Comparative analysis highlights variable genome content of wheat rusts and divergence of the mating loci

USDA-ARS?s Scientific Manuscript database

Wheat is grown around the world and has been plagued by three rust fungi for centuries. Leaf rust, stripe rust, and stem rust each cause significant damage and can adapt quickly to overcome resistance that is present in wheat cultivars. Using advanced DNA sequencing technology, the genomes of leaf ...

Characterization of Lr75: a partial, broad-spectrum leaf rust resistance gene in wheat.

PubMed

Singla, Jyoti; Lüthi, Linda; Wicker, Thomas; Bansal, Urmil; Krattinger, Simon G; Keller, Beat

2017-01-01

Here, we describe a strategy to improve broad-spectrum leaf rust resistance by marker-assisted combination of two partial resistance genes. One of them represents a novel partial adult plant resistance gene, named Lr75. Leaf rust caused by the fungal pathogen Puccinia triticina is a damaging disease of wheat (Triticum aestivum L.). The combination of several, additively-acting partial disease resistance genes has been proposed as a suitable strategy to breed wheat cultivars with high levels of durable field resistance. The Swiss winter wheat cultivar 'Forno' continues to show near-immunity to leaf rust since its release in the 1980s. This resistance is conferred by the presence of at least six quantitative trait loci (QTL), one of which is associated with the morphological trait leaf tip necrosis. Here, we used a marker-informed strategy to introgress two 'Forno' QTLs into the leaf rust-susceptible Swiss winter wheat cultivar 'Arina'. The resulting backcross line 'ArinaLrFor' showed markedly increased leaf rust resistance in multiple locations over several years. One of the introgressed QTLs, QLr.sfr-1BS, is located on chromosome 1BS. We developed chromosome 1B-specific microsatellite markers by exploiting the Illumina survey sequences of wheat cv. 'Chinese Spring' and mapped QLr.sfr-1BS to a 4.3 cM interval flanked by the SSR markers gwm604 and swm271. QLr.sfr-1BS does not share a genetic location with any of the described leaf rust resistance genes present on chromosome 1B. Therefore, QLr.sfr-1BS is novel and was designated as Lr75. We conclude that marker-assisted combination of partial resistance genes is a feasible strategy to increase broad-spectrum leaf rust resistance. The identification of Lr75 adds a novel and highly useful gene to the small set of known partial, adult plant leaf rust resistance genes.

Genome-Wide Association Mapping of Leaf Rust Response in a Durum Wheat Worldwide Germplasm Collection.

PubMed

Aoun, Meriem; Breiland, Matthew; Kathryn Turner, M; Loladze, Alexander; Chao, Shiaoman; Xu, Steven S; Ammar, Karim; Anderson, James A; Kolmer, James A; Acevedo, Maricelis

2016-11-01

Leaf rust (caused by Erikss. []) is increasingly impacting durum wheat ( L. var. ) production with the recent appearance of races with virulence to widely grown cultivars in many durum producing areas worldwide. A highly virulent race on durum wheat was recently detected in Kansas. This race may spread to the northern Great Plains, where most of the US durum wheat is produced. The objective of this study was to identify sources of resistance to several races from the United States and Mexico at seedling stage in the greenhouse and at adult stage in field experiments. Genome-wide association study (GWAS) was used to identify single-nucleotide polymorphism (SNP) markers associated with leaf rust response in a worldwide durum wheat collection of 496 accessions. Thirteen accessions were resistant across all experiments. Association mapping revealed 88 significant SNPs associated with leaf rust response. Of these, 33 SNPs were located on chromosomes 2A and 2B, and 55 SNPs were distributed across all other chromosomes except for 1B and 7B. Twenty markers were associated with leaf rust response at seedling stage, while 68 markers were associated with leaf rust response at adult plant stage. The current study identified a total of 14 previously uncharacterized loci associated with leaf rust response in durum wheat. The discovery of these loci through association mapping (AM) is a significant step in identifying useful sources of resistance that can be used to broaden the relatively narrow leaf rust resistance spectrum in durum wheat germplasm. Copyright © 2016 Crop Science Society of America.

Genome-Wide Association Mapping Reveals Novel QTL for Seedling Leaf Rust Resistance in a Worldwide Collection of Winter Wheat.

PubMed

Li, Genqiao; Xu, Xiangyang; Bai, Guihua; Carver, Brett F; Hunger, Robert; Bonman, J Michael; Kolmer, James; Dong, Hongxu

2016-11-01

Leaf rust of wheat ( L.) is a major disease that causes significant yield losses worldwide. The short-lived nature of leaf rust resistance () genes necessitates a continuous search for novel sources of resistance. We performed a genome-wide association study (GWAS) on a panel of 1596 wheat accessions. The panel was evaluated for leaf rust reaction by testing with a bulk of Eriks. () isolates collected from multiple fields of Oklahoma in 2013 and two predominant races in the fields of Oklahoma in 2015. The panel was genotyped with a set of 5011 single-nucleotide polymorphism (SNP) markers. A total of 14 quantitative trait loci (QTL) for leaf rust resistance were identified at a false discovery rate (FDR) of 0.01 using the mixed linear model (MLM). Of these, eight QTL reside in the vicinity of known genes or QTL, and more studies are needed to determine their relationship with known loci. is a new QTL to bread wheat but is close to a locus previously identified in durum wheat [ L. subsp. (Desf.) Husn.]. The other five QTL, including , , , , and , are likely novel loci for leaf rust resistance. The uneven distribution of the 14 QTL in the six subpopulations of the panel suggests that wheat breeders can enhance leaf rust resistance by selectively introgressing some of these QTL into their breeding materials. In addition, another 31 QTL were significantly associated with leaf rust resistance at a FDR of 0.05. Copyright © 2016 Crop Science Society of America.

Novel sources of leaf rust resistance in winter wheat

USDA-ARS?s Scientific Manuscript database

Leaf rust is one of the most widespread diseases of wheat, causing significant yield losses. More than 70 leaf rust resistance genes have been reported, but most of them have lost their effectiveness in the southern Great Plains of the USA. Thus continuous search for new sources of resistance is e...

Genome-wide association mapping reveals novel QTL for seedling leaf rust resistance in a worldwide collection of winter wheat

USDA-ARS?s Scientific Manuscript database

Leaf rust is a major disease that causes significant wheat yield losses worldwide. Growing resistant cultivars is an effective approach to reduce disease losses. The short-lived nature of leaf rust resistance (Lr) genes necessitates a continuous search for novel sources of resistance. We performe...

Genetics of leaf rust resistance in the hard red winter wheat cultivars Santa Fe and Duster

USDA-ARS?s Scientific Manuscript database

Leaf rust caused by Puccinia triticina is a common and important disease of hard red winter wheat in the Great Plains of the United States. The hard red winter wheat cultivars 'Santa Fe' and 'Duster' have had effective leaf rust resistance since their release in 2003 and 2006, respectively. Both cul...

Adult plant leaf rust resistance derived from Toropi wheat is conditioned by Lr78 and three minor QTL

USDA-ARS?s Scientific Manuscript database

Brazil, was noted to have long lasting leaf rust resistance that was effective only in adult plants. The objectives of this study were to determine the chromosome location of the leaf rust resistance genes derived from Toropi in two populations of recombinant inbred lines in a partial Thatcher wheat...

Mapping and characterization of the new adult plant leaf rust resistance gene Lr77 derived from Santa Fe winter wheat.

PubMed

Kolmer, James A; Su, Zhenqi; Bernardo, Amy; Bai, Guihua; Chao, Shiaoman

2018-07-01

A new gene for adult plant leaf rust resistance in wheat was mapped to chromosome 3BL. This gene was designated as Lr77. 'Santa Fe' is a hard red winter cultivar that has had long-lasting resistance to the leaf rust fungus, Puccinia triticina. The objective of this study was to determine the chromosome location of the adult plant leaf rust resistance in Santa Fe wheat. A partial backcross line of 'Thatcher' (Tc) wheat with adult plant leaf rust resistance derived from Santa Fe was crossed with Thatcher to develop a Thatcher//Tc*2/Santa Fe F 6 recombinant inbred line (RIL) population. The RIL population and parental lines were evaluated for segregation of leaf rust resistance in three field plot tests and in an adult plant greenhouse test. A genetic map of the RIL population was constructed using 90,000 single-nucleotide polymorphism (SNP) markers with the Illumina Infinium iSelect 90K wheat bead array. A significant quantitative trait locus for reduction of leaf rust severity in all four tests was found on chromosome 3BL that segregated as a single adult plant resistance gene. The RILs with the allele from the resistant parent for SNP marker IWB10344 had lower leaf rust severity and a moderately resistant to moderately susceptible response compared to the susceptible RILs and Thatcher. The gene derived from Santa Fe on chromosome 3BL was designated as Lr77. Kompetitive allele-specific polymerase chain reaction assay markers linked to Lr77 on 3BL should be useful for selection of wheat germplasm with this gene.

Effect of Continuous Cropping Generations on Each Component Biomass of Poplar Seedlings during Different Growth Periods

PubMed Central

Xia, Jiangbao; Zhang, Shuyong; Li, Tian; Liu, Xia; Zhang, Ronghua; Zhang, Guangcan

2014-01-01

In order to investigate the change rules and response characteristics of growth status on each component of poplar seedling followed by continuous cropping generations and growth period, we clear the biomass distribution pattern of poplar seedling, adapt continuous cropping, and provide theoretical foundation and technical reference on cultivation management of poplar seedling, the first generation, second generation, and third generation continuous cropping poplar seedlings were taken as study objects, and the whole poplar seedling was harvested to measure and analyze the change of each component biomass on different growth period poplar leaves, newly emerging branches, trunks and root system, and so forth. The results showed that the whole biomass of poplar seedling decreased significantly with the leaf area and its ratio increased, and the growth was inhibited obviously. The biomass aboveground was more than that underground. The ratios of leaf biomass and newly emerging branches biomass of first continuous cropping poplar seedling were relatively high. With the continuous cropping generations and growth cycle increasing, poplar seedling had a growth strategy to improve the ratio of root-shoot and root-leaf to adapt the limited soil nutrient of continuous cropping. PMID:25401150

Leaf rust of cultivated barley: pathology and control.

PubMed

Park, Robert F; Golegaonkar, Prashant G; Derevnina, Lida; Sandhu, Karanjeet S; Karaoglu, Haydar; Elmansour, Huda M; Dracatos, Peter M; Singh, Davinder

2015-01-01

Leaf rust of barley is caused by the macrocyclic, heteroecious rust pathogen Puccinia hordei, with aecia reported from selected species of the genera Ornithogalum, Leopoldia, and Dipcadi, and uredinia and telia occurring on Hordeum vulgare, H. vulgare ssp. spontaneum, Hordeum bulbosum, and Hordeum murinum, on which distinct parasitic specialization occurs. Although Puccinia hordei is sporadic in its occurrence, it is probably the most common and widely distributed rust disease of barley. Leaf rust has increased in importance in recent decades in temperate barley-growing regions, presumably because of more intensive agricultural practices. Although total crop loss does not occur, under epidemic conditions yield reductions of up to 62% have been reported in susceptible varieties. Leaf rust is primarily controlled by the use of resistant cultivars, and, to date, 21 seedling resistance genes and two adult plant resistance (APR) genes have been identified. Virulence has been detected for most seedling resistance genes but is unknown for the APR genes Rph20 and Rph23. Other potentially new sources of APR have been reported, and additivity has been described for some of these resistances. Approaches to achieving durable resistance to leaf rust in barley are discussed.

Genetics of Leaf Rust Resistance in the Soft Red Winter Wheat Cultivars Coker 9663 and Pioneer 26R61

USDA-ARS?s Scientific Manuscript database

Leaf rust, caused by the fungus Puccinia triticina, is an important disease of soft red winter wheat cultivars that are grown in the southern and eastern United States. The objectives of this study were to identify the leaf rust resistance genes in two soft red winter wheat cultivars, Coker 9663 and...

Fungal pathogen (mis-) identifications: a case study with DNA barcodes on Melampsora rusts of aspen and white poplar.

PubMed

Feau, Nicolas; Vialle, Agathe; Allaire, Mathieu; Tanguay, Philippe; Joly, David L; Frey, Pascal; Callan, Brenda E; Hamelin, Richard C

2009-01-01

Wide variation and overlap in morphological characters have led to confusion in species identification within the fungal rust genus Melampsora. The Melampsora species with uredinial-telial stages on white poplar and aspens are especially prone to misidentification. This group includes the Melampsora populnea species complex and the highly destructive pine twisting rust, Melampsora pinitorqua, which alternates between hosts in Populus section Populus and Pinus. Our objective was to compare morphologically based identification to genetic material extracted from Melampsora species pathogenic to aspen and white poplar. We compared morphometric traits and DNA barcodes obtained from internal transcribed spacer (ITS), large ribosomal RNA subunit (28S), and mitochondrial cytochrome oxidase 1 (CO1) sequences to delimit within this taxonomically difficult group. Eight different Melampsora species were initially defined based on host specificity and morphometric data. DNA barcodes were then overlaid on these initial species definitions. The DNA barcodes, specifically those defined on ITS and 28S sequences, provided a highly accurate means of identifying and resolving Melampsora taxa. We highlighted species misidentification in specimens from Canadian herbaria related to either Melampsora medusae f. sp. tremuloidae or Melampsora aecidioides. Finally, we evidenced that the north-American species found on Populus alba, M. aecidioides is closely related but distinct from the four species of the M. populnea complex (Melampsora larici-tremulae, Melampsora magnusiana, Melampsora pinitorqua, and Melampsora rostrupii) found in Eurasia.

Mapping of leaf rust resistance genes and molecular characterization of the 2NS/2AS translocation in the wheat cultivar Jagger

USDA-ARS?s Scientific Manuscript database

Winter wheat cultivar 'Jagger' was recently found to have an alien chromosomal segment 'VPM1' that should carry Lr37, a gene conferring resistance against leaf rust caused by Puccinia triticina, and this cultivar was also reported to have the wheat gene Lr17 against leaf rust. Both Lr17 and Lr37 wer...

Development of COS-SNP and HRM markers for cost efficient and reliable haplotype-based detection of Lr14a in durum wheat (Triticum durum Desf.)

USDA-ARS?s Scientific Manuscript database

Leaf rust (Puccinia triticina Eriks. & Henn.) is a major disease affecting durum wheat production. The Lr14a leaf rust resistant gene present in the durum wheat cv. Creso and its derivative Colosseo is one of the best characterized leaf rust resistance sources presently deployed in durum wheat breed...

Mapping of stripe rust resistance gene in an Aegilops caudate introgression line in wheat and its genetic association with leaf rust resistance.

PubMed

Toor, Puneet Inder; Kaur, Satinder; Bansal, Mitaly; Yadav, Bharat; Chhuneja, Parveen

2016-12-01

A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcrossrecombinant inbred line (BC-RIL) population derived from the cross of a wheat-Ae. caudata introgression line (IL) T291- 2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%. IL T291-2 had earlier been reported to carry introgressions on wheat chromosomes 2D, 3D, 4D, 5D, 6D and 7D. Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS enriched the target region harbouring stripe and leaf rust resistance genes. Stripe rust resistance locus, temporarily designated as YrAc, mapped at the distal most end of 5DS linked with a group of four colocated SSRs and two resistance gene analogue (RGA)-STS markers at a distance of 5.3 cM. LrAc mapped at a distance of 9.0 cM from the YrAc and at 2.8 cM from RGA-STS marker Ta5DS_2737450, YrAc and LrAc appear to be the candidate genes for marker-assisted enrichment of the wheat gene pool for rust resistance.

Introgression of leaf rust and stripe rust resistance from Sharon goatgrass (Aegilops sharonensis Eig) into bread wheat (Triticum aestivum L.).

PubMed

Millet, E; Manisterski, J; Ben-Yehuda, P; Distelfeld, A; Deek, J; Wan, A; Chen, X; Steffenson, B J

2014-06-01

Leaf rust and stripe rust are devastating wheat diseases, causing significant yield losses in many regions of the world. The use of resistant varieties is the most efficient way to protect wheat crops from these diseases. Sharon goatgrass (Aegilops sharonensis or AES), which is a diploid wild relative of wheat, exhibits a high frequency of leaf and stripe rust resistance. We used the resistant AES accession TH548 and induced homoeologous recombination by the ph1b allele to obtain resistant wheat recombinant lines carrying AES chromosome segments in the genetic background of the spring wheat cultivar Galil. The gametocidal effect from AES was overcome by using an "anti-gametocidal" wheat mutant. These recombinant lines were found resistant to highly virulent races of the leaf and stripe rust pathogens in Israel and the United States. Molecular DArT analysis of the different recombinant lines revealed different lengths of AES segments on wheat chromosome 6B, which indicates the location of both resistance genes.

Biological Control of Septoria Leaf Spot Disease of Hybrid Poplar in the Field

Treesearch

Laszlo Gyenis; Neil A. Anderson; Michael E. Ostry

2003-01-01

Biological control of Septoria leaf spot of hrhrid poplars was investigated using disease-suppressive Streptomyces strains. Field experiments were conducted in 1998 and 1999 on potted trees placed in a hybrid poplar plantation near Rosemount, MN, and on field-planted trees in 1998 at St. Paul. At both locations, one resistant and three susceptible...

Pre symptomatic detection of wheat leaf rust in the susceptible cv Skalmeje and the resistant cv Esket by means of UV laser-induced fluorescence.

PubMed

Bürling, K; Hunsche, M; Noga, G

2010-01-01

In modern agriculture there is a great demand for a rapid and objective screening method for stress resistance, because so far, the resistance of new cultivars is tested in time- and money consuming field experiments. Based on fluorescence ratios, and lifetime of fluorophores measured by fluorescence spectroscopy, we have postulated that an early discrimination of susceptible and resistant wheat cultivars to the leaf rust pathogen Puccinia triticina can be accomplished. As representative for leaf rust resistant and leaf rust susceptible wheat genotypes the cultivars Esket and Skalmeje, respectively, were chosen. Plants were grown under controlled environment conditions and inoculated with the leaf rust pathogen at the second-leaf-stage by single-droplet application. Fluorescence measurements were carried out from two to four days after inoculation (dai) by using a compact fibre-optic fluorescence spectrometer with nanosecond time-resolution. Experimental results indicated that UV laser-induced spectral characteristics as well as determination of fluorescence lifetime are suited to detect leaf rust two dai. For this purpose several ratios and wavelength can be considered. In general, the tested cultivars showed distinct responses to the pathogen development. In this context the ratio F451/F687 measured three dai and mean lifetimes at 500 nm and 530 nm are suited to differentiate the resistant Esket from the susceptible Skalmeje genotypes.

Identification and Severity Determination of Wheat Stripe Rust and Wheat Leaf Rust Based on Hyperspectral Data Acquired Using a Black-Paper-Based Measuring Method.

PubMed

Wang, Hui; Qin, Feng; Ruan, Liu; Wang, Rui; Liu, Qi; Ma, Zhanhong; Li, Xiaolong; Cheng, Pei; Wang, Haiguang

2016-01-01

It is important to implement detection and assessment of plant diseases based on remotely sensed data for disease monitoring and control. Hyperspectral data of healthy leaves, leaves in incubation period and leaves in diseased period of wheat stripe rust and wheat leaf rust were collected under in-field conditions using a black-paper-based measuring method developed in this study. After data preprocessing, the models to identify the diseases were built using distinguished partial least squares (DPLS) and support vector machine (SVM), and the disease severity inversion models of stripe rust and the disease severity inversion models of leaf rust were built using quantitative partial least squares (QPLS) and support vector regression (SVR). All the models were validated by using leave-one-out cross validation and external validation. The diseases could be discriminated using both distinguished partial least squares and support vector machine with the accuracies of more than 99%. For each wheat rust, disease severity levels were accurately retrieved using both the optimal QPLS models and the optimal SVR models with the coefficients of determination (R2) of more than 0.90 and the root mean square errors (RMSE) of less than 0.15. The results demonstrated that identification and severity evaluation of stripe rust and leaf rust at the leaf level could be implemented based on the hyperspectral data acquired using the developed method. A scientific basis was provided for implementing disease monitoring by using aerial and space remote sensing technologies.

Identification and Severity Determination of Wheat Stripe Rust and Wheat Leaf Rust Based on Hyperspectral Data Acquired Using a Black-Paper-Based Measuring Method

PubMed Central

Ruan, Liu; Wang, Rui; Liu, Qi; Ma, Zhanhong; Li, Xiaolong; Cheng, Pei; Wang, Haiguang

2016-01-01

It is important to implement detection and assessment of plant diseases based on remotely sensed data for disease monitoring and control. Hyperspectral data of healthy leaves, leaves in incubation period and leaves in diseased period of wheat stripe rust and wheat leaf rust were collected under in-field conditions using a black-paper-based measuring method developed in this study. After data preprocessing, the models to identify the diseases were built using distinguished partial least squares (DPLS) and support vector machine (SVM), and the disease severity inversion models of stripe rust and the disease severity inversion models of leaf rust were built using quantitative partial least squares (QPLS) and support vector regression (SVR). All the models were validated by using leave-one-out cross validation and external validation. The diseases could be discriminated using both distinguished partial least squares and support vector machine with the accuracies of more than 99%. For each wheat rust, disease severity levels were accurately retrieved using both the optimal QPLS models and the optimal SVR models with the coefficients of determination (R2) of more than 0.90 and the root mean square errors (RMSE) of less than 0.15. The results demonstrated that identification and severity evaluation of stripe rust and leaf rust at the leaf level could be implemented based on the hyperspectral data acquired using the developed method. A scientific basis was provided for implementing disease monitoring by using aerial and space remote sensing technologies. PMID:27128464

QTLs for resistance to the leaf rust Puccinia brachypodii in the model grass Brachypodium distachyon

USDA-ARS?s Scientific Manuscript database

The wild grass Brachypodium distachyon is a useful new model for temperate cereals, but its potential to study the interactions with pathogens remains underexploited. Leaf rust is one of the major fungal diseases affecting cereals, and recently the host status of Brachypodium to Puccinia rusts was i...

Genome-Wide Association Mapping for Resistance to Leaf and Stripe Rust in Winter-Habit Hexaploid Wheat Landraces

PubMed Central

Kertho, Albert; Mamidi, Sujan; Bonman, J. Michael; McClean, Phillip E.; Acevedo, Maricelis

2015-01-01

Leaf rust, caused by Puccinia triticina (Pt), and stripe rust, caused by P. striiformis f. sp. tritici (Pst), are destructive foliar diseases of wheat worldwide. Breeding for disease resistance is the preferred strategy of managing both diseases. The continued emergence of new races of Pt and Pst requires a constant search for new sources of resistance. Here we report a genome-wide association analysis of 567 winter wheat (Triticum aestivum) landrace accessions using the Infinium iSelect 9K wheat SNP array to identify loci associated with seedling resistance to five races of Pt (MDCL, MFPS, THBL, TDBG, and TBDJ) and one race of Pst (PSTv-37) frequently found in the Northern Great Plains of the United States. Mixed linear models identified 65 and eight significant markers associated with leaf rust and stripe rust, respectively. Further, we identified 31 and three QTL associated with resistance to Pt and Pst, respectively. Eleven QTL, identified on chromosomes 3A, 4A, 5A, and 6D, are previously unknown for leaf rust resistance in T. aestivum. PMID:26076040

Identification and characterization of pleiotropic and co-located resistance loci to leaf rust and stripe rust in bread wheat cultivar Sujata.

PubMed

Lan, Caixia; Zhang, Yelun; Herrera-Foessel, Sybil A; Basnet, Bhoja R; Huerta-Espino, Julio; Lagudah, Evans S; Singh, Ravi P

2015-03-01

Two new co-located resistance loci, QLr.cim - 1AS/QYr.cim - 1AS and QLr.cim - 7BL/YrSuj , in combination with Lr46 / Yr29 and Lr67/Yr46 , and a new leaf rust resistance quantitative trait loci, conferred high resistance to rusts in adult plant stage. The tall Indian bread wheat cultivar Sujata displays high and low infection types to leaf rust and stripe rust, respectively, at the seedling stage in greenhouse tests. It was also highly resistant to both rusts at adult plant stage in field trials in Mexico. The genetic basis of this resistance was investigated in a population of 148 F5 recombinant inbred lines (RILs) derived from the cross Avocet × Sujata. The parents and RIL population were characterized in field trials for resistance to leaf rust during 2011 at El Batán, and 2012 and 2013 at Ciudad Obregón, Mexico, and for stripe rust during 2011 and 2012 at Toluca, Mexico; they were also characterized three times for stripe rust at seedling stage in the greenhouse. The RILs were genotyped with diversity arrays technology and simple sequence repeat markers. The final genetic map was constructed with 673 polymorphic markers. Inclusive composite interval mapping analysis detected two new significant co-located resistance loci, QLr.cim-1AS/QYr.cim-1AS and QLr.cim-7BL/YrSuj, on chromosomes 1AS and 7BL, respectively. The chromosomal position of QLr.cim-7BL overlapped with the seedling stripe rust resistance gene, temporarily designated as YrSuj. Two previously reported pleiotropic adult plant resistance genes, Lr46/Yr29 and Lr67/Yr46, and a new leaf rust resistance quantitative trait loci derived from Avocet were also mapped in the population. The two new co-located resistance loci are expected to contribute to breeding durable rust resistance in wheat. Closely linked molecular markers can be used to transfer all four resistance loci simultaneously to modern wheat varieties.

Expression of apoplast-targeted plant defensin MtDef4.2 confers resistance to leaf rust pathogen Puccinia triticina but does not affect mycorrhizal symbiosis in transgenic wheat.

PubMed

Kaur, Jagdeep; Fellers, John; Adholeya, Alok; Velivelli, Siva L S; El-Mounadi, Kaoutar; Nersesian, Natalya; Clemente, Thomas; Shah, Dilip

2017-02-01

Rust fungi of the order Pucciniales are destructive pathogens of wheat worldwide. Leaf rust caused by the obligate, biotrophic basidiomycete fungus Puccinia triticina (Pt) is an economically important disease capable of causing up to 50 % yield losses. Historically, resistant wheat cultivars have been used to control leaf rust, but genetic resistance is ephemeral and breaks down with the emergence of new virulent Pt races. There is a need to develop alternative measures for control of leaf rust in wheat. Development of transgenic wheat expressing an antifungal defensin offers a promising approach to complement the endogenous resistance genes within the wheat germplasm for durable resistance to Pt. To that end, two different wheat genotypes, Bobwhite and Xin Chun 9 were transformed with a chimeric gene encoding an apoplast-targeted antifungal plant defensin MtDEF4.2 from Medicago truncatula. Transgenic lines from four independent events were further characterized. Homozygous transgenic wheat lines expressing MtDEF4.2 displayed resistance to Pt race MCPSS relative to the non-transgenic controls in growth chamber bioassays. Histopathological analysis suggested the presence of both pre- and posthaustorial resistance to leaf rust in these transgenic lines. MtDEF4.2 did not, however, affect the root colonization of a beneficial arbuscular mycorrhizal fungus Rhizophagus irregularis. This study demonstrates that the expression of apoplast-targeted plant defensin MtDEF4.2 can provide substantial resistance to an economically important leaf rust disease in transgenic wheat without negatively impacting its symbiotic relationship with the beneficial mycorrhizal fungus.

McGISH identification and phenotypic description of leaf rust and yellow rust resistant partial amphiploids originating from a wheat × Thinopyrum synthetic hybrid cross.

PubMed

Kruppa, Klaudia; Türkösi, Edina; Mayer, Marianna; Tóth, Viola; Vida, Gyula; Szakács, Éva; Molnár-Láng, Márta

2016-11-01

A Thinopyrum intermedium × Thinopyrum ponticum synthetic hybrid wheatgrass is an excellent source of leaf and stem rust resistance produced by N.V.Tsitsin. Wheat line Mv9kr1 was crossed with this hybrid (Agropyron glael) in Hungary in order to transfer its advantageous agronomic traits into wheat. As the wheat parent was susceptible to leaf rust, the transfer of resistance was easily recognizable in the progenies. Three different partial amphiploid lines with leaf rust resistance were selected from the wheat/Thinopyrum hybrid derivatives by multicolour genomic in situ hybridization. Chromosome counting on the partial amphiploids revealed 58 chromosomes (18 wheatgrass) in line 194, 56 (14 wheatgrass) in line 195 and 54 (12 wheatgrass) in line 196. The wheat chromosomes present in these lines were identified and the wheatgrass chromosomes were characterized by fluorescence in situ hybridization using the repetitive DNA probes Afa-family, pSc119.2 and pTa71. The 3D wheat chromosome was missing from the lines. Molecular marker analysis showed the presence of the Lr24 leaf rust resistance gene in lines 195 and 196. The morphological traits were evaluated in the field during two consecutive seasons in two different locations.

A comparison of height growth and leaf parameters of hybrid poplar cuttings grown in ozone-fumigated atmospheres

Treesearch

Keith F. Jensen

1979-01-01

Hybrid poplar cuttings were fumigated with an ozone dosage of 15 ppm-hours. One treatment was a steady fumigation at 0.2 ppm while the second fumigation fluctuated between 0.1 and 0.3 ppm. No significant differences were found in cutting height, leaf area, leaf width, and leaf dry weight, but significant differences were found in chlorophyll content and carbohydrate...

Identification of Putative Coffee Rust Mycoparasites via Single-Molecule DNA Sequencing of Infected Pustules

PubMed Central

Marino, John A.; Perfecto, Ivette; Vandermeer, John

2015-01-01

The interaction of crop pests with their natural enemies is a fundament to their control. Natural enemies of fungal pathogens of crops are poorly known relative to those of insect pests, despite the diversity of fungal pathogens and their economic importance. Currently, many regions across Latin America are experiencing unprecedented epidemics of coffee rust (Hemileia vastatrix). Identification of natural enemies of coffee rust could aid in developing management strategies or in pinpointing species that could be used for biocontrol. In the present study, we characterized fungal communities associated with coffee rust lesions by single-molecule DNA sequencing of fungal rRNA gene bar codes from leaf discs (≈28 mm2) containing rust lesions and control discs with no rust lesions. The leaf disc communities were hyperdiverse in terms of fungi, with up to 69 operational taxonomic units (putative species) per control disc, and the diversity was only slightly reduced in rust-infected discs, with up to 63 putative species. However, geography had a greater influence on the fungal community than whether the disc was infected by coffee rust. Through comparisons between control and rust-infected leaf discs, as well as taxonomic criteria, we identified 15 putative mycoparasitic fungi. These fungi are concentrated in the fungal family Cordycipitaceae and the order Tremellales. These data emphasize the complexity of diverse fungi of unknown ecological function within a leaf that might influence plant disease epidemics or lead to the development of species for biocontrol of fungal disease. PMID:26567299

Isoprene emission by poplar is not important for the feeding behaviour of poplar leaf beetles.

PubMed

Müller, Anna; Kaling, Moritz; Faubert, Patrick; Gort, Gerrit; Smid, Hans M; Van Loon, Joop J A; Dicke, Marcel; Kanawati, Basem; Schmitt-Kopplin, Philippe; Polle, Andrea; Schnitzler, Jörg-Peter; Rosenkranz, Maaria

2015-06-30

Chrysomela populi (poplar leaf beetle) is a common herbivore in poplar plantations whose infestation causes major economic losses. Because plant volatiles act as infochemicals, we tested whether isoprene, the main volatile organic compound (VOC) produced by poplars (Populus x canescens), affects the performance of C. populi employing isoprene emitting (IE) and transgenic isoprene non-emitting (NE) plants. Our hypothesis was that isoprene is sensed and affects beetle orientation or that the lack of isoprene affects plant VOC profiles and metabolome with consequences for C. populi feeding. Electroantennographic analysis revealed that C. populi can detect higher terpenes, but not isoprene. In accordance to the inability to detect isoprene, C. populi showed no clear preference for IE or NE poplar genotypes in the choice experiments, however, the beetles consumed a little bit less leaf mass and laid fewer eggs on NE poplar trees in field experiments. Slight differences in the profiles of volatile terpenoids between IE and NE genotypes were detected by gas chromatography - mass spectrometry. Non-targeted metabolomics analysis by Fourier Transform Ion Cyclotron Resonance Mass Spectrometer revealed genotype-, time- and herbivore feeding-dependent metabolic changes both in the infested and adjacent undamaged leaves under field conditions. We show for the first time that C. populi is unable to sense isoprene. The detected minor differences in insect feeding in choice experiments and field bioassays may be related to the revealed changes in leaf volatile emission and metabolite composition between the IE and NE poplars. Overall our results indicate that lacking isoprene emission is of minor importance for C. populi herbivory under natural conditions, and that the lack of isoprene is not expected to change the economic losses in poplar plantations caused by C. populi infestation.

Conserved loci of leaf and stem rust fungi of wheat share synteny interrupted by lineage-specific influx of repeat elements

USDA-ARS?s Scientific Manuscript database

Background: Wheat leaf rust (Puccinia triticina Eriks; Pt) and stem rust (P. graminis f.sp. tritici; Pgt) are significant economic pathogens having similar host ranges and life cycles, but different alternate hosts. The Pt genome, currently estimated at 135 Mb, is significantly larger than Pgt, at ...

Proteomic characterization of the Rph15 barley resistance gene-mediated defence responses to leaf rust

PubMed Central

2012-01-01

Background Leaf rust, caused by the biotrophic fungal pathogen Puccinia hordei, is one of the most important foliar disease of barley (Hordeum vulgare) and represents a serious threat in many production regions of the world. The leaf rust resistance gene Rph15 is of outstanding interest for resistance breeding because it confers resistance to over 350 Puccinia hordei isolates collected from around the world. Molecular and biochemical mechanisms responsible for the Rph15 effectiveness are currently not investigated. The aim of the present work was to study the Rph15-based defence responses using a proteomic approach. Results Protein pattern changes in response to the leaf rust pathogen infection were investigated in two barley near isogenic lines (NILs), Bowman (leaf rust susceptible) and Bowman-Rph15 (leaf rust resistant), differing for the introgression of the leaf rust resistance gene Rph15. Two infection time points, 24 hours and four days post inoculation (dpi), were analysed. No statistically significant differences were identified at the early time point, while at 4 dpi eighteen protein spots were significantly up or down regulated with a fold-change equal or higher than two in response to pathogen infection. Almost all the pathogen-responsive proteins were identified in the Bowman-Rph15 resistant NIL. Protein spots were characterized by LC-MS/MS analysis and found to be involved in photosynthesis and energy metabolism, carbohydrate metabolism, protein degradation and defence. Proteomic data were complemented by transcriptional analysis of the respective genes. The identified proteins can be related to modulation of the photosynthetic apparatus components, re-direction of the metabolism to sustain defence responses and deployment of defence proteins. Conclusions The identification of leaf rust infection-modulated defence responses restricted to the resistant NIL support the hypothesis that basal defence responses of Bowman, but not the Rph15 resistance gene-based ones, are suppressed or delayed by pathogen effectors to levels below the detection power of the adopted proteomic approach. Additionally, Rph15-mediated resistance processes identified mainly resides on a modulation of primary metabolism, affecting photosyntesis and carbohydrate pool. PMID:23167439

Genetic analysis and mapping of adult plant resistance loci to leaf rust in durum wheat cultivar Bairds.

PubMed

Lan, Caixia; Basnet, Bhoja R; Singh, Ravi P; Huerta-Espino, Julio; Herrera-Foessel, Sybil A; Ren, Yong; Randhawa, Mandeep S

2017-03-01

New leaf rust adult plant resistance (APR) QTL QLr.cim - 6BL was mapped and confirmed the known pleotropic APR gene Lr46 effect on leaf rust in durum wheat line Bairds. CIMMYT-derived durum wheat line Bairds displays an adequate level of adult plant resistance (APR) to leaf rust in Mexican field environments. A recombinant inbred line (RIL) population developed from a cross of Bairds with susceptible parent Atred#1 was phenotyped for leaf rust response at Ciudad Obregon, Mexico, during 2013, 2014, 2015 and 2016 under artificially created epidemics of Puccinia triticina (Pt) race BBG/BP. The RIL population and its parents were genotyped with the 50 K diversity arrays technology (DArT) sequence system and simple sequence repeat (SSR) markers. A genetic map comprising 1150 markers was used to map the resistance loci. Four significant quantitative trait loci (QTLs) were detected on chromosomes 1BL, 2BC (centromere region), 5BL and 6BL. These QTLs, named Lr46, QLr.cim-2BC, QLr.cim-5BL and QLr.cim-6BL, respectively, explained 13.5-60.8%, 9.0-14.3%, 2.8-13.9%, and 11.6-29.4%, respectively, of leaf rust severity variation by the inclusive composite interval mapping method. All of these resistance loci were contributed by the resistant parent Bairds, except for QLr.cim-2BC, which came from susceptible parent Atred#1. Among these, the QTL on chromosome 1BL was the known pleiotropic APR gene Lr46, whereas QLr.cim-6BL, a consistently detected locus, should be a new leaf rust resistance locus in durum wheat. The mean leaf rust severity of RILs carrying all four QTLs ranged from 8.0 to 17.5%, whereas it ranged from 10.9 to 38.5% for three QTLs (Lr46 + 5BL + 6BL) derived from the resistant parent Bairds. Two RILs with four QTLs combinations can be used as sources of complex APR in durum wheat breeding.

Identification of Putative Coffee Rust Mycoparasites via Single-Molecule DNA Sequencing of Infected Pustules.

PubMed

James, Timothy Y; Marino, John A; Perfecto, Ivette; Vandermeer, John

2016-01-15

The interaction of crop pests with their natural enemies is a fundament to their control. Natural enemies of fungal pathogens of crops are poorly known relative to those of insect pests, despite the diversity of fungal pathogens and their economic importance. Currently, many regions across Latin America are experiencing unprecedented epidemics of coffee rust (Hemileia vastatrix). Identification of natural enemies of coffee rust could aid in developing management strategies or in pinpointing species that could be used for biocontrol. In the present study, we characterized fungal communities associated with coffee rust lesions by single-molecule DNA sequencing of fungal rRNA gene bar codes from leaf discs (≈28 mm(2)) containing rust lesions and control discs with no rust lesions. The leaf disc communities were hyperdiverse in terms of fungi, with up to 69 operational taxonomic units (putative species) per control disc, and the diversity was only slightly reduced in rust-infected discs, with up to 63 putative species. However, geography had a greater influence on the fungal community than whether the disc was infected by coffee rust. Through comparisons between control and rust-infected leaf discs, as well as taxonomic criteria, we identified 15 putative mycoparasitic fungi. These fungi are concentrated in the fungal family Cordycipitaceae and the order Tremellales. These data emphasize the complexity of diverse fungi of unknown ecological function within a leaf that might influence plant disease epidemics or lead to the development of species for biocontrol of fungal disease. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Uncovering leaf rust responsive miRNAs in wheat (Triticum aestivum L.) using high-throughput sequencing and prediction of their targets through degradome analysis.

PubMed

Kumar, Dhananjay; Dutta, Summi; Singh, Dharmendra; Prabhu, Kumble Vinod; Kumar, Manish; Mukhopadhyay, Kunal

2017-01-01

Deep sequencing identified 497 conserved and 559 novel miRNAs in wheat, while degradome analysis revealed 701 targets genes. QRT-PCR demonstrated differential expression of miRNAs during stages of leaf rust progression. Bread wheat (Triticum aestivum L.) is an important cereal food crop feeding 30 % of the world population. Major threat to wheat production is the rust epidemics. This study was targeted towards identification and functional characterizations of micro(mi)RNAs and their target genes in wheat in response to leaf rust ingression. High-throughput sequencing was used for transcriptome-wide identification of miRNAs and their expression profiling in retort to leaf rust using mock and pathogen-inoculated resistant and susceptible near-isogenic wheat plants. A total of 1056 mature miRNAs were identified, of which 497 miRNAs were conserved and 559 miRNAs were novel. The pathogen-inoculated resistant plants manifested more miRNAs compared with the pathogen infected susceptible plants. The miRNA counts increased in susceptible isoline due to leaf rust, conversely, the counts decreased in the resistant isoline in response to pathogenesis illustrating precise spatial tuning of miRNAs during compatible and incompatible interaction. Stem-loop quantitative real-time PCR was used to profile 10 highly differentially expressed miRNAs obtained from high-throughput sequencing data. The spatio-temporal profiling validated the differential expression of miRNAs between the isolines as well as in retort to pathogen infection. Degradome analysis provided 701 predicted target genes associated with defense response, signal transduction, development, metabolism, and transcriptional regulation. The obtained results indicate that wheat isolines employ diverse arrays of miRNAs that modulate their target genes during compatible and incompatible interaction. Our findings contribute to increase knowledge on roles of microRNA in wheat-leaf rust interactions and could help in rust resistance breeding programs.

Cytogenetic analysis and mapping of leaf rust resistance in Aegilops speltoides Tausch derived bread wheat line Selection2427 carrying putative gametocidal gene(s).

PubMed

Niranjana, M; Vinod; Sharma, J B; Mallick, Niharika; Tomar, S M S; Jha, S K

2017-12-01

Leaf rust (Puccinia triticina) is a major biotic stress affecting wheat yields worldwide. Host-plant resistance is the best method for controlling leaf rust. Aegilops speltoides is a good source of resistance against wheat rusts. To date, five Lr genes, Lr28, Lr35, Lr36, Lr47, and Lr51, have been transferred from Ae. speltoides to bread wheat. In Selection2427, a bread wheat introgresed line with Ae. speltoides as the donor parent, a dominant gene for leaf rust resistance was mapped to the long arm of chromosome 3B (LrS2427). None of the Lr genes introgressed from Ae. speltoides have been mapped to chromosome 3B. Since none of the designated seedling leaf rust resistance genes have been located on chromosome 3B, LrS2427 seems to be a novel gene. Selection2427 showed a unique property typical of gametocidal genes, that when crossed to other bread wheat cultivars, the F 1 showed partial pollen sterility and poor seed setting, whilst Selection2427 showed reasonable male and female fertility. Accidental co-transfer of gametocidal genes with LrS2427 may have occurred in Selection2427. Though LrS2427 did not show any segregation distortion and assorted independently of putative gametocidal gene(s), its utilization will be difficult due to the selfish behavior of gametocidal genes.

Can we use short rotation coppice poplar for sugar based biorefinery feedstock? Bioconversion of 2-year-old poplar grown as short rotation coppice.

PubMed

Dou, Chang; Marcondes, Wilian F; Djaja, Jessica E; Bura, Renata; Gustafson, Rick

2017-01-01

Feedstock cost is a substantial barrier to the commercialization of lignocellulosic biorefineries. Poplar grown using a short rotation coppice (SRC) system has the potential to provide a low-cost feedstock and economically viable sugar yields for fuels and chemicals production. In the coppice management regime, poplars are harvested after 2 years' growth to develop the root system and establish the trees. The biomass from these 2-year-old trees is very heterogeneous, and includes components of leaf, bark, branch, and wood chip. This material is quite different than the samples that have been used in most poplar bioconversion research, which come from mature trees of short rotation forestry (SRF) plantations. If the coppice management regime is to be used, it is important that feedstock growers maximize their revenue from this initial harvest, but the heterogeneous nature of the biomass may be challenging for bioconversion. This work evaluates bioconversion of 2-year-old poplar coppice and compares its performance to whitewood chips from 12-year-old poplar. The 2-year-old whole tree coppice (WTC) is comprised of 37% leaf, 9% bark, 12% branch, and 42% wood chip. As expected, the chemical compositions of each component were markedly different. The leaf has a low sugar content but is high in phenolics, ash, and extractives. By removing the leaves, the sugar content of the biomass increased significantly, while the phenolic, ash, and extractives contents decreased. Leaf removal improved monomeric sugar yield by 147 kg/tonne of biomass following steam pretreatment and enzymatic hydrolysis. Bioconversion of the no-leaf coppice (NLC) achieved a 67% overall sugar recovery, showing no significant difference to mature whitewood from forestry plantation (WWF, 71%). The overall sugar yield of NLC was 135 kg/tonne less than that of WWF, due to the low inherent sugar content in original biomass. An economic analysis shows the minimum ethanol selling price required to cover the operating cost of NLC bioconversion was $1.69/gallon. Leaf removal resulted in significant improvement in overall monomeric sugar production from SRC biomass. Leaf removal is essential to achieve good yields in bioconversion of poplar. Economic analysis suggests the NLC could be a reasonable feedstock provided it can be obtained at a discounted price.

