue and to evolve efficient technology and its transfer to the farmers' fields.

  10. Effect of yoga practices on pulmonary function tests including transfer factor of lung for carbon monoxide (TLCO) in asthma patients.

    PubMed

    Singh, Savita; Soni, Ritu; Singh, K P; Tandon, O P

    2012-01-01

    Prana is the energy, when the self-energizing force embraces the body with extension and expansion and control, it is pranayama. It may affect the milieu at the bronchioles and the alveoli particularly at the alveolo-capillary membrane to facilitate diffusion and transport of gases. It may also increase oxygenation at tissue level. Aim of our study is to compare pulmonary functions and diffusion capacity in patients of bronchial asthma before and after yogic intervention of 2 months. Sixty stable asthmatic-patients were randomized into two groups i.e group 1 (Yoga training group) and group 2 (control group). Each group included thirty patients. Lung functions were recorded on all patients at baseline, and then after two months. Group 1 subjects showed a statistically significant improvement (P<0.001) in Transfer factor of the lung for carbon monoxide (TLCO), forced vital capacity (FVC), forced expiratory volume in 1st sec (FEV1), peak expiratory flow rate (PEFR), maximum voluntary ventilation (MVV) and slow vital capacity (SVC) after yoga practice. Quality of life also increased significantly. It was concluded that pranayama & yoga breathing and stretching postures are used to increase respiratory stamina, relax the chest muscles, expand the lungs, raise energy levels, and calm the body.

  11. Abiotic Versus Biotic Weathering Of Olivine As Possible Biosignatures

    NASA Technical Reports Server (NTRS)

    Longazo, Teresa G.; Wentworth, Susan J.; Clemett, Simon J.; Southam, Gordon; McKay, David S.

    2001-01-01

    We are investigating the weathering of silicate minerals by both purely inorganic, and biologically mediated processes using field-emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDS). By resolving surface textures and chemical compositions of weathered surfaces at the sub-micron scale we hope to be able to distinguish abiotic from biotic weathering processes and so establish a new biosignature applicable to the study of astromaterials including but not limited to the Martian meteorites. Sterilized olivine grains (San Carlos, Arizona) no more than 1-2 mm in their longest dimension were optically assayed to be uniform in color and free of inclusions were selected as weathering subjects. Prior to all experiments surface morphologies and Fe/Mg ratios were determined for each grain using FE-SEM and EDS. Experiments were divided into two categories abiotic and biotic and were compared with "naturally" weathered samples. For the preliminary experiments, two trials (open and closed to the ambient laboratory environment) were performed under abiotic conditions, and three trials under biotic conditions (control, day 1 and day 2). The open system abiotic trials used sterile grains heated at 98 C and 200 C for both 24 and 48 hours in 1L double distilled de-ionized water. The closed system abiotic trials were conducted under the same conditions but in a sealed two layer steel/Teflon "bomb" apparatus. The biotic trials used sterile grains mounted in a flow-through device attached to a wellhead on the Columbia River aquifer. Several discolored, altered, grains were selected to document "natural" weathering surface textures for comparison with the experimental samples. Preliminary results indicate there are qualitative differences in weathered surface textures among all the designed experiments. The olivine grains in abiotic trials displayed etching, pitting, denticulate margins, dissolution and clay formation. The scale of the features

  12. Abiotic Versus Biotic Weathering Of Olivine As Possible Biosignatures

    NASA Technical Reports Server (NTRS)

    Longazo, Teresa G.; Wentworth, Susan J.; Clemett, Simon J.; Southam, Gordon; McKay, David S.