QTL-seq approach identified genomic regions and diagnostic markers for rust and late leaf spot resistance in groundnut (Arachis hypogaea L.)

USDA-ARS?s Scientific Manuscript database

Rust and late leaf spot (LLS) are the two major foliar fungal diseases in groundnut, and their co-occurrence leads to yield loss up to 50–70% in addition to the deterioration of fodder quality. To identify candidate genomic regions controlling rust and LLS resistance, we deployed whole genome re-seq...

Effect of acid mist and air pollutants on yellow-poplar seedling height and leaf growth

Treesearch

Leon S. Dochinger; Keith F. Jensen; Keith F. Jensen

1985-01-01

One-year-old yellow-poplar seedlings were treated with acid mist at pH 2.5, 3.5, 4.5, and 5.5 either alone or in combination with 0.1 ppm 03, S02, and NO2 or NO2 plus S02. After 4 and 8 weeks of treatment, height, leaf area, and leaf and new shoot weight were determined and growth analysis variables calculated. Height, leaf area, and dry weight decreased with...

RNAi-mediated downregulation of poplar plasma membrane intrinsic proteins (PIPs) changes plasma membrane proteome composition and affects leaf physiology.

PubMed

Bi, Zhen; Merl-Pham, Juliane; Uehlein, Norbert; Zimmer, Ina; Mühlhans, Stefanie; Aichler, Michaela; Walch, Axel Karl; Kaldenhoff, Ralf; Palme, Klaus; Schnitzler, Jörg-Peter; Block, Katja

2015-10-14

Plasma membrane intrinsic proteins (PIPs) are one subfamily of aquaporins that mediate the transmembrane transport of water. To reveal their function in poplar, we generated transgenic poplar plants in which the translation of PIP genes was downregulated by RNA interference investigated these plants with a comprehensive leaf plasma membrane proteome and physiome analysis. First, inhibition of PIP synthesis strongly altered the leaf plasma membrane protein composition. Strikingly, several signaling components and transporters involved in the regulation of stomatal movement were differentially regulated in transgenic poplars. Furthermore, hormonal crosstalk related to abscisic acid, auxin and brassinosteroids was altered, in addition to cell wall biosynthesis/cutinization, the organization of cellular structures and membrane trafficking. A physiological analysis confirmed the proteomic results. The leaves had wider opened stomata and higher net CO2 assimilation and transpiration rates as well as greater mesophyll conductance for CO2 (gm) and leaf hydraulic conductance (Kleaf). Based on these results, we conclude that PIP proteins not only play essential roles in whole leaf water and CO2 flux but have important roles in the regulation of stomatal movement. Copyright © 2015. Published by Elsevier B.V.

Molecular Cytogenetic Characterization of two Triticum-Secale-Thinopyrum Trigeneric Hybrids Exhibiting Superior Resistance to Fusarium Head Blight, Leaf Rust, and Stem Rust Race Ug99.

PubMed

Dai, Yi; Duan, Yamei; Liu, Huiping; Chi, Dawn; Cao, Wenguang; Xue, Allen; Gao, Yong; Fedak, George; Chen, Jianmin

2017-01-01

Fusarium head blight (FHB), leaf rust, and stem rust are the most destructive fungal diseases in current world wheat production. The diploid wheatgrass, Thinopyrum elongatum (Host) Dewey (2 n = 2 x = 14, EE) is an excellent source of disease resistance genes. Two new Triticum-Secale-Thinopyrum trigeneric hybrids were derived from a cross between a hexaploid triticale (X Triticosecale Wittmack, 2 n = 6 x = 42, AABBRR) and a hexaploid Triticum trititrigia (2 n = 6 x = 42, AABBEE), were produced and analyzed using genomic in situ hybridization and molecular markers. The results indicated that line RE21 contained 14 A-chromosomes, 14 B-chromosomes, three pairs of R-chromosomes (4R, 6R, and 7R), and four pairs of E-chromosomes (1E, 2E, 3E, and 5E) for a total chromosome number of 2 n = 42. Line RE62 contained 14 A-chromosomes, 14 B-chromosomes, six pairs of R-chromosomes, and one pair of translocation chromosomes between chromosome 5R and 5E, for a total chromosome number of 2 n = 42. At the seedling and adult growth stages under greenhouse conditions, line RE21 showed high levels of resistance to FHB, leaf rust, and stem rust race Ug99, and line RE62 was highly resistant to leaf rust and stem rust race Ug99. These two lines (RE21 and RE62) display superior disease resistance characteristics and have the potential to be utilized as valuable germplasm sources for future wheat improvement.

The Lr34 adult plant rust resistance gene provides seedling resistance in durum wheat without senescence.

PubMed

Rinaldo, Amy; Gilbert, Brian; Boni, Rainer; Krattinger, Simon G; Singh, Davinder; Park, Robert F; Lagudah, Evans; Ayliffe, Michael

2017-07-01

The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad-spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only apparent in adult plants and not effective in field-grown seedlings. Lr34 also causes leaf tip necrosis (Ltn1) in mature adult plant leaves when grown under field conditions. This D genome-encoded bread wheat gene was transferred to tetraploid durum wheat (T. turgidum) cultivar Stewart by transformation. Transgenic durum lines were produced with elevated gene expression levels when compared with the endogenous hexaploid gene. Unlike nontransgenic hexaploid and durum control lines, these transgenic plants showed robust seedling resistance to pathogens causing wheat leaf rust, stripe rust and powdery mildew disease. The effectiveness of seedling resistance against each pathogen correlated with the level of transgene expression. No evidence of accelerated leaf necrosis or up-regulation of senescence gene markers was apparent in these seedlings, suggesting senescence is not required for Lr34 resistance, although leaf tip necrosis occurred in mature plant flag leaves. Several abiotic stress-response genes were up-regulated in these seedlings in the absence of rust infection as previously observed in adult plant flag leaves of hexaploid wheat. Increasing day length significantly increased Lr34 seedling resistance. These data demonstrate that expression of a highly durable, broad-spectrum adult plant resistance gene can be modified to provide seedling resistance in durum wheat. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Identification and molecular characterization of a trans-acting small interfering RNA producing locus regulating leaf rust responsive gene expression in wheat (Triticum aestivum L.).

PubMed

Dutta, Summi; Kumar, Dhananjay; Jha, Shailendra; Prabhu, Kumble Vinod; Kumar, Manish; Mukhopadhyay, Kunal

2017-11-01

A novel leaf rust responsive ta-siRNA-producing locus was identified in wheat showing similarity to 28S rRNA and generated four differentially expressing ta-siRNAs by phasing which targeted stress responsive genes. Trans-acting-small interfering RNAs (Ta-siRNAs) are plant specific molecules generally involved in development and are also stress responsive. Ta-siRNAs identified in wheat till date are all responsive to abiotic stress only. Wheat cultivation is severely affected by rusts and leaf rust particularly affects grain filling. This study reports a novel ta-siRNA producing locus (TAS) in wheat which is a segment of 28S ribosomal RNA but shows differential expression during leaf rust infestation. Four small RNA libraries prepared from wheat Near Isogenic Lines were treated with leaf rust pathogen and compared with untreated controls. A TAS with the ability to generate four ta-siRNAs by phasing events was identified along with the microRNA TamiR16 as the phase initiator. The targets of the ta-siRNAs included α-gliadin, leucine rich repeat, trans-membrane proteins, glutathione-S-transferase, and fatty acid desaturase among others, which are either stress responsive genes or are essential for normal growth and development of plants. Expression of the TAS, its generated ta-siRNAs, and their target genes were profiled at five different time points after pathogen inoculation of susceptible and resistant wheat isolines and compared with mock-inoculated controls. Comparative analysis of expression unveiled differential and reciprocal relationship as well as discrete patterns between susceptible and resistant isolines. The expression profiles of the target genes of the identified ta-siRNAs advocate more towards effector triggered susceptibility favouring pathogenesis. The study helps in discerning the functions of wheat genes regulated by ta-siRNAs in response to leaf rust.

Response of the Imported Willow Leaf Beetle to Bacillus thuringiensis var. san diego on Poplar Willow1

Treesearch

Leah S. Bauer

1992-01-01

The imported willow leaf beetle, Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae), a multivoltine defoliator of willow and poplar (Salicaceae), is considered a significant pest throughout eastern North America (W.T. Johnson and H.H Lyon, "Insects that Feed on Trees and Shrubs," Cornell University Press, Ithaca, 1988)....

Pathogenesis-related protein expression in the apoplast of wheat leaves protected against leaf rust following application of plant extracts.

PubMed

Naz, Rabia; Bano, Asghari; Wilson, Neil L; Guest, David; Roberts, Thomas H

2014-09-01

Leaf rust (Puccinia triticina) is a major disease of wheat. We tested aqueous leaf extracts of Jacaranda mimosifolia (Bignoniaceae), Thevetia peruviana (Apocynaceae), and Calotropis procera (Apocynaceae) for their ability to protect wheat from leaf rust. Extracts from all three species inhibited P. triticina urediniospore germination in vitro. Plants sprayed with extracts before inoculation developed significantly lower levels of disease incidence (number of plants infected) than unsprayed, inoculated controls. Sprays combining 0.6% leaf extracts and 2 mM salicylic acid with the fungicide Amistar Xtra at 0.05% (azoxystrobin at 10 μg/liter + cyproconazole at 4 μg/liter) reduced disease incidence significantly more effectively than sprays of fungicide at 0.1% alone. Extracts of J. mimosifolia were most active, either alone (1.2%) or in lower doses (0.6%) in combination with 0.05% Amistar Xtra. Leaf extracts combined with fungicide strongly stimulated defense-related gene expression and the subsequent accumulation of pathogenesis-related (PR) proteins in the apoplast of inoculated wheat leaves. The level of protection afforded was significantly correlated with the ability of extracts to increase PR protein expression. We conclude that pretreatment of wheat leaves with spray formulations containing previously untested plant leaf extracts enhances protection against leaf rust provided by fungicide sprays, offering an alternative disease management strategy.

LEAF WHORL INOCULATION METHOD FOR SCREENING SUGARCANE RUST RESISTANCE

USDA-ARS?s Scientific Manuscript database

Technical Abstract: Sugarcane rust diseases, brown rust caused by Puccinia melanocephala, and orange rust caused by P. kuehnii, are agronomically important diseases in Florida. Cultivar resistance is the best means of controlling these diseases. Natural infection has been the primary means of asses...

Specificity of a Rust Resistance Suppressor on 7DL in the Spring Wheat Cultivar Canthatch.

PubMed

Talajoor, Mina; Jin, Yue; Wan, Anmin; Chen, Xianming; Bhavani, Sridhar; Tabe, Linda; Lagudah, Evans; Huang, Li

2015-04-01

The spring wheat 'Canthatch' has been shown to suppress stem rust resistance genes in the background due to the presence of a suppressor gene located on the long arm of chromosome 7D. However, it is unclear whether the suppressor also suppresses resistance genes against leaf rust and stripe rust. In this study, we investigated the specificity of the resistance suppression. To determine whether the suppression is genome origin specific, chromosome location specific, or rust species or race specific, we introduced 11 known rust resistance genes into the Canthatch background, including resistance to leaf, stripe, or stem rusts, originating from A, B, or D genomes and located on different chromosome homologous groups. F1 plants of each cross were tested with the corresponding rust race, and the infection types were scored and compared with the parents. Our results show that the Canthatch 7DL suppressor only suppressed stem rust resistance genes derived from either the A or B genome, and the pattern of the suppression is gene specific and independent of chromosomal location.

Comparison of multi- and hyperspectral imaging data of leaf rust infected wheat plants

NASA Astrophysics Data System (ADS)

Franke, Jonas; Menz, Gunter; Oerke, Erich-Christian; Rascher, Uwe

2005-10-01

In the context of precision agriculture, several recent studies have focused on detecting crop stress caused by pathogenic fungi. For this purpose, several sensor systems have been used to develop in-field-detection systems or to test possible applications of remote sensing. The objective of this research was to evaluate the potential of different sensor systems for multitemporal monitoring of leaf rust (puccinia recondita) infected wheat crops, with the aim of early detection of infected stands. A comparison between a hyperspectral (120 spectral bands) and a multispectral (3 spectral bands) imaging system shows the benefits and limitations of each approach. Reflectance data of leaf rust infected and fungicide treated control wheat stand boxes (1sqm each) were collected before and until 17 days after inoculation. Plants were grown under controlled conditions in the greenhouse and measurements were taken under consistent illumination conditions. The results of mixture tuned matched filtering analysis showed the suitability of hyperspectral data for early discrimination of leaf rust infected wheat crops due to their higher spectral sensitivity. Five days after inoculation leaf rust infected leaves were detected, although only slight visual symptoms appeared. A clear discrimination between infected and control stands was possible. Multispectral data showed a higher sensitivity to external factors like illumination conditions, causing poor classification accuracy. Nevertheless, if these factors could get under control, even multispectral data may serve a good indicator for infection severity.

Somaclonal variation in hybrid poplars for resistance to Septoria leaf spot

Treesearch

M.E. Ostry; D. D. Skilling

1987-01-01

Tissue culture techniques have been used to obtain hybrid poplars with putative resistance to leaf spot caused by Septoria musiva from clones previously susceptible to the disease. Stem internode explants were used to obtain proliferating callus cultures. Adventitious bud formation and shoot proliferation were then induced. Elongated shoots were excised and rooted in a...

Boron accumulation and toxicity in hybrid poplar (Populus nigra × euramericana).

PubMed

Rees, Rainer; Robinson, Brett H; Menon, Manoj; Lehmann, Eberhard; Günthardt-Goerg, Madeleine S; Schulin, Rainer

2011-12-15

Poplars accumulate high B concentrations and are thus used for the phytomanagement of B contaminated soils. Here, we performed pot experiments in which Populus nigra × euramericana were grown on a substrate with B concentrations ranging from 13 to 280 mg kg(-1) as H(3)BO(3). Salix viminalis, Brassica juncea, and Lupinus albus were grown under some growing conditions for comparison. Poplar growth was unaffected at soil B treatment levels up to 93 mg kg(-1). Growth was progressively reduced at levels of 168 and 280 mg kg(-1). None of the other species survived at these substrate B levels. At leaf B concentrations <900 mg kg(-1) only <10% of the poplar leaf area showed signs of toxicity. Neutron radiography revealed that chlorotic leaf tissues had B concentrations of 1000-2000 mg kg(-1), while necrotic tissues had >2000 mg kg(-1). Average B concentrations of up to 3500 mg kg(-1) were found in leaves, while spots within leaves had concentrations >7000 mg kg(-1), showing that B accumulation in leaf tissue continued even after the onset of necrosis. The B accumulation ability of P. nigra × euramericana is associated with B hypertolerance in the living tissue and storage of B in dead leaf tissue.

Association Mapping of Leaf Rust Response in Durum Wheat

USDA-ARS?s Scientific Manuscript database

Resistance to leaf rust (Puccinia triticina Eriks.) is a main objective for durum wheat (Triticum durum Desf.) breeding.Association mapping on germplasm collections is now being used as an additional approach for the discovery and validation of major genes/QTLs. In this study, a collection of 164 el...

Lr67/Yr46 confers adult plant resistance to stem rust and powdery mildew in wheat.

PubMed

Herrera-Foessel, Sybil A; Singh, Ravi P; Lillemo, Morten; Huerta-Espino, Julio; Bhavani, Sridhar; Singh, Sukhwinder; Lan, Caixia; Calvo-Salazar, Violeta; Lagudah, Evans S

2014-04-01

We demonstrate that Lr67/Yr46 has pleiotropic effect on stem rust and powdery mildew resistance and is associated with leaf tip necrosis. Genes are designated as Sr55, Pm46 and Ltn3 , respectively. Wheat (Triticum aestivum) accession RL6077, known to carry the pleiotropic slow rusting leaf and yellow rust resistance genes Lr67/Yr46 in Thatcher background, displayed significantly lower stem rust (P. graminis tritici; Pgt) and powdery mildew (Blumeria graminis tritici; Bgt) severities in Kenya and in Norway, respectively, compared to its recurrent parent Thatcher. We investigated the resistance of RL6077 to stem rust and powdery mildew using Avocet × RL6077 F6 recombinant inbred lines (RILs) derived from two photoperiod-insensitive F3 families segregating for Lr67/Yr46. Greenhouse seedling tests were conducted with Mexican Pgt race RTR. Field evaluations were conducted under artificially initiated stem rust epidemics with Pgt races RTR and TTKST (Ug99 + Sr24) at Ciudad Obregon (Mexico) and Njoro (Kenya) during 2010-2011; and under natural powdery mildew epiphytotic in Norway at Ås and Hamar during 2011 and 2012. In Mexico, a mean reduction of 41 % on stem rust severity was obtained for RILs carrying Lr67/Yr46, compared to RILs that lacked the gene, whereas in Kenya the difference was smaller (16 %) but significant. In Norway, leaf tip necrosis was associated with Lr67/Yr46 and RILs carrying Lr67/Yr46 showed a 20 % reduction in mean powdery mildew severity at both sites across the 2 years of evaluation. Our study demonstrates that Lr67/Yr46 confers partial resistance to stem rust and powdery mildew and is associated with leaf tip necrosis. The corresponding pleiotropic, or tightly linked, genes, designated as Sr55, Pm46, and Ltn3, can be utilized to provide broad-spectrum durable disease resistance in wheat.

Comparison of yellow poplar growth models on the basis of derived growth analysis variables

Treesearch

Keith F. Jensen; Daniel A. Yaussy

1986-01-01

Quadratic and cubic polynomials, and Gompertz and Richards asymptotic models were fitted to yellow poplar growth data. These data included height, leaf area, leaf weight and new shoot height for 23 weeks. Seven growth analysis variables were estimated from each function. The Gompertz and Richards models fitted the data best and provided the most accurate derived...

The bionomics of the cottonwood leaf beetle, Chrysomela scripta Fab., on tissue culture hybrid poplars

Treesearch

T.R. Burkot; D.M. Benjamin

1977-01-01

Tissue culture methods are applied to poplars of the Aigeiros group in attempts to overcome premature decline thought to be associated with viral infections. Hybrid selections from such cultures outplanted in 1975 at the F. G. Wilson Nursery in Boscobel, Wisconsin subsequently were severely infested by the Cottonwood Leaf Beetle, Chrysomela scripta Fab. Beetle...

Genetic variability among the brown rust resistant and susceptible genotypes of sugarcane by RAPD technique

USDA-ARS?s Scientific Manuscript database

Brown leaf rust in sugarcane is caused by Puccinia melanocephala (Syd. & P. Syd.), which is major cause of cultivar withdrawal. We attempted to analyze the RAPD diversity of two discrete phenotypic classes i.e. rust resistant (R) and rust susceptible (S) of six commercially available sugarcane elite...

Wheat Rusts in the United States in 2007

USDA-ARS?s Scientific Manuscript database

In 2007 90% of wheat stem rust races were QFC and 10% were RCRS Both races are relatively avirulent to wheat cultiars grown in the U.S. Wheat stem rust occurred in scattered locations on research plots of susceptible wheat cultivars in 2007, and did not cause yield loss. Wheat leaf rust was widespr...

Mapping of Leaf Rust Resistance Genes and Molecular Characterization of the 2NS/2AS Translocation in the Wheat Cultivar Jagger.

PubMed

Xue, Shulin; Kolmer, James A; Wang, Shuwen; Yan, Liuling

2018-05-31

Winter wheat cultivar 'Jagger' was recently found to have an alien chromosomal segment 2NS that has Lr37 , a gene conferring resistance against leaf rust caused by Puccinia triticina The objective of this study was to map and characterize the gene(s) for seedling leaf rust resistance in Jagger. The recombinant inbred line (RIL) population of Jagger × '2174' was inoculated with leaf rust pathogen THBJG and BBBDB, and evaluated for infection type (IT) response. A major quantitative trait locus (QTL) for THBJG and BBBDB was coincidently mapped to chromosome arm 2AS, and the QTL accounted for 56.6-66.2% of total phenotypic variation in infection type (IT) response to THBJG, and 72.1-86.9% to BBBDB. The causal gene for resistance to these rust races was mapped to the 2NS segment in Jagger. The 2NS segment was located in a region of approximately 27.8 Mb starting from the telomere of chromosome arm 2AS, based on the sequences of the A genome in tetraploid wheat. The Lr17a gene on chromosome arm 2AS was delimited to 3.1 Mb in the genomic region, which was orthologous to the 2NS segment. Therefore, the Lr37 gene in the 2NS segment can be pyramided with other effective resistance genes, rather than Lr17a in wheat, to improve resistance to rust diseases. Copyright © 2018 Xue et al.

Genetic differentiation of the wheat leaf rust fungus Puccinia triticina in Europe

USDA-ARS?s Scientific Manuscript database

Leaf rust, caused by Puccinia triticina is a common disease of wheat in Europe. The objective of this study was to determine whether genetically differentiated groups of P. triticina are present in Europe. In total, 133 isolates of P. triticina collected from western Europe, central Europe, and Turk...

First report of leaf rust of blueberry caused by Thekopsora minima in Mexico

USDA-ARS?s Scientific Manuscript database

Blueberry (Vaccinium corymbosum L.) is becoming an important crop in the states of Jalisco and Michoacan in Mexico. As the area under blueberry cultivation increases, new diseases causing severe losses are appearing. Leaf rust is one of the most destructive diseases of blueberry in Mexico. Sori on t...

Genome-wide association mapping of leaf rust response in a durum wheat worldwide germplasm collection

USDA-ARS?s Scientific Manuscript database

Leaf rust (caused by Puccinia triticina Eriks.) is increasingly impacting durum wheat production with the recent appearance of races with virulence to widely grown cultivars in many durum producing areas worldwide. A highly virulent P. triticina race on durum wheat was recently collected in Kansas....

Efficient Agrobacterium-Mediated Transformation of Hybrid Poplar Populus davidiana Dode × Populus bollena Lauche

PubMed Central

Han, Xue; Ma, Shurong; Kong, Xianghui; Takano, Tetsuo; Liu, Shenkui

2013-01-01

Poplar is a model organism for high in vitro regeneration in woody plants. We have chosen a hybrid poplar Populus davidiana Dode × Populus bollena Lauche. By optimizing the Murashige and Skoog medium with (0.3 mg/L) 6-benzylaminopurine and (0.08 mg/L) naphthaleneacetic acid, we have achieved the highest frequency (90%) for shoot regeneration from poplar leaves. It was also important to improve the transformation efficiency of poplar for genetic breeding and other applications. In this study, we found a significant improvement of the transformation frequency by controlling the leaf age. Transformation efficiency was enhanced by optimizing the Agrobacterium concentration (OD600 = 0.8–1.0) and an infection time (20–30 min). According to transmission electron microscopy observations, there were more Agrobacterium invasions in the 30-day-old leaf explants than in 60-day-old and 90-day-old explants. Using the green fluorescent protein (GFP) marker, the expression of MD–GFP fusion proteins in the leaf, shoot, and root of hybrid poplar P. davidiana Dode × P. bollena Lauche was visualized for confirmation of transgene integration. Southern and Northern blot analysis also showed the integration of T-DNA into the genome and gene expression of transgenic plants. Our results suggest that younger leaves had higher transformation efficiency (~30%) than older leaves (10%). PMID:23354481

Heritable, De Novo Resistance to Leaf Rust and Other Novel Traits in Selfed Descendants of Wheat Responding to Inoculation with Wheat Streak Mosaic Virus

PubMed Central

Seifers, Dallas L.; Haber, Steve; Martin, Terry J.; McCallum, Brent D.

2014-01-01

Stable resistance to infection with Wheat streak mosaic virus (WSMV) can be evolved de novo in selfing bread wheat lines subjected to cycles of WSMV inoculation and selection of best-performing plants or tillers. To learn whether this phenomenon might be applied to evolve resistance de novo to pathogens unrelated to WSMV, we examined the responses to leaf rust of succeeding generations of the rust- and WSMV-susceptible cultivar ‘Lakin’ following WSMV inoculation and derived rust-resistant sublines. After three cycles of the iterative protocol five plants, in contrast to all others, expressed resistance to leaf and stripe rust. A subset of descendant sublines of one of these, ‘R1’, heritably and uniformly expressed the new trait of resistance to leaf rust. Such sublines, into which no genes from a known source of resistance had been introgressed, conferred resistance to progeny of crosses with susceptible parents. The F1 populations produced from crosses between, respectively, susceptible and resistant ‘Lakin’ sublines 4-3-3 and 4-12-3 were not all uniform in their response to seedling inoculation with race TDBG. In seedling tests against TDBG and MKPS races the F2s from F1 populations that were uniformly resistant had 3∶1 ratios of resistant to susceptible individuals but the F2s from susceptible F1 progenitors were uniformly susceptible. True-breeding lines derived from resistant individuals in F2 populations were resistant to natural stripe and leaf rust inoculum in the field, while the ‘Lakin’ progenitor was susceptible. The next generation of six of the ‘Lakin’-derived lines exhibited moderate to strong de novo resistance to stem rust races TPMK, QFCS and RKQQ in seedling tests while the ‘Lakin’ progenitor was susceptible. These apparently epigenetic effects in response to virus infection may help researchers fashion a new tool that expands the range of genetic resources already available in adapted germplasm. PMID:24497941

BIG LEAF is a regulator of organ size and adventitious root formation in poplar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yordanov, Yordan S.; Ma, Cathleen; Yordanova, Elena

Here we report the discovery through activation tagging and subsequent characterization of the BIG LEAF (BL) gene from poplar. In poplar, BL regulates leaf size via positively affecting cell proliferation. Up and downregulation of the gene led to increased and decreased leaf size, respectively, and these phenotypes corresponded to increased and decreased cell numbers. BL function encompasses the early stages of leaf development as native BL expression was specific to the shoot apical meristem and leaf primordia and was absent from the later stages of leaf development and other organs. Consistently, BL downregulation reduced leaf size at the earliest stagesmore » of leaf development. Ectopic expression in mature leaves resulted in continued growth most probably via sustained cell proliferation and thus the increased leaf size. In contrast to the positive effect on leaf growth, ectopic BL expression in stems interfered with and significantly reduced stem thickening, suggesting that BL is a highly specific activator of growth. Additionally, stem cuttings from BL overexpressing plants developed roots, whereas the wild type was difficult to root, demonstrating that BL is a positive regulator of adventitious rooting. Large transcriptomic changes in plants that overexpressed BL indicated that BL may have a broad integrative role, encompassing many genes linked to organ growth. Here, we conclude that BL plays a fundamental role in control of leaf size and thus may be a useful tool for modifying plant biomass productivity and adventitious rooting.« less

BIG LEAF is a regulator of organ size and adventitious root formation in poplar

PubMed Central

Yordanov, Yordan S.; Ma, Cathleen; Yordanova, Elena; Meilan, Richard; Strauss, Steven H.; Busov, Victor B.

2017-01-01

Here we report the discovery through activation tagging and subsequent characterization of the BIG LEAF (BL) gene from poplar. In poplar, BL regulates leaf size via positively affecting cell proliferation. Up and downregulation of the gene led to increased and decreased leaf size, respectively, and these phenotypes corresponded to increased and decreased cell numbers. BL function encompasses the early stages of leaf development as native BL expression was specific to the shoot apical meristem and leaf primordia and was absent from the later stages of leaf development and other organs. Consistently, BL downregulation reduced leaf size at the earliest stages of leaf development. Ectopic expression in mature leaves resulted in continued growth most probably via sustained cell proliferation and thus the increased leaf size. In contrast to the positive effect on leaf growth, ectopic BL expression in stems interfered with and significantly reduced stem thickening, suggesting that BL is a highly specific activator of growth. In addition, stem cuttings from BL overexpressing plants developed roots, whereas the wild type was difficult to root, demonstrating that BL is a positive regulator of adventitious rooting. Large transcriptomic changes in plants that overexpressed BL indicated that BL may have a broad integrative role, encompassing many genes linked to organ growth. We conclude that BL plays a fundamental role in control of leaf size and thus may be a useful tool for modifying plant biomass productivity and adventitious rooting. PMID:28686626

BIG LEAF is a regulator of organ size and adventitious root formation in poplar

DOE PAGES

Yordanov, Yordan S.; Ma, Cathleen; Yordanova, Elena; ...

2017-07-07

Here we report the discovery through activation tagging and subsequent characterization of the BIG LEAF (BL) gene from poplar. In poplar, BL regulates leaf size via positively affecting cell proliferation. Up and downregulation of the gene led to increased and decreased leaf size, respectively, and these phenotypes corresponded to increased and decreased cell numbers. BL function encompasses the early stages of leaf development as native BL expression was specific to the shoot apical meristem and leaf primordia and was absent from the later stages of leaf development and other organs. Consistently, BL downregulation reduced leaf size at the earliest stagesmore » of leaf development. Ectopic expression in mature leaves resulted in continued growth most probably via sustained cell proliferation and thus the increased leaf size. In contrast to the positive effect on leaf growth, ectopic BL expression in stems interfered with and significantly reduced stem thickening, suggesting that BL is a highly specific activator of growth. Additionally, stem cuttings from BL overexpressing plants developed roots, whereas the wild type was difficult to root, demonstrating that BL is a positive regulator of adventitious rooting. Large transcriptomic changes in plants that overexpressed BL indicated that BL may have a broad integrative role, encompassing many genes linked to organ growth. Here, we conclude that BL plays a fundamental role in control of leaf size and thus may be a useful tool for modifying plant biomass productivity and adventitious rooting.« less

BIG LEAF is a regulator of organ size and adventitious root formation in poplar.

PubMed

Yordanov, Yordan S; Ma, Cathleen; Yordanova, Elena; Meilan, Richard; Strauss, Steven H; Busov, Victor B

2017-01-01

Here we report the discovery through activation tagging and subsequent characterization of the BIG LEAF (BL) gene from poplar. In poplar, BL regulates leaf size via positively affecting cell proliferation. Up and downregulation of the gene led to increased and decreased leaf size, respectively, and these phenotypes corresponded to increased and decreased cell numbers. BL function encompasses the early stages of leaf development as native BL expression was specific to the shoot apical meristem and leaf primordia and was absent from the later stages of leaf development and other organs. Consistently, BL downregulation reduced leaf size at the earliest stages of leaf development. Ectopic expression in mature leaves resulted in continued growth most probably via sustained cell proliferation and thus the increased leaf size. In contrast to the positive effect on leaf growth, ectopic BL expression in stems interfered with and significantly reduced stem thickening, suggesting that BL is a highly specific activator of growth. In addition, stem cuttings from BL overexpressing plants developed roots, whereas the wild type was difficult to root, demonstrating that BL is a positive regulator of adventitious rooting. Large transcriptomic changes in plants that overexpressed BL indicated that BL may have a broad integrative role, encompassing many genes linked to organ growth. We conclude that BL plays a fundamental role in control of leaf size and thus may be a useful tool for modifying plant biomass productivity and adventitious rooting.

Potential impacts of ambient ozone on wheat rust diseases and the role of plant ozone sensitivity

USDA-ARS?s Scientific Manuscript database

The resurgence of rust diseases and the continued rise in tropospheric ozone (O3) levels have the potential to limit global wheat production. We conducted a series of experiments to understand the potential interactions between these two stress factors. Both stem rust and leaf rust were increased o...

Development and validation of a breeder-friendly KASPar marker for wheat leaf rust resistance locus Lr21

USDA-ARS?s Scientific Manuscript database

Development and utilization of genetic markers play a pivotal role in marker assisted breeding of wheat cultivars with pyramids of disease resistance genes. The objective of this study is to develop a closed tube, gel-free assay for high throughput genotyping of leaf rust resistance locus Lr21. Poly...

Genetic differentiation of the wheat leaf rust fungus Puccinia triticina in Pakistan and genetic relationship to other worldwide populations

USDA-ARS?s Scientific Manuscript database

Collections of Puccinia triticina, the wheat leaf rust pathogen, were obtained from Pakistan in 2008, 2010, 2011, 2013, and 2014. Collections were also obtained from Bhutan in 2013. Single uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ fo...

Adult plant leaf rust resistance derived from the soft red winter wheat cultivar Caldwell maps to chromosome 3BS

USDA-ARS?s Scientific Manuscript database

'Caldwell' is a U.S. soft red winter wheat that has partial, adult plant resistance to the leaf rust pathogen Puccinia triticina. A line of 'Thatcher*2/Caldwell' with adult plant resistance derived from Caldwell was crossed with 'Thatcher' to develop a population of recombinant inbred lines (RILs). ...

Cometabolic degradation of trichloroethylene by Burkholderia cepacia G4 with poplar leaf homogenate.

PubMed

Kang, Jun Won; Doty, Sharon Lafferty

2014-07-01

Trichloroethylene (TCE), a chlorinated organic solvent, is one of the most common and widespread groundwater contaminants worldwide. Among the group of TCE-degrading aerobic bacteria, Burkholderia cepacia G4 is the best-known representative. This strain requires the addition of specific substrates, including toluene, phenol, and benzene, to induce the enzymes to degrade TCE. However, the substrates are toxic and introducing them into the soil can result in secondary contamination. In this study, poplar leaf homogenate containing natural phenolic compounds was tested for the ability to induce the growth of and TCE degradation by B. cepacia G4. The results showed that the G4 strain could grow and degrade TCE well with the addition of phytochemicals. The poplar leaf homogenate also functioned as an inducer of the toluene-ortho-monooxygenase (TOM) gene in B. cepacia G4.

Genome Wide Association Study of Seedling and Adult Plant Leaf Rust Resistance in Elite Spring Wheat Breeding Lines.

PubMed

Gao, Liangliang; Turner, M Kathryn; Chao, Shiaoman; Kolmer, James; Anderson, James A

2016-01-01

Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resistance genes or QTLs in 338 spring wheat breeding lines from public and private sectors that were predominately developed in the Americas. A total of 46 QTLs were identified for field and seedling traits and approximately 20-30 confer field resistance in varying degrees. The 10 QTLs accounting for the most variation in field resistance explained 26-30% of the total variation (depending on traits: percent severity, coefficient of infection or response type). Similarly, the 10 QTLs accounting for most of the variation in seedling resistance to different races explained 24-34% of the variation, after correcting for population structure. Two potentially novel QTLs (QLr.umn-1AL, QLr.umn-4AS) were identified. Identification of novel genes or QTLs and validation of previously identified genes or QTLs for seedling and especially adult plant resistance will enhance understanding of leaf rust resistance and assist breeding for resistant wheat varieties. We also developed computer programs to automate field and seedling rust phenotype data conversions. This is the first GWAS study of leaf rust resistance in elite wheat breeding lines genotyped with high density 90K SNP arrays.

Glyphosate inhibits rust diseases in glyphosate-resistant wheat and soybean.

PubMed

Feng, Paul C C; Baley, G James; Clinton, William P; Bunkers, Greg J; Alibhai, Murtaza F; Paulitz, Timothy C; Kidwell, Kimberlee K

2005-11-29

Glyphosate is a broad-spectrum herbicide used for the control of weeds in glyphosate-resistant crops. Glyphosate inhibits 5-enolpyruvyl shikimate 3-phosphate synthase, a key enzyme in the synthesis of aromatic amino acids in plants, fungi, and bacteria. Studies with glyphosate-resistant wheat have shown that glyphosate provided both preventive and curative activities against Puccinia striiformis f. sp. tritici and Puccinia triticina, which cause stripe and leaf rusts, respectively, in wheat. Growth-chamber studies demonstrated wheat rust control at multiple plant growth stages with a glyphosate spray dose typically recommended for weed control. Rust control was absent in formulation controls without glyphosate, dependent on systemic glyphosate concentrations in leaf tissues, and not mediated through induction of four common systemic acquired resistance genes. A field test with endemic stripe rust inoculum confirmed the activities of glyphosate pre- and postinfestation. Preliminary greenhouse studies also demonstrated that application of glyphosate in glyphosate-resistant soybeans suppressed Asian soybean rust, caused by Phakopsora pachyrhizi.

Characterization and genome-wide association mapping of resistance to leaf rust, stem rust and stripe rust in a geographically diverse collection of spring wheat landraces

USDA-ARS?s Scientific Manuscript database

The challenge posed by rapidly changing wheat rust pathogens, both in virulence and in environmental adaptation, calls for the development and application of new techniques to accelerate the process of breeding for durable resistance. To expand the wheat resistance gene pool available for germplasm ...

ERTS-1 data collection systems used to predict wheat disease severities. [Riley County, Kansas

NASA Technical Reports Server (NTRS)

Kanemasu, E. T.; Schimmelpfenning, H.; Choy, E. C.; Eversmeyer, M. G.; Lenhert, D.

1974-01-01

The author has identified the following significant results. The feasibility of using the data collection system on ERTS-1 to predict wheat leaf rust severity and resulting yield loss was tested. Ground-based data collection platforms (DCP'S), placed in two commercial wheat fields in Riley County, Kansas, transmitted to the satellite such meteorological information as maximum and minimum temperature, relative humidity, and hours of free moisture. Meteorological data received from the two DCP'S from April 23 to 29 were used to estimate the disease progress curve. Values from the curve were used to predict the percentage decrease in wheat yields resulting from leaf rust. Actual decrease in yield was obtained by applying a zinc and maneb spray (5.6 kg/ha) to control leaf rust, then comparing yields of the controlled (healthy) and the noncontrolled (rusted) areas. In each field a 9% decrease in yield was predicted by the DCP-derived data; actual decreases were 12% and 9%.

Sonora exploratory study for the detection of wheat-leaf rust

NASA Technical Reports Server (NTRS)

Payne, R. W. (Principal Investigator)

1980-01-01

The applicability of LANDSAT remote sensing technology to the detection of a wheat-leaf-rust epidemic in Sonora, Mexico, during 1977 was investigated. LANDSAT data acquired during crop years 1975-76 and 1976-77 were clustered, classified, and analyzed in order to detect agricultural changes. Analysis of 1977 data indicates a significant proportion of the identified wheat is stressed (potentially rust-infected). Additional analyses show a significant increase in fallowing during the year, as well as a substantial decrease in reservoir levels in the Sonora agricultural region. Ground observations are required to substantiate these analyses. The possibility exists that heat-rust is not LANDSAT detectable and that the clusters identified as containing stressed signatures represent different varieties of wheat or perhaps nonwheat crops.

Development of monitoring method of coffee leaf rust fungus (Hemileia vastatrix) infected area using satellite remote sensing

NASA Astrophysics Data System (ADS)

Katsuhama, N.; Ikeda, K.; Imai, M.; Watanabe, K.; Marpaung, F.; Yoshii, T.; Naruse, N.; Takahashi, Y.

2016-12-01

Since 2008, coffee leaf rust fungus (Hemileia vastatrix) has expanded its infection in Latin America, and early trimming and burning infected trees have been only effective countermeasures to prevent spreading infection. Although some researchers reported a case about the monitoring of coffee leaf rust using satellite remote sensing in 1970s, the spatial resolution was unsatisfied, and therefore, further technological development has been required. The purpose of this research is to develop effective method of discovering coffee leaf rust infected areas using satellite remote sensing. Annual changes of vegetation indices, i.e. Normalized Difference Vegetation Index (NDVI) and Modified Structure Insensitive Pigment Index (MSIPI), around Cuchumatanes Mountains, Republic of Guatemala, were analyzed by Landsat 7 images. Study fields in the research were limited by the coffee farm areas based on a previous paper about on site surveys in different damage areas. As the result of the analysis, the annual change of NDVI at the coffee farm areas with damages tended to be lower than those without damages. Moreover, the decline of NDVI appear from 2008 before the damage was reported. On the other hand, the change of MSIPI had no significant difference. NDVI and MSIPI are mainly related to the amount of chlorophyll and carotenoid in the leaves respectively. This means that the infected coffee leaves turned yellow without defoliation. This situation well matches the symptom of coffee leaf rust. The research concluded that the property of infected leaves turning yellow is effective to monitoring of infection areas by satellite remote sensing.

Growth and physiological responses of isohydric and anisohydric poplars to drought

DOE PAGES

Attia, Ziv; Domec, Jean-Christophe; Oren, Ram; ...

2015-05-07

Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsamifera (BS, isohydric genotype), P. simonii (SI, previously uncharacterized stomatal behaviour), and their cross, P. balsamifera x simonii (BSxSI, anisohydric genotype) were studied to assess the physiological basis for biomass accumulation and water-use efficiency across a range of water availabilities. Under ample water, whole plant stomatal conductance (g s), transpiration (E), and growth rates were higher in anisohydric genotypes (SI and BSxSI) than in isohydric poplars (BS). Undermore » drought, all genotypes regulated the leaf to stem water potential gradient via changes in gs, synchronizing leaf hydraulic conductance (K leaf) and E: isohydric plants reduced K leaf, g s, and E, whereas anisohydric genotypes maintained high K leaf and E, which reduced both leaf and stem water potentials. Nevertheless, SI poplars reduced their plant hydraulic conductance (K plant) during water stress and, unlike, BSxSI plants, recovered rapidly from drought. Low gs of the isohydric BS under drought reduced CO 2 assimilation rates and biomass potential under moderate water stress. While anisohydric genotypes had the fastest growth under ample water and higher photosynthetic rates under increasing water stress, isohydric poplars had higher water-use efficiency. Overall, the results indicate three strategies for how closely related biomass species deal with water stress: survival-isohydric (BS), sensitive-anisohydric (BSxSI), and resilience-anisohydric (SI). Lastly, we discuss implications for woody biomass growth, water-use efficiency, and survival under variable environmental conditions.« less

Genotyping-by-sequencing to re-map QTL for type II Fusarium head blight and leaf rust resistance in a wheat-tall wheatgrass introgression recombinant inbred population

USDA-ARS?s Scientific Manuscript database

Fusarium graminaerum (Fusarium head blight; FHB) and Puccinia recondita Roberge ex Desmaz. f. sp. tritici Eriks. & E. Henn (leaf rust; LR) are two major fungal pathogens threatening the wheat crop; consequently identifying resistance genes from various sources is always of importance to wheat breede...

Using RNA-sequencing and in silico subtraction to identify resistance gene analog markers for Lr16 in wheat

USDA-ARS?s Scientific Manuscript database

Leaf rust, caused by Puccinia triticina Eriks., is one of the most widespread diseases of wheat worldwide and breeding for resistance is one of the most effective methods of control. Lr16 is a wheat leaf rust resistance gene that provides resistance at both the seedling and adult stages. Simple s...

Ecophysiological Competence of Populus alba L., Fraxinus angustifolia Vahl., and Crataegus monogyna Jacq. Used in Plantations for the Recovery of Riparian Vegetation

NASA Astrophysics Data System (ADS)

Manzanera, Jose A.; Martínez-Chacón, Maria F.

2007-12-01

In many semi-arid environments of Mediterranean ecosystems, white poplar ( Populus alba L.) is the dominant riparian tree and has been used to recover degraded areas, together with other native species, such as ash ( Fraxinus angustifolia Vahl.) and hawthorn ( Crataegus monogyna Jacq.). We addressed three main objectives: (1) to gain an improved understanding of some specific relationships between environmental parameters and leaf-level physiological factors in these riparian forest species, (2) to compare the leaf-level physiology of these riparian species to each other, and (3) to compare leaf-level responses within native riparian plots to adjacent restoration plots, in order to evaluate the competence of the plants used for the recovery of those degraded areas. We found significant differences in physiological performance between mature and young white poplars in the natural stand and among planted species. The net assimilation and transpiration rates, diameter, and height of white poplar plants were superior to those of ash and hawthorn. Ash and hawthorn showed higher water use efficiency than white poplar. White poplar also showed higher levels of stomatal conductance, behaving as a fast-growing, water-consuming species with a more active gas exchange and ecophysiological competence than the other species used for restoration purposes. In the restoration zones, the planted white poplars had higher rates of net assimilation and water use efficiency than the mature trees in the natural stand. We propose the use of white poplar for the rapid restoration of riparian vegetation in semi-arid Mediterranean environments. Ash and hawthorn can also play a role as accompanying species for the purpose of biodiversity.

A mutagenesis-derived broad-spectrum disease resistance locus in wheat

USDA-ARS?s Scientific Manuscript database

Wheat leaf rust, stem rust, stripe rust, and powdery mildew caused by the fungal pathogens Puccinia triticina, P. graminis f. sp. tritici, P. striiformis f. sp. tritici, and Blumeria graminis f. sp. tritici, respectively, are destructive diseases of wheat worldwide. The most effective and widely uti...