    2001-01-01

    We are investigating the weathering of silicate minerals by both purely inorganic, and biologically mediated processes using field-emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDS). By resolving surface textures and chemical compositions of weathered surfaces at the sub-micron scale we hope to be able to distinguish abiotic from biotic weathering processes and so establish a new biosignature applicable to the study of astromaterials including but not limited to the Martian meteorites. Sterilized olivine grains (San Carlos, Arizona) no more than 1-2 mm in their longest dimension were optically assayed to be uniform in color and free of inclusions were selected as weathering subjects. Prior to all experiments surface morphologies and Fe/Mg ratios were determined for each grain using FE-SEM and EDS. Experiments were divided into two categories abiotic and biotic and were compared with "naturally" weathered samples. For the preliminary experiments, two trials (open and closed to the ambient laboratory environment) were performed under abiotic conditions, and three trials under biotic conditions (control, day 1 and day 2). The open system abiotic trials used sterile grains heated at 98 C and 200 C for both 24 and 48 hours in 1L double distilled de-ionized water. The closed system abiotic trials were conducted under the same conditions but in a sealed two layer steel/Teflon "bomb" apparatus. The biotic trials used sterile grains mounted in a flow-through device attached to a wellhead on the Columbia River aquifer. Several discolored, altered, grains were selected to document "natural" weathering surface textures for comparison with the experimental samples. Preliminary results indicate there are qualitative differences in weathered surface textures among all the designed experiments. The olivine grains in abiotic trials displayed etching, pitting, denticulate margins, dissolution and clay formation. The scale of the features

  13. The Functions of the A1A2A3 Domains in Von Willebrand Factor Include Multimerin 1 Binding

    PubMed Central

    Parker, D’Andra N.; Tasneem, Subia; Farndale, Richard W.; Bihan, Dominique; Sadler, J. Evan; Sebastian, Silvie; De Groot, Philip G.

    2016-01-01

    Summary Multimerin 1 (MMRN1) is a massive, homopolymeric protein that is stored in platelets and endothelial cells for activation-induced release. In vitro, MMRN1 binds to the outer surfaces of activated platelets and endothelial cells, the extracellular matrix (including collagen) and von Willebrand factor (VWF) to support platelet adhesive functions. VWF associates with MMRN1 at high shear, not static conditions, suggesting that shear exposes cryptic sites within VWF that support MMRN1 binding. Modified ELISA and surface plasmon resonance were used to study the structural features of VWF that support MMRN1 binding, and determine the affinities for VWF-MMRN1 binding. High shear microfluidic platelet adhesion assays determined the functional consequences for VWF-MMRN1 binding. VWF binding to MMRN1 was enhanced by shear exposure and ristocetin, and required VWF A1A2A3 region, specifically the A1 and A3 domains. VWF A1A2A3 bound to MMRN1 with a physiologically relevant binding affinity (KD: 2.0 ± 0.4 nM), whereas the individual VWF A1 (KD: 39.3 ± 7.7 nM) and A3 domains (KD: 229 ± 114 nM) bound to MMRN1 with lower affinities. VWF A1A2A3 was also sufficient to support the adhesion of resting platelets to MMRN1 at high shear, by a mechanism dependent on VWF-GPIbα binding. Our study provides new information on the molecular basis of MMRN1 binding to VWF, and its role in supporting platelet adhesion at high shear. We propose that at sites of vessel injury, MMRN1 that is released following activation of platelets and endothelial cells, binds to VWF A1A2A3 region to support platelet adhesion at arterial shear rates. PMID:27052467

  14. Abiotic-biotic characterization of Pt/Ir microelectrode arrays in chronic implants.

    PubMed

    Prasad, Abhishek; Xue, Qing-Shan; Dieme, Robert; Sankar, Viswanath; Mayrand, Roxanne C; Nishida, Toshikazu; Streit, Wolfgang J; Sanchez, Justin C

    2014-01-01

    Pt/Ir electrodes have been extensively used in neurophysiology research in recent years as they provide a more inert recording surface as compared to tungsten or stainless steel. While floating microelectrode arrays (FMA) consisting of Pt/Ir electrodes are an option for neuroprosthetic applications, long-term in vivo functional performance characterization of these FMAs is lacking. In this study, we have performed comprehensive abiotic-biotic characterization of Pt/Ir arrays in 12 rats with implant periods ranging from 1 week up to 6 months. Each of the FMAs consisted of 16-channel, 1.5 mm long, and 75 μm diameter microwires with tapered tips that were implanted into the somatosensory cortex. Abiotic characterization included (1) pre-implant and post-explant scanning electron microscopy (SEM) to study recording site changes, insulation delamination and cracking, and (2) chronic in vivo electrode impedance spectroscopy. Biotic characterization included study of microglial responses using a panel of antibodies, such as Iba1, ED1, and anti-ferritin, the latter being indicative of blood-brain barrier (BBB) disruption. Significant structural variation was observed pre-implantation among the arrays in the form of irregular insulation, cracks in insulation/recording surface, and insulation delamination. We observed delamination and cracking of insulation in almost all electrodes post-implantation. These changes altered the electrochemical surface area of the electrodes and resulted in declining impedance over the long-term due to formation of electrical leakage pathways. In general, the decline in impedance corresponded with poor electrode functional performance, which was quantified via electrode yield. Our abiotic results suggest that manufacturing variability and insulation material as an important factor contributing to electrode failure. Biotic results show that electrode performance was not correlated with microglial activation (neuroinflammation) as we were able

  15. Abiotic-biotic characterization of Pt/Ir microelectrode arrays in chronic implants

    PubMed Central

    Prasad, Abhishek; Xue, Qing-Shan; Dieme, Robert; Sankar, Viswanath; Mayrand, Roxanne C.; Nishida, Toshikazu; Streit, Wolfgang J.; Sanchez, Justin C.

    2014-01-01

    Pt/Ir electrodes have been extensively used in neurophysiology research in recent years as they provide a more inert recording surface as compared to tungsten or stainless steel. While floating microelectrode arrays (FMA) consisting of Pt/Ir electrodes are an option for neuroprosthetic applications, long-term in vivo functional performance characterization of these FMAs is lacking. In this study, we have performed comprehensive abiotic-biotic characterization of Pt/Ir arrays in 12 rats with implant periods ranging from 1 week up to 6 months. Each of the FMAs consisted of 16-channel, 1.5 mm long, and 75 μm diameter microwires with tapered tips that were implanted into the somatosensory cortex. Abiotic characterization included (1) pre-implant and post-explant scanning electron microscopy (SEM) to study recording site changes, insulation delamination and cracking, and (2) chronic in vivo electrode impedance spectroscopy. Biotic characterization included study of microglial responses using a panel of antibodies, such as Iba1, ED1, and anti-ferritin, the latter being indicative of blood-brain barrier (BBB) disruption. Significant structural variation was observed pre-implantation among the arrays in the form of irregular insulation, cracks in insulation/recording surface, and insulation delamination. We observed delamination and cracking of insulation in almost all electrodes post-implantation. These changes altered the electrochemical surface area of the electrodes and resulted in declining impedance over the long-term due to formation of electrical leakage pathways. In general, the decline in impedance corresponded with poor electrode functional performance, which was quantified via electrode yield. Our abiotic results suggest that manufacturing variability and insulation material as an important factor contributing to electrode failure. Biotic results show that electrode performance was not correlated with microglial activation (neuroinflammation) as we were able

  16. Towards a Four-Dimensional Model of Burnout: A Multigroup Factor-Analytic Study Including Depersonalization and Cynicism

    ERIC Educational Resources Information Center

    Salanova, Marisa; Llorens, Susana; Garcia-Renedo, Monica; Burriel, Raul; Breso, Edgar; Schaufeli, Wilmar B.

    2005-01-01

    This article investigated whether cynicism and depersonalization are two different dimensions of burnout or whether they may be collapsed into one construct of mental distance. Using confirmatory factor analyses in two samples of teachers (n = 483) and blue-collar workers (n = 474), a superior fit was found for the four-factor model that contained…