High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases

USDA-ARS?s Scientific Manuscript database

Rust, Anthracnose, and angular leaf spot are major diseases of common bean in the world and most particularly in the Americas and Africa, which are the largest common bean production regions of the world. The Mesoamerican black-seeded cultivar Ouro Negro is unusual in that it has resistance to all t...

Landscape context and scale differentially impact coffee leaf rust, coffee berry borer, and coffee root-knot nematodes.

PubMed

Avelino, Jacques; Romero-Gurdián, Alí; Cruz-Cuellar, Héctor F; Declerck, Fabrice A J

2012-03-01

Crop pest and disease incidences at plot scale vary as a result of landscape effects. Two main effects can be distinguished. First, landscape context provides habitats of variable quality for pests, pathogens, and beneficial and vector organisms. Second, the movements of these organisms are dependent on the connectivity status of the landscape. Most of the studies focus on indirect effects of landscape context on pest abundance through their predators and parasitoids, and only a few on direct effects on pests and pathogens. Here we studied three coffee pests and pathogens, with limited or no pressure from host-specific natural enemies, and with widely varying life histories, to test their relationships with landscape context: a fungus, Hemileia vastatrix, causal agent of coffee leaf rust; an insect, the coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae); and root-knot nematodes, Meloidogyne spp. Their incidence was assessed in 29 coffee plots from Turrialba, Costa Rica. In addition, we characterized the landscape context around these coffee plots in 12 nested circular sectors ranging from 50 to 1500 m in radius. We then performed correlation analysis between proportions of different land uses at different scales and coffee pest and disease incidences. We obtained significant positive correlations, peaking at the 150 m radius, between coffee berry borer abundance and proportion of coffee in the landscape. We also found significant positive correlations between coffee leaf rust incidence and proportion of pasture, peaking at the 200 m radius. Even after accounting for plot level predictors of coffee leaf rust and coffee berry borer through covariance analysis, the significance of landscape structure was maintained. We hypothesized that connected coffee plots favored coffee berry borer movements and improved its survival. We also hypothesized that wind turbulence, produced by low-wind-resistance land uses such as pasture, favored removal of coffee leaf rust spore clusters from host surfaces, resulting in increased epidemics. In contrast, root-knot nematode population density was not correlated to landscape context, possibly because nematodes are almost immobile in the soil. We propose fragmenting coffee plots with forest corridors to control coffee berry borer movements between coffee plots without favoring coffee leaf rust dispersal.

Postulation of rust resistance genes in Nordic spring wheat genotypes and identification of widely effective sources of resistance against the Australian rust flora.

PubMed

Randhawa, Mandeep; Bansal, Urmil; Lillemo, Morten; Miah, Hanif; Bariana, Harbans

2016-11-01

Wild relatives, landraces and cultivars from different geographical regions have been demonstrated as the sources of genetic variation for resistance to rust diseases. This study involved assessment of diversity for resistance to three rust diseases among a set of Nordic spring wheat cultivars. These cultivars were tested at the seedling stage against several pathotypes of three rust pathogens in the greenhouse. All stage stem rust resistance genes Sr7b, Sr8a, Sr12, Sr15, Sr17, Sr23 and Sr30, and leaf rust resistance genes Lr1, Lr3a, Lr13, Lr14a, Lr16 and Lr20 were postulated either singly or in different combinations among these cultivars. A high proportion of cultivars were identified to carry linked rust resistance genes Sr15 and Lr20. Although 51 cultivars showed variation against Puccinia striiformis f. sp. tritici (Pst) pathotypes used in this study, results were not clearly contrasting to enable postulation of stripe rust resistance genes in these genotypes. Stripe rust resistance gene Yr27 was postulated in four cultivars and Yr1 was present in cultivar Zebra. Cultivar Tjalve produced low stripe rust response against all Pst pathotypes indicating the presence either of a widely effective resistance gene or combination of genes with compensating pathogenic specificities. Several cultivars carried moderate to high level of APR to leaf rust and stripe rust. Seedling stem rust susceptible cultivar Aston exhibited moderately resistant to moderately susceptible response, whereas other cultivars belonging to this class were rated moderately susceptible or higher. Molecular markers linked with APR genes Yr48, Lr34/Yr18/Sr57, Lr68 and Sr2 detected the presence of these genes in some genotypes.

Recent advances in research of some pest problems of hybrid populus in Michigan and Wisconsin

Treesearch

Lincoln M. Moore; Louis F. Wilson

1983-01-01

Hybrid Populus clones were examined for impact from and resistance to attack from several insects and diseases. Cottonwood leaf beetle, poplar-and-willow borer, and Septoria canker were most injurious. The spotted poplar aphid and poplar-gall saperda, even when abundant, caused only minor impact. The tarnished plant bug, a newly identified pest of...

Fertilizer and Mulch Improves Yellow-Poplar Growth on Exposed harsells Subsoils

Treesearch

John K. Francis

1977-01-01

Fertilizing and mulching of eroded Hartsells soil increased height and diameter of yellow-poplars. To see if chemical infertility of exposed Hartsells subsoils limits yellow-poplar growth and to test fertilizer and mulch as remedial agents, seedlings were planted on undisturbed soil, soil with the topsoil removed, and soil with the topsoil removed but mulched with leaf...

Daytime and nighttime wind differentially affects hydraulic properties and thigmomorphogenic response of poplar saplings.

PubMed

Huang, Ping; Wan, Xianchong; Lieffers, Victor J

2016-05-01

This study tested how wind in daytime and nighttime affects hydraulic properties and thigmomorphogenic response of poplar saplings. It shows that wind in daytime interrupted water balance of poplar plants by aggravating cavitation in the stem xylem under high xylem tension in the daytime, reducing water potential in midday and hence reducing gas exchange, including stomatal conductance and CO2 assimilation. The wind blowing in daytime significantly reduced plant growth, including height, diameter, leaf size, leaf area, root and whole biomass, whereas wind blowing in nighttime only caused a reduction in radial and height growth at the early stage compared with the control but decreased height:diameter ratios. In summary, the interaction between wind loading and xylem tension exerted a negative impact on water balance, gas exchanges and growth of poplar plants, and wind in nighttime caused only a small thigmomorphogenic response. © 2015 Scandinavian Plant Physiology Society.

Genome Wide Association Study of Seedling and Adult Plant Leaf Rust Resistance in Elite Spring Wheat Breeding Lines

PubMed Central

Gao, Liangliang; Turner, M. Kathryn; Chao, Shiaoman; Kolmer, James; Anderson, James A.

2016-01-01

Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resistance genes or QTLs in 338 spring wheat breeding lines from public and private sectors that were predominately developed in the Americas. A total of 46 QTLs were identified for field and seedling traits and approximately 20–30 confer field resistance in varying degrees. The 10 QTLs accounting for the most variation in field resistance explained 26–30% of the total variation (depending on traits: percent severity, coefficient of infection or response type). Similarly, the 10 QTLs accounting for most of the variation in seedling resistance to different races explained 24–34% of the variation, after correcting for population structure. Two potentially novel QTLs (QLr.umn-1AL, QLr.umn-4AS) were identified. Identification of novel genes or QTLs and validation of previously identified genes or QTLs for seedling and especially adult plant resistance will enhance understanding of leaf rust resistance and assist breeding for resistant wheat varieties. We also developed computer programs to automate field and seedling rust phenotype data conversions. This is the first GWAS study of leaf rust resistance in elite wheat breeding lines genotyped with high density 90K SNP arrays. PMID:26849364

An introgression on wheat chromosome 4DL in RL6077 (Thatcher*6/PI 250413) confers adult plant resistance to stripe rust and leaf rust (Lr67).

PubMed

Hiebert, Colin W; Thomas, Julian B; McCallum, Brent D; Humphreys, D Gavin; DePauw, Ronald M; Hayden, Matthew J; Mago, Rohit; Schnippenkoetter, Wendelin; Spielmeyer, Wolfgang

2010-10-01

Adult plant resistance (APR) to leaf rust and stripe rust derived from the wheat (Triticum aestivum L.) line PI250413 was previously identified in RL6077 (=Thatcher*6/PI250413). The leaf rust resistance gene in RL6077 is phenotypically similar to Lr34 which is located on chromosome 7D. It was previously hypothesized that the gene in RL6077 could be Lr34 translocated to another chromosome. Hybrids between RL6077 and Thatcher and between RL6077 and 7DS and 7DL ditelocentric stocks were examined for first meiotic metaphase pairing. RL6077 formed chain quadrivalents and trivalents relative to Thatcher and Chinese Spring; however both 7D telocentrics paired only as heteromorphic bivalents and never with the multivalents. Thus, chromosome 7D is not involved in any translocation carried by RL6077. A genome-wide scan of SSR markers detected an introgression from chromosome 4D of PI250413 transferred to RL6077 through five cycles of backcrossing to Thatcher. Haplotype analysis of lines from crosses of Thatcher × RL6077 and RL6058 (Thatcher*6/PI58548) × RL6077 showed highly significant associations between introgressed markers (including SSR marker cfd71) and leaf rust resistance. In a separate RL6077-derived population, APR to stripe rust was also tightly linked with cfd71 on chromosome 4DL. An allele survey of linked SSR markers cfd71 and cfd23 on a set of 247 wheat lines from diverse origins indicated that these markers can be used to select for the donor segment in most wheat backgrounds. Comparison of RL6077 with Thatcher in field trials showed no effect of the APR gene on important agronomic or quality traits. Since no other known Lr genes exist on chromosome 4DL, the APR gene in RL6077 has been assigned the name Lr67.

A single-nucleotide polymorphism that accounts for allelic variation in the Lr34 gene and leaf rust reaction in hard winter wheat.

PubMed

Cao, Shuanghe; Carver, Brett F; Zhu, Xinkai; Fang, Tilin; Chen, Yihua; Hunger, Robert M; Yan, Liuling

2010-07-01

Leaf rust, caused by Puccinia triticina Eriks, is one of the most common and persistent wheat diseases in the US Great Plains. We report that the Lr34 gene was mapped in the center of a QTL for leaf rust reaction and explained 18-35% of the total phenotypic variation in disease severity of adult plants in a Jagger x 2174 population of recombinant inbred lines (RILs) field-tested for 3 years. The sequence of the complete Lr34 gene was determined for the susceptible Jagger allele and for the resistant 2174 allele. The two alleles had exactly the same sequence as the resistant allele reported previously in Chinese Spring at three polymorphic sites in intron 4, exon 11, and exon 12. A G/T polymorphism was found in exon 22, where a premature stop codon was found in the susceptible Jagger allele (Lr34E22s), confirming a previous report, due to a point mutation compared with the resistant 2174 allele (Lr34E22r). We have experimentally demonstrated a tight association between the point mutation at exon 22 of Lr34 and leaf rust susceptibility in a segregating biparental population. A PCR marker was developed to distinguish between the Lr34E22r and Lr34E22s alleles. A survey of 33 local hard winter wheat cultivars indicated that 7 cultivars carry the Lr34E22s allele and 26 cultivars carry the Lr34E22r allele. This study significantly improves our genetic understanding of allelic variation in the Lr34 gene and provides a functional molecular tool to improve leaf rust resistance in a major US wheat gene pool.

In vivo assessment of plant extracts for control of plant diseases: A sesquiterpene ketolactone isolated from Curcuma zedoaria suppresses wheat leaf rust.

PubMed

Han, Jae Woo; Shim, Sang Hee; Jang, Kyoung Soo; Choi, Yong Ho; Dang, Quang Le; Kim, Hun; Choi, Gyung Ja

2018-02-01

As an alternative to synthetic pesticides, natural materials such as plant extracts and microbes have been considered to control plant diseases. In this study, methanol extracts of 120 plants were explored for in vivo antifungal activity against Rhizoctonia solani, Botrytis cinerea, Phytophthora infestans, Puccinia triticina, and Blumeria graminis f. sp. hordei. Of the 120 plant extracts, eight plant extracts exhibited a disease control efficacy of more than 90% against at least one of five plant diseases. In particular, a methanol extract of Curcuma zedoaria rhizomes exhibited strong activity against wheat leaf rust caused by P. triticina. When the C. zedoaria methanol extracts were partitioned with various solvents, the layers of n-hexane, methylene chloride, and ethyl acetate showed disease control values of 100, 80, and 43%, respectively, against wheat leaf rust. From the C. zedoaria rhizome extracts, an antifungal substance was isolated and identified as a sesquiterpene ketolactone based on the mass and nuclear magnetic resonance spectral data. The active compound controlled the development of rice sheath blight, wheat leaf rust, and tomato late blight. Considering the in vivo antifungal activities of the sesquiterpene ketolactone and the C. zedoaria extracts, these results suggest that C. zedoaria can be used as a potent fungicide in organic agriculture.

Characterization and 2D structural model of corn straw and poplar leaf biochars.

PubMed

Zhao, Nan; Lv, YiZhong; Yang, XiXiang; Huang, Feng; Yang, JianWen

2017-12-22

The integrated experimental methods were used to analyze the physicochemical properties and structural characteristics and to build the 2D structural model of two kinds of biochars. Corn straw and poplar leaf biochars were gained by pyrolysing the raw materials slowly in a furnace at 300, 500, and 700 °C under oxygen-deficient conditions. Scanning electron microscope was applied to observe the surface morphology of the biochars. High temperatures destroyed the pore structures of the biochars, forming a particle mixture of varying sizes. The ash content, yield, pH, and surface area were also observed to describe the biochars' properties. The yield decreases as the pyrolysis temperature increases. The biochars are neutral to alkaline. The biggest surface area is 251.11 m 2 /g for 700 °C corn straw biochar. Elemental analysis, infrared microspectroscopy, solid-state C-13 NMR spectroscopy, and pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) were also used to study the structural characteristics and build the 2D structural models of biochars. The C content in the corn straw and poplar leaf biochars increases with the increase of the pyrolysis temperature. A higher pyrolysis temperature makes the aryl carbon increase, and C=O, OH, and aliphatic hydrocarbon content decrease in the IR spectra. Solid-state C-13 NMR spectra show that a higher pyrolysis temperature makes the alkyl carbon and alkoxy carbon decrease and the aryl carbon increase. The results of IR microspectra and solid-state C-13 NMR spectra reveal that some noticeable differences exist in these two kinds of biochars and in the same type of biochar but under different pyrolysis temperatures. The conceptual elemental compositions of 500 °C corn straw and poplar leaf biochars are C 61 H 33 NO 13 and C 59 H 41 N 3 O 12 , respectively. Significant differences exist in the SEM images, physicochemical properties, and structural characteristics of corn straw and poplar leaf biochars.

Concerted action of two avirulent spore effectors activates Reaction to Puccinia graminis 1 (Rpg1)-mediated cereal stem rust resistance

USDA-ARS?s Scientific Manuscript database

The barley stem rust resistance gene Reaction to Puccinia graminis 1 (Rpg1), encoding a receptor-like kinase, confers durable resistance to the stem rust pathogen Puccinia graminis f. sp. tritici. The fungal urediniospores form adhesion structures with the leaf epidermal cells within 1 h of inocula...

Gene discovery in EST sequences from the wheat leaf rust fungus puccinia triticina sexual spores, asexual spores and haustoria, compared to other rust and corn smut fungi

USDA-ARS?s Scientific Manuscript database

Background: Rust fungi are biotrophic basidiomycete plant pathogens that cause major diseases on plants and trees world-wide, affecting agriculture and forestry. Their biotrophic nature precludes many established molecular genetic manipulations and lines of research. The generation of genomic resour...

Rapid detection of Puccinia triticina causing leaf rust of wheat by PCR and loop mediated isothermal amplification

PubMed Central

Kulshreshtha, Deepika; Gupta, Sangeeta; Singh, Kartar; Bhardwaj, Subhash C.

2018-01-01

Leaf rust of wheat caused by Puccinia triticina has significant impact on wheat production worldwide. Effective and quick detection methodologies are required to mitigate yield loss and time constraints associated with monitoring and management of leaf rust of wheat. In the present study, detection of P. triticina has been simplified by developing a rapid, reliable, efficient and visual colorimetric method i.e., loop mediated isothermal amplification of DNA (LAMP). Based on in silico analysis of P. triticina genome, PTS68, a simple sequence repeat was found highly specific to leaf rust fungus. A marker (PtRA68) was developed and its specificity was validated through PCR technique which gave a unique and sharp band of 919 bp in P. triticina pathotypes only. A novel gene amplification method LAMP which enables visual detection of pathogen by naked eye was developed for leaf rust pathogen. A set of six primers was designed from specific region of P. triticina and conditions were optimised to complete the observation process in 60 minutes at 65o C. The assay developed in the study could detect presence of P. triticina on wheat at 24 hpi (pre-symptomatic stage) which was much earlier than PCR without requiring thermal cycler. Sensitivity of LAMP assay developed in the study was 100 fg which was more sensitive than conventional PCR (50 pg) and equivalent to qPCR (100 fg). The protocol developed in the study was utilized for detection of leaf rust infected samples collected from different wheat fields. LAMP based colorimetric detection assay showed sky blue color in positive reaction and violet color in negative reaction after addition of 120 μM hydroxyl napthol blue (HNB) solution to reaction mixture. Similarly, 0.6 mg Ethidium bromide/ml was added to LAMP products, placed on transilluminator to witness full brightness in positive reaction and no such brightness could be seen in negative reaction mixture. Further, LAMP products spread in a ladder like banding pattern in gel electrophoresis. Our assay is significantly faster than the conventional methods used in the identification of P. triticina. The assay developed in the study shall be very much useful in the development of diagnostic kit for monitoring disease, creation of prediction model and efficient management of disease. PMID:29698484

Rapid detection of Puccinia triticina causing leaf rust of wheat by PCR and loop mediated isothermal amplification.

PubMed

Manjunatha, C; Sharma, Sapna; Kulshreshtha, Deepika; Gupta, Sangeeta; Singh, Kartar; Bhardwaj, Subhash C; Aggarwal, Rashmi

2018-01-01

Leaf rust of wheat caused by Puccinia triticina has significant impact on wheat production worldwide. Effective and quick detection methodologies are required to mitigate yield loss and time constraints associated with monitoring and management of leaf rust of wheat. In the present study, detection of P. triticina has been simplified by developing a rapid, reliable, efficient and visual colorimetric method i.e., loop mediated isothermal amplification of DNA (LAMP). Based on in silico analysis of P. triticina genome, PTS68, a simple sequence repeat was found highly specific to leaf rust fungus. A marker (PtRA68) was developed and its specificity was validated through PCR technique which gave a unique and sharp band of 919 bp in P. triticina pathotypes only. A novel gene amplification method LAMP which enables visual detection of pathogen by naked eye was developed for leaf rust pathogen. A set of six primers was designed from specific region of P. triticina and conditions were optimised to complete the observation process in 60 minutes at 65o C. The assay developed in the study could detect presence of P. triticina on wheat at 24 hpi (pre-symptomatic stage) which was much earlier than PCR without requiring thermal cycler. Sensitivity of LAMP assay developed in the study was 100 fg which was more sensitive than conventional PCR (50 pg) and equivalent to qPCR (100 fg). The protocol developed in the study was utilized for detection of leaf rust infected samples collected from different wheat fields. LAMP based colorimetric detection assay showed sky blue color in positive reaction and violet color in negative reaction after addition of 120 μM hydroxyl napthol blue (HNB) solution to reaction mixture. Similarly, 0.6 mg Ethidium bromide/ml was added to LAMP products, placed on transilluminator to witness full brightness in positive reaction and no such brightness could be seen in negative reaction mixture. Further, LAMP products spread in a ladder like banding pattern in gel electrophoresis. Our assay is significantly faster than the conventional methods used in the identification of P. triticina. The assay developed in the study shall be very much useful in the development of diagnostic kit for monitoring disease, creation of prediction model and efficient management of disease.

New Rust Disease of Korean Willow (Salix koreensis) Caused by Melampsora yezoensis, Unrecorded Pathogen in Korea.

PubMed

Yun, Yeo Hong; Ahn, Geum Ran; Yoon, Seong Kwon; Kim, Hoo Hyun; Son, Seung Yeol; Kim, Seong Hwan

2016-12-01

During the growing season of 2015, leaf specimens with yellow rust spots were collected from Salix koreensis Andersson, known as Korean willow, in riverine areas in Cheonan, Korea. The fungus on S. koreensis was identified as the rust species, Melampsora yezoensis , based on the morphology of urediniospores observed by light and scanning electron microscopy, and the molecular properties of the internal transcribed spacer rDNA region. Pathogenicity tests confirmed that the urediniospores are the causal agent of the rust symptoms on the leaves and young stems of S. koreensis . Here, we report a new rust disease of S. koreensis caused by the rust fungus, M. yezoensis , a previously unrecorded rust pathogen in Korea.

Characterization and mapping of leaf rust resistance in four durum wheat cultivars.

PubMed

Kthiri, Dhouha; Loladze, Alexander; MacLachlan, P R; N'Diaye, Amidou; Walkowiak, Sean; Nilsen, Kirby; Dreisigacker, Susanne; Ammar, Karim; Pozniak, Curtis J

2018-01-01

Widening the genetic basis of leaf rust resistance is a primary objective of the global durum wheat breeding effort at the International Wheat and Maize Improvement Center (CIMMYT). Breeding programs in North America are following suit, especially after the emergence of new races of Puccinia triticina such as BBG/BP and BBBQD in Mexico and the United States, respectively. This study was conducted to characterize and map previously undescribed genes for leaf rust resistance in durum wheat and to develop reliable molecular markers for marker-assisted breeding. Four recombinant inbred line (RIL) mapping populations derived from the resistance sources Amria, Byblos, Geromtel_3 and Tunsyr_2, which were crossed to the susceptible line ATRED #2, were evaluated for their reaction to the Mexican race BBG/BP of P. triticina. Genetic analyses of host reactions indicated that leaf rust resistance in these genotypes was based on major seedling resistance genes. Allelism tests among resistant parents supported that Amria and Byblos carried allelic or closely linked genes. The resistance in Geromtel_3 and Tunsyr_2 also appeared to be allelic. Bulked segregant analysis using the Infinium iSelect 90K single nucleotide polymorphism (SNP) array identified two genomic regions for leaf rust resistance; one on chromosome 6BS for Geromtel_3 and Tunsyr_2 and the other on chromosome 7BL for Amria and Byblos. Polymorphic SNPs identified within these regions were converted to kompetitive allele-specific PCR (KASP) assays and used to genotype the RIL populations. KASP markers usw215 and usw218 were the closest to the resistance genes in Geromtel_3 and Tunsyr_2, while usw260 was closely linked to the resistance genes in Amria and Byblos. DNA sequences associated with these SNP markers were anchored to the wild emmer wheat (WEW) reference sequence, which identified several candidate resistance genes. The molecular markers reported herein will be useful to effectively pyramid these resistance genes with other previously marked genes into adapted, elite durum wheat genotypes.

Characterization and mapping of leaf rust resistance in four durum wheat cultivars

PubMed Central

Kthiri, Dhouha; Loladze, Alexander; MacLachlan, P. R.; N’Diaye, Amidou; Walkowiak, Sean; Nilsen, Kirby; Dreisigacker, Susanne; Ammar, Karim

2018-01-01

Widening the genetic basis of leaf rust resistance is a primary objective of the global durum wheat breeding effort at the International Wheat and Maize Improvement Center (CIMMYT). Breeding programs in North America are following suit, especially after the emergence of new races of Puccinia triticina such as BBG/BP and BBBQD in Mexico and the United States, respectively. This study was conducted to characterize and map previously undescribed genes for leaf rust resistance in durum wheat and to develop reliable molecular markers for marker-assisted breeding. Four recombinant inbred line (RIL) mapping populations derived from the resistance sources Amria, Byblos, Geromtel_3 and Tunsyr_2, which were crossed to the susceptible line ATRED #2, were evaluated for their reaction to the Mexican race BBG/BP of P. triticina. Genetic analyses of host reactions indicated that leaf rust resistance in these genotypes was based on major seedling resistance genes. Allelism tests among resistant parents supported that Amria and Byblos carried allelic or closely linked genes. The resistance in Geromtel_3 and Tunsyr_2 also appeared to be allelic. Bulked segregant analysis using the Infinium iSelect 90K single nucleotide polymorphism (SNP) array identified two genomic regions for leaf rust resistance; one on chromosome 6BS for Geromtel_3 and Tunsyr_2 and the other on chromosome 7BL for Amria and Byblos. Polymorphic SNPs identified within these regions were converted to kompetitive allele-specific PCR (KASP) assays and used to genotype the RIL populations. KASP markers usw215 and usw218 were the closest to the resistance genes in Geromtel_3 and Tunsyr_2, while usw260 was closely linked to the resistance genes in Amria and Byblos. DNA sequences associated with these SNP markers were anchored to the wild emmer wheat (WEW) reference sequence, which identified several candidate resistance genes. The molecular markers reported herein will be useful to effectively pyramid these resistance genes with other previously marked genes into adapted, elite durum wheat genotypes. PMID:29746580

Microscopic and Molecular Characterization of the Prehaustorial Resistance against Wheat Leaf Rust (Puccinia triticina) in Einkorn (Triticum monococcum)

PubMed Central

Serfling, Albrecht; Templer, Sven E.; Winter, Peter; Ordon, Frank

2016-01-01

Puccinia triticina f. sp. tritici (Eriks.), the causal agent of leaf rust, causes substantial yield losses in wheat production. In wheat many major leaf rust resistance genes have been overcome by virulent races. In contrast, the prehaustorial resistance (phr) against wheat leaf rust detected in the diploid wheat Einkorn (Triticum monoccocum var. monococcum) accession PI272560 confers race-independent resistance against isolates virulent on accessions harboring resistance genes located on the A-genome of Triticum aestivum. Phr in PI272560 leads to abortion of fungal development during the formation of haustorial mother cells and to increased hydrogen peroxide concentration in comparison to the susceptible accession 36554 (Triticum boeoticum ssp. thaoudar var. reuteri). Increased peroxidase and endochitinase activity was detected in PI272560 within 6 h after inoculation (hai). Comparative transcriptome profiling using Massive Analysis of cDNA Ends (MACE) in infected and non-infected leaves detected 14220 differentially expressed tags in PI272560 and 15472 in accession 36554. Of these 2908 and 3004, respectively, could be assigned to Gene Ontology (GO) categories of which 463 were detected in both accessions and 311 were differentially expressed between the accessions. In accordance with the concept of non-host resistance in PI272560, genes with similarity to peroxidases, chitinases, β-1,3-glucanases and other pathogenesis-related genes were up-regulated within the first 8 hai, whereas up-regulation of such genes was delayed in 36554. Moreover, a Phosphoribulokinase gene contributing to non-host resistance in rice against stripe rust was exclusively expressed in the resistant accession PI272560. Gene expression underpinned physiological and phenotypic observations at the site of infection and are in accordance with the concept of non-host resistance. PMID:27881987

Alternate Host of Jack Pine Needle rust in Northern Minnesota

Treesearch

Ralph L. Anderson; Neil A. Anderson

1978-01-01

The pine needle rust of jack pine on the Little Sioux Burn in northeastern Minnesota infected large-leaf aster but not goldenrod. The rust was most severe when asters were abundant on the plots. Les than 10 percent of the jack pine were infected over a 3-year period when asters were more than 10 feet (3.05 m) from the mil-acre plots

An Artificial Diet for Cottonwood and Imported Williow leaf Beetles (Coleoptera: Chrysomelidae) and Comparative Performance on Poplar Foliage1,2

Treesearch

Leah S. Bauer; Joann Meerschaert; Thomas O. Forrester

1989-01-01

An artificial diet was developed for labortory rearing of the cottonwood leaf beetle, Chrysomela scripta F., and the imported willow leaf beetle, Plagiodera versicolira (Laicharting). To reduce microbial contamination of the media, procedures were developed for the separating egg masses and sterilizing egg surfaces. Cottonwood leaf...

Simultaneous Transfer of Leaf Rust and Powdery Mildew Resistance Genes from Hexaploid Triticale Cultivar Sorento into Bread Wheat

PubMed Central

Li, Feng; Li, Yinghui; Cao, Lirong; Liu, Peiyuan; Geng, Miaomiao; Zhang, Qiang; Qiu, Lina; Sun, Qixin; Xie, Chaojie

2018-01-01

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, and wheat leaf rust, caused by Puccinia triticina Eriks, are two important diseases that severely threaten wheat production. Sorento, a hexaploid triticale cultivar from Poland, shows high resistance to the wheat powdery mildew isolate E09 and the leaf rust isolate PHT in Beijing, China. To introduce resistance genes into common wheat, Sorento was crossed with wheat line Xuezao, which is susceptible to both diseases, and the F1 hybrids were then backcrossed with Xuezao as the recurrent male parent. By marker analysis, we demonstrate that the long arm of the 2R (2RL) chromosome confers resistance to both the leaf rust and powdery mildew isolates at adult-plant and seedling stages, while the long arm of 4R (4RL) confers resistance only to powdery mildew at both stages. The chromosomal composition of BC2F3 plants containing 2R or 2RL and 4R or 4RL in the form of substitution and translocation were confirmed by GISH (genomic in situ hybridization) and FISH (fluorescence in situ hybridization). Monosomic and disomic substitutions of a wheat chromosome with chromosome 2R or 4R, as well as one 4RS-4DL/4DS-4RL reciprocal translocation homozigote and one 2RL-1DL translocation hemizigote, were recovered. Such germplasms are of great value in wheat improvement. PMID:29459877

Simultaneous Transfer of Leaf Rust and Powdery Mildew Resistance Genes from Hexaploid Triticale Cultivar Sorento into Bread Wheat.

PubMed

Li, Feng; Li, Yinghui; Cao, Lirong; Liu, Peiyuan; Geng, Miaomiao; Zhang, Qiang; Qiu, Lina; Sun, Qixin; Xie, Chaojie

2018-01-01

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici , and wheat leaf rust, caused by Puccinia triticina Eriks, are two important diseases that severely threaten wheat production. Sorento, a hexaploid triticale cultivar from Poland, shows high resistance to the wheat powdery mildew isolate E09 and the leaf rust isolate PHT in Beijing, China. To introduce resistance genes into common wheat, Sorento was crossed with wheat line Xuezao, which is susceptible to both diseases, and the F 1 hybrids were then backcrossed with Xuezao as the recurrent male parent. By marker analysis, we demonstrate that the long arm of the 2R (2RL) chromosome confers resistance to both the leaf rust and powdery mildew isolates at adult-plant and seedling stages, while the long arm of 4R (4RL) confers resistance only to powdery mildew at both stages. The chromosomal composition of BC 2 F 3 plants containing 2R or 2RL and 4R or 4RL in the form of substitution and translocation were confirmed by GISH (genomic in situ hybridization) and FISH (fluorescence in situ hybridization). Monosomic and disomic substitutions of a wheat chromosome with chromosome 2R or 4R, as well as one 4RS-4DL/4DS-4RL reciprocal translocation homozigote and one 2RL-1DL translocation hemizigote, were recovered. Such germplasms are of great value in wheat improvement.

Development of 11 polymorphic microsatellite markers for the blackberry rust fungus Phragmidium violaceum

USDA-ARS?s Scientific Manuscript database

Eleven polymorphic microsatellite markers were developed for the Uredinales fungus Phragmidium violaceum, which causes leaf rust on European blackberry (Rubus fruticosus L. aggregate). Allele frequency ranged between two and seventeen alleles per locus with no evidence of linkage disequilibrium amon...

QTL-seq approach identified genomic regions and diagnostic markers for rust and late leaf spot resistance in groundnut (Arachis hypogaea L.).

PubMed

Pandey, Manish K; Khan, Aamir W; Singh, Vikas K; Vishwakarma, Manish K; Shasidhar, Yaduru; Kumar, Vinay; Garg, Vanika; Bhat, Ramesh S; Chitikineni, Annapurna; Janila, Pasupuleti; Guo, Baozhu; Varshney, Rajeev K

2017-08-01

Rust and late leaf spot (LLS) are the two major foliar fungal diseases in groundnut, and their co-occurrence leads to significant yield loss in addition to the deterioration of fodder quality. To identify candidate genomic regions controlling resistance to rust and LLS, whole-genome resequencing (WGRS)-based approach referred as 'QTL-seq' was deployed. A total of 231.67 Gb raw and 192.10 Gb of clean sequence data were generated through WGRS of resistant parent and the resistant and susceptible bulks for rust and LLS. Sequence analysis of bulks for rust and LLS with reference-guided resistant parent assembly identified 3136 single-nucleotide polymorphisms (SNPs) for rust and 66 SNPs for LLS with the read depth of ≥7 in the identified genomic region on pseudomolecule A03. Detailed analysis identified 30 nonsynonymous SNPs affecting 25 candidate genes for rust resistance, while 14 intronic and three synonymous SNPs affecting nine candidate genes for LLS resistance. Subsequently, allele-specific diagnostic markers were identified for three SNPs for rust resistance and one SNP for LLS resistance. Genotyping of one RIL population (TAG 24 × GPBD 4) with these four diagnostic markers revealed higher phenotypic variation for these two diseases. These results suggest usefulness of QTL-seq approach in precise and rapid identification of candidate genomic regions and development of diagnostic markers for breeding applications. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

The escalatory Red Queen: Population extinction and replacement following arms race dynamics in poplar rust.

PubMed

Persoons, Antoine; Hayden, Katherine J; Fabre, Bénédicte; Frey, Pascal; De Mita, Stéphane; Tellier, Aurélien; Halkett, Fabien

2017-04-01

Host-parasite systems provide convincing examples of Red Queen co-evolutionary dynamics. Yet, a key process underscored in Van Valen's theory - that arms race dynamics can result in extinction - has never been documented. One reason for this may be that most sampling designs lack the breadth needed to illuminate the rapid pace of adaptation by pathogen populations. In this study, we used a 25-year temporal sampling to decipher the demographic history of a plant pathogen: the poplar rust fungus, Melampsora larici-populina. A major adaptive event occurred in 1994 with the breakdown of R7 resistance carried by several poplar cultivars widely planted in Western Europe since 1982. The corresponding virulence rapidly spread in M. larici-populina populations and nearly reached fixation in northern France, even on susceptible hosts. Using both temporal records of virulence profiles and temporal population genetic data, our analyses revealed that (i) R7 resistance breakdown resulted in the emergence of a unique and homogeneous genetic group, the so-called cultivated population, which predominated in northern France for about 20 years, (ii) selection for Vir7 individuals brought with it multiple other virulence types via hitchhiking, resulting in an overall increase in the population-wide number of virulence types and (iii) - above all - the emergence of the cultivated population superseded the initial population which predominated at the same place before R7 resistance breakdown. Our temporal analysis illustrates how antagonistic co-evolution can lead to population extinction and replacement, hence providing direct evidence for the escalation process which is at the core of Red Queen dynamics. © 2016 John Wiley & Sons Ltd.

Controlling sugarcane diseases in Florida: a challenge in constant evolution

USDA-ARS?s Scientific Manuscript database

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with brown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant c...

Controlling sugarcane diseases in Florida: a challenge in constant evolution

USDA-ARS?s Scientific Manuscript database

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with bown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant ...

Controlling sugarcane diseases in Florida: a challenge in constant evolution

USDA-ARS?s Scientific Manuscript database

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with brown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant...

Physiological, vascular and nanomechanical assessment of hybrid poplar leaf traits in micropropagated plants and plants propagated from root cuttings: A contribution to breeding programs.

PubMed

Ďurkovič, Jaroslav; Husárová, Hana; Javoříková, Lucia; Čaňová, Ingrid; Šuleková, Miriama; Kardošová, Monika; Lukáčik, Ivan; Mamoňová, Miroslava; Lagaňa, Rastislav

2017-09-01

Micropropagated plants experience significant stress from rapid water loss when they are transferred from an in vitro culture to either greenhouse or field conditions. This is caused both by inefficient stomatal control of transpiration and the change to a higher light intensity and lower humidity. Understanding the physiological, vascular and biomechanical processes that allow micropropagated plants to modify their phenotype in response to environmental conditions can help to improve both field performance and plant survival. To identify changes between the hybrid poplar [Populus tremula × (Populus × canescens)] plants propagated from in vitro tissue culture and those from root cuttings, we assessed leaf performance for any differences in leaf growth, photosynthetic and vascular traits, and also nanomechanical properties of the tracheary element cell walls. The micropropagated plants showed significantly higher values for leaf area, leaf length, leaf width and leaf dry mass. The greater leaf area and leaf size dimensions resulted from the higher transpiration rate recorded for this stock type. Also, the micropropagated plants reached higher values for chlorophyll a fluorescence parameters and for the nanomechanical dissipation energy of tracheary element cell walls which may indicate a higher damping capacity within the primary xylem tissue under abiotic stress conditions. The performance of the plants propagated from root cuttings was superior for instantaneous water-use efficiency which signifies a higher acclimation capacity to stressful conditions during a severe drought particularly for this stock type. Similarities were found among the majority of the examined leaf traits for both vegetative plant origins including leaf mass per area, stomatal conductance, net photosynthetic rate, hydraulic axial conductivity, indicators of leaf midrib vascular architecture, as well as for the majority of cell wall nanomechanical traits. This research revealed that there were no drawbacks in the leaf physiological performance which could be attributed to the micropropagated plants of fast growing hybrid poplar. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases.

PubMed

Valentini, Giseli; Gonçalves-Vidigal, Maria Celeste; Hurtado-Gonzales, Oscar P; de Lima Castro, Sandra Aparecida; Cregan, Perry B; Song, Qijian; Pastor-Corrales, Marcial A

2017-08-01

Co-segregation analysis and high-throughput genotyping using SNP, SSR, and KASP markers demonstrated genetic linkage between Ur-14 and Co-3 4 /Phg-3 loci conferring resistance to the rust, anthracnose and angular leaf spot diseases of common bean. Rust, anthracnose, and angular leaf spot are major diseases of common bean in the Americas and Africa. The cultivar Ouro Negro has the Ur-14 gene that confers broad spectrum resistance to rust and the gene cluster Co-3 4 /Phg-3 containing two tightly linked genes conferring resistance to anthracnose and angular leaf spot, respectively. We used co-segregation analysis and high-throughput genotyping of 179 F 2:3 families from the Rudá (susceptible) × Ouro Negro (resistant) cross-phenotyped separately with races of the rust and anthracnose pathogens. The results confirmed that Ur-14 and Co-3 4 /Phg-3 cluster in Ouro Negro conferred resistance to rust and anthracnose, respectively, and that Ur-14 and the Co-3 4 /Phg-3 cluster were closely linked. Genotyping the F 2:3 families, first with 5398 SNPs on the Illumina BeadChip BARCBEAN6K_3 and with 15 SSR, and eight KASP markers, specifically designed for the candidate region containing Ur-14 and Co-3 4 /Phg-3, permitted the creation of a high-resolution genetic linkage map which revealed that Ur-14 was positioned at 2.2 cM from Co-3 4 /Phg-3 on the short arm of chromosome Pv04 of the common bean genome. Five flanking SSR markers were tightly linked at 0.1 and 0.2 cM from Ur-14, and two flanking KASP markers were tightly linked at 0.1 and 0.3 cM from Co-3 4 /Phg-3. Many other SSR, SNP, and KASP markers were also linked to these genes. These markers will be useful for the development of common bean cultivars combining the important Ur-14 and Co-3 4 /Phg-3 genes conferring resistance to three of the most destructive diseases of common bean.

Cavitation vulnerability in roots and shoots: does Populus euphratica Oliv., a poplar from arid areas of Central Asia, differ from other poplar species?

PubMed

Hukin, D; Cochard, H; Dreyer, E; Le Thiec, D; Bogeat-Triboulot, M B

2005-08-01

Populus euphratica is a poplar species growing in arid regions of Central Asia, where its distribution remains nevertheless restricted to river-banks or to areas with an access to deep water tables. To test whether the hydraulic architecture of this species differs from that of other poplars with respect to this ecological distribution, the vulnerability to cavitation of P. euphratica was compared with that of P. alba and of P. trichocarpa x koreana. The occurrence of a potential hydraulic segmentation through cavitation was also investigated by assessing the vulnerability of roots, stems, and leaf mid-rib veins. Cryo-scanning electron microscopy (cryo-SEM) was used to assess the level of embolism in fine roots and leaf mid-ribs and a low pressure flowmeter (LPFM) was used for stems and main roots. The cryo-SEM technique was validated against LPFM measurements on paired samples. In P. alba and P. trichocarpa x koreana, leaf mid-ribs were more vulnerable to cavitation than stems and roots. In P. euphratica, leaf mid-ribs and stems were equally vulnerable and, contrary to what has been observed in other species, roots were significantly less vulnerable than shoots. P. euphratica was by far the most vulnerable. The water potential inducing 50% loss of conductivity in stems was close to -0.7 MPa, against approximately -1.45 MPa for the two others species. Such a large vulnerability was confirmed by recording losses of conductivity during a gradual drought. Moreover, significant stem embolism was recorded before stomatal closure, indicating the lack of an efficient safety margin for hydraulic functions in this species. Embolism was not reversed by rewatering. These observations are discussed with respect to the ecology of P. euphratica.

Nutrient composition of blades, petioles, and whole leaves from fertilized and unfertilized yellow-poplar

Treesearch

L. R. Auchmoody

1974-01-01

Nitrogen (N) and phosphorus (P) concentrations in leaf blades and petioles obtained from three fertilized and three unfertilized yellow-poplar sample trees were determined annually during a 4-year period. Concentrations were substantially higher in blades than in petioles. Fertilization increased N and P concentrations in blades, but petioles showed only a slight...

Leafing-out date not indicative of growth rate in hybrid poplars

Treesearch

Harold F. Ford; Edward I. Sucoff

1961-01-01

In breeding trees for rapid growth, testing the progeny usually requires many years. To shorten the testing period, geneticists have tried to find characteristics in juvenile trees that would indicate mature-tree performance. With hybrid poplars (Populus spp.), work at the Northeastern Forest Experiment Station has shown that the thickness of bark on...

Effects of neolignans from the stem bark of Magnolia obovata on plant pathogenic fungi.

PubMed

Choi, N H; Choi, G J; Min, B-S; Jang, K S; Choi, Y H; Kang, M S; Park, M S; Choi, J E; Bae, B K; Kim, J-C

2009-06-01

To characterize antifungal principles from the methanol extract of Magnolia obovata and to evaluate their antifungal activities against various plant pathogenic fungi. Four neolignans were isolated from stem bark of M. obovata as antifungal principles and identified as magnolol, honokiol, 4-methoxyhonokiol and obovatol. In mycelial growth inhibition assay, both magnolol and honokiol displayed more potent antifungal activity than 4-methoxyhonokiol and obovatol. Both magnolol and honokiol showed similar in vivo antifungal spectrum against seven plant diseases tested; both compounds effectively suppressed the development of rice blast, tomato late blight, wheat leaf rust and red pepper anthracnose. 4-Methoxyhonokiol and obovatol were highly active to only rice blast and wheat leaf rust respectively. The extract of M. obovata and four neolignans had potent in vivo antifungal activities against plant pathogenic fungi. Neolignans from Magnolia spp. can be used and suggested as a novel antifungal lead compound for the development of new fungicide and directly as a natural fungicide for the control of plant diseases such as rice blast and wheat leaf rust.

Field performance of Populus expressing somaclonal variation in resistance to Septoria musiva

Treesearch

M. E. Ostry; K. T. Ward

2003-01-01

Over 1500 trees from two hybrid poplar clones regenerated from tissue culture and expressing somatic variation in leaf disease resistance in a laboratory leaf disk bioassay were field-tested for 5-11 years to examine their resistance to Septoria leaf spot and canker and to assess their growth characteristics compared with the source clones....

Prediction and analysis of three gene families related to leaf rust (Puccinia triticina) resistance in wheat (Triticum aestivum L.).

PubMed

Peng, Fred Y; Yang, Rong-Cai

2017-06-20

The resistance to leaf rust (Lr) caused by Puccinia triticina in wheat (Triticum aestivum L.) has been well studied over the past decades with over 70 Lr genes being mapped on different chromosomes and numerous QTLs (quantitative trait loci) being detected or mapped using DNA markers. Such resistance is often divided into race-specific and race-nonspecific resistance. The race-nonspecific resistance can be further divided into resistance to most or all races of the same pathogen and resistance to multiple pathogens. At the molecular level, these three types of resistance may cover across the whole spectrum of pathogen specificities that are controlled by genes encoding different protein families in wheat. The objective of this study is to predict and analyze genes in three such families: NBS-LRR (nucleotide-binding sites and leucine-rich repeats or NLR), START (Steroidogenic Acute Regulatory protein [STaR] related lipid-transfer) and ABC (ATP-Binding Cassette) transporter. The focus of the analysis is on the patterns of relationships between these protein-coding genes within the gene families and QTLs detected for leaf rust resistance. We predicted 526 ABC, 1117 NLR and 144 START genes in the hexaploid wheat genome through a domain analysis of wheat proteome. Of the 1809 SNPs from leaf rust resistance QTLs in seedling and adult stages of wheat, 126 SNPs were found within coding regions of these genes or their neighborhood (5 Kb upstream from transcription start site [TSS] or downstream from transcription termination site [TTS] of the genes). Forty-three of these SNPs for adult resistance and 18 SNPs for seedling resistance reside within coding or neighboring regions of the ABC genes whereas 14 SNPs for adult resistance and 29 SNPs for seedling resistance reside within coding or neighboring regions of the NLR gene. Moreover, we found 17 nonsynonymous SNPs for adult resistance and five SNPs for seedling resistance in the ABC genes, and five nonsynonymous SNPs for adult resistance and six SNPs for seedling resistance in the NLR genes. Most of these coding SNPs were predicted to alter encoded amino acids and such information may serve as a starting point towards more thorough molecular and functional characterization of the designated Lr genes. Using the primer sequences of 99 known non-SNP markers from leaf rust resistance QTLs, we found candidate genes closely linked to these markers, including Lr34 with distances to its two gene-specific markers being 1212 bases (to cssfr1) and 2189 bases (to cssfr2). This study represents a comprehensive analysis of ABC, NLR and START genes in the hexaploid wheat genome and their physical relationships with QTLs for leaf rust resistance at seedling and adult stages. Our analysis suggests that the ABC (and START) genes are more likely to be co-located with QTLs for race-nonspecific, adult resistance whereas the NLR genes are more likely to be co-located with QTLs for race-specific resistance that would be often expressed at the seedling stage. Though our analysis was hampered by inaccurate or unknown physical positions of numerous QTLs due to the incomplete assembly of the complex hexaploid wheat genome that is currently available, the observed associations between (i) QTLs for race-specific resistance and NLR genes and (ii) QTLs for nonspecific resistance and ABC genes will help discover SNP variants for leaf rust resistance at seedling and adult stages. The genes containing nonsynonymous SNPs are promising candidates that can be investigated in future studies as potential new sources of leaf rust resistance in wheat breeding.

Impacts of transgenic poplar-cotton agro-ecosystems upon target pests and non-target insects under field conditions.

PubMed

Zhang, D J; Liu, J X; Lu, Z Y; Li, C L; Comada, E; Yang, M S

2015-07-27

Poplar-cotton agro-ecosystems are the main agricultural planting modes of cotton fields in China. With increasing acres devoted to transgenic insect-resistant poplar and transgenic insect-resistant cotton, studies examining the effects of transgenic plants on target and non-target insects become increasingly important. We systematically surveyed populations of both target pests and non-target insects for 4 different combinations of poplar-cotton eco-systems over 3 years. Transgenic Bt cotton strongly resisted the target insects Fall webworm moth [Hyphantria cunea (Drury)], Sylepta derogata Fabrieius, and American bollworm (Heliothis armigera), but no clear impact on non-target insect cotton aphids (Aphis gossypii). Importantly, intercrops containing transgenic Pb29 poplar significantly increased the inhibitory effects of Bt cotton on Fall webworm moth in ecosystem IV. Highly resistant Pb29 poplar reduced populations of the target pests Grnsonoma minutara Hubner and non-target insect poplar leaf aphid (Chaitophorus po-pulialbae), while Fall webworm moth populations were unaffected. We determined the effects of Bt toxin from transgenic poplar and cotton on target and non-target pests in different ecosystems of cotton-poplar intercrops and identified the synergistic effects of such combinations toward both target and non-target insects.

Protection of wheat against leaf and stem rust and powdery mildew diseases by inhibition of polyamine metabolism

NASA Technical Reports Server (NTRS)

Weinstein, L. H.; Osmeloski, J. F.; Wettlaufer, S. H.; Galston, A. W.

1987-01-01

In higher plants, polyamines arise from arginine by one of two pathways: via ornithine and ornithine decarboxylase or via agmatine and arginine decarboxylase but in fungi, only the ornithine decarboxylase pathway is present. Since polyamines are required for normal growth of microorganisms and plants and since the ornithine pathway can be irreversibly blocked by alpha-difluoromethylornithine (DFMO) which has no effect on arginine decarboxylase, fungal infection of green plants might be controlled by the site-directed use of such a specific metabolic inhibitor. DFMO at relatively low concentrations provided effective control of the three biotrophic fungal pathogens studied, Puccinia recondita (leaf rust), P. graminis f. sp. tritici (stem rust), and Erysiphe graminis (powdery mildew) on wheat (Triticum aestivum L.) Effective control of infection by leaf or stem rust fungi was obtained with sprays of DFMO that ranged from about 0.01 to 0.20 mM in experiments where the inhibitor was applied after spore inoculation. The powdery mildew fungus was somewhat more tolerant of DFMO, but good control of the pathogen was obtained at less than 1.0 mM. In general, application of DFMO after spore inoculation was more effective than application before inoculation. Less control was obtained following treatment with alpha-difluoromethylarginine (DFMA) but the relatively high degree of control obtained raises the possibility of a DFMA to DFMO conversion by arginase.

Diseases of intensively cultured hybrid poplars: a summary of recent research in the north central region

Treesearch

M. E. Ostry; H. S. McNabb

1983-01-01

Several potentially damaging diseases of hybrid poplars hue been identified in the north-central United States. Among the most serious are leaf and stem diseases caused by Melampsora, Marssonina, and Septoria. Short-term chemical controls are of limited usefulness. The most practical control strategy appears to be the use of resistant clones obtained through local...

QTLs for resistance to the false brome rust Puccinia brachypodii in the model grass Brachypodium distachyon L.

USDA-ARS?s Scientific Manuscript database

The wild grass Brachypodium distachyon (Brachypodium) is a new model system for temperate cereals, but its potential for studying interactions between grasses and their pathogens remains underexploited. Leaf rust caused by members of the fungal genus Puccinia is a major disease affecting temperate c...

Influence of brick air scrubber by-product on growth and development of corn and hybrid poplar.

PubMed

Thomas, Carla N; Bauerle, William L; Owino, Tom O; Chastain, John P; Klaine, Stephen J

2007-03-01

Studies were conducted to determine the effects of spent reagent from air pollution control scrubbers used at a brick manufacturing facility on emergence, growth, and physiological responses of corn and hybrid poplar plants. Scrubber by-product was obtained from General Shale Brick, Louisville, KY. Potting substrate was weighed and quantities of scrubber by-product were added to the substrate to obtain treatments of 0%, 6.25%, 12.5%, 25%, 50%, 75%, and 100% scrubber by-product (w:w) for the corn study. Each treatment mix was potted into nine replicate polyethylene pots and four corn seeds were sown per pot. The pots were randomized in a greenhouse at Clemson University and the number of seedlings emerging from each treatment, dark-adapted leaf chlorophyll a fluorescence, and shoot heights were measured at the end of a 21-day growth period. Then, dry shoot biomass was determined for plants from each treatment and plant tissues were analyzed for selected constituents. For the poplar study, nine-inch cuttings of hybrid poplar clone 15-29 (Populus trichocarpa x P. deltoides) and clone OP367 (P. deltoides x P. nigra) were planted in treatments of scrubber by-product-potting soil mixes of 0% , 5% , 10% , and 25% w:w. Leaf chlorophyll a fluorescence was measured over six weeks and cumulative leaf area, dry biomass, and nutrient content of tissues were determined upon harvest. Results of these studies indicate that percent seedling emergence for corn plants decreased with increasing scrubber by-product application rates. Application rates up to 12.5% scrubber by-product w:w had no adverse effect on corn seedling emergence. Shoot elongation, biomass production, and the status of the photosynthetic apparatus of the seedlings were also not severely impaired at applications below this level. A critical value of 58.2% w:w scrubber by-product was estimated to cause 25% inhibition of seedling emergence. Biomass production, cumulative leaf area, and chlorophyll a fluorescence of hybrid poplar plants were not affected by scrubber by-product applications of up to 5% w:w.

Poplar maintains zinc homeostasis with heavy metal genes HMA4 and PCS1

PubMed Central

Adams, Joshua P.; Adeli, Ardeshir; Hsu, Chuan-Yu; Harkess, Richard L.; Page, Grier P.; dePamphilis, Claude W.; Schultz, Emily B.; Yuceer, Cetin

2011-01-01

Perennial woody species, such as poplar (Populus spp.) must acquire necessary heavy metals like zinc (Zn) while avoiding potential toxicity. Poplar contains genes with sequence homology to genes HMA4 and PCS1 from other species which are involved in heavy metal regulation. While basic genomic conservation exists, poplar does not have a hyperaccumulating phenotype. Poplar has a common indicator phenotype in which heavy metal accumulation is proportional to environmental concentrations but excesses are prevented. Phenotype is partly affected by regulation of HMA4 and PCS1 transcriptional abundance. Wild-type poplar down-regulates several transcripts in its Zn-interacting pathway at high Zn levels. Also, overexpressed PtHMA4 and PtPCS1 genes result in varying Zn phenotypes in poplar; specifically, there is a doubling of Zn accumulation in leaf tissues in an overexpressed PtPCS1 line. The genomic complement and regulation of poplar highlighted in this study supports a role of HMA4 and PCS1 in Zn regulation dictating its phenotype. These genes can be altered in poplar to change its interaction with Zn. However, other poplar genes in the surrounding pathway may maintain the phenotype by inhibiting drastic changes in heavy metal accumulation with a single gene transformation. PMID:21504875

Genome-wide identification and characterization of NB-ARC resistant genes in wheat (Triticum aestivum L.) and their expression during leaf rust infection.

PubMed

Chandra, Saket; Kazmi, Andaleeb Z; Ahmed, Zainab; Roychowdhury, Gargi; Kumari, Veena; Kumar, Manish; Mukhopadhyay, Kunal

2017-07-01

NB-ARC domain-containing resistance genes from the wheat genome were identified, characterized and localized on chromosome arms that displayed differential yet positive response during incompatible and compatible leaf rust interactions. Wheat (Triticum aestivum L.) is an important cereal crop; however, its production is affected severely by numerous diseases including rusts. An efficient, cost-effective and ecologically viable approach to control pathogens is through host resistance. In wheat, high numbers of resistance loci are present but only few have been identified and cloned. A comprehensive analysis of the NB-ARC-containing genes in complete wheat genome was accomplished in this study. Complete NB-ARC encoding genes were mined from the Ensembl Plants database to predict 604 NB-ARC containing sequences using the HMM approach. Genome-wide analysis of orthologous clusters in the NB-ARC-containing sequences of wheat and other members of the Poaceae family revealed maximum homology with Oryza sativa indica and Brachypodium distachyon. The identification of overlap between orthologous clusters enabled the elucidation of the function and evolution of resistance proteins. The distributions of the NB-ARC domain-containing sequences were found to be balanced among the three wheat sub-genomes. Wheat chromosome arms 4AL and 7BL had the most NB-ARC domain-containing contigs. The spatio-temporal expression profiling studies exemplified the positive role of these genes in resistant and susceptible wheat plants during incompatible and compatible interaction in response to the leaf rust pathogen Puccinia triticina. Two NB-ARC domain-containing sequences were modelled in silico, cloned and sequenced to analyze their fine structures. The data obtained in this study will augment isolation, characterization and application NB-ARC resistance genes in marker-assisted selection based breeding programs for improving rust resistance in wheat.

Host-induced silencing of essential genes in Puccinia triticina through transgenic expression of RNAi sequences reduces severity of leaf rust infection in wheat.

PubMed

Panwar, Vinay; Jordan, Mark; McCallum, Brent; Bakkeren, Guus

2018-05-01

Leaf rust, caused by the pathogenic fungus Puccinia triticina (Pt), is one of the most serious biotic threats to sustainable wheat production worldwide. This obligate biotrophic pathogen is prevalent worldwide and is known for rapid adaptive evolution to overcome resistant wheat varieties. Novel disease control approaches are therefore required to minimize the yield losses caused by Pt. Having shown previously the potential of host-delivered RNA interference (HD-RNAi) in functional screening of Pt genes involved in pathogenesis, we here evaluated the use of this technology in transgenic wheat plants as a method to achieve protection against wheat leaf rust (WLR) infection. Stable expression of hairpin RNAi constructs with sequence homology to Pt MAP-kinase (PtMAPK1) or a cyclophilin (PtCYC1) encoding gene in susceptible wheat plants showed efficient silencing of the corresponding genes in the interacting fungus resulting in disease resistance throughout the T 2 generation. Inhibition of Pt proliferation in transgenic lines by in planta-induced RNAi was associated with significant reduction in target fungal transcript abundance and reduced fungal biomass accumulation in highly resistant plants. Disease protection was correlated with the presence of siRNA molecules specific to targeted fungal genes in the transgenic lines harbouring the complementary HD-RNAi construct. This work demonstrates that generating transgenic wheat plants expressing RNAi-inducing transgenes to silence essential genes in rust fungi can provide effective disease resistance, thus opening an alternative way for developing rust-resistant crops. © 2017 Her Majesty the Queen in Right of Canada. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Genomic and pedigree-based prediction for leaf, stem, and stripe rust resistance in wheat.

PubMed

Juliana, Philomin; Singh, Ravi P; Singh, Pawan K; Crossa, Jose; Huerta-Espino, Julio; Lan, Caixia; Bhavani, Sridhar; Rutkoski, Jessica E; Poland, Jesse A; Bergstrom, Gary C; Sorrells, Mark E

2017-07-01

Genomic prediction for seedling and adult plant resistance to wheat rusts was compared to prediction using few markers as fixed effects in a least-squares approach and pedigree-based prediction. The unceasing plant-pathogen arms race and ephemeral nature of some rust resistance genes have been challenging for wheat (Triticum aestivum L.) breeding programs and farmers. Hence, it is important to devise strategies for effective evaluation and exploitation of quantitative rust resistance. One promising approach that could accelerate gain from selection for rust resistance is 'genomic selection' which utilizes dense genome-wide markers to estimate the breeding values (BVs) for quantitative traits. Our objective was to compare three genomic prediction models including genomic best linear unbiased prediction (GBLUP), GBLUP A that was GBLUP with selected loci as fixed effects and reproducing kernel Hilbert spaces-markers (RKHS-M) with least-squares (LS) approach, RKHS-pedigree (RKHS-P), and RKHS markers and pedigree (RKHS-MP) to determine the BVs for seedling and/or adult plant resistance (APR) to leaf rust (LR), stem rust (SR), and stripe rust (YR). The 333 lines in the 45th IBWSN and the 313 lines in the 46th IBWSN were genotyped using genotyping-by-sequencing and phenotyped in replicated trials. The mean prediction accuracies ranged from 0.31-0.74 for LR seedling, 0.12-0.56 for LR APR, 0.31-0.65 for SR APR, 0.70-0.78 for YR seedling, and 0.34-0.71 for YR APR. For most datasets, the RKHS-MP model gave the highest accuracies, while LS gave the lowest. GBLUP, GBLUP A, RKHS-M, and RKHS-P models gave similar accuracies. Using genome-wide marker-based models resulted in an average of 42% increase in accuracy over LS. We conclude that GS is a promising approach for improvement of quantitative rust resistance and can be implemented in the breeding pipeline.

Biochemical and Physiological Studies on the Effects of Senescence Leaves of Populus deltoides on Triticum vulgare

PubMed Central

Khaket, Tejinder Pal; Kumar, Viney; Singh, Jasbir; Dhanda, Suman

2014-01-01

Triticum vulgare (Wheat) based products are the major dietary source of food in developing countries. In India, it grows in association with boundary plantations of Populus deltoids (poplar). During winter, poplar enters in dormancy which cause a heavy leaf fall at the time of wheat seed germination. Large number of poplar senescence leaves may adversely affect the wheat. Therefore, the present study was performed to examine the effect of senescence poplar leaves on wheat germ and some other biochemical parameters. Seed's germination rate was determined by measuring root and shoot lengths, percent germination, germination index, and inhibition percentage. Biochemical parameters, namely, pigment, carbohydrate, protein, and phenol content, were estimated. Activities of catalase and polyphenol oxidase which are stress marker enzymes were also measured. Results revealed that germination and other biochemical parameters of wheat were severely affected by senescence poplar leaves even at very low concentration. So, intercropping of poplar along with wheat may be chosen carefully as wheat is the major dietary staple. PMID:25610892

Interacting elevated CO2 and tropospheric O3 predisposes aspen (Populus tremuloides Michx.) to infection by rust (Melampsora medusa f. sp. tremuloidae).

Treesearch

D.F. Karnosky; Kevin E. Percy; Bixia Xiang; Brenda Callan; Asko Noormets; Blanka Mankovska; Anthony Hopkin; Jaak Sober; Wendy Jones; R.E. Dickson; J.G. Isebrands

2002-01-01

We investigated the interaction of elevated CO2 and/or (Ozone) O3 on the occurrence and severity of aspen leaf rust (Malampsora medusae Thuem. f. sp. tremuloidae) on trembling aspen (Populus tremuloides MIchx.) Furthermore, we examined the role of changes in...

Wheat differential gene expression induced by different races of Puccinia triticina.

PubMed

Neugebauer, Kerri A; Bruce, Myron; Todd, Tim; Trick, Harold N; Fellers, John P

2018-01-01

Puccinia triticina, the causal agent of wheat leaf rust, causes significant losses in wheat yield and quality each year worldwide. During leaf rust infection, the host plant recognizes numerous molecules, some of which trigger host defenses. Although P. triticina reproduces clonally, there is still variation within the population due to a high mutation frequency, host specificity, and environmental adaptation. This study explores how wheat responds on a gene expression level to different P. triticina races. Six P. triticina races were inoculated onto a susceptible wheat variety and samples were taken at six days post inoculation, just prior to pustule eruption. RNA sequence data identified 63 wheat genes differentially expressed between the six races. A time course, conducted over the first seven days post inoculation, was used to examine the expression pattern of 63 genes during infection. Forty-seven wheat genes were verified to have differential expression. Three common expression patterns were identified. In addition, two genes were associated with race specific gene expression. Differential expression of an ER molecular chaperone gene was associated with races from two different P. triticina lineages. Also, differential expression in an alanine glyoxylate aminotransferase gene was associated with races with virulence shifts for leaf rust resistance genes.

Identification of Quantitative Trait Loci Conditioning the Main Biomass Yield Components and Resistance to Melampsora spp. in Salix viminalis × Salix schwerinii Hybrids

PubMed Central

Sulima, Paweł; Przyborowski, Jerzy A.; Kuszewska, Anna; Załuski, Dariusz; Jędryczka, Małgorzata; Irzykowski, Witold

2017-01-01

The biomass of Salix viminalis is the most highly valued source of green energy, followed by S. schwerinii, S. dasyclados and other species. Significant variability in productivity and leaf rust resistance are noted both within and among willow species, which creates new opportunities for improving willow yield parameters through selection of desirable recombinants supported with molecular markers. The aim of this study was to identify quantitative trait loci (QTLs) linked with biomass yield-related traits and the resistance/susceptibility of Salix mapping population to leaf rust. The experimental material comprised a mapping population developed based on S. viminalis × S. schwerinii hybrids. Phenotyping was performed on plants grown in a field experiment that had a balanced incomplete block design with 10 replications. Based on a genetic map, 11 QTLs were identified for plant height, 9 for shoot diameter, 3 for number of shoots and 11 for resistance/susceptibility to leaf rust. The QTLs identified in our study explained 3%–16% of variability in the analyzed traits. Our findings make significant contributions to the development of willow breeding programs and research into shrubby willow crops grown for energy. PMID:28327519

Inhibition of forage seed germination by leaf litter extracts of overstory hardwoods used in silvopastoral systems

USDA-ARS?s Scientific Manuscript database

Silvopastoral management strategies seek to expand spatial and temporal boundaries of forage production and promote ecosystem integrity through a combination of tree thinning and understory pastures. We determined the effects of water extracts of leaf litter from yellow poplar, Liriodendron tulipife...

Characterization and Mapping of Leaf Rust and Stripe Rust Resistance Loci in Hexaploid Wheat Lines UC1110 and PI610750 under Mexican Environments.

PubMed

Lan, Caixia; Hale, Iago L; Herrera-Foessel, Sybil A; Basnet, Bhoja R; Randhawa, Mandeep S; Huerta-Espino, Julio; Dubcovsky, Jorge; Singh, Ravi P

2017-01-01

Growing resistant wheat varieties is a key method of minimizing the extent of yield losses caused by the globally important wheat leaf rust (LR) and stripe rust (YR) diseases. In this study, a population of 186 F 8 recombinant inbred lines (RILs) derived from a cross between a synthetic wheat derivative (PI610750) and an adapted common wheat line (cv. "UC1110") were phenotyped for LR and YR response at both seedling and adult plant stages over multiple seasons. Using a genetic linkage map consisting of single sequence repeats and diversity arrays technology markers, in combination with inclusive composite interval mapping analysis, we detected a new LR adult plant resistance (APR) locus, QLr.cim-2DS , contributed by UC1110. One co-located resistance locus to both rusts, QLr.cim-3DC/QYr.cim-3DC , and the known seedling resistance gene Lr26 were also mapped. QLr.cim-2DS and QLr.cim-3DC showed a marginally significant interaction for LR resistance in the adult plant stage. In addition, two previously reported YR APR loci, QYr.ucw-3BS and Yr48 , were found to exhibit stable performances in rust environments in both Mexico and the United States and showed a highly significant interaction in the field. Yr48 was also observed to confer intermediate seedling resistance against Mexican YR races, thus suggesting it should be re-classified as an all-stage resistance gene. We also identified 5 and 2 RILs that possessed all detected YR and LR resistance loci, respectively. With the closely linked molecular markers reported here, these RILs could be used as donors for multiple resistance loci to both rusts in wheat breeding programs.

Genetic variation for leaf morphology, leaf structure and leaf carbon isotope discrimination in European populations of black poplar (Populus nigra L.).

PubMed

Guet, Justine; Fabbrini, Francesco; Fichot, Régis; Sabatti, Maurizio; Bastien, Catherine; Brignolas, Franck

2015-08-01

To buffer against the high spatial and temporal heterogeneity of the riparian habitat, riparian tree species, such as black poplar (Populus nigra L.), may display a high level of genetic variation and phenotypic plasticity for functional traits. Using a multisite common garden experiment, we estimated the relative contribution of genetic and environmental effects on the phenotypic variation expressed for individual leaf area, leaf shape, leaf structure and leaf carbon isotope discrimination (Δ(13)C) in natural populations of black poplar. Twenty-four to 62 genotypes were sampled in nine metapopulations covering a latitudinal range from 48 °N to 42 °N in France and in Italy and grown in two common gardens at Orléans (ORL) and at Savigliano (SAV). In the two common gardens, substantial genetic variation was expressed for leaf traits within all metapopulations, but its expression was modulated by the environment, as attested by the genotype × environment (G × E) interaction variance being comparable to or even greater than genetic effects. For LA, G × E interactions were explained by both changes in genotype ranking between common gardens and increased variation in SAV, while these interactions were mainly attributed to changes in genotype ranking for Δ(13)C. The nine P. nigra metapopulations were highly differentiated for LA, as attested by the high coefficient of genetic differentiation (QST = 0.50 at ORL and 0.51 at SAV), and the pattern of metapopulation differentiation was highly conserved between the two common gardens. In contrast, they were moderately differentiated for Δ(13)C (QST = 0.24 at ORL and 0.25 at SAV) and the metapopulation clustering changed significantly between common gardens. Our results evidenced that the nine P. nigra metapopulations present substantial genetic variation and phenotypic plasticity for leaf traits, which both represent potentially significant determinants of populations' capacities to respond, on a short-term basis and over generations, to environmental variations. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Occurrence and severity of foliar ozone symptoms on sensitive hardwood species in Shenandoah National Park, VA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hildebrand, E.; Skelly, J.M.

1993-02-01

To assess the extent of foliar symptoms due to ozone on sensitive hardwoods in the Shenandoah National Park in Virginia, three species were sampled and evaluated at sites of differing elevations adjacent to 3 ozone monitors in 1991 and 1992: black cherry, yellow poplar, and white ash. All foliar samples were evaluated to precent of symptomatic leaves on each branch and average precent leaf area affected. The Horsfall-Barratt rating scale was used to estimate the precent leaf area symptomatic. Ozone symptoms were manifested as stipple on the adazial leaf surface. In the preliminary 1991 sampling, 40, 87, and 7% ofmore » black cherry trees sampled were found to be symptomatic at the 3 sites; 63 and 67% of yellow poplar trees sampled were found to be symptomatic at sites 1 and 3, as were 43 and 63% of the white ash at sites 1 and 2 (3 complete sets were not found in 1991). In 1992, the sampling and rating of injury were repeated. Symptoms of ozone injury appeared on 23, 88, and 10% of black cherry, on 17, 7, and 80% of yellow poplar, and 27, 40, and 40% of white ash. Elevation and ozone exposure will be discussed.« less

Creating 13C- and 15N-enriched tree leaf litter for decomposition experiments

NASA Astrophysics Data System (ADS)

Szlavecz, K. A.; Pitz, S.; Chang, C.; Bernard, M.

2013-12-01

Labeling plant material with heavy isotopes of carbon and nitrogen can produce a traceable nutrient signal that can be followed into the different trophic levels and decomposer food web. We treated 60 tree saplings with 13C-enriched CO2 gas and 15N-enriched ammonium nitrate over a three-month period to create dually-labeled plant material for future decomposition experiments. The trees included both early (Red maple, Sweetgum, Tulip poplar) and late (American beech, White oak) successional deciduous tree species, and a conifer, White pine. We constructed a 2.4 m × 2.4 m × 2.4 m environmental chamber that was climate-controlled using an air conditioning system. An Arduino microcontroller interfaced with a Vaisala GMP343 CO2 probe maintained a CO2 concentration between 500-520 ppm by controlling a solenoid valve on the CO2 tank regulator. The trees were placed into the chamber in August 2012 and remained until senescence unless they were lost to death or disease. Ammonium nitrate was added twice, in September and October. Leaf samples were collected prior to the start of the experiment and after senescence, whereas root samples were collected only in December. Samples were dried, ground and analyzed using an isotope ratio mass spectrometer. American beech and White oak had 40% mortality, and 34% of tulip poplar trees were removed because of powdery mildew overgrowth or death. Most tulip poplar trees exhibited a second leaf out following senescence in late September. Nearly 1 kg of litter was produced with tulip poplar representing over half of the total mass. Levels of enrichment varied greatly by species. Beech (-14.2‰) and White oak (-4.8‰) had low levels of enrichment in comparison to early successional species such as Sweetgum (41.7‰) and Tulip poplar (30.7‰ [first leaf fall] and 238.0‰ [second leaf fall]). Leaf enrichment with 15N followed a similar pattern, though it was achieved at a higher level with δ15N values varying from 271.6‰ to 1354.2‰ at the end of the experiment. Enrichment of roots was significantly higher than leaves (δ13C range: 111.5-219.2‰; δ15N range: 1516.9-3939.3‰) indicating that nutrients were translocated away from leaves prior to senescence, which is supported by the increase in C:N ratio between the initial (19.0) and final (60.1) leaf sampling. Despite the variable levels of enrichment, leaves from all species were sufficiently labeled for use in future studies aimed at tracking the transformation of carbon and nitrogen during decomposition. The greatest challenges were treating diseases and pests and creating ideal growing conditions for many species within the same chamber. Reducing the number of individuals and better pest management will lead to even higher level enrichment in the future.

Transcriptome-wide analysis of WRKY transcription factors in wheat and their leaf rust responsive expression profiling.

PubMed

Satapathy, Lopamudra; Singh, Dharmendra; Ranjan, Prashant; Kumar, Dhananjay; Kumar, Manish; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal

2014-12-01

WRKY, a plant-specific transcription factor family, has important roles in pathogen defense, abiotic cues and phytohormone signaling, yet little is known about their roles and molecular mechanism of function in response to rust diseases in wheat. We identified 100 TaWRKY sequences using wheat Expressed Sequence Tag database of which 22 WRKY sequences were novel. Identified proteins were characterized based on their zinc finger motifs and phylogenetic analysis clustered them into six clades consisting of class IIc and class III WRKY proteins. Functional annotation revealed major functions in metabolic and cellular processes in control plants; whereas response to stimuli, signaling and defense in pathogen inoculated plants, their major molecular function being binding to DNA. Tag-based expression analysis of the identified genes revealed differential expression between mock and Puccinia triticina inoculated wheat near isogenic lines. Gene expression was also performed with six rust-related microarray experiments at Gene Expression Omnibus database. TaWRKY10, 15, 17 and 56 were common in both tag-based and microarray-based differential expression analysis and could be representing rust specific WRKY genes. The obtained results will bestow insight into the functional characterization of WRKY transcription factors responsive to leaf rust pathogenesis that can be used as candidate genes in molecular breeding programs to improve biotic stress tolerance in wheat.

Distribution and frequency of a gene for resistance to white pine blister rust in natural populations of sugar pine

Treesearch

Bohun B. Kinloch Jr.

1992-01-01

The gametic frequency of a dominant allcle (R) for resistance to white pine blister rust, a disease caused by an introduced pathogen (Cronartium ribicola), in natural populations of sugar pine was estimated by the kind of leaf symptom expressed after artificial inoculation of wind-pollinated seedlings from susceptible seed-parent...

Poplar Interactome: Project Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaiswal, Pankaj

The feedstock plant Poplar has many advantages over traditional crop plants. Not only Poplar needs low energy input and off season storage as compared to feedstocks such as corn, in the winter season Poplar biomass is stored on the stem/trunk, and Poplar plantations serve as large carbon sink. A key constraint to the expansion of cellulosic bioenergy sources such as in Poplar however, is the negative consequence of converting land use from food crops to energy crops. Therefore in order for Poplar to become a viable energy crop it needs to be grown mostly on marginal land unsuitable agricultural crops.more » For this we need a better understanding of abiotic stress and adaptation response in poplar. In the process we expected to find new and existing poplar genes and their function that respond to sustain abiotic stress. We carried out an extensive gene expression study on the control untreated and stress (drought, salinity, cold and heat) treated poplar plants. The samples were collected from the stem, leaf and root tissues. The RNA of protein coding genes and regulatory smallRNA genes were sequenced generating more than a billion reads. This is the first such known study in Poplar plants. These were used for quantification and genomic analysis to identify stress responsive genes in poplar. Based on the quantification and genomic analysis, a select set of genes were studied for gene-gene interactions to find their association to stress response. The data was also used to find novel stress responsive genes in poplar that were previously not identified in the Poplar reference genome. The data is made available to the public through the national and international genomic data archives.« less

Cytological and molecular analysis of nonhost resistance in rice to wheat powdery mildew and leaf rust pathogens.

PubMed

Cheng, Yulin; Yao, Juanni; Zhang, Hongchang; Huang, Lili; Kang, Zhensheng

2015-07-01

Cereal powdery mildews caused by Blumeria graminis and cereal rusts caused by Puccinia spp. are constant disease threats that limit the production of almost all important cereal crops. Rice is an intensively grown agricultural cereal that is atypical because of its immunity to all powdery mildew and rust fungi. We analyzed the nonhost interactions between rice and the wheat powdery mildew fungus B. graminis f. sp. tritici (Bgt) and the wheat leaf rust fungus Puccinia triticina (Ptr) to identify the basis of nonhost resistance (NHR) in rice against cereal powdery mildew and rust fungi at cytological and molecular levels. No visible symptoms were observed on rice leaves inoculated with Bgt or Ptr. Microscopic observations showed that both pathogens exhibited aberrant differentiation and significantly reduced penetration frequencies on rice compared to wheat. The development of Bgt and Ptr was also completely arrested at early infection stages in cases of successful penetration into rice leaves. Attempted infection of rice by Bgt and Ptr induced similar defense responses, including callose deposition, accumulation of reactive oxygen species, and hypersensitive response in rice epidermal and mesophyll cells, respectively. Furthermore, a set of defense-related genes were upregulated in rice against Bgt and Ptr infection. Rice is an excellent monocot model for genetic and molecular studies. Therefore, our results demonstrate that rice is a useful model to study the mechanisms of NHR to cereal powdery mildew and rust fungi, which provides useful information for the development of novel and durable strategies to control these important pathogens.

TaLHY, a 1R-MYB Transcription Factor, Plays an Important Role in Disease Resistance against Stripe Rust Fungus and Ear Heading in Wheat

PubMed Central

Zhang, Zijin; Chen, Jieming; Su, Yongying; Liu, Hanmei; Chen, Yanger; Luo, Peigao; Du, Xiaogang; Wang, Dan; Zhang, Huaiyu

2015-01-01

LHY (late elongated hypocotyl) is an important gene that regulates and controls biological rhythms in plants. Additionally, LHY is highly expressed in the SSH (suppression subtractive hybridization) cDNA library-induced stripe rust pathogen (CYR32) in our previous research. To identify the function of the LHY gene in disease resistance against stripe rust, we used RACE-PCR technology to clone TaLHY in the wheat variety Chuannong19. The cDNA of TaLHY is 3085 bp long with an open reading frame of 1947 bp. TaLHY is speculated to encode a 70.3 kDa protein of 648 amino acids , which has one typical plant MYB-DNA binding domain; additionally, phylogenetic tree shows that TaLHY has the highest homology with LHY of Brachypodium distachyon(BdLHY-like). Quantitative fluorescence PCR indicates that TaLHY has higher expression in the leaf, ear and stem of wheat but lower expression in the root. Infestation of CYR32 can result in up-regulated expression of TaLHY, peaking at 72 h. Using VIGS (virus-induced gene silencing) technology to disease-resistant wheat in the fourth leaf stage, plants with silenced TaLHY cannot complete their heading stage. Through the compatible interaction with the stripe rust physiological race CYR32, Chuannong 19 loses its immune capability toward the stripe rust pathogen, indicating that TaLHY may regulate and participate in the heading of wheat, as well as the defense responses against stripe rust infection. PMID:26010918

Effects of acidic precipitation on leaf decomposition rates, microbial biomass, and leaf pack macroinvertebrates in six streams on the Allegheny plateau of West Virginia

Treesearch

Erik S. Engstrom; Sean K. Meegan; Sue A. Perry; William B. Perry

1996-01-01

We studied the effects of acidification on leaf litter decomposition in six headwater streams in the Monongahela National Forest. These streams differed in underlying geology and mean baseflow pH (3.99, 4.24, 6.13, 6.47, 6.59, and 7.52). We placed 10-gram leaf packs of white oak, red maple, and yellow poplar in each stream, and retrieved them after two days, two weeks...

Leaf, woody, and root biomass of Populus irrigated with landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; D.R. Coyle; R.B. Hall

2007-01-01

Poplar (Populus spp.) trees can be utilized for ecological leachate disposal when applied as an irrigation source for managed tree systems. Our objective was to evaluate differences in tree height, diameter, volume, and biomass of leaf, stem, branch, and root tissues of Populus trees after two seasons of irrigation with municipal...

Exploiting Natural Variation to Uncover an Alkene Biosynthetic Enzyme in Poplar

DOE PAGES

Gonzales-Vigil, Eliana; Hefer, Charles A.; von Loessl, Michelle E.; ...

2017-07-20

Alkenes are linear hydrocarbons with one or more double bonds. Despite their potential as biofuels and precursors for specialty chemicals, the underlying biochemistry and genetics of alkene biosynthesis in plants remain elusive. Here, we report on a screen of natural accessions of poplar (Populus trichocarpa), revealing that the leaf cuticular waxes are predominantly composed of alkanes and alkenes. Interestingly, the accumulation of alkenes increases with leaf development, is limited to the abaxial side of the leaf, and is impaired in a few accessions. Among other genes, a b-ketoacyl CoA synthase gene (PotriKCS1) was downregulated in leaves from non-alkene-producing accessions. Wemore » demonstrated biochemically that PotriKCS1 elongates monounsaturated fatty acids and is responsible for the recruitment of unsaturated substrates to the cuticular wax. Moreover, we found significant associations between the presence of alkenes and tree growth and resistance to leaf spot. These findings highlight the crucial role of cuticular waxes as the first point of contact with the environment, and they provide a foundation for engineering long-chain monounsaturated oils in other species.« less

Exploiting Natural Variation to Uncover an Alkene Biosynthetic Enzyme in Poplar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzales-Vigil, Eliana; Hefer, Charles A.; von Loessl, Michelle E.

Alkenes are linear hydrocarbons with one or more double bonds. Despite their potential as biofuels and precursors for specialty chemicals, the underlying biochemistry and genetics of alkene biosynthesis in plants remain elusive. Here, we report on a screen of natural accessions of poplar (Populus trichocarpa), revealing that the leaf cuticular waxes are predominantly composed of alkanes and alkenes. Interestingly, the accumulation of alkenes increases with leaf development, is limited to the abaxial side of the leaf, and is impaired in a few accessions. Among other genes, a b-ketoacyl CoA synthase gene (PotriKCS1) was downregulated in leaves from non-alkene-producing accessions. Wemore » demonstrated biochemically that PotriKCS1 elongates monounsaturated fatty acids and is responsible for the recruitment of unsaturated substrates to the cuticular wax. Moreover, we found significant associations between the presence of alkenes and tree growth and resistance to leaf spot. These findings highlight the crucial role of cuticular waxes as the first point of contact with the environment, and they provide a foundation for engineering long-chain monounsaturated oils in other species.« less

N-fertilization has different effects on the growth, carbon and nitrogen physiology, and wood properties of slow- and fast-growing Populus species

PubMed Central

Luo, Zhi-Bin

2012-01-01

To investigate how N-fertilization affects the growth, carbon and nitrogen (N) physiology, and wood properties of poplars with contrasting growth characteristics, slow-growing (Populus popularis, Pp) and fast-growing (P. alba×P. glandulosa, Pg) poplar saplings were exposed to different N levels. Above-ground biomass, leaf area, photosynthetic rates (A), instantaneous photosynthetic nitrogen use efficiency (PNUE i), chlorophyll and foliar sugar concentrations were higher in Pg than in Pp. Foliar nitrate reductase (NR) activities and root glutamate synthase (GOGAT) activities were higher in Pg than in Pp as were the N amount and NUE of new shoots. Lignin contents and calorific values of Pg wood were less than that of Pp wood. N-fertilization reduced root biomass of Pg more than of Pp, but increased leaf biomass, leaf area, A, and PNUEi of Pg more than of Pp. Among 13 genes involved in the transport of ammonium or nitrate or in N assimilation, transcripts showed more pronounced changes to N-fertilization in Pg than in Pp. Increases in NR activities and N contents due to N-fertilization were larger in Pg than in Pp. In both species, N-fertilization resulted in lower calorific values as well as shorter and wider vessel elements/fibres. These results suggest that growth, carbon and N physiology, and wood properties are more sensitive to increasing N availability in fast-growing poplars than in slow-growing ones, which is probably due to prioritized resource allocation to the leaves and accelerated N physiological processes in fast-growing poplars under higher N levels. PMID:23028021

N-fertilization has different effects on the growth, carbon and nitrogen physiology, and wood properties of slow- and fast-growing Populus species.

PubMed

Li, Hong; Li, Mengchun; Luo, Jie; Cao, Xu; Qu, Long; Gai, Ying; Jiang, Xiangning; Liu, Tongxian; Bai, Hua; Janz, Dennis; Polle, Andrea; Peng, Changhui; Luo, Zhi-Bin

2012-10-01

To investigate how N-fertilization affects the growth, carbon and nitrogen (N) physiology, and wood properties of poplars with contrasting growth characteristics, slow-growing (Populus popularis, Pp) and fast-growing (P. alba×P. glandulosa, Pg) poplar saplings were exposed to different N levels. Above-ground biomass, leaf area, photosynthetic rates (A), instantaneous photosynthetic nitrogen use efficiency (PNUE (i)), chlorophyll and foliar sugar concentrations were higher in Pg than in Pp. Foliar nitrate reductase (NR) activities and root glutamate synthase (GOGAT) activities were higher in Pg than in Pp as were the N amount and NUE of new shoots. Lignin contents and calorific values of Pg wood were less than that of Pp wood. N-fertilization reduced root biomass of Pg more than of Pp, but increased leaf biomass, leaf area, A, and PNUE(i) of Pg more than of Pp. Among 13 genes involved in the transport of ammonium or nitrate or in N assimilation, transcripts showed more pronounced changes to N-fertilization in Pg than in Pp. Increases in NR activities and N contents due to N-fertilization were larger in Pg than in Pp. In both species, N-fertilization resulted in lower calorific values as well as shorter and wider vessel elements/fibres. These results suggest that growth, carbon and N physiology, and wood properties are more sensitive to increasing N availability in fast-growing poplars than in slow-growing ones, which is probably due to prioritized resource allocation to the leaves and accelerated N physiological processes in fast-growing poplars under higher N levels.

Detection of soybean rust contamination in soy leaves by FTIR photoacoustic spectroscopy

NASA Astrophysics Data System (ADS)

Andrade, L. H. C.; Freitas, P. G.; Mantovani, B. G.; Figueiredo, M. S.; Lima, R. A.; Lima, S. M.; Rangel, M. A. S.; Mussury, R. M.

2008-01-01

In this work the Photoacoustic Infrared Spectroscopy from 4000 to 400 cm-1 was applied, by the first time to our knowledge, to diagnostic the soy bean rust or Asian rust contamination on soy leafs caused by the fungi Phakopsora pachyrhizi. The obtained results shown that a premature, fast and precise diagnosis can be achieved using this technique before it can be detect by the conventional visual method. The early identification of the fungi infection avoid massive lost in the soy production and decrease the intense use of fungicide whose is necessary when the infection is in advanced stagy.

Interaction of drought and ozone exposure on isoprene emission from extensively cultivated poplar.

PubMed

Yuan, Xiangyang; Calatayud, Vicent; Gao, Feng; Fares, Silvano; Paoletti, Elena; Tian, Yuan; Feng, Zhaozhong

2016-10-01

The combined effects of ozone (O3 ) and drought on isoprene emission were studied for the first time. Young hybrid poplars (clone 546, Populus deltoides cv. 55/56 x P. deltoides cv. Imperial) were exposed to O3 (charcoal-filtered air, CF, and non-filtered air +40 ppb, E-O3 ) and soil water stress (well-watered, WW, and mild drought, MD, one-third irrigation) for 96 days. Consistent with light-saturated photosynthesis (Asat ), intercellular CO2 concentration (Ci ) and chlorophyll content, isoprene emission depended on drought, O3 , leaf position and sampling time. Drought stimulated emission (+38.4%), and O3 decreased it (-40.4%). Ozone increased the carbon cost per unit of isoprene emission. Ozone and drought effects were stronger in middle leaves (13th-15th from the apex) than in upper leaves (6th-8th). Only Asat showed a significant interaction between O3 and drought. When the responses were up-scaled to the entire-plant level, however, drought effects on total leaf area translated into around twice higher emission from WW plants in clean air than in E-O3 . Our results suggest that direct effects on plant emission rates and changes in total leaf area may affect isoprene emission from intensively cultivated hybrid poplar under combined MD and O3 exposure, with important feedbacks for air quality. © 2016 John Wiley & Sons Ltd.