  17. Translating knowledge about abiotic stress tolerance to breeding programmes.

    PubMed

    Gilliham, Matthew; Able, Jason A; Roy, Stuart J

    2017-06-01

    Plant breeding and improvements in agronomic practice are making a consistent contribution to increasing global crop production year upon year. However, the rate of yield improvement currently lags behind the targets set to produce enough food to meet the demands of the predicted global population in 2050. Furthermore, crops that are exposed to harmful abiotic environmental factors (abiotic stresses, e.g. water limitation, salinity, extreme temperature) are prone to reduced yields. Here, we briefly describe the processes undertaken in conventional breeding programmes, which are usually designed to improve yields in near-optimal conditions rather than specifically breeding for improved crop yield stability under stressed conditions. While there is extensive fundamental research activity that examines mechanisms of plant stress tolerance, there are few examples that apply this research to improving commercial crop yields. There are notable exceptions, and we highlight some of these to demonstrate the magnitude of yield gains that could be made by translating agronomic, phenological and genetic solutions focused on improving or mitigating the effect of abiotic stress in the field; in particular, we focus on improvements in crop water-use efficiency and salinity tolerance. We speculate upon the reasons for the disconnect between research and research translation. We conclude that to realise untapped rapid gains towards food security targets new funding structures need to be embraced. Such funding needs to serve both the core and collaborative activities of the fundamental, pre-breeding and breeding research communities in order to expedite the translation of innovative research into the fields of primary producers. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  18. [Biotic and abiotic determinants of seroprevalence of antibodies against Trypanosoma cruzi in Palmar de Bravo, Puebla, Mexico].

    PubMed

    Sosa-Jurado, Francisca; Zumaquero-Ríos, José Lino; Reyes, Pedro A; Cruz-García, Abel; Guzmán-Bracho, Carmen; Monteón, Victor M

    2004-01-01

    To establish the relationship between seroprevalence for antibodies against Trypanosoma cruzi and its relationship with biotic and abiotic factors. A cross-sectional study was conducted between August 2000 and September 2001. The study population consisted of a simple random sample of 390 volunteers residing in Palmar de Bravo, Puebla, Mexico. Sample and data collection procedures included assaying antibodies against T. cruzi with validated assays, and searching for domestic reservoirs and triatomine bugs. The relationship between biotic and abiotic factors with seropositivity was assessed. Statistical analysis was conducted using Kappa values for diagnostic tests; statistical significance was assessed with 2 x 2 tables, chi-squared test with Yates' correction, Fisher exact test, and odds ratios. The seroprevalence of T. cruzi infection in humans was 4%; in domestic reservoirs (horses, pigs, and dogs) only 10% of canine reservoirs were positive. Vector species recognized were T. borberi and T. pallidipennis, with a Dispersion Area Index and a Colonization Index of 55% and 40%, respectively. The most important risk factors associated with positive serology were altitude (>2,150 and <2,180 meters above sea level), presence of triatomines, age, time of residence, and participation in a social assistance program. T. cruzi infection was identified in human beings, vectors, and possibly in domestic reservoirs, in communities located over 2,000 meters above sea level.

  19. Hydrogeomorphic Classification of Wetlands on Mt. Desert Island, Maine, Including Hydrologic Susceptibility Factors for Wetlands in Acadia National Park

    USGS Publications Warehouse

    Nielsen, Martha G.

    2006-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service, developed a hydrogeomorphic (HGM) classification system for wetlands greater than 0.4 hectares (ha) on Mt. Desert Island, Maine, and applied this classification using map-scale data to more than 1,200 mapped wetland units on the island. In addition, two hydrologic susceptibility factors were defined for a subset of these wetlands, using 11 variables derived from landscape-scale characteristics of the catchment areas of these wetlands. The hydrologic susceptibility factors, one related to the potential hydrologic pathways for contaminants and the other to the susceptibility of wetlands to disruptions in water supply from projected future changes in climate, were used to indicate which wetlands (greater than 1 ha) in Acadia National Park (ANP) may warrant further investigation or monitoring. The HGM classification system consists of 13 categories: Riverine-Upper Perennial, Riverine-Nonperennial, Riverine- Tidal, Depressional-Closed, Depressional-Semiclosed, Depressional-Open, Depressional-No Ground-Water Input, Mineral Soil Flat, Organic Soil Flat, Tidal Fringe, Lacustrine Fringe, Slope, and Hilltop/Upper Hillslope. A dichotomous key was developed to aid in the classification of wetlands. The National Wetland Inventory maps produced by the U.S. Fish and Wildlife Service provided the wetland mapping units used for this classification. On the basis of topographic map information and geographic information system (GIS) layers at a scale of 1:24,000 or larger, 1,202 wetland units were assigned a preliminary HGM classification. Two of the 13 HGM classes (Riverine-Tidal and Depressional-No Ground-Water Input) were not assigned to any wetlands because criteria for determining those classes are not available at that map scale, and must be determined by more site-specific information. Of the 1,202 wetland polygons classified, which cover 1,830 ha in ANP, 327 were classified as Slope, 258 were