Variation in Septoria musiva and Implications for Disease Resistance Screening

Treesearch

K.T. Ward; M.E. Ostry

2005-01-01

A set of isolates of Septoria musiva differed in aggressiveness in hybrid poplar leaf disk and stem assays and culture growth in vitro. Clone x isolate interactions were observed in one of the stem assay experiments, but not in the leaf disk assay experiments. Random amplified polymorphic DNA (RAPD) analyses were performed using 52 isolates of

An eQTL Analysis of Partial Resistance to Puccinia hordei in Barley

PubMed Central

Chen, Xinwei; Hackett, Christine A.; Niks, Rients E.; Hedley, Peter E.; Booth, Clare; Druka, Arnis; Marcel, Thierry C.; Vels, Anton; Bayer, Micha; Milne, Iain; Morris, Jenny; Ramsay, Luke; Marshall, David; Cardle, Linda; Waugh, Robbie

2010-01-01

Background Genetic resistance to barley leaf rust caused by Puccinia hordei involves both R genes and quantitative trait loci. The R genes provide higher but less durable resistance than the quantitative trait loci. Consequently, exploring quantitative or partial resistance has become a favorable alternative for controlling disease. Four quantitative trait loci for partial resistance to leaf rust have been identified in the doubled haploid Steptoe (St)/Morex (Mx) mapping population. Further investigations are required to study the molecular mechanisms underpinning partial resistance and ultimately identify the causal genes. Methodology/Principal Findings We explored partial resistance to barley leaf rust using a genetical genomics approach. We recorded RNA transcript abundance corresponding to each probe on a 15K Agilent custom barley microarray in seedlings from St and Mx and 144 doubled haploid lines of the St/Mx population. A total of 1154 and 1037 genes were, respectively, identified as being P. hordei-responsive among the St and Mx and differentially expressed between P. hordei-infected St and Mx. Normalized ratios from 72 distant-pair hybridisations were used to map the genetic determinants of variation in transcript abundance by expression quantitative trait locus (eQTL) mapping generating 15685 eQTL from 9557 genes. Correlation analysis identified 128 genes that were correlated with resistance, of which 89 had eQTL co-locating with the phenotypic quantitative trait loci (pQTL). Transcript abundance in the parents and conservation of synteny with rice allowed us to prioritise six genes as candidates for Rphq11, the pQTL of largest effect, and highlight one, a phospholipid hydroperoxide glutathione peroxidase (HvPHGPx) for detailed analysis. Conclusions/Significance The eQTL approach yielded information that led to the identification of strong candidate genes underlying pQTL for resistance to leaf rust in barley and on the general pathogen response pathway. The dataset will facilitate a systems appraisal of this host-pathogen interaction and, potentially, for other traits measured in this population. PMID:20066049

Lr41, Lr39, and a leaf rust resistance gene from Aegilops cylindrica may be allelic and are located on wheat chromosome 2DS.

PubMed

Singh, Sukhwinder; Franks, C D; Huang, L; Brown-Guedira, G L; Marshall, D S; Gill, B S; Fritz, A

2004-02-01

The leaf rust resistance gene Lr41 in wheat germplasm KS90WGRC10 and a resistance gene in wheat breeding line WX93D246-R-1 were transferred to Triticum aestivum from Aegilops tauschii and Ae. cylindrica, respectively. The leaf rust resistance gene in WX93D246-R-1 was located on wheat chromosome 2D by monosomic analysis. Molecular marker analysis of F(2) plants from non-critical crosses determined that this gene is 11.2 cM distal to marker Xgwm210 on the short arm of 2D. No susceptible plants were detected in a population of 300 F(2) plants from a cross between WX93D246-R-1 and TA 4186 ( Lr39), suggesting that the gene in WX93D246-R-1 is the same as, or closely linked to, Lr39. In addition, no susceptible plants were detected in a population of 180 F(2) plants from the cross between KS90WGRC10 and WX93D246-R-1. The resistance gene in KS90WGRC10, Lr41, was previously reported to be located on wheat chromosome 1D. In this study, no genetic association was found between Lr41 and 51 markers located on chromosome 1D. A population of 110 F(3 )lines from a cross between KS90WGRC10 and TAM 107 was evaluated with polymorphic SSR markers from chromosome 2D and marker Xgdm35 was found to be 1.9 cM proximal to Lr41. When evaluated with diverse isolates of Puccinia triticina, similar reactions were observed on WX93D246-R-1, KS90WGRC10, and TA 4186. The results of mapping, allelism, and race specificity test indicate that these germplasms likely have the same gene for resistance to leaf rust.

Changes in photosynthesis, mesophyll conductance to CO2, and isoprenoid emissions in Populus nigra plants exposed to excess nickel.

PubMed

Velikova, Violeta; Tsonev, Tsonko; Loreto, Francesco; Centritto, Mauro

2011-05-01

Poplar (Populus nigra) plants were grown hydroponically with 30 and 200 μM Ni (Ni30 and Ni200). Photosynthesis limitations and isoprenoid emissions were investigated in two leaf types (mature and developing). Ni stress significantly decreased photosynthesis, and this effect depended on the leaf Ni content, which was lower in mature than in developing leaves. The main limitations to photosynthesis were attributed to mesophyll conductance and metabolism impairment. In Ni-stressed developing leaves, isoprene emission was significantly stimulated. We attribute such stimulation to the lower chloroplastic [CO2] than in control leaves. However chloroplastic [CO2] did not control isoprene emission in mature leaves. Ni stress induced the emission of cis-β-ocimene in mature leaves, and of linalool in both leaf types. Induced biosynthesis and emission of isoprenoids reveal the onset of antioxidant processes that may also contribute to reduce Ni stress, especially in mature poplar leaves. Copyright © 2010 Elsevier Ltd. All rights reserved.

Detection and validation of genomic regions associated with resistance to rust diseases in a worldwide hexaploid wheat landrace collection using BayesR and mixed linear model approaches.

PubMed

Pasam, Raj K; Bansal, Urmil; Daetwyler, Hans D; Forrest, Kerrie L; Wong, Debbie; Petkowski, Joanna; Willey, Nicholas; Randhawa, Mandeep; Chhetri, Mumta; Miah, Hanif; Tibbits, Josquin; Bariana, Harbans; Hayden, Matthew J

2017-04-01

BayesR and MLM association mapping approaches in common wheat landraces were used to identify genomic regions conferring resistance to Yr, Lr, and Sr diseases. Deployment of rust resistant cultivars is the most economically effective and environmentally friendly strategy to control rust diseases in wheat. However, the highly evolving nature of wheat rust pathogens demands continued identification, characterization, and transfer of new resistance alleles into new varieties to achieve durable rust control. In this study, we undertook genome-wide association studies (GWAS) using a mixed linear model (MLM) and the Bayesian multilocus method (BayesR) to identify QTL contributing to leaf rust (Lr), stem rust (Sr), and stripe rust (Yr) resistance. Our study included 676 pre-Green Revolution common wheat landrace accessions collected in the 1920-1930s by A.E. Watkins. We show that both methods produce similar results, although BayesR had reduced background signals, enabling clearer definition of QTL positions. For the three rust diseases, we found 5 (Lr), 14 (Yr), and 11 (Sr) SNPs significant in both methods above stringent false-discovery rate thresholds. Validation of marker-trait associations with known rust QTL from the literature and additional genotypic and phenotypic characterisation of biparental populations showed that the landraces harbour both previously mapped and potentially new genes for resistance to rust diseases. Our results demonstrate that pre-Green Revolution landraces provide a rich source of genes to increase genetic diversity for rust resistance to facilitate the development of wheat varieties with more durable rust resistance.

Transgenic Hybrid Poplar for Sustainable and Scalable Production of the Commodity/Specialty Chemical, 2-Phenylethanol

PubMed Central

Costa, Michael A.; Marques, Joaquim V.; Dalisay, Doralyn S.; Herman, Barrington; Bedgar, Diana L.; Davin, Laurence B.; Lewis, Norman G.

2013-01-01

Fast growing hybrid poplar offers the means for sustainable production of specialty and commodity chemicals, in addition to rapid biomass production for lignocellulosic deconstruction. Herein we describe transformation of fast-growing transgenic hybrid poplar lines to produce 2-phenylethanol, this being an important fragrance, flavor, aroma, and commodity chemical. It is also readily converted into styrene or ethyl benzene, the latter being an important commodity aviation fuel component. Introducing this biochemical pathway into hybrid poplars marks the beginnings of developing a platform for a sustainable chemical delivery system to afford this and other valuable specialty/commodity chemicals at the scale and cost needed. These modified plant lines mainly sequester 2-phenylethanol via carbohydrate and other covalently linked derivatives, thereby providing an additional advantage of effective storage until needed. The future potential of this technology is discussed. MALDI metabolite tissue imaging also established localization of these metabolites in the leaf vasculature. PMID:24386157

Genome-wide Identification of TCP Family Transcription Factors from Populus euphratica and Their Involvement in Leaf Shape Regulation

PubMed Central

Ma, Xiaodong; Ma, Jianchao; Fan, Di; Li, Chaofeng; Jiang, Yuanzhong; Luo, Keming

2016-01-01

Higher plants have been shown to experience a juvenile vegetative phase, an adult vegetative phase, and a reproductive phase during its postembryonic development and distinct lateral organ morphologies have been observed at the different development stages. Populus euphratica, commonly known as a desert poplar, has developed heteromorphic leaves during its development. The TCP family genes encode a group of plant-specific transcription factors involved in several aspects of plant development. In particular, TCPs have been shown to influence leaf size and shape in many herbaceous plants. However, whether these functions are conserved in woody plants remains unknown. In the present study, we carried out genome-wide identification of TCP genes in P. euphratica and P. trichocarpa, and 33 and 36 genes encoding putative TCP proteins were found, respectively. Phylogenetic analysis of the poplar TCPs together with Arabidopsis TCPs indicated a biased expansion of the TCP gene family via segmental duplications. In addition, our results have also shown a correlation between different expression patterns of several P. euphratica TCP genes and leaf shape variations, indicating their involvement in the regulation of leaf shape development. PMID:27605130

Inoculation of hybrid poplar with the endophytic bacterium Enterobacter sp. 638 increases biomass but does not impact leaf level physiology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, A.; McDonald, K.; Muehlbauer, M. F.

Endophytic bacteria have been shown to provide several advantages to their host, including enhanced growth. Inoculating biofuel species with endophytic bacteria is therefore an attractive option to increase the productivity of biofuel feedstocks. Here, we investigated the effect of inoculating hard wood cuttings of Populus deltoides Bartr. x Populus. nigra L. clone OP367 with Enterobacter sp. 638. After 17 weeks, plants inoculated with Enterobacter sp. 638 had 55% greater total biomass than un-inoculated control plants. Study of gas exchange and fluorescence in developing and mature leaves over a diurnal cycle and over a 5 week measurement campaign revealed no effectsmore » of inoculation on photosynthesis, stomatal conductance, photosynthetic water use efficiency or the maximum and operating efficiency of photosystem II. However, plants inoculated with Enterobacter sp. 638 had a canopy that was 39% larger than control plants indicating that the enhanced growth was fueled by increased leaf area, not by improved physiology. Leaf nitrogen content was determined at two stages over the 5 week measurement period. No effect of Enterobacter sp. 638 on leaf nitrogen content was found indicating that the larger plants were acquiring sufficient nitrogen. Enterobacter sp. 638 lacks the genes for N{sub 2} fixation, therefore the increased availability of nitrogen likely resulted from enhanced nitrogen acquisition by the 84% larger root system. These data show that Enterobacter sp. 638 has the potential to dramatically increase productivity in poplar. If fully realized in the production environment, these results indicate that an increase in the environmental and economic viability of poplar as a biofuel feedstock is possible when inoculated with endophytic bacteria like Enterobacter sp. 638.« less

Evaluation of 19,460 Wheat Accessions Conserved in the Indian National Genebank to Identify New Sources of Resistance to Rust and Spot Blotch Diseases.

PubMed

Kumar, Sundeep; Archak, Sunil; Tyagi, R K; Kumar, Jagdish; Vk, Vikas; Jacob, Sherry R; Srinivasan, Kalyani; Radhamani, J; Parimalan, R; Sivaswamy, M; Tyagi, Sandhya; Yadav, Mamata; Kumari, Jyotisna; Deepali; Sharma, Sandeep; Bhagat, Indoo; Meeta, Madhu; Bains, N S; Chowdhury, A K; Saha, B C; Bhattacharya, P M; Kumari, Jyoti; Singh, M C; Gangwar, O P; Prasad, P; Bharadwaj, S C; Gogoi, Robin; Sharma, J B; Gm, Sandeep Kumar; Saharan, M S; Bag, Manas; Roy, Anirban; Prasad, T V; Sharma, R K; Dutta, M; Sharma, Indu; Bansal, K C

2016-01-01

A comprehensive germplasm evaluation study of wheat accessions conserved in the Indian National Genebank was conducted to identify sources of rust and spot blotch resistance. Genebank accessions comprising three species of wheat-Triticum aestivum, T. durum and T. dicoccum were screened sequentially at multiple disease hotspots, during the 2011-14 crop seasons, carrying only resistant accessions to the next step of evaluation. Wheat accessions which were found to be resistant in the field were then assayed for seedling resistance and profiled using molecular markers. In the primary evaluation, 19,460 accessions were screened at Wellington (Tamil Nadu), a hotspot for wheat rusts. We identified 4925 accessions to be resistant and these were further evaluated at Gurdaspur (Punjab), a hotspot for stripe rust and at Cooch Behar (West Bengal), a hotspot for spot blotch. The second round evaluation identified 498 accessions potentially resistant to multiple rusts and 868 accessions potentially resistant to spot blotch. Evaluation of rust resistant accessions for seedling resistance against seven virulent pathotypes of three rusts under artificial epiphytotic conditions identified 137 accessions potentially resistant to multiple rusts. Molecular analysis to identify different combinations of genetic loci imparting resistance to leaf rust, stem rust, stripe rust and spot blotch using linked molecular markers, identified 45 wheat accessions containing known resistance genes against all three rusts as well as a QTL for spot blotch resistance. The resistant germplasm accessions, particularly against stripe rust, identified in this study can be excellent potential candidates to be employed for breeding resistance into the background of high yielding wheat cultivars through conventional or molecular breeding approaches, and are expected to contribute toward food security at national and global levels.

Evaluation of 19,460 Wheat Accessions Conserved in the Indian National Genebank to Identify New Sources of Resistance to Rust and Spot Blotch Diseases

PubMed Central

Jacob, Sherry R.; Srinivasan, Kalyani; Radhamani, J.; Parimalan, R.; Sivaswamy, M.; Tyagi, Sandhya; Yadav, Mamata; Kumari, Jyotisna; Deepali; Sharma, Sandeep; Bhagat, Indoo; Meeta, Madhu; Bains, N. S.; Chowdhury, A. K.; Saha, B. C.; Bhattacharya, P. M.; Kumari, Jyoti; Singh, M. C.; Gangwar, O. P.; Prasad, P.; Bharadwaj, S. C.; Gogoi, Robin; Sharma, J. B.; GM, Sandeep Kumar; Saharan, M. S.; Bag, Manas; Roy, Anirban; Prasad, T. V.; Sharma, R. K.; Dutta, M.; Sharma, Indu; Bansal, K. C.

2016-01-01

A comprehensive germplasm evaluation study of wheat accessions conserved in the Indian National Genebank was conducted to identify sources of rust and spot blotch resistance. Genebank accessions comprising three species of wheat–Triticum aestivum, T. durum and T. dicoccum were screened sequentially at multiple disease hotspots, during the 2011–14 crop seasons, carrying only resistant accessions to the next step of evaluation. Wheat accessions which were found to be resistant in the field were then assayed for seedling resistance and profiled using molecular markers. In the primary evaluation, 19,460 accessions were screened at Wellington (Tamil Nadu), a hotspot for wheat rusts. We identified 4925 accessions to be resistant and these were further evaluated at Gurdaspur (Punjab), a hotspot for stripe rust and at Cooch Behar (West Bengal), a hotspot for spot blotch. The second round evaluation identified 498 accessions potentially resistant to multiple rusts and 868 accessions potentially resistant to spot blotch. Evaluation of rust resistant accessions for seedling resistance against seven virulent pathotypes of three rusts under artificial epiphytotic conditions identified 137 accessions potentially resistant to multiple rusts. Molecular analysis to identify different combinations of genetic loci imparting resistance to leaf rust, stem rust, stripe rust and spot blotch using linked molecular markers, identified 45 wheat accessions containing known resistance genes against all three rusts as well as a QTL for spot blotch resistance. The resistant germplasm accessions, particularly against stripe rust, identified in this study can be excellent potential candidates to be employed for breeding resistance into the background of high yielding wheat cultivars through conventional or molecular breeding approaches, and are expected to contribute toward food security at national and global levels. PMID:27942031

De Novo Assembled Wheat Transcriptomes Delineate Differentially Expressed Host Genes in Response to Leaf Rust Infection.

PubMed

Chandra, Saket; Singh, Dharmendra; Pathak, Jyoti; Kumari, Supriya; Kumar, Manish; Poddar, Raju; Balyan, Harindra Singh; Gupta, Puspendra Kumar; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal

2016-01-01

Pathogens like Puccinia triticina, the causal organism for leaf rust, extensively damages wheat production. The interaction at molecular level between wheat and the pathogen is complex and less explored. The pathogen induced response was characterized using mock- or pathogen inoculated near-isogenic wheat lines (with or without seedling leaf rust resistance gene Lr28). Four Serial Analysis of Gene Expression libraries were prepared from mock- and pathogen inoculated plants and were subjected to Sequencing by Oligonucleotide Ligation and Detection, which generated a total of 165,767,777 reads, each 35 bases long. The reads were processed and multiple k-mers were attempted for de novo transcript assembly; 22 k-mers showed the best results. Altogether 21,345 contigs were generated and functionally characterized by gene ontology annotation, mining for transcription factors and resistance genes. Expression analysis among the four libraries showed extensive alterations in the transcriptome in response to pathogen infection, reflecting reorganizations in major biological processes and metabolic pathways. Role of auxin in determining pathogenesis in susceptible and resistant lines were imperative. The qPCR expression study of four LRR-RLK (Leucine-rich repeat receptor-like protein kinases) genes showed higher expression at 24 hrs after inoculation with pathogen. In summary, the conceptual model of induced resistance in wheat contributes insights on defense responses and imparts knowledge of Puccinia triticina-induced defense transcripts in wheat plants.

De Novo Assembled Wheat Transcriptomes Delineate Differentially Expressed Host Genes in Response to Leaf Rust Infection

PubMed Central

Pathak, Jyoti; Kumari, Supriya; Kumar, Manish; Poddar, Raju; Balyan, Harindra Singh; Gupta, Puspendra Kumar; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal

2016-01-01

Pathogens like Puccinia triticina, the causal organism for leaf rust, extensively damages wheat production. The interaction at molecular level between wheat and the pathogen is complex and less explored. The pathogen induced response was characterized using mock- or pathogen inoculated near-isogenic wheat lines (with or without seedling leaf rust resistance gene Lr28). Four Serial Analysis of Gene Expression libraries were prepared from mock- and pathogen inoculated plants and were subjected to Sequencing by Oligonucleotide Ligation and Detection, which generated a total of 165,767,777 reads, each 35 bases long. The reads were processed and multiple k-mers were attempted for de novo transcript assembly; 22 k-mers showed the best results. Altogether 21,345 contigs were generated and functionally characterized by gene ontology annotation, mining for transcription factors and resistance genes. Expression analysis among the four libraries showed extensive alterations in the transcriptome in response to pathogen infection, reflecting reorganizations in major biological processes and metabolic pathways. Role of auxin in determining pathogenesis in susceptible and resistant lines were imperative. The qPCR expression study of four LRR-RLK (Leucine-rich repeat receptor-like protein kinases) genes showed higher expression at 24 hrs after inoculation with pathogen. In summary, the conceptual model of induced resistance in wheat contributes insights on defense responses and imparts knowledge of Puccinia triticina-induced defense transcripts in wheat plants. PMID:26840746

Characterization of expressed resistance gene analogs (RGAs) from peanut expressed sequence tags (ESTs)

USDA-ARS?s Scientific Manuscript database

Cultivated peanut (Arachis hypogaea L.) is one of the most important food legume crops grown worldwide, and is a major source for edible oil and protein. However, due to low genetic variation, peanut is very vulnerable to a variety of pathogens, such as early leaf spot, late leaf spot, rust and Toma...

Genetically divergent types of the wheat leaf fungus Puccinia triticina in Ethiopia, a center of tetraploid wheat diversity

USDA-ARS?s Scientific Manuscript database

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. ...

Structure, inheritance, and expression of hybrid poplar (Populus trichocarpa x Populus deltoides) phenylalanine ammonia-lyase genes.

PubMed Central

Subramaniam, R; Reinold, S; Molitor, E K; Douglas, C J

1993-01-01

A heterologous probe encoding phenylalanine ammonia-lyase (PAL) was used to identify PAL clones in cDNA libraries made with RNA from young leaf tissue of two Populus deltoides x P. trichocarpa F1 hybrid clones. Sequence analysis of a 2.4-kb cDNA confirmed its identity as a full-length PAl clone. The predicted amino acid sequence is conserved in comparison with that of PAL genes from several other plants. Southern blot analysis of popular genomic DNA from parental and hybrid individuals, restriction site polymorphism in PAL cDNA clones, and sequence heterogeneity in the 3' ends of several cDNA clones suggested that PAL is encoded by at least two genes that can be distinguished by HindIII restriction site polymorphisms. Clones containing each type of PAL gene were isolated from a poplar genomic library. Analysis of the segregation of PAL-specific HindIII restriction fragment-length polymorphisms demonstrated the existence of two independently segregating PAL loci, one of which was mapped to a linkage group of the poplar genetic map. Developmentally regulated PAL expression in poplar was analyzed using RNA blots. Highest expression was observed in young stems, apical buds, and young leaves. Expression was lower in older stems and undetectable in mature leaves. Cellular localization of PAL expression by in situ hybridization showed very high levels of expression in subepidermal cells of leaves early during leaf development. In stems and petioles, expression was associated with subepidermal cells and vascular tissues. PMID:8108506

Phakopsora euvitis Causes Unusual Damage to Leaves and Modifies Carbohydrate Metabolism in Grapevine

PubMed Central

Nogueira Júnior, Antonio F.; Ribeiro, Rafael V.; Appezzato-da-Glória, Beatriz; Soares, Marli K. M.; Rasera, Júlia B.; Amorim, Lilian

2017-01-01

Asian grapevine rust (Phakopsora euvitis) is a serious disease, which causes severe leaf necrosis and early plant defoliation. These symptoms are unusual for a strict biotrophic pathogen. This work was performed to quantify the effects of P. euvitis on photosynthesis, carbohydrates, and biomass accumulation of grapevine. The reduction in photosynthetic efficiency of the green leaf tissue surrounding the lesions was quantified using the virtual lesion concept (β parameter). Gas exchange and responses of CO2 assimilation to increasing intercellular CO2 concentration were analyzed. Histopathological analyses and quantification of starch were also performed on diseased leaves. Biomass and carbohydrate accumulation were quantified in different organs of diseased and healthy plants. Rust reduced the photosynthetic rate, and β was estimated at 5.78, indicating a large virtual lesion. Mesophyll conductance, maximum rubisco carboxylation rate, and regeneration of ribulose-1,5-bisphosphate dependent on electron transport rate were reduced, causing diffusive and biochemical limitations to photosynthesis. Hypertrophy, chloroplast degeneration of mesophyll cells, and starch accumulation in cells close to lesions were observed. Root carbohydrate concentration was reduced, even at low rust severity. Asian grapevine rust dramatically reduced photosynthesis and altered the dynamics of production and accumulation of carbohydrates, unlike strict biotrophic pathogens. The reduction in carbohydrate reserves in roots would support polyetic damage on grapevine, caused by a polycyclic disease. PMID:29018470

In situ hybridization for the detection of rust fungi in paraffin embedded plant tissue sections.

PubMed

Ellison, Mitchell A; McMahon, Michael B; Bonde, Morris R; Palmer, Cristi L; Luster, Douglas G

2016-01-01

Rust fungi are obligate pathogens with multiple life stages often including different spore types and multiple plant hosts. While individual rust pathogens are often associated with specific plants, a wide range of plant species are infected with rust fungi. To study the interactions between these important pathogenic fungi and their host plants, one must be able to differentiate fungal tissue from plant tissue. This can be accomplished using the In situ hybridization (ISH) protocol described here. To validate reproducibility using the ISH protocol, samples of Chrysanthemum × morifolium infected with Puccinia horiana, Gladiolus × hortulanus infected with Uromyces transversalis and Glycine max infected with Phakopsora pachyrhizi were tested alongside uninfected leaf tissue samples. The results of these tests show that this technique clearly distinguishes between rust pathogens and their respective host plant tissues. This ISH protocol is applicable to rust fungi and potentially other plant pathogenic fungi as well. It has been shown here that this protocol can be applied to pathogens from different genera of rust fungi with no background staining of plant tissue. We encourage the use of this protocol for the study of plant pathogenic fungi in paraffin embedded sections of host plant tissue.

Transcriptome Profiling of Rust Resistance in Switchgrass Using RNA-Seq Analysis

DOE PAGES

Serba, Desalegn D.; Uppalapati, Srinivasa Rao; Mukherjee, Shreyartha; ...

2015-03-16

Switchgrass rust caused by Puccinia emaculata is a major limiting factor for switchgrass (Panicum virgatum L.) production, especially in monoculture. Natural populations of switchgrass displayed diverse reactions to P. emaculata when evaluated in an Ardmore, OK, field. In order to identify the differentially expressed genes during the rust infection process and the mechanisms of switchgrass rust resistance, transcriptome analysis using RNA-Seq was conducted in two pseudo-F 1 parents ('PV281' and 'NFGA472'), and three moderately resistant and three susceptible progenies selected from a three-generation, four-founder switchgrass population (K5 x A4) x (AP13 x VS16). On average, 23.5 million reads per samplemore » (leaf tissue was collected at 0, 24, and 60 h post-inoculation (hpi)) were obtained from paired-end (2 x 100 bp) sequencing on the Illumina HiSeq2000 platform. Furthermore, mapping of the RNA-Seq reads to the switchgrass reference genome (AP13 ver. 1.1 assembly) constructed a total of 84,209 transcripts from 98,007 gene loci among all of the samples. Further analysis revealed that host defense- related genes, including the nucleotide binding site-leucinerich repeat domain containing disease resistance gene analogs, play an important role in resistance to rust infection. Rust-induced gene (RIG) transcripts inherited across generations were identified. The rust-resistant gene transcripts can be a valuable resource for developing molecular markers for rust resistance. Finally we identified the rust-resistant genotypes and gene transcripts which can expedite rust-resistant cultivar development in switchgrass.« less

Transcriptome Profiling of Rust Resistance in Switchgrass Using RNA-Seq Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serba, Desalegn D.; Uppalapati, Srinivasa Rao; Mukherjee, Shreyartha

Switchgrass rust caused by Puccinia emaculata is a major limiting factor for switchgrass (Panicum virgatum L.) production, especially in monoculture. Natural populations of switchgrass displayed diverse reactions to P. emaculata when evaluated in an Ardmore, OK, field. In order to identify the differentially expressed genes during the rust infection process and the mechanisms of switchgrass rust resistance, transcriptome analysis using RNA-Seq was conducted in two pseudo-F 1 parents ('PV281' and 'NFGA472'), and three moderately resistant and three susceptible progenies selected from a three-generation, four-founder switchgrass population (K5 x A4) x (AP13 x VS16). On average, 23.5 million reads per samplemore » (leaf tissue was collected at 0, 24, and 60 h post-inoculation (hpi)) were obtained from paired-end (2 x 100 bp) sequencing on the Illumina HiSeq2000 platform. Furthermore, mapping of the RNA-Seq reads to the switchgrass reference genome (AP13 ver. 1.1 assembly) constructed a total of 84,209 transcripts from 98,007 gene loci among all of the samples. Further analysis revealed that host defense- related genes, including the nucleotide binding site-leucinerich repeat domain containing disease resistance gene analogs, play an important role in resistance to rust infection. Rust-induced gene (RIG) transcripts inherited across generations were identified. The rust-resistant gene transcripts can be a valuable resource for developing molecular markers for rust resistance. Finally we identified the rust-resistant genotypes and gene transcripts which can expedite rust-resistant cultivar development in switchgrass.« less

Influence of Environmental Conditions and Genetic Background of Arabica Coffee (C. arabica L) on Leaf Rust (Hemileia vastatrix) Pathogenesis

PubMed Central

Toniutti, Lucile; Breitler, Jean-Christophe; Etienne, Hervé; Campa, Claudine; Doulbeau, Sylvie; Urban, Laurent; Lambot, Charles; Pinilla, Juan-Carlos H.; Bertrand, Benoît

2017-01-01

Global warming is a major threat to agriculture worldwide. Between 2008 and 2013, some coffee producing countries in South and Central America suffered from severe epidemics of coffee leaf rust (CLR), resulting in high economic losses with social implications for coffee growers. The climatic events not only favored the development of the pathogen but also affected the physiological status of the coffee plant. The main objectives of the study were to evaluate how the physiological status of the coffee plant modified by different environmental conditions impact on the pathogenesis of CLR and to identify indicators of the physiological status able to predict rust incidence. Three rust susceptible genotypes (one inbred line and two hybrids) were grown in controlled conditions with a combination of thermal regime (TR), nitrogen and light intensity close to the field situation before being inoculated with the rust fungus Hemileia vastatrix. It has been demonstrated that a TR of 27-22°C resulted in 2000 times higher sporulation than with a TR of 23–18°C. It has been also shown that high light intensity combined with low nitrogen fertilization modified the CLR pathogenesis resulting in huge sporulation. CLR sporulation was significantly lower in the F1 hybrids than in the inbred line. The hybrid vigor may have reduced disease incidence. Among the many parameters studied, parameters related to photosystem II and photosynthetic electron transport chain components appeared as indicators of the physiological status of the coffee plant able to predict rust sporulation intensity. Taken together, these results show that CLR sporulation not only depends on the TR but also on the physiological status of the coffee plant, which itself depends on agronomic conditions. Our work suggests that vigorous varieties combined with a shaded system and appropriate nitrogen fertilization should be part of an agro-ecological approach to disease control. PMID:29234340

Influence of Environmental Conditions and Genetic Background of Arabica Coffee (C. arabica L) on Leaf Rust (Hemileia vastatrix) Pathogenesis.

PubMed

Toniutti, Lucile; Breitler, Jean-Christophe; Etienne, Hervé; Campa, Claudine; Doulbeau, Sylvie; Urban, Laurent; Lambot, Charles; Pinilla, Juan-Carlos H; Bertrand, Benoît

2017-01-01

Global warming is a major threat to agriculture worldwide. Between 2008 and 2013, some coffee producing countries in South and Central America suffered from severe epidemics of coffee leaf rust (CLR), resulting in high economic losses with social implications for coffee growers. The climatic events not only favored the development of the pathogen but also affected the physiological status of the coffee plant. The main objectives of the study were to evaluate how the physiological status of the coffee plant modified by different environmental conditions impact on the pathogenesis of CLR and to identify indicators of the physiological status able to predict rust incidence. Three rust susceptible genotypes (one inbred line and two hybrids) were grown in controlled conditions with a combination of thermal regime (TR), nitrogen and light intensity close to the field situation before being inoculated with the rust fungus Hemileia vastatrix . It has been demonstrated that a TR of 27-22°C resulted in 2000 times higher sporulation than with a TR of 23-18°C. It has been also shown that high light intensity combined with low nitrogen fertilization modified the CLR pathogenesis resulting in huge sporulation. CLR sporulation was significantly lower in the F1 hybrids than in the inbred line. The hybrid vigor may have reduced disease incidence. Among the many parameters studied, parameters related to photosystem II and photosynthetic electron transport chain components appeared as indicators of the physiological status of the coffee plant able to predict rust sporulation intensity. Taken together, these results show that CLR sporulation not only depends on the TR but also on the physiological status of the coffee plant, which itself depends on agronomic conditions. Our work suggests that vigorous varieties combined with a shaded system and appropriate nitrogen fertilization should be part of an agro-ecological approach to disease control.

The durable wheat disease resistance gene Lr34 confers common rust and northern corn leaf blight resistance in maize.

PubMed

Sucher, Justine; Boni, Rainer; Yang, Ping; Rogowsky, Peter; Büchner, Heike; Kastner, Christine; Kumlehn, Jochen; Krattinger, Simon G; Keller, Beat

2017-04-01

Maize (corn) is one of the most widely grown cereal crops globally. Fungal diseases of maize cause significant economic damage by reducing maize yields and by increasing input costs for disease management. The most sustainable control of maize diseases is through the release and planting of maize cultivars with durable disease resistance. The wheat gene Lr34 provides durable and partial field resistance against multiple fungal diseases of wheat, including three wheat rust pathogens and wheat powdery mildew. Because of its unique qualities, Lr34 became a cornerstone in many wheat disease resistance programmes. The Lr34 resistance is encoded by a rare variant of an ATP-binding cassette (ABC) transporter that evolved after wheat domestication. An Lr34-like disease resistance phenotype has not been reported in other cereal species, including maize. Here, we transformed the Lr34 resistance gene into the maize hybrid Hi-II. Lr34-expressing maize plants showed increased resistance against the biotrophic fungal disease common rust and the hemi-biotrophic disease northern corn leaf blight. Furthermore, the Lr34-expressing maize plants developed a late leaf tip necrosis phenotype, without negative impact on plant growth. With this and previous reports, it could be shown that Lr34 is effective against various biotrophic and hemi-biotrophic diseases that collectively parasitize all major cereal crop species. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Spatio-temporal Variability of Stemflow Volume in a Beech-Yellow Poplar Forest in Relation to Tree Species and Size

NASA Astrophysics Data System (ADS)

Levia, D. F.; van Stan, J. T.; Mage, S.; Hauske, P. W.

2009-05-01

Stemflow is a localized point input at the base of trees that can account for more than 10% of the incident gross precipitation in deciduous forests. Despite the fact that stemflow has been documented to be of hydropedological importance, affecting soil moisture patterns, soil erosion, soil chemistry, and the distribution of understory vegetation, our current understanding of the temporal variability of stemflow yield is poor. The aim of the present study, conducted in a beech-yellow poplar forest in northeastern Maryland (39°42'N, 75°50'W), was to better understand the temporal and variability of stemflow production from Fagus grandifolia Ehrh. (American beech) and Liriodendron tulipifera L. (yellow poplar) in relation to meteorological conditions and season in order to better assess its importance to canopy-soil interactions. The experimental plot had a stand density of 225 trees/ha, a stand basal area of 36.8 sq. m/ha, a mean dbh of 40.8 cm, and a mean tree height of 27.8 m. The stand leaf area index (LAI) is 5.3. Yellow poplar and beech constitute three- quarters of the stand basal area. Using a high resolution (5 min) sequential stemflow sampling network, consisting of tipping-bucket gauges interfaced with a Campbell CR1000 datalogger, the temporal variability of stemflow yield was examined. Beech produced significantly larger stemflow amounts than yellow poplar. The amount of stemflow produced by individual beech trees in 5 minute intervals reached three liters. Stemflow yield and funneling ratios decreased with increasing rain intensity. Temporal variability of stemflow inputs were affected by the nature of incident gross rainfall, season, tree species, tree size, and bark water storage capacity. Stemflow was greater during the leafless period than full leaf period. Stemflow yield was greater for larger beech trees and smaller yellow poplar trees, owing to differences in bark water storage capacity. The findings of this study indicate that stemflow has a detectable affect on soil moisture patterning and the hydraulic conductivity of forest soils.

Study on adsorption and remediation of heavy metals by poplar and larch in contaminated soil.

PubMed

Wang, Xin; Jia, Youngfeng

2010-08-01

Field experiments at the Shenyang Experimental Station of Ecology were conducted to study the adsorption, accumulation, and remediation of heavy metals by poplar and larch grown in artificially contaminated soil. The soil was spiked with a combination of Cd, Cu, and Zn at concentrations of 1.5, 100, and 200 mg.kg(-1), respectively. The results showed that the biomass of poplar (Populus canadensis Moench) was lower by 26.0% in the soil spiked with a mixture of Cd, Cu, and Zn, compared with the control. Concentrations of Cd in poplar leaf and Cu in poplar roots in the treated soil were 4.11 and 14.55 mg kg(-1), respectively, which are much greater than in corresponding controls. The migration of heavy metals in woody plant body was in the order Cd > Zn > Cu. Poplar had higher metal concentrations in aboveground tissues and a higher biomass compared with larch of the same age and therefore is potentially more suitable for remediation. In the heavy metal-polluted soil of this study, phytoremediation by poplar may take 56 and 245 years for Cd and Cu, respectively, for meeting the soil standards of heavy metals, and the corresponding phytoremediation times by larch would take 211 and 438 years. The research findings could be used as a basis to develop ecological engineering technologies for environmental control and remediation of pollution caused by heavy metals in soils.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landry, L.G.; Pell, E.J.

Exposing hybrid poplar (Populus maximowizii x trichocarpa) plants to ozone (O[sub 3]) resulted in an acceleration of the visual symptoms of senescence and a decrease in the activity and quantity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Whole plants, crude leaf extracts, and isolated intact chloroplasts of hybrid poplar clone 245 were used to test the hypothesis that O[sub 3]-induced structural modifications of Rubisco affect the activity of this key photosynthetic enzyme. Proteolytic activity, per se, could not account for losses in Rubisco; acidic and alkaline protease activities declined or were unaffected in foliage of O[sub 3]-treated poplar saplings. In vitro treatment ofmore » leaf extracts with O[sub 3] decreased total Rubisco activity and binding of the enzyme's transition-state analog, 2-carboxyarabinitol bisphosphate. Additionally, O[sub 3] increased the loss of Rubisco large subunit (LSU) when extracts were incubated at 37[degrees]C. Treatment of isolated intact chloroplasts with O[sub 3] accelerated both the loss of the 55-kD Rubisco LSU and the accumulation of Rubisco LSU aggregates, as visualized by immunoblotting. The time-dependent modification in rubisco structure was the primary response of the isolated organelles to O[sub 3] treatment, with little proteolytic degradation of the LSU detected. 32 refs., 5 figs., 1 tab.« less

Marker-Assisted Molecular Profiling, Deletion Mutant Analysis, and RNA-Seq Reveal a Disease Resistance Cluster Associated with Uromyces appendiculatus Infection in Common Bean Phaseolus vulgaris L.

PubMed

Todd, Antonette R; Donofrio, Nicole; Sripathi, Venkateswara R; McClean, Phillip E; Lee, Rian K; Pastor-Corrales, Marcial; Kalavacharla, Venu Kal

2017-05-23

Common bean ( Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of the common bean. The Ur-3 locus provides race specific resistance to virulent strains or races of the bean rust pathogen along with Crg , (Complements resistance gene), which is required for Ur-3 -mediated rust resistance. In this study, we inoculated two common bean genotypes (resistant "Sierra" and susceptible crg) with rust race 53 of U. appendiculatus , isolated leaf RNA at specific time points, and sequenced their transcriptomes. First, molecular markers were used to locate and identify a 250 kb deletion on chromosome 10 in mutant crg (which carries a deletion at the Crg locus). Next, we identified differential expression of several disease resistance genes between Mock Inoculated (MI) and Inoculated (I) samples of "Sierra" leaf RNA within the 250 kb delineated region. Both marker assisted molecular profiling and RNA-seq were used to identify possible transcriptomic locations of interest regarding the resistance in the common bean to race 53. Identification of differential expression among samples in disease resistance clusters in the bean genome may elucidate significant genes underlying rust resistance. Along with preserving favorable traits in the crop, the current research may also aid in global sustainability of food stocks necessary for many populations.

Marker-Assisted Molecular Profiling, Deletion Mutant Analysis, and RNA-Seq Reveal a Disease Resistance Cluster Associated with Uromyces appendiculatus Infection in Common Bean Phaseolus vulgaris L.

PubMed Central

Todd, Antonette R.; Donofrio, Nicole; Sripathi, Venkateswara R.; McClean, Phillip E.; Lee, Rian K.; Pastor-Corrales, Marcial; Kalavacharla, Venu (Kal)

2017-01-01

Common bean (Phaseolus vulgaris L.) is an important legume, useful for its high protein and dietary fiber. The fungal pathogen Uromyces appendiculatus (Pers.) Unger can cause major loss in susceptible varieties of the common bean. The Ur-3 locus provides race specific resistance to virulent strains or races of the bean rust pathogen along with Crg, (Complements resistance gene), which is required for Ur-3-mediated rust resistance. In this study, we inoculated two common bean genotypes (resistant “Sierra” and susceptible crg) with rust race 53 of U. appendiculatus, isolated leaf RNA at specific time points, and sequenced their transcriptomes. First, molecular markers were used to locate and identify a 250 kb deletion on chromosome 10 in mutant crg (which carries a deletion at the Crg locus). Next, we identified differential expression of several disease resistance genes between Mock Inoculated (MI) and Inoculated (I) samples of “Sierra” leaf RNA within the 250 kb delineated region. Both marker assisted molecular profiling and RNA-seq were used to identify possible transcriptomic locations of interest regarding the resistance in the common bean to race 53. Identification of differential expression among samples in disease resistance clusters in the bean genome may elucidate significant genes underlying rust resistance. Along with preserving favorable traits in the crop, the current research may also aid in global sustainability of food stocks necessary for many populations. PMID:28545258

Nonhost resistance to rust pathogens - a continuation of continua.

PubMed

Bettgenhaeuser, Jan; Gilbert, Brian; Ayliffe, Michael; Moscou, Matthew J

2014-01-01

The rust fungi (order: Pucciniales) are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. Rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. Like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (Puccinia triticina), which can only infect species in the genera Triticum and Aegilops, whereas Asian soybean rust (Phakopsora pachyrhizi) is known to infect over 95 species from over 42 genera. A greater understanding of the genetic basis determining host range has the potential to identify sources of durable resistance for agronomically important crops. Delimiting the boundary between host and nonhost has been complicated by the quantitative nature of phenotypes in the transition between these two states. Plant-pathogen interactions in this intermediate state are characterized either by (1) the majority of accessions of a species being resistant to the rust or (2) the rust only being able to partially complete key components of its life cycle. This leads to a continuum of disease phenotypes in the interaction with different plant species, observed as a range from compatibility (host) to complete immunity within a species (nonhost). In this review we will highlight how the quantitative nature of disease resistance in these intermediate interactions is caused by a continuum of defense barriers, which a pathogen needs to overcome for successfully establishing itself in the host. To illustrate continua as this underlying principle, we will discuss the advances that have been made in studying nonhost resistance towards rust pathogens, particularly cereal rust pathogens.

Nonhost resistance to rust pathogens – a continuation of continua

PubMed Central

Bettgenhaeuser, Jan; Gilbert, Brian; Ayliffe, Michael; Moscou, Matthew J.

2014-01-01

The rust fungi (order: Pucciniales) are a group of widely distributed fungal plant pathogens, which can infect representatives of all vascular plant groups. Rust diseases significantly impact several crop species and considerable research focuses on understanding the basis of host specificity and nonhost resistance. Like many pathogens, rust fungi vary considerably in the number of hosts they can infect, such as wheat leaf rust (Puccinia triticina), which can only infect species in the genera Triticum and Aegilops, whereas Asian soybean rust (Phakopsora pachyrhizi) is known to infect over 95 species from over 42 genera. A greater understanding of the genetic basis determining host range has the potential to identify sources of durable resistance for agronomically important crops. Delimiting the boundary between host and nonhost has been complicated by the quantitative nature of phenotypes in the transition between these two states. Plant–pathogen interactions in this intermediate state are characterized either by (1) the majority of accessions of a species being resistant to the rust or (2) the rust only being able to partially complete key components of its life cycle. This leads to a continuum of disease phenotypes in the interaction with different plant species, observed as a range from compatibility (host) to complete immunity within a species (nonhost). In this review we will highlight how the quantitative nature of disease resistance in these intermediate interactions is caused by a continuum of defense barriers, which a pathogen needs to overcome for successfully establishing itself in the host. To illustrate continua as this underlying principle, we will discuss the advances that have been made in studying nonhost resistance towards rust pathogens, particularly cereal rust pathogens. PMID:25566270

Genetical genomics of Populus leaf shape variation

DOE PAGES

Drost, Derek R.; Puranik, Swati; Novaes, Evandro; ...