  20. Psychological Factors, Including Alexithymia, in the Prediction of Cardiovascular Risk in HIV Infected Patients: Results of a Cohort Study

    PubMed Central

    Sozio, Federica; Mazzott, Elena; Ursini, Tamara; Polill, Ennio; Di Stefano, Paola; Tontodonati, Monica; Verrocchio, Maria C.; Fulcheri, Mario; Calella, Giulio; Santilli, Francesca; Manzoli, Lamberto

    2013-01-01

    Background Psychological factors are known predictors of cardiovascular disease in many clinical settings, but data are lacking for HIV infection. We carried out a prospective cohort study to evaluate potential psychological predictors of preclinical and clinical vascular disease in HIV patients. Methodology/Principal Findings HIV patients were consecutively enrolled. Demographics, viral and immune parameters and traditional cardiovascular predictors were considered; Intima-Media Thickness (c-IMT, continuous measure) and Carotid Plaques (CPs, focal thickening ≥1.5 mm) were investigated by B-mode ultrasonography; depressive symptoms by the Beck Depression Inventory (BDI-II), Type D personality (Distressed Personality or Type D) by the DS14, alexithymia by the Toronto Alexithymia Scale (TAS-20). Vascular outcomes included transient ischemic attacks or stroke, acute coronary syndrome, myocardial or other organ infarction. We enrolled 232 HIV subjects, 73.9% males, aged 44.5±9.9 y, 38.2% with AIDS diagnosis, 18.3% untreated. Mean Nadir CD4 T-cell counts were 237.5±186.2/mmc. Of them, 224 (96.5%) attended IMT measurements; 201 (86.6%) attended both IMT assessment and psychological profiling. Mean follow-up was 782±308 days. Fifty-nine patients (29.4%) had CPs at baseline. Nineteen patients (9.5%) had ≥1 vascular event; 12 (6.0%) died due to such events (n = 4) or any cause. At baseline cross-sectional multivariate analysis, increasing age, total cholesterol, current smoking and Alexithymia score≥50 were significantly associated with both increased cIMT (linear regression) and CPs (logistic regression). At follow-up analysis, log-rank tests and Cox’s regression revealed that only older age (p = 0.001), current smoking (p = 0.019) and alexithymia score≥50 (p = 0.013) were independently associated with vascular events. Conclusions/Significance In HIV-infected subjects, the Alexithymic trait emerges as a strong predictor of increased IMT

  1. Psychological factors, including alexithymia, in the prediction of cardiovascular risk in HIV infected patients: results of a cohort study.

    PubMed

    Parruti, Giustino; Vadini, Francesco; Sozio, Federica; Mazzott, Elena; Ursini, Tamara; Polill, Ennio; Di Stefano, Paola; Tontodonati, Monica; Verrocchio, Maria C; Fulcheri, Mario; Calella, Giulio; Santilli, Francesca; Manzoli, Lamberto