2015-06-30

Leaf morphology varies extensively among plant species and is under strong genetic control. Mutagenic screens in model systems have identified genes and established molecular mechanisms regulating leaf initiation, development, and shape. However, it is not known whether this diversity across plant species is related to naturally occurring variation at these genes. Quantitative trait locus (QTL) analysis has revealed a polygenic control for leaf shape variation in different species suggesting that loci discovered by mutagenesis may only explain part of the naturally occurring variation in leaf shape. Here we undertook a genetical genomics study in a poplar intersectional pseudo-backcross pedigree tomore » identify genetic factors controlling leaf shape. Here, the approach combined QTL discovery in a genetic linkage map anchored to the Populus trichocarpa reference genome sequence and transcriptome analysis.« less

Threshold response of mesophyll CO2 conductance to leaf hydraulics in highly transpiring hybrid poplar clones exposed to soil drying

PubMed Central

Pepin, Steeve

2014-01-01

Mesophyll conductance (g m) has been shown to impose significant limitations to net CO2 assimilation (A) in various species during water stress. Net CO2 assimilation is also limited by stomatal conductance to water (g sw), both having been shown to co-vary with leaf hydraulic conductance (K leaf). Lately, several studies have suggested a close functional link between K leaf, g sw, and g m. However, such relationships could only be circumstantial since a recent study has shown that the response of g m to drought could merely be an artefactual consequence of a reduced intercellular CO2 mole fraction (C i). Experiments were conducted on 8-week-old hybrid poplar cuttings to determine the relationship between K leaf, g sw, and g m in clones of contrasting drought tolerance. It was hypothesized that changes in g sw and K leaf in response to drought would not impact on g m over most of its range. The results show that K leaf decreased in concert with g sw as drought proceeded, whereas g m measured at a normalized C i remained relatively constant up to a g sw threshold of ~0.15mol m–2 s–1. This delayed g m response prevented a substantial decline in A at the early stage of the drought, thereby enhancing water use efficiency. Reducing the stomatal limitation of droughted plants by diminishing the ambient CO2 concentration of the air did not modify g m or K leaf. The relationship between gas exchange and leaf hydraulics was similar in both drought-tolerant and drought-sensitive clones despite their contrasting vulnerability to stem cavitation and stomatal response to soil drying. The results support the hypothesis of a partial hydraulic isolation of the mesophyll from the main transpiration pathway. PMID:24368507

Three-Dimension Visualization for Primary Wheat Diseases Based on Simulation Model

NASA Astrophysics Data System (ADS)

Shijuan, Li; Yeping, Zhu

Crop simulation model has been becoming the core of agricultural production management and resource optimization management. Displaying crop growth process makes user observe the crop growth and development intuitionisticly. On the basis of understanding and grasping the occurrence condition, popularity season, key impact factors for main wheat diseases of stripe rust, leaf rust, stem rust, head blight and powdery mildew from research material and literature, we designed 3D visualization model for wheat growth and diseases occurrence. The model system will help farmer, technician and decision-maker to use crop growth simulation model better and provide decision-making support. Now 3D visualization model for wheat growth on the basis of simulation model has been developed, and the visualization model for primary wheat diseases is in the process of development.

Adsorption Mechanisms of Dodecylbenzene Sulfonic Acid by Corn Straw and Poplar Leaf Biochars

PubMed Central

Zhao, Nan; Yang, Xixiang; Zhang, Jing; Zhu, Ling; Lv, Yizhong

2017-01-01

Biochar is an eco-friendly, renewable, and cost-effective material that can be used as an adsorbent for the remediation of contaminated environments. In this paper, two types of biochar were prepared through corn straw and poplar leaf pyrolysis at 300 °C and 700 °C (C300, C700, P300, P700). Brunaer–Emmett–Teller N2 surface area, scanning electron microscope, elemental analysis, and infrared spectra were used to characterize their structures. These biochars were then used as adsorbents for the adsorption of dodecylbenzene sulfonic acid (DBSA). The microscopic adsorption mechanisms were studied by using infrared spectra, 13C-nuclear magnetic resonance spectra, and electron spin resonance spectra. The surface area and pore volume of C700 (375.89 m2/g and 0.2302 cm3/g) were the highest among all samples. Elemental analysis results showed that corn straw biochars had a higher aromaticity and carbon to nitrogen (C/N) ratio than the poplar leaf biochars. High temperature caused the increase of carbon content and the decrease of oxygen content, which also gave the biochars a higher adsorption rate. Pseudo-second order kinetic provided a better fit with the experimental data. Adsorption isotherm experiments showed that the adsorption isotherm of C300 fit the linear model. For other biochars, the adsorption isotherms fitted Langmuir model. Biochars with high temperatures exhibited enhanced adsorption capacity compared with ones at low temperatures. The qmax values of biochars to DBSA followed the order of P700 > C700 > P300. The adsorption mechanisms were complex, including partition, anion exchange, the formation of H bonds, covalent bonds, and charge transfer. The adsorption by covalent bonding might be the key mechanism determining the adsorption capacity of P700. PMID:28937637

Adsorption Mechanisms of Dodecylbenzene Sulfonic Acid by Corn Straw and Poplar Leaf Biochars.

PubMed

Zhao, Nan; Yang, Xixiang; Zhang, Jing; Zhu, Ling; Lv, Yizhong

2017-09-22

Biochar is an eco-friendly, renewable, and cost-effective material that can be used as an adsorbent for the remediation of contaminated environments. In this paper, two types of biochar were prepared through corn straw and poplar leaf pyrolysis at 300 °C and 700 °C (C300, C700, P300, P700). Brunaer-Emmett-Teller N₂ surface area, scanning electron microscope, elemental analysis, and infrared spectra were used to characterize their structures. These biochars were then used as adsorbents for the adsorption of dodecylbenzene sulfonic acid (DBSA). The microscopic adsorption mechanisms were studied by using infrared spectra, 13 C-nuclear magnetic resonance spectra, and electron spin resonance spectra. The surface area and pore volume of C700 (375.89 m²/g and 0.2302 cm³/g) were the highest among all samples. Elemental analysis results showed that corn straw biochars had a higher aromaticity and carbon to nitrogen (C/N) ratio than the poplar leaf biochars. High temperature caused the increase of carbon content and the decrease of oxygen content, which also gave the biochars a higher adsorption rate. Pseudo-second order kinetic provided a better fit with the experimental data. Adsorption isotherm experiments showed that the adsorption isotherm of C300 fit the linear model. For other biochars, the adsorption isotherms fitted Langmuir model. Biochars with high temperatures exhibited enhanced adsorption capacity compared with ones at low temperatures. The q max values of biochars to DBSA followed the order of P700 > C700 > P300. The adsorption mechanisms were complex, including partition, anion exchange, the formation of H bonds, covalent bonds, and charge transfer. The adsorption by covalent bonding might be the key mechanism determining the adsorption capacity of P700.

The development of quick, robust, quantitative phenotypic assays for describing the host–nonhost landscape to stripe rust

PubMed Central

Dawson, Andrew M.; Bettgenhaeuser, Jan; Gardiner, Matthew; Green, Phon; Hernández-Pinzón, Inmaculada; Hubbard, Amelia; Moscou, Matthew J.

2015-01-01

Nonhost resistance is often conceptualized as a qualitative separation from host resistance. Classification into these two states is generally facile, as they fail to fully describe the range of states that exist in the transition from host to nonhost. This poses a problem when studying pathosystems that cannot be classified as either host or nonhost due to their intermediate status relative to these two extremes. In this study, we investigate the efficacy of the Poaceae-stripe rust (Puccinia striiformis Westend.) interaction for describing the host–nonhost landscape. First, using barley (Hordeum vulgare L.) and Brachypodium distachyon (L.) P. Beauv. We observed that macroscopic symptoms of chlorosis and leaf browning were associated with hyphal colonization by P. striiformis f. sp. tritici, respectively. This prompted us to adapt a protocol for visualizing fungal structures into a phenotypic assay that estimates the percent of leaf colonized. Use of this assay in intermediate host and intermediate nonhost systems found the frequency of infection decreases with evolutionary divergence from the host species. Similarly, we observed that the pathogen’s ability to complete its life cycle decreased faster than its ability to colonize leaf tissue, with no incidence of pustules observed in the intermediate nonhost system and significantly reduced pustule formation in the intermediate host system as compared to the host system, barley-P. striiformis f. sp. hordei. By leveraging the stripe rust pathosystem in conjunction with macroscopic and microscopic phenotypic assays, we now hope to dissect the genetic architecture of intermediate host and intermediate nonhost resistance using structured populations in barley and B. distachyon. PMID:26579142

Effects of UV-B radiation on phenolic composition and deposition patterns and leaf physiology in three Eastern tree species

NASA Astrophysics Data System (ADS)

Sullivan, Joseph H.; Gitz, Dennis C.; Peek, Michael S.; McElrone, Andrew J.

2002-01-01

Quantitative changes in foliar chemistry in response to UVB radiation are frequently reported but less is known about the qualitative changes in putative UV-screening compounds. It has also not been conclusively shown whether qualitative differences in screening compounds or differences in localization patterns influences the sensitivity of plants to damage from UVB radiation. In this study we evaluated the chemical composition and deposition patterns of UV-absorbing compounds in three tree species and assayed these species for possible effects on gas exchange and photosynthetic carbon assimilation. Branches of mature trees of sweetgum (Liquidambar styraciflua), tulip poplar (Liriodendron tulipifera) and red maple (Acer rubrum) were exposed to supplemental levels of UVB radiation over three growing seasons. Controls for UVA were also measured by exposing branches to supplemental UVA only, and additional branches not irradiated were also used for controls. These species demonstrated contrasting chemical composition and deposition patterns with poplar being the most responsive in terms of epidermal accumulation of phenolics including flavonols and chlorogenic acid and hydroxycinnamates. Sweetgum and red maple showed increases primarily in hydroxycinnamates, particularly in the mesophyll in red maple. Leaf area was marginally influenced by UV exposure level. Assimilation was generally not reduced by UVB radiation in these species and was enhanced in red maple by both UVB and UVA and by UVA in sweetgum. These finding are consistent with a hypothesis that epidermal attenuation of UVB would only be reduced in poplar, which accumulated the additional epidermal screening compounds. It is possible that photosynthetic efficiency was enhanced in red maple by the increased absorption of blue light within the mesophyll. Stomatal conductance was generally reduced, and this led to an increase in water use efficiency in red maple and poplar.

Comparative physiological and proteomic responses to drought stress in two poplar species originating from different altitudes.

PubMed

Yang, Fan; Wang, Yong; Miao, Ling-Feng

2010-08-01

Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana Rehder were examined during a single growing season in a greenhouse for comparative analysis of their physiological and proteomic responses to drought stress. The said species originate from high and low altitudes, respectively, of the eastern Himalaya. Results revealed that the adaptive responses to drought stress vary between the two poplar species. As a consequence of drought stress, the stem height increment and leaf number increment are more significantly inhibited in P. cathayana compared with P. kangdingensis. On the other hand, in response to drought stress, more significant cellular damages such as reduction in leaf relative water content and CO(2) assimilation rate, increments in the contents of malondialdehyde and hydrogen peroxide and downregulation or degradation of proteins related to photosynthesis occur in P. cathayana compared with P. kangdingensis. On the other hand, P. kangdingensis can cope better with the negative impact on the entire regulatory network. This includes more efficient increases in content of solute sugar, soluble protein and free proline and activities of antioxidant enzymes, as well as specific expressions of certain proteins related to protein processing, redox homeostasis and sugar metabolism. Morphological consequences as well as physiological and proteomic responses to drought stress between species revealed that P. kangdingensis originating from a high altitude manifest stronger drought adaptation than did P. cathayana originating from a low altitude. Functions of various proteins identified by proteomic experiment are related with physiological phenomena. Physiological and proteomic responses to drought stress in poplar may work cooperatively to establish a new cellular homeostasis, allowing poplar to develop a certain level of drought tolerance.

Using SNP genetic markers to elucidate the linkage of the Co-34/Phg-3 anthracnose and angular leaf spot resistance gene cluster with the Ur-14 resistance gene

USDA-ARS?s Scientific Manuscript database

The Ouro Negro common bean cultivar contains the Co-34/Phg-3 gene cluster that confers resistance to the anthracnose (ANT) and angular leaf spot (ALS) pathogens. These genes are tightly linked on chromosome 4. Ouro Negro also has the Ur-14 rust resistance gene, reportedly in the vicinity of Co- 34; ...

Development of wheat lines carrying stem rust resistance gene Sr39 with reduced Aegilops speltoides chromatin and simple PCR markers for marker-assisted selection.

PubMed

Mago, Rohit; Zhang, P; Bariana, H S; Verlin, D C; Bansal, U K; Ellis, J G; Dundas, I S

2009-11-01

The use of major resistance genes is a cost-effective strategy for preventing stem rust epidemics in wheat crops. The stem rust resistance gene Sr39 provides resistance to all currently known pathotypes of Puccinia graminis f. sp. tritici (Pgt) including Ug99 (TTKSK) and was introgressed together with leaf rust resistance gene Lr35 conferring adult plant resistance to P. triticina (Pt), into wheat from Aegilops speltoides. It has not been used extensively in wheat breeding because of the presumed but as yet undocumented negative agronomic effects associated with Ae. speltoides chromatin. This investigation reports the production of a set of recombinants with shortened Ae. speltoides segments through induction of homoeologous recombination between the wheat and the Ae. speltoides chromosome. Simple PCR-based DNA markers were developed for resistant and susceptible genotypes (Sr39#22r and Sr39#50s) and validated across a set of recombinant lines and wheat cultivars. These markers will facilitate the pyramiding of ameliorated sources of Sr39 with other stem rust resistance genes that are effective against the Pgt pathotype TTKSK and its variants.

Spatial distribution of cadmium in leaves and its impact on photosynthesis: examples of different strategies in willow and poplar clones.

PubMed

Pietrini, F; Zacchini, M; Iori, V; Pietrosanti, L; Ferretti, M; Massacci, A

2010-03-01

The interaction of cadmium (Cd) with photosynthesis was investigated in poplar (Populus x canadensis Mönch., clone A4A, Populus nigra L., clone Poli) and willow (Salix alba L., clone SS5) clones that had different leaf metal concentrations in preliminary experiments. Plants grown in the presence of 50 microm CdSO(4) for 3 weeks under hydroponic conditions were used to examine leaf gas exchange, chlorophyll fluorescence parameters and images, and for Cd detection using energy dispersive X-ray fluorescence (ED-XRF). Leaves were finally analysed for Cd and phytochelatin concentrations. Results showed that SS5 had the highest leaf Cd concentration and high gas exchange activity similar to that of Poli, which had the lowest Cd concentration. Leaf fluorescence images evidenced in large undamaged areas of SS5 corresponded to high values of F(v)/F(m), F(o), PhiPSII, qP and NPQ, while patches of dark colour (visible necrosis) close to the main vein corresponded to low values of these parameters. In A4A, these necrotic patches were more diffuse on the leaf blade and associated with a range of fluorescence parameter values. ED-XRF analysis indicated that Cd was only detectable in necroses of SS5 leaves, while in A4A it was relatively more diffuse. Phytochelatins (PCs) were not detected in SS5, while their concentration was high in both Poli and A4A. The absence of these molecules in SS5 is thought to favour confinement of high accumulations of Cd to necrotic areas and gives SS5 the ability to maintain high photosynthesis and transpiration in remaining parts of the leaf.

Functional repression of PtSND2 represses growth and development by disturbing auxin biosynthesis, transport and signaling in transgenic poplar.

PubMed

Wang, Haihai; Tang, Renjie; Wang, Cuiting; Qi, Qi; Gai, Ying; Jiang, Xiangning; Zhang, Hongxia

2015-01-01

Using chimeric repressor silencing technology, we previously reported that functional repression of PtSND2 severely arrested wood formation in transgenic poplar (Populus). Here, we provide further evidence that auxin biosynthesis, transport and signaling were disturbed in these transgenic plants, leading to pleiotropic defects in their growth patterns, including inhibited leaf enlargement and vascular tissue development in the leaf central vein, suppressed cambial growth and fiber elongation in the stem, and arrested growth in the root system. Two transgenic lines, which displayed the most remarkable phenotypic deviation from the wild-type, were selected for detailed studies. In both transgenic lines, expression of genes for auxin biosynthesis, transport and signaling was down-regulated, and indole-3-acetic acid distribution was severely disturbed in the apical buds, leaves, stems and roots of field-grown transgenic plants. Transient transcription dual-luciferase assays of ProPtTYDC2::LUC, ProPttLAX2::LUC and ProPoptrIAA20.2::LUC in poplar protoplasts revealed that expression of auxin-related genes might be regulated by PtSND2 at the transcriptional level. All these results indicate that functional repression of PtSND2 altered auxin biosynthesis, transport and signaling, and thereby disturbed the normal growth and development of transgenic plants. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

CENL1 Expression in the Rib Meristem Affects Stem Elongation and the Transition to Dormancy in Populus[W][OA

PubMed Central

Ruonala, Raili; Rinne, Päivi L.H.; Kangasjärvi, Jaakko; van der Schoot, Christiaan

2008-01-01

We investigated the short day (SD)–induced transition to dormancy in wild-type hybrid poplar (Populus tremula × P. tremuloides) and its absence in transgenic poplar overexpressing heterologous PHYTOCHROME A (PHYA). CENTRORADIALIS-LIKE1 (CENL1), a poplar ortholog of Arabidopsis thaliana TERMINAL FLOWER1 (TFL1), was markedly downregulated in the wild-type apex coincident with SD-induced growth cessation. By contrast, poplar overexpressing a heterologous Avena sativa PHYA construct (P35S:AsPHYA), with PHYA accumulating in the rib meristem (RM) and adjacent tissues but not in the shoot apical meristem (SAM), upregulated CENL1 in the RM area coincident with an acceleration of stem elongation. In SD-exposed heterografts, both P35S:AsPHYA and wild-type scions ceased growth and formed buds, whereas only the wild type assumed dormancy and P35S:AsPHYA showed repetitive flushing. This shows that the transition is not dictated by leaf-produced signals but dependent on RM and SAM properties. In view of this, callose-enforced cell isolation in the SAM, associated with suspension of indeterminate growth during dormancy, may require downregulation of CENL1 in the RM. Accordingly, upregulation of CENL1/TFL1 might promote stem elongation in poplar as well as in Arabidopsis during bolting. Together, the results suggest that the RM is particularly sensitive to photoperiodic signals and that CENL1 in the RM influences transition to dormancy in hybrid poplar. PMID:18192437

The proteomics of nitrogen remobilization in poplar bark

USDA-ARS?s Scientific Manuscript database

Seasonal nitrogen (N) cycling in temperate deciduous trees involves the accumulation of bark storage proteins (BSPs), a class of vegetative storage proteins in phloem parenchyma and xylem ray cells. BSPs are anabolized using recycled N in the form of amino acids after autumn leaf senescence and lat...

Phenylalanine as a nitrogen source induces root growth and nitrogen-use efficiency in Populus × canescens.

PubMed

Jiao, Yu; Chen, Yinghao; Ma, Chaofeng; Qin, Jingjing; Nguyen, Thi Hong Nhung; Liu, Di; Gan, Honghao; Ding, Shen; Luo, Zhi-Bin

2018-01-01

To investigate the physiological responses of poplars to amino acids as sole nitrogen (N) sources, Populus × canescens (Ait.) Smith plants were supplied with one of three nitrogen fertilizers (NH4NO3, phenylalanine (Phe) or the mixture of NH4NO3 and Phe) in sand culture. A larger root system, and decreased leaf size and CO2 assimilation rate was observed in Phe- versus NH4NO3-treated poplars. Consistently, a greater root biomass and a decreased shoot growth were detected in Phe-supplied poplars. Decreased enzymatic activities of nitrate reductase (NR), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) and elevated activities of nitrite reductase (NiR), phenylalanine ammonia lyase (PAL), glutamine synthetase (GS) and asparagine synthase (AS) were found in Phe-treated roots. Accordingly, reduced concentrations of NH4+, NO3- and total N, and enhanced N-use efficiencies (NUEs) were detected in Phe-supplied poplars. Moreover, the transcript levels of putative Phe transporters ANT1 and ANT3 were upregulated, and the mRNA levels of NR, glutamine synthetase 2 (GS2), NADH-dependent glutamate synthase (NADH-GOGAT), GDH and asparagine synthetase 2 (ASN2) were downexpressed in Phe-treated roots and/or leaves. The 15N-labeled Phe was mainly allocated in the roots and only a small amount of 15N-Phe was translocated to poplar aerial parts. These results indicate that poplar roots can acquire Phe as an N source to support plant growth and that Phe-induced NUEs in the poplars are probably associated with NH4+ re-utilization after Phe deamination and the carbon bonus simultaneously obtained during Phe uptake. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Development and Characterization of a Psathyrostachys huashanica Keng 7Ns Chromosome Addition Line with Leaf Rust Resistance

PubMed Central

Du, Wanli; Wang, Jing; Wang, Liangming; Zhang, Jun; Chen, Xinhong; Zhao, Jixin; Yang, Qunhui; Wu, Jun

2013-01-01

The aim of this study was to characterize a Triticum aestivum-Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs) disomic addition line 2-1-6-3. Individual line 2-1-6-3 plants were analyzed using cytological, genomic in situ hybridization (GISH), EST-SSR, and EST-STS techniques. The alien addition line 2-1-6-3 was shown to have two P. huashanica chromosomes, with a meiotic configuration of 2n = 44 = 22 II. We tested 55 EST-SSR and 336 EST-STS primer pairs that mapped onto seven different wheat chromosomes using DNA from parents and the P. huashanica addition line. One EST-SSR and nine EST-STS primer pairs indicated that the additional chromosome of P. huashanica belonged to homoeologous group 7, the diagnostic fragments of five EST-STS markers (BE404955, BE591127, BE637663, BF482781 and CD452422) were cloned, sequenced and compared. The results showed that the amplified polymorphic bands of P. huashanica and disomic addition line 2-1-6-3 shared 100% sequence identity, which was designated as the 7Ns disomic addition line. Disomic addition line 2-1-6-3 was evaluated to test the leaf rust resistance of adult stages in the field. We found that one pair of the 7Ns genome chromosomes carried new leaf rust resistance gene(s). Moreover, wheat line 2-1-6-3 had a superior numbers of florets and grains per spike, which were associated with the introgression of the paired P. huashanica chromosomes. These high levels of disease resistance and stable, excellent agronomic traits suggest that this line could be utilized as a novel donor in wheat breeding programs. PMID:23976963

Smallholder Food and Water Security in the Face of Climatic Stress and the Coffee Leaf Rust: Lessons from Nicaragua

NASA Astrophysics Data System (ADS)

Stewart, I. T.; Bacon, C. M.; Sundstrom, W.

2015-12-01

Smallholder farmers in Nicaragua and throughout much of Central America preserve forest biodiversity and contribute to the sustainable production of coffee and other crops while, paradoxically, they themselves must cope with recurring periods of seasonal hunger. Smallholder food and water security in the region is affected by hurricanes, periodic drought events, climatic changes, an on-going outbreak of the coffee leaf rust, and fluctuations in food prices. Using regression analysis, our research examines what factors strengthened resilience to these hazards at the household level over the 1981 - 2014 time period. To this end, we integrate qualitative research on coping responses and local institutions, a participatory survey of 368 households, and an analysis of hydro-climatic data. Our results indicate that coping responses to the coffee leaf rust outbreak and the 2014 drought are comparable in severity to those used to endure Hurricane Mitch in 1998, and a severe 2009 drought. Higher smallholder resilience to stresses affecting food and water security is associated with larger farms, off-farm employment, more on-farm food production, higher numbers of fruit trees, and greater coffee harvests. Households that reported more severe coping responses to hazards earlier in the study period tended to be more strongly impacted by later hazards and reported generally greater seasonal hunger. Affiliation with local farmer-to-farmer institutions prioritizing either subsistence-oriented production or sales to international fair-trade markets did not correlate strongly with coping responses; however, subsistence-oriented institutions promote several resilience-enhancing practices. Lessons learned by adapting to past hazards may be used to develop adaptation and mitigation strategies for smallholders under continued climate variability and change.

A Plant Gene Up-Regulated at Rust Infection Sites

PubMed Central

Ayliffe, Michael A.; Roberts, James K.; Mitchell, Heidi J.; Zhang, Ren; Lawrence, Gregory J.; Ellis, Jeffrey G.; Pryor, Tony J.

2002-01-01

Expression of the fis1 gene from flax (Linum usitatissimum) is induced by a compatible rust (Melampsora lini) infection. Infection of transgenic plants containing a β-glucuronidase (GUS) reporter gene under the control of the fis1 promoter showed that induction is highly localized to those leaf mesophyll cells within and immediately surrounding rust infection sites. The level of induction reflects the extent of fungal growth. In a strong resistance reaction, such as the hypersensitive fleck mediated by the L6 resistance gene, there is very little fungal growth and a microscopic level of GUS expression. Partially resistant flax leaves show levels of GUS expression that were intermediate to the level observed in the fully susceptible infection. Sequence and deletion analysis using both transient Agrobacterium tumefaciens expression and stable transformation assays have shown that the rust-inducible fis1 promoter is contained within a 580-bp fragment. Homologs of fis1 were identified in expressed sequence tag databases of a range of plant species including dicots, monocots, and a gymnosperm. Homologous genes isolated from maize (Zea mays; mis1), barley (Hordeum vulgare; bis1), wheat (Triticum aestivum; wis1), and Arabidopsis encode proteins that are highly similar (76%–82%) to the FIS1 protein. The Arabidopsis homologue has been reported to encode a Δ1-pyrroline-5-carboxylate dehydrogenase that is involved in the catabolism of proline to glutamate. RNA-blot analysis showed that mis1 in maize and the bis1 homolog in barley are both up-regulated by a compatible infection with the corresponding species-specific rust. The rust-induced genes homologous to fis1 are present in many plants. The promoters of these genes have potential roles for the engineering of synthetic rust resistance genes by targeting transgene expression to the sites of rust infection. PMID:12011348

Isolate Specificity and Polygenic Inheritance of Resistance in Barley to Diverse Heterologous Puccinia striiformis Isolates.

PubMed

Haghdoust, R; Singh, D; Garnica, D P; Park, R F; Dracatos, P M

2018-05-01

Barley is a host to Puccinia striiformis f. sp. hordei, and is an intermediate or near nonhost to the formae speciales adapted to wheat (P. striiformis f. sp. tritici) and to barley grass (P. striiformis f. sp. pseudo-hordei). The genetic basis of resistance to these forms of P. striiformis is not well understood. Accordingly, a recombinant inbred line (RIL) population was developed using a P. striiformis-susceptible accession (Biosaline-19) and the immune cultivar Pompadour. We investigated the genetic basis of resistance to four diverse P. striiformis isolates (P. striiformis f. sp. pseudo-hordei, and P. striiformis f. sp. tritici pathotypes 104 E137 A-, 134 E16 A+, and 64 E0 A-). and determined that the immunity in Pompadour at the seedling stage to the different P. striiformis isolates was due to quantitative trait loci (QTL) on chromosomes 1H, 3H, 5H, and 7H with both overlapping and distinct specificities. Further histological analysis confirmed the presence of isolate specificity. The RILs were also assessed in the field for resistance to P. striiformis f. sp. pseudo-hordei, P. striiformis f. sp. hordei, and the leaf rust pathogen (P. hordei) to identify pleiotropic QTL loci effective at the adult plant stage and determine whether the leaf rust resistance in Pompadour (Rph20) was also effective to P. striiformis. RILs that were seedling susceptible to P. striiformis f. sp. pseudo-hordei were resistant in the field, implicating the involvement of adult plant resistance (APR). Additional QTLs were identified on chromosome 7H at the same genetic position as Rph23 (APR to leaf rust), suggesting either pleiotropic resistance or the presence of a stripe rust resistance gene closely linked to or allelic with Rph23. Unlike many pleiotropic APR genes identified and isolated in wheat, our data suggest that the Rph20 locus does not confer resistance to the P. striiformis isolates used in this study (P. striiformis f. sp. hordei [χ 2 (independence) = 2.47 P > 0.12] and P. striiformis f. sp. pseudo-hordei [χ 2 (independence) = 0.42 P > 0.60]).

The control of Asian rust by glyphosate in glyphosate-resistant soybeans.

PubMed

Feng, Paul C C; Clark, Celeste; Andrade, Gabriella C; Balbi, Maria C; Caldwell, Pat

2008-04-01

Glyphosate is a widely used broad-spectrum herbicide. Recent studies in glyphosate-resistant (GR) crops have shown that, in addition to its herbicidal activity, glyphosate exhibits activity against fungi, thereby providing disease control benefits. In GR wheat, glyphosate has shown both preventive and curative activities against Puccinia striiformis f. sp. tritici (Erikss) CO Johnston and Puccinia triticina Erikss, which cause stripe and leaf rusts respectively. Laboratory studies confirmed earlier observations that glyphosate has activity against Phakopsora pachyrhizi Syd & P Syd which causes Asian soybean rust (ASR) in GR soybeans. The results showed that glyphosate at rates between 0.84 and 1.68 kg ha(-1) delayed the onset of ASR in GR soybeans. However, field trials conducted in Argentina and Brazil under natural infestations showed variable ASR control from application of glyphosate in GR soybeans. Further field studies are ongoing to define the activity of glyphosate against ASR. These results demonstrate the disease control activities of glyphosate against rust diseases in GR wheat and GR soybeans. Copyright (c) 2007 Society of Chemical Industry.

Correlating laser-induced breakdown spectroscopy with neutron activation analysis to determine the elemental concentration in the ionome of the Populus trichocarpa leaf

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madhavi Z.; Glasgow, David C.; Tschaplinski, Timothy J.

The black cottonwood poplar (Populus trichocarpa) leaf ionome (inorganic trace elements and mineral nutrients) is an important aspect for determining the physiological and developmental processes contributing to biomass production. A number of techniques are used to measure the ionome, yet characterizing the leaf spatial heterogeneity remains a challenge, especially in solid samples. Laser-induced breakdown spectroscopy (LIBS) has been used to determine the elemental composition of leaves and is able to raster across solid matrixes at 10 μm resolution. Here, we evaluate the use of LIBS for solid sample leaf elemental characterization in relation to neutron activation. In fact, neutron activationmore » analysis is a laboratory-based technique which is used by the National Institute of Standards and Technology (NIST) to certify trace elements in candidate reference materials including plant leaf matrices. Introduction to the techniques used in this research has been presented in this manuscript. Neutron activation analysis (NAA) data has been correlated to the LIBS spectra to achieve quantification of the elements or ions present within poplar leaves. The regression coefficients of calibration and validation using multivariate analysis (MVA) methodology for six out of seven elements have been determined and vary between 0.810 and 0.998. LIBS and NAA data has been presented for the elements such as, calcium, magnesium, manganese, aluminum, copper, and potassium. Chlorine was also detected but it did not show good correlation between the LIBS and NAA techniques. This research shows that LIBS can be used as a fast, high-spatial resolution technique to quantify elements as part of large-scale field phenotyping projects.« less

Correlating laser-induced breakdown spectroscopy with neutron activation analysis to determine the elemental concentration in the ionome of the Populus trichocarpa leaf

NASA Astrophysics Data System (ADS)

Martin, Madhavi Z.; Glasgow, David C.; Tschaplinski, Timothy J.; Tuskan, Gerald A.; Gunter, Lee E.; Engle, Nancy L.; Wymore, Ann M.; Weston, David J.

2017-12-01

The black cottonwood poplar (Populus trichocarpa) leaf ionome (inorganic trace elements and mineral nutrients) is an important aspect for determining the physiological and developmental processes contributing to biomass production. A number of techniques are used to measure the ionome, yet characterizing the leaf spatial heterogeneity remains a challenge, especially in solid samples. Laser-induced breakdown spectroscopy (LIBS) has been used to determine the elemental composition of leaves and is able to raster across solid matrixes at 10 μm resolution. Here, we evaluate the use of LIBS for solid sample leaf elemental characterization in relation to neutron activation. In fact, neutron activation analysis is a laboratory-based technique which is used by the National Institute of Standards and Technology (NIST) to certify trace elements in candidate reference materials including plant leaf matrices. Introduction to the techniques used in this research has been presented in this manuscript. Neutron activation analysis (NAA) data has been correlated to the LIBS spectra to achieve quantification of the elements or ions present within poplar leaves. The regression coefficients of calibration and validation using multivariate analysis (MVA) methodology for six out of seven elements have been determined and vary between 0.810 and 0.998. LIBS and NAA data has been presented for the elements such as, calcium, magnesium, manganese, aluminum, copper, and potassium. Chlorine was also detected but it did not show good correlation between the LIBS and NAA techniques. This research shows that LIBS can be used as a fast, high-spatial resolution technique to quantify elements as part of large-scale field phenotyping projects.

Correlating laser-induced breakdown spectroscopy with neutron activation analysis to determine the elemental concentration in the ionome of the Populus trichocarpa leaf

DOE PAGES

Martin, Madhavi Z.; Glasgow, David C.; Tschaplinski, Timothy J.; ...

2017-10-17

The black cottonwood poplar (Populus trichocarpa) leaf ionome (inorganic trace elements and mineral nutrients) is an important aspect for determining the physiological and developmental processes contributing to biomass production. A number of techniques are used to measure the ionome, yet characterizing the leaf spatial heterogeneity remains a challenge, especially in solid samples. Laser-induced breakdown spectroscopy (LIBS) has been used to determine the elemental composition of leaves and is able to raster across solid matrixes at 10 μm resolution. Here, we evaluate the use of LIBS for solid sample leaf elemental characterization in relation to neutron activation. In fact, neutron activationmore » analysis is a laboratory-based technique which is used by the National Institute of Standards and Technology (NIST) to certify trace elements in candidate reference materials including plant leaf matrices. Introduction to the techniques used in this research has been presented in this manuscript. Neutron activation analysis (NAA) data has been correlated to the LIBS spectra to achieve quantification of the elements or ions present within poplar leaves. The regression coefficients of calibration and validation using multivariate analysis (MVA) methodology for six out of seven elements have been determined and vary between 0.810 and 0.998. LIBS and NAA data has been presented for the elements such as, calcium, magnesium, manganese, aluminum, copper, and potassium. Chlorine was also detected but it did not show good correlation between the LIBS and NAA techniques. This research shows that LIBS can be used as a fast, high-spatial resolution technique to quantify elements as part of large-scale field phenotyping projects.« less

Utilization of leaf litter as a potential feed source

USDA-ARS?s Scientific Manuscript database

Proximate analysis and In-situ nylon bag ruminal dry matter degradation of fall dropped Liriodendron tulipifera (tulip poplar) and Quercus alba (white oak) leaves were used to determine their potential use as a feed source for ruminant livestock animals. Ash content was 8.24 and 4.69 ...

The physiological response of Populus tremula x alba leaves to the down-regulation of PIP1 aquaporin gene expression under no water stress

PubMed Central

Secchi, Francesca; Zwieniecki, Maciej A.

2013-01-01

In order to study the role of PIP1 aquaporins in leaf water and CO2 transport, several lines of PIP1-deficient transgenic Populus tremula x alba were generated using a reverse genetic approach. These transgenic lines displayed no visible developmental or morphological phenotypes when grown under conditions of no water stress. Major photosynthetic parameters were also not affected by PIP1 down regulation. However, low levels of PIP1 expression resulted in greater leaf hydraulic resistance (an increase of 27%), which effectively implicated PIP1 role in water transport. Additionally, the expression level of PIP1 genes in the various transgenic lines was correlated with reductions in mesophyll conductance to CO2 (gm), suggesting that in poplar, these aquaporins influenced membrane permeability to CO2. Overall, although analysis showed that PIP1 genes contributed to the mass transfer of water and CO2 in poplar leaves, their down-regulation did not dramatically impair the physiological needs of this fast growing tree when cultivated under conditions of no stress. PMID:24379822

Prospects for advancing defense to cereal rusts through genetical genomics

PubMed Central

Ballini, Elsa; Lauter, Nick; Wise, Roger

2013-01-01

Rusts are one of the most severe threats to cereal crops because new pathogen races emerge regularly, resulting in infestations that lead to large yield losses. In 1999, a new race of stem rust, Puccinia graminis f. sp. tritici (Pgt TTKSK or Ug99), was discovered in Uganda. Most of the wheat and barley cultivars grown currently worldwide are susceptible to this new race. Pgt TTKSK has already spread northward into Iran and will likely spread eastward throughout the Indian subcontinent in the near future. This scenario is not unique to stem rust; new races of leaf rust (Puccinia triticina) and stripe rust (Puccinia striiformis) have also emerged recently. One strategy for countering the persistent adaptability of these pathogens is to stack complete- and partial-resistance genes, which requires significant breeding efforts in order to reduce deleterious effects of linkage drag. These varied resistance combinations are typically more difficult for the pathogen to defeat, since they would be predicted to apply lower selection pressure. Genetical genomics or expression Quantitative Trait Locus (eQTL) analysis enables the identification of regulatory loci that control the expression of many to hundreds of genes. Integrated deployment of these technologies coupled with efficient phenotyping offers significant potential to elucidate the regulatory nodes in genetic networks that orchestrate host defense responses. The focus of this review will be to present advances in genetical genomic experimental designs and analysis, particularly as they apply to the prospects for discovering partial disease resistance alleles in cereals. PMID:23641250

Intraguild interactions among specialised pollen feeders and generalist phytoseiids and their effect on citrus rust mite suppression.

PubMed

Maoz, Yonatan; Gal, Shira; Argov, Yael; Domeratzky, Sylvie; Coll, Moshe; Palevsky, Eric

2016-05-01

Antagonistic interactions among predators with shared prey are thought to hamper their ability to suppress herbivores. Our aim was to quantify intraguild interactions in omnivorous predatory mite assemblages in the presence of pollen, and assess their effect on pest populations. We focused on the following naturally occurring phytoseiid species in Israeli citrus orchards and their ability to suppress a key pest, the citrus rust mite (CRM) Phyllocoptruta oleivora (Eriophyidae): the generalists Amblyseius swirskii and Typhlodromus athiasae and the specialised pollen feeders Iphiseius degenerans, Euseius scutalis, E. stipulatus and E. victoriensis. Evaluations were performed on two spatial scales, tree seedlings and leaf discs. On seedlings, experiments were conducted to quantify the interactions between predators in the presence of pollen and its effects on CRM suppression. On leaf discs, intraguild interactions were studied between pairs of phytoseiid species in the presence of pollen without CRM. On seedlings, the specialised pollen predators were more effective at suppressing CRM populations than the generalist predators. In most cases, the more aggressive intraguild predator was the specialised pollen feeder. Similarly, leaf-disc experiments suggest that in these interactions the specialised pollen feeders tend to be the intraguild predators more often than the intraguild prey. © 2015 Society of Chemical Industry.

Registration of 'TAM 305' hard red winter Wheat

USDA-ARS?s Scientific Manuscript database

Leaf and stripe rusts (cause by Puccinia triticina Erikss. and Puccinia striiformis Westend. f. sp. tritici Erikss., respectively) are major disease problems in South Texas, Rolling Plains, and the Blacklands area of the state where hard red winter wheat (HRW; Triticum aestivum L.) is a major crop a...

Identification of novel powdery mildew resistance sources in wheat

USDA-ARS?s Scientific Manuscript database

Powdery mildew is a globally dominating disease of wheat with a high occurrence frequency, and genetic resistance plays an important role in managing this devastating disease. The objectives of this study were to evaluate leaf rust resistance and the underlying genes of breeding lines in the USA, a...

Virulence Phenotypes and Molecular Genotypes of Puccinia triticina Isolates from Italy

USDA-ARS?s Scientific Manuscript database

Twenty-four isolates of Puccinia triticina from Italy were characterized for virulence to seedlings of 22 common wheat cv. Thatcher isolines each with a different leaf rust resistance gene, and for molecular genotypes at 15 simple sequence repeat (SSR) loci. The isolates were compared with a set of ...

Chloroplast parameters differ in wild type and transgenic poplars overexpressing gsh1 in the cytosol.

PubMed

Ivanova, L A; Ronzhina, D A; Ivanov, L A; Stroukova, L V; Peuke, A D; Rennenberg, H

2009-07-01

Poplar mutants overexpressing the bacterial genes gsh1 or gsh2 encoding the enzymes of glutathione biosynthesis are among the best-characterised transgenic plants. However, this characterisation originates exclusively from laboratory studies, and the performance of these mutants under field conditions is largely unknown. Here, we report a field experiment in which the wild-type poplar hybrid Populus tremula x P. alba and a transgenic line overexpressing the bacterial gene gsh1 encoding gamma-glutamylcysteine synthetase in the cytosol were grown for 3 years at a relatively clean (control) field site and a field site contaminated with heavy metals. Aboveground biomass accumulation was slightly smaller in transgenic compared to wild-type plants; soil contamination significantly decreased biomass accumulation in both wild-type and transgenic plants by more than 40%. Chloroplasts parameters, i.e., maximal diameter, projection area and perimeter, surface area and volume, surface/volume ratio and a two-dimensional form coefficient, were found to depend on plant type, leaf tissue and soil contamination. The greatest differences between wild and transgenic poplars were observed at the control site. Under these conditions, chloroplast sizes in palisade tissue of transgenic poplar significantly exceeded those of the wild type. In contrast to the wild type, palisade chloroplast volume exceeded that of spongy chloroplasts in transgenic poplars at both field sites. Chlorophyll content per chloroplast was the same in wild and transgenic poplars. Apparently, the increase in chloroplast volume was not connected to changes in the photosynthetic centres. Chloroplasts of transgenic poplar at the control site were more elongated in palisade cells and close to spherical in spongy mesophyll chloroplasts. At the contaminated site, palisade and spongy cell chloroplasts of leaves from transgenic trees and the wild type were the same shape. Transgenic poplars also had a smaller chloroplast surface/volume ratio, both at the control and the contaminated site. Chloroplast number per cell did not differ between wild and transgenic poplars at the control site. Soil contamination led to suppression of chloroplast replication in wild-type plants. From these results, we assume that overexpressing the bacterial gsh1 gene in the cytosol interacts with processes in the chloroplast and that sequestration of heavy metal phytochelatin complexes into the vacuole may partially counteract this interaction in plants grown at heavy metal-contaminated field sites. Further experiments are required to test these assumptions.

Analyzing Genetic Diversity for Virulence and Resistance Phenotypes in Populations of Stem Rust (Puccinia graminis f. sp. secalis) and Winter Rye (Secale cereale).

PubMed

Miedaner, Thomas; Schmitt, Ann-Kristin; Klocke, Bettina; Schmiedchen, Brigitta; Wilde, Peer; Spieß, Hartmut; Szabo, Lilla; Koch, Silvia; Flath, Kerstin

2016-11-01

Stem rust (Puccinia graminis f. sp. secalis) leads to considerable yield losses in rye-growing areas with continental climate, from Eastern Germany to Siberia. For implementing resistance breeding, it is of utmost importance to (i) analyze the diversity of stem rust populations in terms of pathotypes (= virulence combinations) and (ii) identify resistance sources in winter rye populations. We analyzed 323 single-uredinial isolates mainly collected from German rye-growing areas across 3 years for their avirulence/virulence on 15 rye inbred differentials. Out of these, 226 pathotypes were detected and only 56 pathotypes occurred more than once. This high diversity was confirmed by a Simpson index of 1.0, a high Shannon index (5.27), and an evenness index of 0.97. In parallel, we investigated stem rust resistance among and within 121 heterogeneous rye populations originating mainly from Russia, Poland, Austria, and the United States across 3 to 15 environments (location-year combinations). While German rye populations had an average stem rust severity of 49.7%, 23 nonadapted populations were significantly (P < 0.01) more resistant with a stem rust severity ranging from 3 to 40%. Out of these, two modern Russian breeding populations and two old Austrian landraces were the best harboring 32 to 70% fully resistant plants across 8 to 10 environments. These populations with the lowest disease severity in adult-plant stage in the field also displayed resistance in leaf segment tests. In conclusion, stem rust populations are highly diverse and the majority of resistances in rye populations seems to be race specific.

Effects of Heavy Metals and Arbuscular Mycorrhiza on the Leaf Proteome of a Selected Poplar Clone: A Time Course Analysis

PubMed Central

Lingua, Guido; Bona, Elisa; Todeschini, Valeria; Cattaneo, Chiara; Marsano, Francesco; Berta, Graziella; Cavaletto, Maria

2012-01-01

Arbuscular mycorrhizal (AM) fungi establish a mutualistic symbiosis with the roots of most plant species. While receiving photosynthates, they improve the mineral nutrition of the plant and can also increase its tolerance towards some pollutants, like heavy metals. Although the fungal symbionts exclusively colonize the plant roots, some plant responses can be systemic. Therefore, in this work a clone of Populus alba L., previously selected for its tolerance to copper and zinc, was used to investigate the effects of the symbiosis with the AM fungus Glomus intraradices on the leaf protein expression. Poplar leaf samples were collected from plants maintained in a glasshouse on polluted (copper and zinc contaminated) or unpolluted soil, after four, six and sixteen months of growth. For each harvest, about 450 proteins were reproducibly separated on 2DE maps. At the first harvest the most relevant effect on protein modulation was exerted by the AM fungi, at the second one by the metals, and at the last one by both treatments. This work demonstrates how importantly the time of sampling affects the proteome responses in perennial plants. In addition, it underlines the ability of a proteomic approach, targeted on protein identification, to depict changes in a specific pattern of protein expression, while being still far from elucidating the biological function of each protein. PMID:22761694

Poplar response to cadmium and lead soil contamination.

PubMed

Radojčić Redovniković, Ivana; De Marco, Alessandra; Proietti, Chiara; Hanousek, Karla; Sedak, Marija; Bilandžić, Nina; Jakovljević, Tamara

2017-10-01

An outdoor pot experiment was designed to study the potential of poplar (Populus nigra 'Italica') in phytoremediation of cadmium (Cd) and lead (Pb). Poplar was treated with a combination of different concentrations of Cd (w = 10, 25, 50mgkg -1 soil) and Pb (400, 800, 1200mgkg -1 soil) and several physiological and biochemical parameters were monitored including the accumulation and distribution of metals in different plant parts (leaf, stem, root). Simultaneously, the changes in the antioxidant system in roots and leaves were monitored to be able to follow synergistic effects of both heavy metals. Moreover, a statistical analysis based on the Random Forests Analysis (RFA) was performed in order to determine the most important predictors affecting growth and antioxidative machinery activities of poplar under heavy metal stress. The study demonstrated that tested poplar could be a good candidate for phytoextraction processes of Cd in moderately contaminated soils, while in heavily contaminated soil it could be only considered as a phytostabilisator. For Pb remediation only phytostabilisation process could be considered. By using RFA we pointed out that it is important to conduct the experiments in an outdoor space and include environmental conditions in order to study more realistic changes of growth parameters and accumulation and distribution of heavy metals. Also, to be able to better understand the interactions among previously mentioned parameters, it is important to conduct the experiments during prolonged time exposure., This is especially important for the long life cycle woody species. Copyright © 2017. Published by Elsevier Inc.

Greater efficiency of water use in poplar clones having a delayed response of mesophyll conductance to drought.

PubMed

Théroux Rancourt, Guillaume; Éthier, Gilbert; Pepin, Steeve

2015-02-01

Improvement of water use efficiency is a key objective to improve the sustainability of cultivated plants, especially fast growing species with high water consumption like poplar. It is well known that water use efficiency (WUE) varies considerably among poplar genotypes, and it was recently suggested that the use of the mesophyll-to-stomatal conductance ratio (gm/gs) would be an appropriate trait to improve WUE. The responses of 7-week-old cuttings of four hybrid poplar clones and one native Balsam poplar (Populus balsamifera L.) to a water stress-recovery cycle were examined to evaluate the relation between the gm/gs ratio and transpiration efficiency (TE), a leaf-level component of WUE. A contrasting gs response to water stress was observed among the five clones, from stomatal closure early on during soil drying up to limited closure in Balsam poplar. However in the hybrids, the decline in gm was consistently delayed by a few days compared with gs. Moreover, in the most water use-efficient hybrids, the recovery following rehydration occurred faster for gm than for gs. Thus, the delay in the response of gm to drought and its faster recovery upon rewatering increased the gm/gs of the hybrids and this ratio scaled positively with TE. Our results support the use of the gm/gs ratio to select genotypes with improved WUE, and the notion that breeding strategies focusing mainly on stomatal responses to soil drying should also look for a strong curvilinearity between net carbon assimilation rate and gs, the indication of a significant increase in gm/gs in the earlier stages of stomatal closure. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Water relations and gas exchange in poplar and willow under water stress and elevated atmospheric CO2.

PubMed

Johnson, Jon D; Tognetti, Roberto; Paris, Piero

2002-05-01

Predictions of shifts in rainfall patterns as atmospheric [CO2] increases could impact the growth of fast growing trees such as Populus spp. and Salix spp. and the interaction between elevated CO2 and water stress in these species is unknown. The objectives of this study were to characterize the responses to elevated CO2 and water stress in these two species, and to determine if elevated CO2 mitigated drought stress effects. Gas exchange, water potential components, whole plant transpiration and growth response to soil drying and recovery were assessed in hybrid poplar (clone 53-246) and willow (Salix sagitta) rooted cuttings growing in either ambient (350 &mgr;mol mol-1) or elevated (700 &mgr;mol mol-1) atmospheric CO2 concentration ([CO2]). Predawn water potential decreased with increasing water stress while midday water potentials remained unchanged (isohydric response). Turgor potentials at both predawn and midday increased in elevated [CO2], indicative of osmotic adjustment. Gas exchange was reduced by water stress while elevated [CO2] increased photosynthetic rates, reduced leaf conductance and nearly doubled instantaneous transpiration efficiency in both species. Dark respiration decreased in elevated [CO2] and water stress reduced Rd in the trees growing in ambient [CO2]. Willow had 56% lower whole plant hydraulic conductivity than poplar, and showed a 14% increase in elevated [CO2] while poplar was unresponsive. The physiological responses exhibited by poplar and willow to elevated [CO2] and water stress, singly, suggest that these species respond like other tree species. The interaction of [CO2] and water stress suggests that elevated [CO2] did mitigate the effects of water stress in willow, but not in poplar.

The cloning and characterization of a poplar stomatal density gene

Treesearch

Shaneka S. Lawson; Paula M. Pijut; Charles H. Michler

2014-01-01

EPIDERMAL PATTERNING FACTOR1 (EPF1) is a well characterized negative regulator of cell division in Arabidopsis thaliana (AtEPF1) where the primary region of localization is the leaf. However, little data have been reported on the role of EPF1 in other plant species. In this study, the EPF1 gene from ...

Energy partitioning and surface resistance of a poplar plantation in northern China

NASA Astrophysics Data System (ADS)

Kang, M.; Zhang, Z.; Noormets, A.; Fang, X.; Zha, T.; Zhou, J.; Sun, G.; McNulty, S. G.; Chen, J.

2015-07-01

Poplar (Populus sp.) plantations have been, on the one hand, broadly used in northern China for urban greening, combating desertification, as well as for paper and wood production. On the other hand, such plantations have been questioned occasionally for their possible negative impacts on water availability due to the higher water-use nature of poplar trees compared with other tree species in water-limited dryland regions. To further understand the acclimation of poplar species to semiarid environments and to evaluate the potential impacts of these plantations on the broader context of the region's water supply, we examine the variability of bulk resistance parameters and energy partitioning in a poplar (Populus euramericana cv. "74/76") plantation located in northern China over a 4-year period, encompassing both dry and wet conditions. The partitioning of available energy to latent heat flux (LE) decreased from 0.62 to 0.53 under mediated meteorological drought by irrigation applications. A concomitant increase in sensible heat flux (H) resulted in the increase of a Bowen ratio from 0.83 to 1.57. Partial correlation analysis indicated that surface resistance (Rs) normalized by leaf area index (LAI; Rs:LAI) increased by 50 % under drought conditions and was the dominant factor controlling the Bowen ratio. Furthermore, Rs was the main factor controlling LE during the growing season, even in wet years, as indicated by the decoupling coefficient (Ω = 0.45 and 0.39 in wet and dry years, respectively). Rs was also a major regulator of the LE / LEeq ratio, which decreased from 0.81 in wet years to 0.68 in dry years. All physiological and bioclimatological metrics indicated that the water demands of the poplar plantation were greater than the amount available through precipitation, highlighting the poor match of a water-intensive species like poplar for this water-limited region.

Developing xylem-preferential expression of PdGA20ox1, a gibberellin 20-oxidase 1 from Pinus densiflora, improves woody biomass production in a hybrid poplar.

PubMed

Jeon, Hyung-Woo; Cho, Jin-Seong; Park, Eung-Jun; Han, Kyung-Hwan; Choi, Young-Im; Ko, Jae-Heung

2016-04-01

Woody biomass has gained popularity as an environmentally friendly, renewable and sustainable resource for liquid fuel production. Here, we demonstrate biotechnological improvement of the quantity and quality of woody biomass by employing developing xylem (DX)-preferential production of gibberellin (GA), a phytohormone that positively regulates stem growth. First, for the proof of concept experiment, we produced transgenic Arabidopsis plants expressing GA20-oxidase, a key enzyme in the production of bioactive GAs, from Pinus densiflora (PdGA20ox1) under the control of either a constitutive 35S promoter, designated 35S::PdGA20ox1, or a DX-specific promoter (originated from poplar), designated DX15::PdGA20ox1. As we hypothesized, both transgenic Arabidopsis plants (35S::PdGA20ox1 and DX15::PdGA20ox1) exhibited an accelerated stem growth that resulted in a large increase of biomass, up to 300% compared to wild-type control plants, together with increased secondary wall thickening and elongation of fibre cells. Next, we applied our concept to the production of transgenic poplar trees. Both transgenic poplar trees (35S::PdGA20ox1 and DX15::PdGA20ox1) showed dramatic increases in biomass, up to 300%, with accelerated stem growth and xylem differentiation. Cell wall monosaccharide composition analysis revealed that in both Arabidopsis and poplar, glucose and xylose contents were significantly increased. However, undesirable phenotypes of 35S::PdGA20ox1 poplar, including poor root growth and leaf development, were found. Interestingly, DX15::PdGA20ox1 poplar resulted in a reduction of undesirable phenotypes. Our results indicate that the controlled production of GAs through a tissue-specific promoter can be utilized as an efficient biotechnological tool for producing enhanced plant biomass, minimizing unwanted effects. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

QTL mapping for benzoxazinoid content, preharvest sprouting, α-amylase activity, and leaf rust resistance in rye (Secale cereale L.)

PubMed Central

Masojć, Piotr; Krajewski, Paweł; Stochmal, Anna; Kowalczyk, Mariusz; Angelov, Mihail; Ivanova, Valentina; Schollenberger, Małgorzata; Wakuliński, Wojciech; Banaszak, Zofia; Banaszak, Katarzyna; Rakoczy-Trojanowska, Monika

2017-01-01

Mapping population of recombinant inbred lines (RILs) representing 541 × Ot1-3 cross exhibited wide variations of benzoxazinoid (BX) content in leaves and roots, brown rust resistance, α-amylase activity in the grain, and resistance to preharvest sprouting. QTL mapping of major BX species using a DArT-based map revealed a complex genetic architecture underlying the production of these main secondary metabolites engaged in stress and allelopathy responses. The synthesis of BX in leaves and roots was found to be regulated by different QTL. The QTL for the BX content, rust resistance, α-amylase activity, and preharvest sprouting partially overlapped; this points to their common genetic regulation by a definite subset of genes. Only one QTL for BX located on chromosome 7R coincided with the loci of the ScBx genes, which were mapped as two clusters on chromosomes 5RS (Bx3-Bx5) and 7R (Bx1-Bx2). The QTL common for several BX species, rust resistance, preharvest sprouting, and α-amylase activity are interesting objects for further exploration aimed at developing common markers for these important agronomic traits. PMID:29267335

Structural variability and niche differentiation in the rhizosphere and endosphere bacterial microbiome of field-grown poplar trees.

PubMed

Beckers, Bram; Op De Beeck, Michiel; Weyens, Nele; Boerjan, Wout; Vangronsveld, Jaco

2017-02-23

The plant microbiome represents one of the key determinants of plant health and productivity by providing a plethora of functional capacities such as access to low-abundance nutrients, suppression of phytopathogens, and resistance to biotic and/or abiotic stressors. However, a robust understanding of the structural composition of the bacterial microbiome present in different plant microenvironments and especially the relationship between below-ground and above-ground communities has remained elusive. In this work, we addressed hypotheses regarding microbiome niche differentiation and structural stability of the bacterial communities within different ecological plant niches. We sampled the rhizosphere soil, root, stem, and leaf endosphere of field-grown poplar trees (Populus tremula × Populus alba) and applied 16S rRNA amplicon pyrosequencing to unravel the bacterial communities associated with the different plant habitats. We found that the structural variability of rhizosphere microbiomes in field-grown poplar trees (P. tremula × P. alba) is much lower than that of the endosphere microbiomes. Furthermore, our data not only confirm microbiome niche differentiation reports at the rhizosphere soil-root interface but also clearly show additional fine-tuning and adaptation of the endosphere microbiome in the stem and leaf compartment. Each plant compartment represents an unique ecological niche for the bacterial communities. Finally, we identified the core bacterial microbiome associated with the different ecological niches of Populus. Understanding the complex host-microbe interactions of Populus could provide the basis for the exploitation of the eukaryote-prokaryote associations in phytoremediation applications, sustainable crop production (bio-energy efficiency), and/or the production of secondary metabolites.

Identification and characterization of expressed resistance gene analogs (RGSs) from peanut (Arachis hypogaea L.) expressed sequence tags (ESTs)

USDA-ARS?s Scientific Manuscript database

Cultivated peanut (Arachis hypogaea L.) is an important food legume grown worldwide for providing edible oil and protein. However, due to scarcity of genetic diversity, peanut is very vulnerable to a variety of pathogens, such as rust (Puccinia arachidis Speg.), early leaf spot (Cercospora arachidic...

Using transcription of six Puccinia triticina races to identify the secretome during infection of wheat

USDA-ARS?s Scientific Manuscript database

Wheat leaf rust, caused by the basidiomycete Puccinia triticina, can cause yield losses of up to 20% in wheat-producing regions. During infection, the fungus forms haustoria that secrete proteins into the plant cell and effect changes in plant transcription, metabolism and defense. It is hypothesize...

Physiologic specialization of Puccinia triticina on Wheat in the United States in 2015

USDA-ARS?s Scientific Manuscript database

Collections of Puccinia triticina obtained from wheat fields and breeding plots in the Great Plains, Ohio River Valley, and southeastern states, were tested for virulence in 2015 in order to determine the virulence of the wheat leaf rust pathogen population in the United States. Single uredinial iso...

Bulked segregant analysis identifies molecular markers linked to Melampsora medusae resistance in Populus deltoides

Treesearch

G. M. Tabor; Thomas L. Kubisiak; N. B. Klopfenstein; R. B. Hall; Henry S. McNabb

2000-01-01

In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides...

WHEAT LEAF RUST SEVERITY AS AFFECTED BY PLANT DENSITY AND SPECIES PROPORTION IN SIMPLE COMMUNITIES OF WHEAT AND WILD OATS

EPA Science Inventory

While it is generally accepted that dense stands of plants exacerbate epidemics caused by foliar pathogens, there is little experimental evidence to support this view. We grew model plant communities consisting of wheat and wild oats at different densities and proportions and exp...

WHEAT LEAF RUST SEVERITY AS AFFECTED BY PLANT DENSITY AND SPECIES PROPORTION IN SIMPLE COMMUNITIES OF WHEAT AND WILD OATS

EPA Science Inventory

While it is generally accepted that dense stands of plants exacerbate epidermics caused by foliar pathogens, there is little experimental evidence to support this view. We grew model plant communities consisting of wheat and wild oats at different densities and proportions and ex...

Ornamental and Turf Pest Control. Bulletin 764.

ERIC Educational Resources Information Center

Bowyer, Timothy H.; And Others

This manual gives descriptions of and methods for control of diseases and insect pests of ornamental plants, weeds, and diseases and insect pests of turf plants. Included are diseases caused by fungi such as cankers, leaf galls, and rust; diseases caused by bacteria such as bacterial blight and crown gall; and diseases caused by nematodes and…

Dehydro-alpha-lapachone isolated from Catalpa ovata stems: activity against plant pathogenic fungi.

PubMed

Cho, Jun Young; Kim, Hae Young; Choi, Gyung Ja; Jang, Kyoung Soo; Lim, He Kyoung; Lim, Chi Hwan; Cho, Kwang Yun; Kim, Jin-Cheol

2006-05-01

The methanol extract of stems of Catalpa ovata G Don exhibits potent in vivo antifungal activity against Magnaporthe grisea (Hebert) Barr (rice blast) on rice plants, Botrytis cinerea Pers ex Fr (tomato grey mould) and Phytophthora infestans (Mont) de Bary (tomato late blight) on tomato plants, Puccinia recondita Rob ex Desm (wheat leaf rust) on wheat plants and Blumeria graminis (DC) Speer f. sp. hordei Marchal (barley powdery mildew) on barley plants. An antifungal substance was isolated and identified as dehydro-alpha-lapachone from mass and nuclear magnetic resonance spectral data. It completely inhibited the mycelial growth of B. cinerea, Colletotrichum acutatum Simmonds, Colletotrichum gloeosporioides Simmonds, M. grisea and Pythium ultimum Trow over a range of 0.4-33.3 mg litre(-1). It also controlled the development of rice blast, tomato late blight, wheat leaf rust, barley powdery mildew and red pepper anthracnose (Colletotrichum coccodes (Wallr) S Hughes). The chemical was particularly effective in suppressing red pepper anthracnose by 95% at a concentration of 125 mg litre(-1). Copyright 2006 Society of Chemical Industry.

Investigation of the effect of AtWIN1/SHN1 overexpression on poplar trees

Treesearch

Shaneka S.  Lawson

2016-01-01

Background: Interactions between plants and the environment occur primarily at the leaf level. The plant cuticle consists of a menagerie of lipids, waxes and polymers merging to form an insoluble membrane to protect plant leaves from contamination. In Arabidopsis, wax Inducer1/shine1 (WIN1/SHN1) and its family members have demonstrated roles in wax...

Registration of spring wheat sources of the resistance genes Lr53, Lr56, Lr59 and Lr62

USDA-ARS?s Scientific Manuscript database

Spring wheat (Triticum aestivum L.) germplasm with the alien derived leaf rust (caused by Puccinia triticina Erikss) resistance genes, Lr53, Lr56, Lr59, and Lr62 has been developed with infrastructure and financial support provided consecutively by the University of Stellenbosch (South Africa), the ...

Molecular markers linked to genes important for Hard Winter Wheat production and marketing in the U.S. Great Plains

USDA-ARS?s Scientific Manuscript database

Biotic stresses including diseases [leaf, stem and stripe rusts, and wheat streak mosaic virus (WSMV)] and insects [greenbug (GB), Hessian fly (Hf), Russian wheat aphid (RWA) and wheat curl mite (WCM)] significantly affect grain yield and end-use quality of hard winter wheat (HWW, Triticum aestivum ...

Controlling Infectious Diseases in Nurseries

Treesearch

T. H. Filer

1968-01-01

At least 300 publications have been written about non-infectious and infectious diseases of tree seedlings. I will outline some of the progress that is being made in finding ways to control infectious diseases, those caused by pathogens. I will touch upon pre- and post-emergence damping-off, root rots, leaf spots, and fusiform rust, which are the most serious diseases...

The potential of pathogens as biological control of parthenium weed (Parthenium hysterophorus L.) in Ethiopia.

PubMed

Taye, T; Gossmann, M; Einhorn, G; Büttner, C; Metz, R; Abate, D

2002-01-01

P. hsyterophorus is an exotic invasive annual weed now causing severe infestation in Ethiopia. Studies on diagnosis, incidence and distribution of pathogens associated with parthenium weed in Ethiopia were carried out from 1998-2002. Several fungal isolates were obtained from seed and other parts of parthenium plants. Among them were putative pathogenic fungal species of the genus Helminthosporium, Phoma, Curvularia, Chaetomium, Alternaria, and Fusarium. However, pathogenecity test of the isolates obtained showed no or non-specific symptoms. It was concluded that these pathogens could be opportunistic with insignificant potential for biological control of parthenium. Two most important diseases associated with parthenium were a rust disease, caused by Puccinia abrupta var. partheniicola, and a phyllody disease, caused by a phytoplasma of fababean phyllody (PBP) phytoplasma group. The rust was commonly found in cool mid altitude (1500-2500 m) areas while phyllody was observed in low to mid altitude regions (900-2500 m) of Ethiopia, with a disease incidence up to 100% and 75%, respectively, in some locations. Study of the individual effects of the rust and phyllody diseases under field conditions showed a reduction on weed morphological parameters (plant height, leaf area, and dry matter yield). Parthenium seed production was reduced by 42% and 85% due to rust and phyllody, respectively. Phyllody and rust diseases of parthenium showed significant potential for classical biological control of parthenium after further confirmation of insect vectors that transmit phyllody and host range of phyllody disease to the related economic plants in Ethiopia.

Limitations for phytoextraction management on metal-polluted soils with poplar short rotation coppice-evidence from a 6-year field trial.

PubMed

Michels, E; Annicaerta, B; De Moor, S; Van Nevel, L; De Fraeye, M; Meiresonne, L; Vangronsveld, J; Tack, F M G; Ok, Y S; Meers, Erik

2018-01-02

Poplar clones were studied for their phytoextraction capacity in the second growth cycle (6-year growth) on a site in the Belgian Campine region, which is contaminated with Cd and Zn via historic atmospheric deposition of nearby zinc smelter activities. The field trial revealed regrowth problems for some clones that could not be predicted in the first growth cycle. Four allometric relations were assessed for their capacity to predict biomass yield in the second growth cycle. A power function based on the shoot diameter best estimates the biomass production of poplar with R 2 values between 0.94 and 0.98. The woody biomass yield ranged from 2.1 to 4.8 ton woody Dry Mass (DM) ha -1 y -1 . The primary goal was to reduce soil concentrations of metals caused by phytoextraction. Nevertheless, increased metal concentrations were determined in the topsoil. This increase can partially be explained by the input of metals from deeper soil layers in the top soil through litterfall. The phytoextraction option with poplar short rotation coppice in this setup did not lead to the intended soil remediation in a reasonable time span. Therefore, harvest of the leaf biomass is put forward as a crucial part of the strategy for soil remediation through Cd/Zn phytoextraction.

Hybrid wheat: quantitative genetic parameters and consequences for the design of breeding programs.

PubMed

Longin, Carl Friedrich Horst; Gowda, Manje; Mühleisen, Jonathan; Ebmeyer, Erhard; Kazman, Ebrahim; Schachschneider, Ralf; Schacht, Johannes; Kirchhoff, Martin; Zhao, Yusheng; Reif, Jochen Christoph

2013-11-01

Commercial heterosis for grain yield is present in hybrid wheat but long-term competiveness of hybrid versus line breeding depends on the development of heterotic groups to improve hybrid prediction. Detailed knowledge of the amount of heterosis and quantitative genetic parameters are of paramount importance to assess the potential of hybrid breeding. Our objectives were to (1) examine the extent of midparent, better-parent and commercial heterosis in a vast population of 1,604 wheat (Triticum aestivum L.) hybrids and their parental elite inbred lines and (2) discuss the consequences of relevant quantitative parameters for the design of hybrid wheat breeding programs. Fifteen male lines were crossed in a factorial mating design with 120 female lines, resulting in 1,604 of the 1,800 potential single-cross hybrid combinations. The hybrids, their parents, and ten commercial wheat varieties were evaluated in multi-location field experiments for grain yield, plant height, heading time and susceptibility to frost, lodging, septoria tritici blotch, yellow rust, leaf rust, and powdery mildew at up to five locations. We observed that hybrids were superior to the mean of their parents for grain yield (10.7 %) and susceptibility to frost (-7.2 %), leaf rust (-8.4 %) and septoria tritici blotch (-9.3 %). Moreover, 69 hybrids significantly (P < 0.05) outyielded the best commercial inbred line variety underlining the potential of hybrid wheat breeding. The estimated quantitative genetic parameters suggest that the establishment of reciprocal recurrent selection programs is pivotal for a successful long-term hybrid wheat breeding.

The effects of high-tannin leaf litter from transgenic poplars on microbial communities in microcosm soils.

PubMed

Winder, Richard S; Lamarche, Josyanne; Constabel, C Peter; Hamelin, Richard C

2013-01-01

The impacts of leaf litter from genetically modified hybrid poplar accumulating high levels of condensed tannins (proanthocyanidins) were examined in soil microcosms consisting of moss growing on sieved soil. Moss preferentially proliferated in microcosms with lower tannin content; DGGE (denaturing gradient gel electrophoresis) detected increased fungal diversity in microcosms with low-tannin litter. The proportion of cloned rDNA sequences from Actinobacteria decreased with litter addition while Bacteroidetes, Chloroflexi, Cyanobacteria, and α-Proteobacteria significantly increased. β-Proteobacteria were proportionally more numerous at high-tannin levels. Tannins had no significant impact on overall diversity of bacterial communities analyzed with various estimators. There was an increased proportion of N-fixing bacteria corresponding to the addition of litter with low-tannin levels. The addition of litter increased the proportion of Ascomycota/Basidiomycota. Dothideomycetes, Pucciniomycetes, and Tremellomycetes also increased and Agaricomycetes decreased. Agaricomycetes and Sordariomycetes were significantly more abundant in controls, whereas Pucciniomycetes increased in soil with litter from transformed trees (P = 0.051). Richness estimators and diversity indices revealed no significant difference in the composition of fungal communities; PCoA (principal coordinate analyses) partitioned the fungal communities into three groups: (i) those with higher amounts of added tannin from both transformed and untransformed treatments, (ii) those corresponding to soils without litter, and (iii) those corresponding to microcosms with litter added from trees transformed only with a β-glucuronidase control vector. While the litter from transformed poplars had significant effects on soil microbe communities, the observed impacts reflected known impacts on soil processes associated with tannins, and were similar to changes that would be expected from natural variation in tannin levels.

Water use of a multigenotype poplar short-rotation coppice from tree to stand scale.

PubMed

Bloemen, Jasper; Fichot, Régis; Horemans, Joanna A; Broeckx, Laura S; Verlinden, Melanie S; Zenone, Terenzio; Ceulemans, Reinhart

2017-02-01

Short-rotation coppice (SRC) has great potential for supplying biomass-based heat and energy, but little is known about SRC's ecological footprint, particularly its impact on the water cycle. To this end, we quantified the water use of a commercial scale poplar ( Populus ) SRC plantation in East Flanders (Belgium) at tree and stand level, focusing primarily on the transpiration component. First, we used the AquaCrop model and eddy covariance flux data to analyse the different components of the stand-level water balance for one entire growing season. Transpiration represented 59% of evapotranspiration (ET) at stand scale over the whole year. Measured ET and modelled ET were lower as compared to the ET of reference grassland, suggesting that the SRC only used a limited amount of water. Secondly, we compared leaf area scaled and sapwood area scaled sap flow ( F s ) measurements on individual plants vs. stand scale eddy covariance flux data during a 39-day intensive field campaign in late summer 2011. Daily stem diameter variation (∆ D ) was monitored simultaneously with F s to understand water use strategies for three poplar genotypes. Canopy transpiration based on sapwood area or leaf area scaling was 43.5 and 50.3 mm, respectively, and accounted for 74%, respectively, 86%, of total ecosystem ET measured during the intensive field campaign. Besides differences in growth, the significant intergenotypic differences in daily ∆ D (due to stem shrinkage and swelling) suggested different water use strategies among the three genotypes which were confirmed by the sap flow measurements. Future studies on the prediction of SRC water use, or efforts to enhance the biomass yield of SRC genotypes, should consider intergenotypic differences in transpiration water losses at tree level as well as the SRC water balance at stand level.

Defeating the Warrior: genetic architecture of triticale resistance against a novel aggressive yellow rust race.

PubMed

Losert, Dominik; Maurer, Hans Peter; Leiser, Willmar L; Würschum, Tobias

2017-04-01

Genome-wide association mapping of resistance against the novel, aggressive 'Warrior' race of yellow rust in triticale revealed a genetic architecture with some medium-effect QTL and a quantitative component, which in combination confer high levels of resistance on both leaves and ears. Yellow rust is an important destructive fungal disease in small grain cereals and the exotic 'Warrior' race has recently conquered Europe. The aim of this study was to investigate the genetic architecture of yellow rust resistance in hexaploid winter triticale as the basis for a successful resistance breeding. To this end, a diverse panel of 919 genotypes was evaluated for yellow rust infection on leaves and ears in multi-location field trials and genotyped by genotyping-by-sequencing as well as for known Yr resistance loci. Genome-wide association mapping identified ten quantitative trait loci (QTL) for yellow rust resistance on the leaves and seven of these also for ear resistance. The total genotypic variance explained by the QTL amounted to 44.0% for leaf and 26.0% for ear resistance. The same three medium-effect QTL were identified for both traits on chromosomes 1B, 2B, and 7B. Interestingly, plants pyramiding the resistance allele of all three medium-effect QTL were generally most resistant, but constitute less than 5% of the investigated triticale breeding material. Nevertheless, a genome-wide prediction yielded a higher predictive ability than prediction based on these three QTL. Taken together, our results show that yellow rust resistance in winter triticale is genetically complex, including both medium-effect QTL as well as a quantitative resistance component. Resistance to the novel 'Warrior' race of this fungal pathogen is consequently best achieved by recurrent selection in the field based on identified resistant lines and can potentially be assisted by genomic approaches.

Influence of regeneration method and tissue source on the frequency of somatic variation in Populus to infection by Septoria musiva

Treesearch

Michael E. Ostry; Ronald L. Hackett; Charles H. Michler; R. Serres; B. McCown

1994-01-01

Septoria leaf spot and canker are serious diseases of many hybrid poplar clones in plantations established for biomass production. Developing resistant clones through breeding is the best long-term strategy to minimize tree damage caused by this disease. Tissue culture and somaclonal selection techniques may reduce the time needed to develop disease resistance in...

Projected and actual biomass production of 2- to 10- year-old intensively cultured Populus 'Tristis # 1'

Treesearch

J. Zavitkovski

1983-01-01

Intensively cultured plantations of Populus 'Tristis # 1' produce more than 10 mt/ha/year of woody biomass at most spacings as long as they are harvested when mean annual biomass increment (MABI) culminates. In addition, fully stocked plantations produce up to 4.4 mt/ha of leaf litter. Plantations of other poplar clones produce about 30% more woody biomass,...

Genetic and molecular characterization of leaf rust resistance in two durum landraces against the durum- specific Puccinia triticina races

USDA-ARS?s Scientific Manuscript database

The Portuguese durum landraces, Aus26582 and Aus26579, showed resistance against two very different durum-specific Puccinia triticina (Pt) races CA 1.2 and ETH 12.5-2 collected from California and Ethiopia, respectively. Aus26582 and Aus26579 were crossed with a susceptible landrace Bansi to develop...

Plantation forestry under global warming: hybrid poplars with improved thermotolerance provide new insights on the in vivo function of small heat shock protein chaperones.

PubMed

Merino, Irene; Contreras, Angela; Jing, Zhong-Ping; Gallardo, Fernando; Cánovas, Francisco M; Gómez, Luis

2014-02-01

Climate-driven heat stress is a key factor affecting forest plantation yields. While its effects are expected to worsen during this century, breeding more tolerant genotypes has proven elusive. We report here a substantial and durable increase in the thermotolerance of hybrid poplar (Populus tremula×Populus alba) through overexpression of a major small heat shock protein (sHSP) with convenient features. Experimental evidence was obtained linking protective effects in the transgenic events with the unique chaperone activity of sHSPs. In addition, significant positive correlations were observed between phenotype strength and heterologous sHSP accumulation. The remarkable baseline levels of transgene product (up to 1.8% of total leaf protein) have not been reported in analogous studies with herbaceous species. As judged by protein analyses, such an accumulation is not matched either by endogenous sHSPs in both heat-stressed poplar plants and field-grown adult trees. Quantitative real time-polymerase chain reaction analyses supported these observations and allowed us to identify the poplar members most responsive to heat stress. Interestingly, sHSP overaccumulation was not associated with pleiotropic effects that might decrease yields. The poplar lines developed here also outperformed controls under in vitro and ex vitro culture conditions (callus biomass, shoot production, and ex vitro survival), even in the absence of thermal stress. These results reinforce the feasibility of improving valuable genotypes for plantation forestry, a field where in vitro recalcitrance, long breeding cycles, and other practical factors constrain conventional genetic approaches. They also provide new insights into the biological functions of the least understood family of heat shock protein chaperones.

Modelling the growth of Populus species using Ecosystem Demography (ED) model

NASA Astrophysics Data System (ADS)

Wang, D.; Lebauer, D. S.; Feng, X.; Dietze, M. C.

2010-12-01

Hybrid poplar plantations are an important source being evaluated for biomass production. Effective management of such plantations requires adequate growth and yield models. The Ecosystem Demography model (ED) makes predictions about the large scales of interest in above- and belowground ecosystem structure and the fluxes of carbon and water from a description of the fine-scale physiological processes. In this study, we used a workflow management tool, the Predictive Ecophysiological Carbon flux Analyzer (PECAn), to integrate literature data, field measurement and the ED model to provide predictions of ecosystem functioning. Parameters for the ED ensemble runs were sampled from the posterior distribution of ecophysiological traits of Populus species compiled from the literature using a Bayesian meta-analysis approach. Sensitivity analysis was performed to identify the parameters which contribute the most to the uncertainties of the ED model output. Model emulation techniques were used to update parameter posterior distributions using field-observed data in northern Wisconsin hybrid poplar plantations. Model results were evaluated with 5-year field-observed data in a hybrid poplar plantation at New Franklin, MO. ED was then used to predict the spatial variability of poplar yield in the coterminous United States (United States minus Alaska and Hawaii). Sensitivity analysis showed that root respiration, dark respiration, growth respiration, stomatal slope and specific leaf area contribute the most to the uncertainty, which suggests that our field measurements and data collection should focus on these parameters. The ED model successfully captured the inter-annual and spatial variability of the yield of poplar. Analyses in progress with the ED model focus on evaluating the ecosystem services of short-rotation woody plantations, such as impacts on soil carbon storage, water use, and nutrient retention.

Genome-wide transcriptome profiling of black poplar (Populus nigra L.) under boron toxicity revealed candidate genes responsible in boron uptake, transport and detoxification.

PubMed

Yıldırım, Kubilay; Uylaş, Senem

2016-12-01

Boron (B) is an essential nutrient for normal growth of plants. Despite its low abundance in soils, it could be highly toxic to plants in especially arid and semi-arid environments. Poplars are known to be tolerant species to B toxicity and accumulation. However, physiological and gene regulation responses of these trees to B toxicity have not been investigated yet. Here, B accumulation and tolerance level of black poplar clones were firstly tested in the current study. Rooted cutting of these clones were treated with elevated B toxicity to select the most B accumulator and tolerant genotype. Then we carried out a microarray based transcriptome experiment on the leaves and roots of this genotype to find out transcriptional networks, genes and molecular mechanisms behind B toxicity tolerance. The results of the study indicated that black poplar is quite suitable for phytoremediation of B pollution. It could resist 15 ppm soil B content and >1500 ppm B accumulation in leaves, which are highly toxic concentrations for almost all agricultural plants. Transcriptomics results of study revealed totally 1625 and 1419 altered probe sets under 15 ppm B toxicity in leaf and root tissues, respectively. The highest induction were recorded for the probes sets annotated to tyrosine aminotransferase, ATP binding cassette transporters, glutathione S transferases and metallochaperone proteins. Strong up regulation of these genes attributed to internal excretion of B into the cell vacuole and existence of B detoxification processes in black poplar. Many other candidate genes functional in signalling, gene regulation, antioxidation, B uptake and transport processes were also identified in this hyper B accumulator plant for the first time with the current study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Boron accumulation and tolerance of hybrid poplars grown on a B-laden mixed paper mill waste landfill.

PubMed

Rees, Rainer; Robinson, Brett H; Rog, Christopher J; Papritz, Andreas; Schulin, Rainer

2013-03-01

Paper mill wastes are a mixture of by-products from pulp production and on-site energy production, consisting of paper mill sludge, ash and cinders. Landfilling of these highly boron (B) and heavy metal laden waste products carries environmental risks. Poplars have been successfully employed in the phytomanagement and hydraulic control of B contaminated sites. Here, we assess the performance of hybrid poplars on a paper-mill waste landfill, investigate the accumulation of B by the trees and explore the relationship between local-scale root growth and substrate properties. Leaf and root tissue samples were collected on three plots and analyzed for their chemical properties and root traits. Additionally, we sampled four soil cores in the vicinity of each of the trees and determined chemical and physical properties. Using a principal component analysis followed by a cluster analysis, we identified three substrate types. This method delineated the soil effects on tree survival and growth, although correlations with individual soil element concentrations were weak. Despite signs of B toxicity in some leaves, B was not the key limiting factor for poplar growth. Instead, Ca deficiency caused by a Mg:Ca imbalance was the primary reason for the poor performance of some trees. Root growth was not limited by toxicity effects of soil contaminants. Our results show that hybrid poplars perform well under the harsh growing conditions on a multi-contaminated, B-laden substrate in a hemiboreal climate. Exploiting the differences in the performance of the four clones in relation to the soil types, could increase the success of revegetation on this and other landfills. Copyright © 2012 Elsevier B.V. All rights reserved.

[Analysis of methylation-sensitive amplified polymorphism in wheat genome under the wheat leaf rust stress].

PubMed

Fu, Sheng-Jie; Wang, Hui; Feng, Li-Na; Sun, Yi; Yang, Wen-Xiang; Liu, Da-Qun

2009-03-01

Intrinsic DNA methylation pattern is an integral component of the epigenetic network in many eukaryotes. DNA methylation plays an important role in regulating gene expression in eukaryotes. Biological stress in plant provides an inherent epigenetic driving force of evolution. Study of DNA methylation patterns arising from biological stress will help us fully understand the epigenetic regulation of gene expression and DNA methylation of biological functions. The wheat near-isogenic lines TcLr19 and TcLr41 were resistant to races THTT and TKTJ, respectively, and Thatcher is compatible in the interaction with Puccinia triticina THTT and TKTJ, respectively. By means of methylation-sensitive amplified polymorphism (MSAP) analysis, the patterns of cytosine methylation in TcLr19, TcLr41, and Thatcher inoculated with P. triticina THTT and TKTJ were compared with those of the untreated samples. All the DNA fragments, each representing a recognition site cleaved by each or both of isoschizomers, were amplified using 60 pairs of selective primers. The results indicated that there was no significant difference between the challenged and unchallenged plants at DNA methylation level. However, epigenetic difference between the near-isogenic line for wheat leaf rust resistance gene Lr41 and Thatcher was present.

Verification of STS markers for leaf rust resistance genes of wheat by seven European laboratories.

PubMed

Błaszczyk, Lidia; Chełkowski, Jerzy; Korzun, Victor; Kraic, Jan; Ordon, Frank; Ovesná, Jaroslava; Purnhauser, Laszlo; Tar, Melinda; Vida, Gyula

2004-01-01

A set of Thatcher near-isogenic lines and two breeding lines were used to examine sequence tagged site (STS) markers linked to leaf rust resistance genes Lr9, Lr10, Lr19, Lr24, Lr28, Lr29, Lr35, and a simple sequenced repeat (SSR) marker for Lr39. The selected STS markers for resistance genes Lr9, Lr10, Lr19, Lr24 and Lr28 were identified in seven accessions by seven European laboratories. Near-isogenic lines of the spring wheat Thatcher were used as positive controls. Markers for resistance genes Lr9, Lr10, Lr19, Lr24 were identified in all seven laboratories as amplification products of 1100 bp, 310 bp, 130 bp and 310 bp, respectively. The STS markers linked to resistance genes Lr9, Lr10, Lr19, Lr24, Lr29, Lr35 and the SSR marker for Lr39 were robust and highly specific for these genes and will be useful in marker-assisted selection in wheat. However, the amplification product of 378 bp that corresponded with resistance gene Lr28 was detected in all accessions including genotypes lacking this gene in all seven laboratories. This marker needs to be improved.

Dry deposition of sulfate to Quercus rubra and Liriodendron tulipifera foliage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vandenberg, J.J.

1987-01-01

Estimates were made of the rate of dry deposition to red oak (Quercus rubra) and tulip poplar (Liriodendron tulipifera) foliage. In the laboratory, radioactive ammonium sulfate aerosols were generated in an exposure chamber. These aerosols were dry deposited onto leaves that were sequentially washed to examine the efficacy of washing procedures in removal of surface deposits. Over 90% of dry deposited sulfate was removed after a 30 second wash duration. Laboratory procedures also estimated the magnitude of foliar sulfur that leached into leaf wash solutions. The majority of laboratory leaves demonstrated no leaching of sulfur from the internal pool. However,more » some leaves showed significant sulfur leaching. It was concluded that leaching of internal sulfur was highly leaf specific. This indicated that each leaf used in field experiments needed to be individually examined for leaching.« less

Major Transcriptome Reprogramming Underlies Floral Mimicry Induced by the Rust Fungus Puccinia monoica in Boechera stricta

PubMed Central

Haugen, Riston H.; Saunders, Diane G. O.; Leonelli, Lauriebeth; MacLean, Dan; Hogenhout, Saskia A.; Kamoun, Sophien

2013-01-01

Pucciniamonoica is a spectacular plant parasitic rust fungus that triggers the formation of flower-like structures (pseudoflowers) in its Brassicaceae host plant Boechera stricta . Pseudoflowers mimic in shape, color, nectar and scent co-occurring and unrelated flowers such as buttercups. They act to attract insects thereby aiding spore dispersal and sexual reproduction of the rust fungus. Although much ecological research has been performed on P . monoica -induced pseudoflowers, this system has yet to be investigated at the molecular or genomic level. To date, the molecular alterations underlying the development of pseudoflowers and the genes involved have not been described. To address this, we performed gene expression profiling to reveal 256 plant biological processes that are significantly altered in pseudoflowers. Among these biological processes, plant genes involved in cell fate specification, regulation of transcription, reproduction, floral organ development, anthocyanin (major floral pigments) and terpenoid biosynthesis (major floral volatile compounds) were down-regulated in pseudoflowers. In contrast, plant genes involved in shoot, cotyledon and leaf development, carbohydrate transport, wax biosynthesis, cutin transport and L-phenylalanine metabolism (pathway that results in phenylethanol and phenylacetaldehyde volatile production) were up-regulated. These findings point to an extensive reprogramming of host genes by the rust pathogen to induce floral mimicry. We also highlight 31 differentially regulated plant genes that are enriched in the biological processes mentioned above, and are potentially involved in the formation of pseudoflowers. This work illustrates the complex perturbations induced by rust pathogens in their host plants, and provides a starting point for understanding the molecular mechanisms of pathogen-induced floral mimicry. PMID:24069397

Major transcriptome reprogramming underlies floral mimicry induced by the rust fungus Puccinia monoica in Boechera stricta.

PubMed

Cano, Liliana M; Raffaele, Sylvain; Haugen, Riston H; Saunders, Diane G O; Leonelli, Lauriebeth; MacLean, Dan; Hogenhout, Saskia A; Kamoun, Sophien

2013-01-01

Pucciniamonoica is a spectacular plant parasitic rust fungus that triggers the formation of flower-like structures (pseudoflowers) in its Brassicaceae host plant Boecherastricta. Pseudoflowers mimic in shape, color, nectar and scent co-occurring and unrelated flowers such as buttercups. They act to attract insects thereby aiding spore dispersal and sexual reproduction of the rust fungus. Although much ecological research has been performed on P. monoica-induced pseudoflowers, this system has yet to be investigated at the molecular or genomic level. To date, the molecular alterations underlying the development of pseudoflowers and the genes involved have not been described. To address this, we performed gene expression profiling to reveal 256 plant biological processes that are significantly altered in pseudoflowers. Among these biological processes, plant genes involved in cell fate specification, regulation of transcription, reproduction, floral organ development, anthocyanin (major floral pigments) and terpenoid biosynthesis (major floral volatile compounds) were down-regulated in pseudoflowers. In contrast, plant genes involved in shoot, cotyledon and leaf development, carbohydrate transport, wax biosynthesis, cutin transport and L-phenylalanine metabolism (pathway that results in phenylethanol and phenylacetaldehyde volatile production) were up-regulated. These findings point to an extensive reprogramming of host genes by the rust pathogen to induce floral mimicry. We also highlight 31 differentially regulated plant genes that are enriched in the biological processes mentioned above, and are potentially involved in the formation of pseudoflowers. This work illustrates the complex perturbations induced by rust pathogens in their host plants, and provides a starting point for understanding the molecular mechanisms of pathogen-induced floral mimicry.