    2013-01-01

    Psychological factors are known predictors of cardiovascular disease in many clinical settings, but data are lacking for HIV infection. We carried out a prospective cohort study to evaluate potential psychological predictors of preclinical and clinical vascular disease in HIV patients. HIV patients were consecutively enrolled. Demographics, viral and immune parameters and traditional cardiovascular predictors were considered; Intima-Media Thickness (c-IMT, continuous measure) and Carotid Plaques (CPs, focal thickening ≥1.5 mm) were investigated by B-mode ultrasonography; depressive symptoms by the Beck Depression Inventory (BDI-II), Type D personality (Distressed Personality or Type D) by the DS14, alexithymia by the Toronto Alexithymia Scale (TAS-20). Vascular outcomes included transient ischemic attacks or stroke, acute coronary syndrome, myocardial or other organ infarction. We enrolled 232 HIV subjects, 73.9% males, aged 44.5±9.9 y, 38.2% with AIDS diagnosis, 18.3% untreated. Mean Nadir CD4 T-cell counts were 237.5±186.2/mmc. Of them, 224 (96.5%) attended IMT measurements; 201 (86.6%) attended both IMT assessment and psychological profiling. Mean follow-up was 782±308 days. Fifty-nine patients (29.4%) had CPs at baseline. Nineteen patients (9.5%) had ≥1 vascular event; 12 (6.0%) died due to such events (n = 4) or any cause. At baseline cross-sectional multivariate analysis, increasing age, total cholesterol, current smoking and Alexithymia score≥50 were significantly associated with both increased cIMT (linear regression) and CPs (logistic regression). At follow-up analysis, log-rank tests and Cox's regression revealed that only older age (p = 0.001), current smoking (p = 0.019) and alexithymia score≥50 (p = 0.013) were independently associated with vascular events. In HIV-infected subjects, the Alexithymic trait emerges as a strong predictor of increased IMT, presence of CPs and vascular events. Such results are preliminary and require confirmation

  2. Genome-wide characterization and expression profiling of the NAC genes under abiotic stresses in Cucumis sativus.

    PubMed

    Zhang, Xiao Meng; Yu, Hong Jun; Sun, Chao; Deng, Jie; Zhang, Xue; Liu, Peng; Li, Yun Yun; Li, Qiang; Jiang, Wei Jie

    2017-04-01

    The NAC (standing for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF] and cup-shaped cotyledon [CUC]) proteins pertain to one of the plant-specific transcription factor families that play important roles in plant development, abiotic stress resistance and signalling transduction. In the present study, the genomic features of the NAC genes in cucumber were analysed in depth using in silico tools. To reveal a tissue-specific, abiotic stress and hormone-responsive expression profile of CsNAC genes, RT-qPCR was performed under different treatments. Phylogenetic analyses and genome-wide annotation indicated that 82 high-confidence CsNAC genes were clustered into 13 sub-groups with uneven distribution in the cucumber genome. Furthermore, the CsNAC genes exhibited different tissue-specific expression patterns in 10 tissues under normal growth conditions, while 13 (16%) and 28 (34%) genes displayed preferential expression in roots and flowers, respectively. Moreover, CsNAC genes were more sensitive to salinity than other stresses; however, their responses were relatively rapid and transient to nutrition deprivation. Several CsNAC genes, including CsNAC35, which is an orthologue of the known stress-responsive Arabidopsis RD26, were identified as highly responsive to abiotic stresses and hormones. Overall, our findings revealed the genomic landscape and expression profiling of the CsNAC genes in response to multiple stresses and hormones, offering clues for further function analyses and molecular breeding. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. The Role and Regulation of ABI5 (ABA-Insensitive 5) in Plant Development, Abiotic Stress Responses and Phytohormone Crosstalk

    PubMed Central

    Skubacz, Anna; Daszkowska-Golec, Agata; Szarejko, Iwona

    2016-01-01

    ABA Insensitive 5 (ABI5) is a basic leucine zipper transcription factor that plays a key role in the regulation of seed germination and early seedling growth in the presence of ABA and abiotic stresses. ABI5 functions in the core ABA signaling, which is composed of PYR/PYL/RCAR receptors, PP2C phosphatases and SnRK2 kinases, through the regulation of the expression of genes that contain the ABSCISIC ACID RESPONSE ELEMENT (ABRE) motif within their promoter region. The regulated targets include stress adaptation genes, e.g., LEA proteins. However, the expression and activation of ABI5 is not only dependent on the core ABA signaling. Many transcription factors such as ABI3, ABI4, MYB7 and WRKYs play either a positive or a negative role in the regulation of ABI5 expression. Additionally, the stability and activity of ABI5 are also regulated by other proteins through post-translational modifications such as phosphorylation, ubiquitination, sumoylation and S-nitrosylation. Moreover, ABI5 also acts as an ABA and other phytohormone signaling integrator. Components of auxin, cytokinin, gibberellic acid, jasmonate and brassinosteroid signaling and metabolism pathways were shown to take part in ABI5 regulation and/or to be regulated by ABI5. Monocot orthologs of AtABI5 have been identified. Although their roles in the molecular and physiological adaptations during abiotic stress have been elucidated, knowledge about their detailed action still remains elusive. Here, we describe the recent advances in understanding the action of ABI5 in early developmental processes and the adaptation of plants to unfavorable environmental conditions. We also focus on ABI5 relation to other phytohormones in the abiotic stress response of plants. PMID:28018412

  4. Assessing Utilization and Environmental Risks of Important Genes in Plant Abiotic Stress Tolerance

    PubMed Central

    Khan, Mohammad S.; Khan, Muhammad A.; Ahmad, Dawood

    2016-01-01

    Transgenic plants with improved salt and drought stress tolerance have been developed with a large number of abiotic stress-related genes. Among these, the most extensively used genes are the glycine betaine biosynthetic codA, the DREB transcription factors, and vacuolar membrane Na+/H+ antiporters. The use of codA, DREBs, and Na+/H+ antiporters in transgenic plants has conferred stress tolerance and improved plant phenotype. However, the future deployment and commercialization of these plants depend on their safety to the environment. Addressing environmental risk assessment is challenging since mechanisms governing abiotic stress tolerance are much more complex than that of insect resistance and herbicide tolerance traits, which have been considered to date. Therefore, questions arise, whether abiotic stress tolerance genes need additional considerations and new measurements in risk assessment and, whether these genes would have effects on weediness and invasiveness potential of transgenic plants? While considering these concerns, the environmental risk assessment of abiotic stress tolerance genes would need to focus on the magnitude of stress tolerance, plant phenotype and characteristics of the potential receiving environment. In the present review, we discuss environmental concerns and likelihood of concerns associated with the use of abiotic stress tolerance genes. Based on our analysis, we conclude that the uses of these genes in domesticated crop plants are safe for the environment. Risk assessment, however, should be carefully conducted on biofeedstocks and perennial plants taking into account plant phenotype and the potential receiving environment. PMID:27446095

  5. A NAP-Family Histone Chaperone Functions in Abiotic Stress Response and Adaptation1[OPEN

    PubMed Central

    Pareek, Ashwani; Singla-Pareek, Sneh Lata

    2016-01-01

    Modulation of gene expression is one of the most significant molecular mechanisms of abiotic stress response in plants. Via altering DNA accessibility, histone chaperones affect the transcriptional competence of genomic loci. However, in contrast to other factors affecting chromatin dynamics, the role of plant histone chaperones in abiotic stress response and adaptation remains elusive. Here, we studied the physiological function of a stress-responsive putative rice (Oryza sativa) histone chaperone of the NAP superfamily: OsNAPL6. We show that OsNAPL6 is a nuclear-localized H3/H4 histone chaperone capable of assembling a nucleosome-like structure. Utilizing overexpression and knockdown approaches, we found a positive correlation between OsNAPL6 expression levels and adaptation to multiple abiotic stresses. Results of comparative transcriptome profiling and promoter-recruitment studies indicate that OsNAPL6 functions during stress response via modulation of expression of various genes involved in diverse functions. For instance, we show that OsNAPL6 is recruited to OsRad51 promoter, activating its expression and leading to more efficient DNA repair and abrogation of programmed cell death under salinity and genotoxic stress conditions. These results suggest that the histone chaperone OsNAPL6 may serve a regulatory role in abiotic stress physiology possibly via modulating nucleosome dynamics at various stress-associated genomic loci. Taken together, our findings establish a hitherto unknown link between histone chaperones and abiotic stress response in plants. PMID:27342307

  6. Silicon's Role in Abiotic and Biotic Plant Stresses.

    PubMed

    Debona, Daniel; Rodrigues, Fabrício A; Datnoff, Lawrence E

    2017-08-04

    Silicon (Si) plays a pivotal role in the nutritional status of a wide variety of monocot and dicot plant species and helps them, whether directly or indirectly, counteract abiotic and/or biotic stresses. In general, plants with a high root or shoot Si concentration are less prone to pest attack and exhibit enhanced tolerance to abiotic stresses such as drought, low temperature, or metal toxicity. However, the most remarkable effect of Si is the reduction in the intensities of a number of seedborne, soilborne, and foliar diseases in many economically important crops that are caused by biotrophic, hemibiotrophic, and necrotrophic plant pathogens. The reduction in disease symptom expression is due to the effect of Si on some components of host resistance, including incubation period, lesion size, and lesion number. The mechanical barrier formed by the polymerization of Si beneath the cuticle and in the cell walls was the first proposed hypothesis to explain how this element reduced the severity of plant diseases. However, new insights have revealed that many plant species supplied with Si have the phenylpropanoid and terpenoid pathways potentiated and have a faster and stronger transcription of defense genes and higher activities of defense enzymes. Photosynthesis and the antioxidant system are also improved for Si-supplied plants. Although the current understanding of how this overlooked element improves plant reaction against pathogen infections, pest attacks, and abiotic stresses has advanced, the exact mechanism(s) by which it modulates plant physiology through the potentiation of host defense mechanisms still needs further investigation at the genomic, metabolomic, and proteomic levels.

  7. Distinguishing Biotic from Abiotic Phosphate Oxygen Isotopic Signatures

    NASA Astrophysics Data System (ADS)

    Blake, R.; Moyer, C.; Colman, A.; Liang, Y.; Dogru, D.

    2006-05-01

    On earth, phosphate has a strong biological oxygen isotope signature due to its concentration and intense cycling by living organisms as an essential nutrient. Phosphate does not undergo oxygen isotope exchange with water at low temperature without enzymatic catalysis, making the oxygen isotope ratio (18O/16O) of phosphate, δ18OP, an attractive biosignature in the search for early and extraterrestrial life. Recent laboratory and field studies have demonstrated that the δ18OP value of dissolved inorganic phosphate (PO4) records specific microbial activity and enzymatic reaction pathways in both laboratory cultures and natural waters/sediments (Blake et al., 2005; Colman et al 2005; Liang and Blake, 2005). Phosphate oxygen isotope biosignatures may be distinguished from abiotic signatures by: (1) evaluating the degree of temperature-dependent PO4-water oxygen isotope exchange in aqueous systems and deviation from equilibrium; and (2) evolution from an abiotic P reservoir signature towards a biotic P reservoir signature. Important abiotic processes potentially affecting phosphate δ18OP values include dissolution/precipitation, adsorption/desorption, recrystallization of PO4 mineral phases, diagenesis and metamorphism. For most of these processes, the recording, retention and alteration of δ18OP biosignatures have not been evaluated. Deep-sea hydrothermal vent fields are an ideal system in which to study the preservation and alteration of δ18OP biosignatures, as well as potential look-alikes produced by heat-promoted PO4 -water oxygen isotope exchange. Results from recent studies of δ18OP biosignatures in hydrothermal deposits near 9 and 21 degrees N. EPR and at Loihi seamount will be presented.

  8. [Risk factors for infection in total knee artrhoplasty, including previously unreported intraoperative fracture and deep venous thrombosis].

    PubMed

    de Dios, M; Cordero-Ampuero, J

    2015-01-01

    To carry out a statistical analysis on the significant risk factors for deep late infection (prosthetic joint infection, PJI) in patients with a knee arthroplasty (TKA). A retrospective observational case-control study was conducted on a case series of 32 consecutive knee infections, using an analysis of all the risk factors reported in the literature. A control series of 100 randomly selected patients operated in the same Department of a University General Hospital during the same period of time, with no sign of deep infection in their knee arthroplasty during follow-up. Statistical comparisons were made using Pearson for qualitative and ANOVA for quantitative variables. The significant (p>0.05) factors found in the series were: Preoperative previous knee surgery, glucocorticoids, immunosuppressants, inflamm