The response of high and low polyamine producing cell lines to aluminum and calcium stress

Treesearch

Sridev Mohapatra; Smita Cherry; Rakesh Minocha; Rajtilak Majumdar; Palaniswamy Thangavel; Stephanie Long; Subhash C. Minocha

2010-01-01

The diamine putrescine (Put) has been shown to accumulate in tree leaves in response to high Al and low Ca in the soil, leading to the suggestion that this response may provide a physiological advantage to leaf cells under conditions of Al stress. The increase in Put is reversed by Ca supplementation in the soil. Using two cell lines of poplar (Populus nigra...

Laboratory-scale measurements of N2O and CH4 emissions from hybrid poplars (Populus deltoides x Populus nigra).

PubMed

McBain, M C; Warland, J S; McBride, R A; Wagner-Riddle, C

2004-12-01

The purpose of this study was to determine whether or not young hybrid poplar (Populus deltoides x Populus nigra) could transport landfill biogas internally from the root zone to the atmosphere, thereby acting as conduits for landfill gas release. Fluxes of methane (CH4) and nitrous oxide (N2O) from the seedlings to the atmosphere were measured under controlled conditions using dynamic flux chambers and a tunable diode laser trace gas analyser (TDLTGA). Nitrous oxide was emitted from the seedlings, but only when extremely high soil N2O concentrations were applied to the root zone. In contrast, no detectable emissions of CH4 were measured in a similar experimental trial. Visible plant morphological responses, characteristic of flood-tolerant trees attempting to cope with the negative effects of soil hypoxia, were observed during the CH4 experiments. Leaf chlorosis, leaf abscission and adventitious roots were all visible plant responses. In addition, seedling survival was observed to be highest in the biogas 'hot spot' areas of a local municipal solid waste landfill involved in this study. Based on the available literature, these observations suggest that CH4 can be transported internally by Populus deltoides x Populus nigra seedlings in trace amounts, although future research is required to fully test this hypothesis.

A DIGE analysis of developing poplar leaves subjected to ozone reveals major changes in carbon metabolism.

PubMed

Bohler, Sacha; Bagard, Matthieu; Oufir, Mouhssin; Planchon, Sébastien; Hoffmann, Lucien; Jolivet, Yves; Hausman, Jean-François; Dizengremel, Pierre; Renaut, Jenny

2007-05-01

Tropospheric ozone pollution is described as having major negative effects on plants, compromising plant survival. Carbon metabolism is especially affected. In the present work, the effects of chronic ozone exposure were evaluated at the proteomic level in developing leaves of young poplar plants exposed to 120 ppb of ozone for 35 days. Soluble proteins (excluding intrinsic membrane proteins) were extracted from leaves after 3, 14 and 35 days of ozone exposure, as well as 10 days after a recovery period. Proteins (pI 4 to 7) were analyzed by 2-D DIGE experiments, followed by MALDI-TOF-TOF identification. Additional observations were obtained on growth, lesion formation, and leaf pigments analysis. Although treated plants showed large necrotic spots and chlorosis in mature leaves, growth decreased only slightly and plant height was not affected. The number of abscised leaves was higher in treated plants, but new leaf formation was not affected. A decrease in chlorophylls and lutein contents was recorded. A large number of proteins involved in carbon metabolism were identified. In particular, proteins associated with the Calvin cycle and electron transport in the chloroplast were down-regulated. In contrast, proteins associated with glucose catabolism increased in response to ozone exposure. Other identified enzymes are associated with protein folding, nitrogen metabolism and oxidoreductase activity.

Leaf ontogeny dominates the seasonal exchange of volatile organic compounds (VOC) in a SRC-poplar plantation during an entire growing season

NASA Astrophysics Data System (ADS)

Brilli, Federico; Gioli, Beniamino; Fares, Silvano; Zenone, Terenzio; Zona, Donatella; Gielen, Bert; Loreto, Francesco; Janssens, Ivan; Ceulemans, Reinhart

2015-04-01

The declining cost of many renewable energy technologies and changes in the prices of fossil fuels have recently encouraged governments policies to subsidize the use of biomass as a sustainable source of energy. Deciduous poplars (Populus spp.) trees are often selected for biomass production in short rotation coppiced (SRC) for their high CO2 photosynthetic assimilation rates and their capacity to develop dense canopies with high values of leaf area index (LAI). So far, observations and projections of seasonal variations of many VOC fluxes has been limited to strong isoprenoids emitting evergreen ecosystems such tropical and Mediterranean forests as well as Citrus and oil palm plantation, all having constant values of LAI. We run a long-term field campaign where the exchange of VOC, together with CO2 and water vapor was monitored during an entire growing season (June - November, 2012) above a SRC-based poplar plantation. Our results confirmed that isoprene and methanol were the most abundant fluxes emitted, accounting for more than 90% of the total carbon released in form of VOC. However, Northern climates characterized by fresh summertime temperatures and recurring precipitations favored poplar growth while inhibiting the development of isoprene emission that resulted in only 0.7% of the net ecosystem carbon exchange (NEE). Besides, measurements of a multitude of VOC fluxes by PTR-TOF-MS showed bi-directional exchange of oxygenated-VOC (OVOC) such as: formaldehyde, acetaldehyde, acetone, isoprene oxidation products (iox, namely MVK, MAC and MEK) as well as ethanol and formic acid. The application of Self Organizing Maps to visualize the relationship between the full time-series of many VOC fluxes and the observed seasonal variations of environmental, physiological and structural parameters proved the most abundant isoprene ad methanol fluxes to occur mainly on the hottest days under mid-high light intensities when also NEE and evapotraspiration reached the highest rates. However, the seasonal pattern of methanol emission was also highly correlated with high VPD and NEE, whereas the highest isoprene emissions were mostly associated with the highest values of LAI. During the hottest and sunniest days we observed iox production triggered by photochemical reactions and deposition to the canopies. Nevertheless, peaks in formaldehyde deposition did not match with those of iox and isoprene emission. The emission of other OVOC species was mainly related to low values of LAI, most likely as a result of leaf senescence. We have compared the observed time-series of isoprene and methanol fluxes with the simulated seasonal patterns obtained from the canopy-scale model of emissions of gases and aerosols from nature (MEGAN). The model accuracy increased when a dynamic function to predict seasonal changes in the basal emission factor was applied. However, the simulated cumulative carbon emitted in form of isoprene underestimated the observed amount by 30% on a seasonal basis, whereas good agreement was found between observed and prediceted methanol emissions. Current research is aimed at improving process-based models that account for the ontogeny of leaves in order to predict the impact of VOC emitted from deciduous SRC-poplar plantations on air chemistry and quality.

Two small secreted proteins from Puccinia triticina induce reduction of ß-glucoronidase transient expression in wheat isolines containing Lr9, Lr24, and Lr26

USDA-ARS?s Scientific Manuscript database

Little is known about the molecular interaction of wheat and leaf rust (Puccinia triticina Eriks). However, genomic tools are now becoming available so that the host-pathogen interaction can be understood. In this work, a cDNA library was made from haustoria isolated from P. triticina race PBJL inf...

A new leaf rust resistance gene Lr79 mapped in chromosome 3BL from the durum wheat landrace Aus26582.

PubMed

Qureshi, Naeela; Bariana, Harbans; Kumran, Vikas Venu; Muruga, Sivasamy; Forrest, Kerrie L; Hayden, Mathew J; Bansal, Urmil

2018-05-01

A new leaf rust resistance gene Lr79 has been mapped in the long arm of chromosome 3B and a linked marker was identified for marker-assisted selection. Aus26582, a durum wheat landrace from the A. E. Watkins Collection, showed seedling resistance against durum-specific and common wheat-specific Puccinia triticina (Pt) pathotypes. Genetic analysis using a recombinant inbred line (RIL) population developed from a cross between Aus26582 and the susceptible parent Bansi with Australian Pt pathotype showed digenic inheritance and the underlying loci were temporarily named LrAW2 and LrAW3. LrAW2 was located in chromosome 6BS and this study focused on characterisation of LrAW3 using RILs lacking LrAW2. LrAW3 was incorporated into the DArTseq map of Aus26582/Bansi and was located in chromosome 3BL. Markers linked with LrAW3 were developed from the chromosome survey sequence contig 3B_10474240 in which closely-linked DArTseq markers 1128708 and 3948563 were located. Although bulk segregant analysis (BSA) with the 90 K Infinium array identified 51 SNPs associated with LrAW3, only one SNP-derived KASP marker mapped close to the locus. Deletion bin mapping of LrAW3-linked markers located LrAW3 between bins 3BL11-0.85-0.90 and 3BL7-0.63. Since no other all stage leaf rust resistance gene is located in chromosome 3BL, LrAW3 represented a new locus and was designated Lr79. Marker sun786 mapped 1.8 cM distal to Lr79 and Aus26582 was null for this locus. However, the marker can be reliably scored as it also amplifies a monomorphic fragment that serves as an internal control to differentiate the null status of Aus26582 from reaction failure. This marker was validated among a set of durum and common wheat cultivars and was shown to be useful for marker-assisted selection of Lr79 at both ploidy levels.

An evaluation of the rust fungus Gymnoconia nitensas a potential biological control agent for alien Rubus species in Hawaii

USGS Publications Warehouse

Gardner, D.E.; Hodges, C.S.; Killgore, E.; Anderson, R.C.

1997-01-01

The rust fungus Gymnoconia nitens infects blackberry (Rubus argutus) systemically in regions of the continental United States, producing bright yellow–orange masses of spores on newly developing floricanes during springtime. In tests to determine the suitability of this rust as a biological control agent for R. penetransin Hawaii, a species now thought to be conspecific with R. argutus,rooted cuttings of the Hawaiian plants were grown at North Carolina State University, inoculated, and observed. Other introduced weedy Rubus spp. in Hawaii, including R. ellipticus, R. rosifolius, and R. glaucus,as well as the two endemic species R. hawaiensis and R. macraei,also were inoculated. No species of Rubusare of commercial importance in Hawaii, but the protection of the native species, of which R. macraei is rare, was of utmost concern. The native Hawaiian species did not survive well in North Carolina in this study, however. Later availability of a plant pathogen containment laboratory in Hawaii enabled similar tests to be conducted at that facility. In addition to the above species, R. spectabilis (salmonberry), a species native to the Pacific Northwest with which the Hawaiian Rubus spp. are thought to share a common ancestor, was inoculated in Hawaii. Infection with G. nitens under natural field conditions becomes apparent only when sporulation occurs on floricanes the second year following infection. However, experimental inoculation led to early responses of chlorotic leaf flecking and puckering, leaf and stem contortion, and stem gall formation, indicating the sensitivity of R. penetrans (=R. argutus), R. hawaiensis, and R. macraei to this rust. Apparent systemic infection also resulted in sporulation on one plant of R. macraei. Ability to attack the endemic species suggests that G. nitens would not be suitable for release in Hawaii as a biological control agent, at least on the islands with populations of the native species.

Vapour pressure deficit during growth has little impact on genotypic differences of transpiration efficiency at leaf and whole-plant level: an example from Populus nigra L.

PubMed

Rasheed, Fahad; Dreyer, Erwin; Richard, Béatrice; Brignolas, Franck; Brendel, Oliver; Le Thiec, Didier

2015-04-01

Poplar genotypes differ in transpiration efficiency (TE) at leaf and whole-plant level under similar conditions. We tested whether atmospheric vapour pressure deficit (VPD) affected TE to the same extent across genotypes. Six Populus nigra genotypes were grown under two VPD. We recorded (1) (13)C content in soluble sugars; (2) (18)O enrichment in leaf water; (3) leaf-level gas exchange; and (4) whole-plant biomass accumulation and water use. Whole-plant and intrinsic leaf TE and (13)C content in soluble sugars differed significantly among genotypes. Stomatal conductance contributed more to these differences than net CO2 assimilation rate. VPD increased water use and reduced whole-plant TE. It increased intrinsic leaf-level TE due to a decline in stomatal conductance. It also promoted higher (18)O enrichment in leaf water. VPD had no genotype-specific effect. We detected a deviation in the relationship between (13)C in leaf sugars and (13)C predicted from gas exchange and the standard discrimination model. This may be partly due to genotypic differences in mesophyll conductance, and to its lack of sensitivity to VPD. Leaf-level (13)C discrimination was a powerful predictor of the genetic variability of whole-plant TE irrespective of VPD during growth. © 2014 John Wiley & Sons Ltd.

USE OF NATIVE PLANTS FOR REMEDIATION OF TRICHLOROETHYLENE: I. DECIDUOUS TREES.

PubMed

Strycharz, S; Newman, L

2009-02-01

Phytoremediation of trichloroethylene (TCE) can be accomplished using fast-growing, deep-rooting trees. The most commonly used tree for phytoremediation of TCE has been the hybrid poplar. This study looks at native southeastern trees of the United States as alternatives to the use of hybrid poplar. The use of native trees for phytoremediation allows for simultaneous restoration of contaminated sites. A 2-mo, greenhouse-based study was conducted to determine if sycamore (Plantanus L.), eastern cottonwood (Populus deltoides), sweetgum (Liquidambar styraciflua L.), and willow (Salix sachalinensis) trees possess the ability to degrade TCE by assessing TCE metabolite formation in the plant tissue. In addition to the metabolic capabilities of each tree species, growth parameters were measured including change in height, water usage, total fresh weight of each tissue type, and calculated total leaf surface area. Willow trees had the greatest increase in height among all trees tested; however, at higher concentrations TCE inhibits growth. Sycamore trees had the highest overall leaf surface area and total biomass, which correlated with sycamore trees also having the highest average water usage over the course of the experiment. Carbon tubes used to sample transpiration gases from sycamore, sweetgum, and cottonwood trees did not contain detectable levels of TCE. Tenex sample collection tubes used to sample willow trees during TCE exposure showed average TCE concentrations of up to 0.354 ng TCE cm -2 leaf tissue. All exposed trees contained TCE in the root, stem, and leaf tissues. The concentration of TCE remaining in tissues at the conclusion of the experiment varied, with the highest levels found in the roots and the lowest levels found in the leaves. Metabolites were also observed in different tissue types of all trees tested. The highest concentrations of trichloroacetic acid were observed in the leaves of the sycamore trees and cottonwood trees. Based on the growth parameters tested and the ability to metabolize TCE, sycamore and native cottonwood species are the best candidates for phytoremediation from this study.

Clonal tests of new cottonwood selections from the southeast

Treesearch

Jonathan Paul Jeffreys; Samuel B. Land; Emily B. Schultz; Andrew J. Londo

2006-01-01

One hundred “new” clones and 20 “check” clones were established with unrooted cuttings during March-April 2003 in a second-stage clonal trial in Missouri and Georgia. The new clones had been selected for 2-year superiority in Melampsora leaf rust resistance, height growth, and diameter growth during first-stage rooted cutting trials. All 120 clones were vegetatively...

An Integrated Functional Genomics Consortium to Increase Carbon Sequestration in Poplars: Optimizing Aboveground Carbon Gain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karnosky, David F; Podila, G Krishna; Burton, Andrew J

2009-02-17

This project used gene expression patterns from two forest Free-Air CO2 Enrichment (FACE) experiments (Aspen FACE in northern Wisconsin and POPFACE in Italy) to examine ways to increase the aboveground carbon sequestration potential of poplars (Populus). The aim was to use patterns of global gene expression to identify candidate genes for increased carbon sequestration. Gene expression studies were linked to physiological measurements in order to elucidate bottlenecks in carbon acquisition in trees grown in elevated CO2 conditions. Delayed senescence allowing additional carbon uptake late in the growing season, was also examined, and expression of target genes was tested in elitemore » P. deltoides x P. trichocarpa hybrids. In Populus euramericana, gene expression was sensitive to elevated CO2, but the response depended on the developmental age of the leaves. Most differentially expressed genes were upregulated in elevated CO2 in young leaves, while most were downregulated in elevated CO2 in semi-mature leaves. In P. deltoides x P. trichocarpa hybrids, leaf development and leaf quality traits, including leaf area, leaf shape, epidermal cell area, stomatal number, specific leaf area, and canopy senescence were sensitive to elevated CO2. Significant increases under elevated CO2 occurred for both above- and belowground growth in the F-2 generation. Three areas of the genome played a role in determining aboveground growth response to elevated CO2, with three additional areas of the genome important in determining belowground growth responses to elevated CO2. In Populus tremuloides, CO2-responsive genes in leaves were found to differ between two aspen clones that showed different growth responses, despite similarity in many physiological parameters (photosynthesis, stomatal conductance, and leaf area index). The CO2-responsive clone shunted C into pathways associated with active defense/response to stress, carbohydrate/starch biosynthesis and subsequent growth. The CO2-unresponsive clone partitioned C into pathways associated with passive defense and cell wall thickening. These results indicate that there is significant variation in gene expression patterns between different tree genotypes. Consequently, future efforts to improve productivity or other advantageous traits for carbon sequestration should include an examination of genetic variability in CO2 responsiveness.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, E.; Netzer, D.; Ostry, M.

Tree plantations at several sites have numerous clones with heights greater than 45 feet and diameters of 6+ inches in eight years. The fastest growth rates have been attained in a plantation on a wet site at Milaca, MN, a plantation at Granite Falls, WI, and a plantation at Mondovi, WI, where the largest trees are up to 8 inches DBH at age 8. Mean annual production ranges from 4 to 5+ dry tons per acre in the best clonal blocks, and up to 8.1 tons per acre for the best new hybrids. Reduced growth at some sites was relatedmore » primarily to insufficient soil water during the growing season, and susceptibility to the disease Septoria musiva. Most tree mortality (36 percent) occurred during the establishment year with only an additional 2 percent mortality over the next 7 years. Leaf tissue nitrogen (N) levels decreased as trees aged and approached the hypothesized 3 percent critical level as trees reached 5- and 6-years old. Fertilization at 75 and 150 lbs/acre N resulted in significant increases in leaf tissue. However, no significant increase in tree growth has been detected. There are significant clonal differences in leaf tissue nitrogen. Hybrid poplar plantations planted on agricultural fields produce significant increases in soil carbon, although there may be carbon loss during the early years of plantation establishment. Septoria musiva is the major pathogen affecting survival and growth of hybrid poplar plantations. A collection of 859 Septoria musiva and Septoria populicola isolates has shown considerably variability in the microorganism. Tissue culture techniques are being used to increase resistance to Septoria in clone NE-308. Over 200 generation 2 plants are ready for field testing in 1995.« less

Threshold response of mesophyll CO2 conductance to leaf hydraulics in highly transpiring hybrid poplar clones exposed to soil drying.

PubMed

Théroux-Rancourt, Guillaume; Éthier, Gilbert; Pepin, Steeve

2014-02-01

Mesophyll conductance (gm) has been shown to impose significant limitations to net CO2 assimilation (A) in various species during water stress. Net CO2 assimilation is also limited by stomatal conductance to water (gsw), both having been shown to co-vary with leaf hydraulic conductance (Kleaf). Lately, several studies have suggested a close functional link between Kleaf, gsw, and gm. However, such relationships could only be circumstantial since a recent study has shown that the response of gm to drought could merely be an artefactual consequence of a reduced intercellular CO2 mole fraction (Ci). Experiments were conducted on 8-week-old hybrid poplar cuttings to determine the relationship between Kleaf, gsw, and g m in clones of contrasting drought tolerance. It was hypothesized that changes in gsw and Kleaf in response to drought would not impact on gm over most of its range. The results show that Kleaf decreased in concert with g sw as drought proceeded, whereas gm measured at a normalized Ci remained relatively constant up to a g sw threshold of ~0.15 mol m(-2) s(-1). This delayed gm response prevented a substantial decline in A at the early stage of the drought, thereby enhancing water use efficiency. Reducing the stomatal limitation of droughted plants by diminishing the ambient CO2 concentration of the air did not modify gm or Kleaf. The relationship between gas exchange and leaf hydraulics was similar in both drought-tolerant and drought-sensitive clones despite their contrasting vulnerability to stem cavitation and stomatal response to soil drying. The results support the hypothesis of a partial hydraulic isolation of the mesophyll from the main transpiration pathway.

Water consumption and biomass production of protoplast fusion lines of poplar hybrids under drought stress

PubMed Central

Hennig, Anne; Kleinschmit, Jörg R. G.; Schoneberg, Sebastian; Löffler, Sonja; Janßen, Alwin; Polle, Andrea

2015-01-01

Woody crops such as poplars (Populus) can contribute to meet the increasing energy demand of a growing human population and can therefore enhance the security of energy supply. Using energy from biomass increases ecological sustainability as biomass is considered to play a pivotal role in abating climate change. Because areas for establishing poplar plantations are often confined to marginal sites drought tolerance is one important trait for poplar genotypes cultivated in short rotation coppice. We tested 9-month-old plants of four tetraploid Populus tremula (L.) × P. tremuloides (Michx.) lines that were generated by protoplast fusion and their diploid counterpart for water consumption and drought stress responses in a greenhouse experiment. The fusion lines showed equivalent or decreased height growth, stem biomass and total leaf area compared to the diploid line. The relative height increment of the fusion lines was not reduced compared to the diploid line when the plants were exposed to drought. The fusion lines were distinguished from the diploid counterpart by stomatal characteristics such as increased size and lower density. The changes in the stomatal apparatus did not affect the stomatal conductance. When exposed to drought the carbohydrate concentrations increased more strongly in the fusion lines than in the diploid line. Two fusion lines consumed significantly less water with regard to height growth, producing equivalent or increased relative stem biomass under drought compared to their diploid relative. Therefore, these tetraploid fusion lines are interesting candidates for short rotation biomass plantation on dry sites. PMID:26042130

Facing the Future: Effects of Short-Term Climate Extremes on Isoprene-Emitting and Nonemitting Poplar1

PubMed Central

Vanzo, Elisa; Jud, Werner; Li, Ziru; Albert, Andreas; Domagalska, Malgorzata A.; Ghirardo, Andrea; Niederbacher, Bishu; Frenzel, Juliane; Beemster, Gerrit T.S.; Asard, Han; Rennenberg, Heinz; Sharkey, Thomas D.; Hansel, Armin; Schnitzler, Jörg-Peter

2015-01-01

Isoprene emissions from poplar (Populus spp.) plantations can influence atmospheric chemistry and regional climate. These emissions respond strongly to temperature, [CO2], and drought, but the superimposed effect of these three climate change factors are, for the most part, unknown. Performing predicted climate change scenario simulations (periodic and chronic heat and drought spells [HDSs] applied under elevated [CO2]), we analyzed volatile organic compound emissions, photosynthetic performance, leaf growth, and overall carbon (C) gain of poplar genotypes emitting (IE) and nonemitting (NE) isoprene. We aimed (1) to evaluate the proposed beneficial effect of isoprene emission on plant stress mitigation and recovery capacity and (2) to estimate the cumulative net C gain under the projected future climate. During HDSs, the chloroplastidic electron transport rate of NE plants became impaired, while IE plants maintained high values similar to unstressed controls. During recovery from HDS episodes, IE plants reached higher daily net CO2 assimilation rates compared with NE genotypes. Irrespective of the genotype, plants undergoing chronic HDSs showed the lowest cumulative C gain. Under control conditions simulating ambient [CO2], the C gain was lower in the IE plants than in the NE plants. In summary, the data on the overall C gain and plant growth suggest that the beneficial function of isoprene emission in poplar might be of minor importance to mitigate predicted short-term climate extremes under elevated [CO2]. Moreover, we demonstrate that an analysis of the canopy-scale dynamics of isoprene emission and photosynthetic performance under multiple stresses is essential to understand the overall performance under proposed future conditions. PMID:26162427

bZIP transcription factor CgAP1 is essential for oxidative stress tolerance and full virulence of the poplar anthracnose fungus Colletotrichum gloeosporioides.

PubMed

Sun, Yingjiao; Wang, Yonglin; Tian, Chengming

2016-10-01

Yeast AP1 transcription factor is a regulator of oxidative stress response. Here, we report the identification and characterization of CgAP1, an ortholog of YAP1 in poplar anthracnose fungus Colletotrichum gloeosporioides. The expression of CgAP1 was highly induced by reactive oxygen species. CgAP1 deletion mutants displayed enhanced sensitivity to oxidative stress compared with the wild-type strain, and their poplar leaf virulence was obviously reduced. However, the mutants exhibited no obvious defects in aerial hyphal growth, conidia production, and appressoria formation. CgAP1::eGFP fusion protein localized to the nucleus after TBH (tert-Butyl hydroperoxide) treatment, suggesting that CgAP1 functions as a redox sensor in C. gloeosporioides. In addition, CgAP1 prevented the accumulation of ROS during early stages of biotrophic growth. CgAP1 also acted as a positive regulator of several ROS-related genes (i.e., Glr1, Hyr1, and Cyt1) involved in the antioxidative response. These results highlight the key regulatory role of CgAP1 transcription factor in oxidative stress response and provide insights into the function of ROS detoxification in virulence of C. gloeosporioides. Copyright © 2016 Elsevier Inc. All rights reserved.

Gene regulation network behind drought escape, avoidance and tolerance strategies in black poplar (Populus nigra L.).

PubMed

Yıldırım, Kubilay; Kaya, Zeki

2017-06-01

Drought is the major environmental problem limiting the productivity and survival of plant species. Here, previously identified three black poplar genotypes having contrasting response to drought were subjected to gradual soil water depletion in a pot trial to identify their physiological, morphological and antioxidation related adaptations. We also performed a microarray based transcriptome analyses on the leaves of genotypes by using Affymetrix poplar Genome Array containing 56,000 transcripts. Phenotypic analyses of each genotype confirmed their differential adaptations to drought that could be classified as drought escape, avoidance and tolerance. Comparative transcriptomic analysis indicated highly divergent gene expression patterns among the genotypes in response to drought and post drought re-watering (PDR). We identified 10641, 3824 and 9411 transcripts exclusively regulated in drought escape, avoidance and tolerant genotypes, respectively. The key genes involved in metabolic pathways, such as carbohydrate metabolism, photosynthesis, lipid metabolism, generation of precursor metabolites/energy, protein folding, redox homeostasis, secondary metabolic process and cell wall component biogenesis, were affected by drought stresses in the leaves of these genotypes. Transcript isoforms showed increased expression specificity in the genes coding for bark storage proteins and small heat shock proteins in drought tolerant genotype. On the other hand, drought-avoiding genotype specifically induced the transcripts annotated to the genes functional in secondary metabolite production that linked to enhanced leaf water content and growth performance under drought stress. Transcriptome profiling of drought escape genotype indicated specific regulation of the genes functional in programmed cell death and leaf senescence. Specific upregulation of GTP cyclohydrolase II and transcription factors (WRKY and ERFs) in only this genotype were associated to ROS dependent signalling pathways and gene regulation network responsible in induction of many degrading enzymes acting on cell wall carbohydrates, fatty acids and proteins under drought stress. Our findings provide new insights into the transcriptome dynamics and components of regulatory network associated with drought adaptation strategies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Towards a map of the Populus biomass protein-protein interaction network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beers, Eric; Brunner, Amy; Helm, Richard

Biofuels can be produced from a variety of plant feedstocks. The value of a particular feedstock for biofuels production depends in part on the degree of difficulty associated with the extraction of fermentable sugars from the plant biomass. The wood of trees is potentially a rich source fermentable sugars. However, the sugars in wood exist in a tightly cross-linked matrix of cellulose, hemicellulose, and lignin, making them largely recalcitrant to release and fermentation for biofuels production. Before breeders and genetic engineers can effectively develop plants with reduced recalcitrance to fermentation, it is necessary to gain a better understanding of themore » fundamental biology of the mechanisms responsible for wood formation. Regulatory, structural, and enzymatic proteins are required for the complicated process of wood formation. To function properly, proteins must interact with other proteins. Yet, very few of the protein-protein interactions necessary for wood formation are known. The main objectives of this project were to 1) identify new protein-protein interactions relevant to wood formation, and 2) perform in-depth characterizations of selected protein-protein interactions. To identify relevant protein-protein interactions, we cloned a set of approximately 400 genes that were highly expressed in the wood-forming tissue (known as secondary xylem) of poplar (Populus trichocarpa). We tested whether the proteins encoded by these biomass genes interacted with each other in a binary matrix design using the yeast two-hybrid (Y2H) method for protein-protein interaction discovery. We also tested a subset of the 400 biomass proteins for interactions with all proteins present in wood-forming tissue of poplar in a biomass library screen design using Y2H. Together, these two Y2H screens yielded over 270 interactions involving over 75 biomass proteins. For the second main objective we selected several interacting pairs or groups of interacting proteins for in-depth characterizations. Characterizations involved both in vivo and in vitro independent methods to confirm protein-protein interactions and the evaluation of novel phenotypes resulting from creation of transgenic poplar and Arabidopsis plants engineered for increased or decreased expression of the selected genes. Transgenic poplar trees were studied in growth chamber, greenhouse, and two separate replicated field trials involving over 25 distinct wood-associated proteins. In-depth characterizations yielding positive results include the following. First, a NAC domain transcription factor (NAC154) that is a promoter of stress response and dormancy in trees was discovered. Increasing expression of NAC154 caused stunted growth and premature senescence, while decreasing expression led to both delayed bud and leaf expansion in spring and delayed leaf drop (i.e., prolonged leaf retention) in fall. Second, we discovered and characterized a new connection between a negative regulator of wood formation, the NAC domain transcription factor XND1, and an important regulator of cell division and cell differentiation, RBR. Third, we identified a new network of interacting wood-associated transcription factors belonging to the MYB and HD families. One of the HD family proteins, WOX13, was used to prepare transgenic poplar for high-level expression, resulting in significantly increased lateral branch growth. Finally, we modeled and performed in vitro analyses of the insect protein rubber resilin and we prepared transgenic Arabidopsis plants for expression of resilin to test the feasibility of using resilin to modify lignin cross-linking in wood and reduce recalcitrance and improve yield of fermentable sugars for biofuels production. Analysis of these and additional transgenics created with this support is continuing.« less

Tree and stand water fluxes of hybrid poplar clone (Populus nigra x P. maximowiczii) in short rotation coppice culture

NASA Astrophysics Data System (ADS)

Fischer, M.; Trnka, M.; Kucera, J.; Zalud, Z.

2010-09-01

This study reports on evapotranspiration and tree water use in short rotation coppice culture of hybrid poplar (Populus nigra x P. maximowiczii) for biomass energy in the Czech Republic. The high density poplar plantation (10 000 trees per ha) was established in 2003 on arable land in Czech-Moravian Highland (49°32´ N, 16°15´ E, 530 m a.s.l.) and has been coppiced in rotation period of 7 years. Firstly, evapotranspiration of the stand has been estimated by applying the Bowen ratio-energy budget method, which is considered as reliable, robust, quite simple and inexpensive technique with comparable results to eddy covariance and lysimeters. The gaps in evapotranspiration diurnal patterns caused by limitation of the bowen ratio method were filled with simple linear regression model based on relation between potential and actual evapotranspiration with regard to soil water availability and leaf area index and thus the daily, monthly and seasonal totals could be calculated. The amount of evapotranspiration during the growing season 2009 (1 March - 31 October) was 593 mm with highest monthly total 116 mm in June. Mean daily water loss over the season reached 2.43 mm per day. During the hot summer day, the maximal value 5.73 mm per day, which presented 89 % of potential evapotranspiration calculated by Penman equation, was recorded with a peak rate 0.94 mm per hour. Secondly, the transpiration was measured by sap flow tissue heat balance techniques on four individual trees with greatest stem diameters (11 - 12 cm d.b.h.) and height of 12 - 12.5 m. Relatively high transpiration values by the poplars were found during the measured part of growing season (18 June - 31 October), with maximum and mean daily transpiration of 44.41 dm3 and 16.69 dm3 per day, respectively. The seasonal transpiration of the most vigorous from the investigated individuals amounted 2542 dm3. Because in this study we didńt evaluate the transpiration of thinner trees (technical features of sap flow method dońt enable to assess trees smaller than 10 cm and bigger than 2 cm d.b.h.), scaling the transpiration to the whole stand through the relation between leaf area index, d.b.h. and the sap flow is under evaluation and results will be presented at the conference. The presentation will also include comparison between actual evapotranspiration over the reference grass surface in the immediate vicinity of the poplar plantation. The differences between the actual evapotranspiration and transpiration of the poplar stand and other special features of this bioenergy production system will be revealed in more detail. Acknowledgement: We gratefully acknowledge the support of the In-house Grant Agency at Mendel university in Brno no. IP 19/2010, In-house Grant Agency at Mendel university in Brno no. TP 11/2010 and the Research plan no. MSM6215648905 "Biological and technological aspects of sustainability of controlled ecosystems and their adaptability to climate change".

Genotype differences in 13C discrimination between atmosphere and leaf matter match differences in transpiration efficiency at leaf and whole-plant levels in hybrid Populus deltoides x nigra.

PubMed

Rasheed, Fahad; Dreyer, Erwin; Richard, Béatrice; Brignolas, Franck; Montpied, Pierre; Le Thiec, Didier

2013-01-01

(13) C discrimination between atmosphere and bulk leaf matter (Δ(13) C(lb) ) is frequently used as a proxy for transpiration efficiency (TE). Nevertheless, its relevance is challenged due to: (1) potential deviations from the theoretical discrimination model, and (2) complex time integration and upscaling from leaf to whole plant. Six hybrid genotypes of Populus deltoides×nigra genotypes were grown in climate chambers and tested for whole-plant TE (i.e. accumulated biomass/water transpired). Net CO(2) assimilation rates (A) and stomatal conductance (g(s) ) were recorded in parallel to: (1) (13) C in leaf bulk material (δ(13) C(lb) ) and in soluble sugars (δ(13) C(ss) ) and (2) (18) O in leaf water and bulk leaf material. Genotypic means of δ(13) C(lb) and δ(13) C(ss) were tightly correlated. Discrimination between atmosphere and soluble sugars was correlated with daily intrinsic TE at leaf level (daily mean A/g(s) ), and with whole-plant TE. Finally, g(s) was positively correlated to (18) O enrichment of bulk matter or water of leaves at individual level, but not at genotype level. We conclude that Δ(13) C(lb) captures efficiently the genetic variability of whole-plant TE in poplar. Nevertheless, scaling from leaf level to whole-plant TE requires to take into account water losses and respiration independent of photosynthesis, which remain poorly documented. © 2012 Blackwell Publishing Ltd.

Characterization of a tryptophan 2-monooxygenase gene from Puccinia graminis f. sp. tritici involved in auxin biosynthesis and rust pathogenicity.

PubMed

Yin, Chuntao; Park, Jeong-Jin; Gang, David R; Hulbert, Scot H

2014-03-01

The plant hormone indole-3-acetic acid (IAA) is best known as a regulator of plant growth and development but its production can also affect plant-microbe interactions. Microorganisms, including numerous plant-associated bacteria and several fungi, are also capable of producing IAA. The stem rust fungus Puccinia graminis f. sp. tritici induced wheat plants to accumulate auxin in infected leaf tissue. A gene (Pgt-IaaM) encoding a putative tryptophan 2-monooxygenase, which makes the auxin precursor indole-3-acetamide (IAM), was identified in the P. graminis f. sp. tritici genome and found to be expressed in haustoria cells in infected plant tissue. Transient silencing of the gene in infected wheat plants indicated that it was required for full pathogenicity. Expression of Pgt-IaaM in Arabidopsis caused a typical auxin expression phenotype and promoted susceptibility to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000.

Modelling coffee leaf rust risk in Colombia with climate reanalysis data.

PubMed

Bebber, Daniel P; Castillo, Ángela Delgado; Gurr, Sarah J

2016-12-05

Many fungal plant diseases are strongly controlled by weather, and global climate change is thus likely to have affected fungal pathogen distributions and impacts. Modelling the response of plant diseases to climate change is hampered by the difficulty of estimating pathogen-relevant microclimatic variables from standard meteorological data. The availability of increasingly sophisticated high-resolution climate reanalyses may help overcome this challenge. We illustrate the use of climate reanalyses by testing the hypothesis that climate change increased the likelihood of the 2008-2011 outbreak of Coffee Leaf Rust (CLR, Hemileia vastatrix) in Colombia. We develop a model of germination and infection risk, and drive this model using estimates of leaf wetness duration and canopy temperature from the Japanese 55-Year Reanalysis (JRA-55). We model germination and infection as Weibull functions with different temperature optima, based upon existing experimental data. We find no evidence for an overall trend in disease risk in coffee-growing regions of Colombia from 1990 to 2015, therefore, we reject the climate change hypothesis. There was a significant elevation in predicted CLR infection risk from 2008 to 2011 compared with other years. JRA-55 data suggest a decrease in canopy surface water after 2008, which may have helped terminate the outbreak. The spatial resolution and accuracy of climate reanalyses are continually improving, increasing their utility for biological modelling. Confronting disease models with data requires not only accurate climate data, but also disease observations at high spatio-temporal resolution. Investment in monitoring, storage and accessibility of plant disease observation data are needed to match the quality of the climate data now available.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Authors.

Facing the Future: Effects of Short-Term Climate Extremes on Isoprene-Emitting and Nonemitting Poplar.

PubMed

Vanzo, Elisa; Jud, Werner; Li, Ziru; Albert, Andreas; Domagalska, Malgorzata A; Ghirardo, Andrea; Niederbacher, Bishu; Frenzel, Juliane; Beemster, Gerrit T S; Asard, Han; Rennenberg, Heinz; Sharkey, Thomas D; Hansel, Armin; Schnitzler, Jörg-Peter

2015-09-01

Isoprene emissions from poplar (Populus spp.) plantations can influence atmospheric chemistry and regional climate. These emissions respond strongly to temperature, [CO2], and drought, but the superimposed effect of these three climate change factors are, for the most part, unknown. Performing predicted climate change scenario simulations (periodic and chronic heat and drought spells [HDSs] applied under elevated [CO2]), we analyzed volatile organic compound emissions, photosynthetic performance, leaf growth, and overall carbon (C) gain of poplar genotypes emitting (IE) and nonemitting (NE) isoprene. We aimed (1) to evaluate the proposed beneficial effect of isoprene emission on plant stress mitigation and recovery capacity and (2) to estimate the cumulative net C gain under the projected future climate. During HDSs, the chloroplastidic electron transport rate of NE plants became impaired, while IE plants maintained high values similar to unstressed controls. During recovery from HDS episodes, IE plants reached higher daily net CO2 assimilation rates compared with NE genotypes. Irrespective of the genotype, plants undergoing chronic HDSs showed the lowest cumulative C gain. Under control conditions simulating ambient [CO2], the C gain was lower in the IE plants than in the NE plants. In summary, the data on the overall C gain and plant growth suggest that the beneficial function of isoprene emission in poplar might be of minor importance to mitigate predicted short-term climate extremes under elevated [CO2]. Moreover, we demonstrate that an analysis of the canopy-scale dynamics of isoprene emission and photosynthetic performance under multiple stresses is essential to understand the overall performance under proposed future conditions. © 2015 American Society of Plant Biologists. All Rights Reserved.

Localization of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) in poplar and switchgrass plants using phosphor imager autoradiography.

PubMed

Brentner, Laura B; Mukherji, Sachiyo T; Walsh, Susan A; Schnoor, Jerald L

2010-02-01

Phosphor imager autoradiography is a technique for rapid, sensitive analysis of the localization of xenobiotics in plant tissues. Use of this technique is relatively new to research in the field of plant science, and the potential for enhancing visualization and understanding of plant uptake and transport of xenobiotics remains largely untapped. Phosphor imager autoradiography is used to investigate the uptake and translocation of the explosives 1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene within Populus deltoides x nigra DN34 (poplar) and Panicum vigratum Alamo (switchgrass). In both plant types, TNT and/or TNT-metabolites remain predominantly in root tissues while RDX and/or RDX-metabolites are readily translocated to leaf tissues. Phosphor imager autoradiography is further investigated for use in semi-quantitative analysis of uptake of TNT by switchgrass. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Functional analysis of a pathogenesis-related thaumatin-like protein gene TaLr35PR5 from wheat induced by leaf rust fungus.

PubMed

Zhang, Jiarui; Wang, Fei; Liang, Fang; Zhang, Yanjun; Ma, Lisong; Wang, Haiyan; Liu, Daqun

2018-05-04

Plants have evolved multifaceted defence mechanisms to resist pathogen infection. Production of the pathogenesis-related (PR) proteins in response to pathogen attack has been implicated in plant disease resistance specialized in systemic-acquired resistance (SAR). Our earlier studies have reported that a full length TaLr35PR5 gene, encoding a protein exhibiting amino acid and structural similarity to a sweet protein thaumatin, was isolated from wheat near-isogenic line TcLr35. The present study aims to understand the function of TaLr35PR5 gene in Lr35-mediated adult resistance to Puccinia triticina. We determined that the TaLr35PR5 protein contained a functional secretion peptide by utilizing the yeast signal sequence trap system. Using a heterologous expression assay on onion epidermal cells we found that TaLr35PR5 protein was secreted into the apoplast of onion cell. Expression of TaLr35PR5 was significantly reduced in BSMV-induced gene silenced wheat plants, and pathology test on these silenced plants revealed that Lr35-mediated resistance phenotype was obviously altered, indicating that Lr35-mediated resistance was compromised. All these findings strongly suggest that TaLr35PR5 is involved in Lr35-mediated adult wheat defense in response to leaf rust attack.

Leaf-associated bacterial microbiota of coffee and its correlation with manganese and calcium levels on leaves.

PubMed

de Sousa, Leandro Pio de; da Silva, Marcio José da; Mondego, Jorge Maurício

2018-05-17

Coffee is one of the most valuable agricultural commodities and the plants' leaves are the primary site of infection for most coffee diseases, such as the devastating coffee leaf rust. Therefore, the use of bacterial microbiota that inhabits coffee leaves to fight infections could be an alternative agricultural method to protect against coffee diseases. Here, we report the leaf-associated bacteria in three coffee genotypes over the course of a year, with the aim to determine the diversity of bacterial microbiota. The results indicate a prevalence of Enterobacteriales in Coffea canephora, Pseudomonadales in C. arabica 'Obatã', and an intriguing lack of bacterial dominance in C. arabica 'Catuaí'. Using PERMANOVA analyses, we assessed the association between bacterial abundance in the coffee genotypes and environmental parameters such as temperature, precipitation, and mineral nutrients in the leaves. We detected a close relationship between the amount of Mn and the abundance of Pseudomonadales in 'Obatã' and the amount of Ca and the abundance of Enterobacteriales in C. canephora. We suggest that mineral nutrients can be key drivers that shape leaf microbial communities.

Green revolution trees: semidwarfism transgenes modify gibberellins, promote root growth, enhance morphological diversity, and reduce competitiveness in hybrid poplar.

PubMed

Elias, Ani A; Busov, Victor B; Kosola, Kevin R; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W; Rood, Stewart B; Strauss, Steven H

2012-10-01

Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA(20) and GA(8), in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations.

Green Revolution Trees: Semidwarfism Transgenes Modify Gibberellins, Promote Root Growth, Enhance Morphological Diversity, and Reduce Competitiveness in Hybrid Poplar1[C][W][OA

PubMed Central

Elias, Ani A.; Busov, Victor B.; Kosola, Kevin R.; Ma, Cathleen; Etherington, Elizabeth; Shevchenko, Olga; Gandhi, Harish; Pearce, David W.; Rood, Stewart B.; Strauss, Steven H.

2012-01-01

Semidwarfism has been used extensively in row crops and horticulture to promote yield, reduce lodging, and improve harvest index, and it might have similar benefits for trees for short-rotation forestry or energy plantations, reclamation, phytoremediation, or other applications. We studied the effects of the dominant semidwarfism transgenes GA Insensitive (GAI) and Repressor of GAI-Like, which affect gibberellin (GA) action, and the GA catabolic gene, GA 2-oxidase, in nursery beds and in 2-year-old high-density stands of hybrid poplar (Populus tremula × Populus alba). Twenty-nine traits were analyzed, including measures of growth, morphology, and physiology. Endogenous GA levels were modified in most transgenic events; GA20 and GA8, in particular, had strong inverse associations with tree height. Nearly all measured traits varied significantly among genotypes, and several traits interacted with planting density, including aboveground biomass, root-shoot ratio, root fraction, branch angle, and crown depth. Semidwarfism promoted biomass allocation to roots over shoots and substantially increased rooting efficiency with most genes tested. The increased root proportion and increased leaf chlorophyll levels were associated with changes in leaf carbon isotope discrimination, indicating altered water use efficiency. Semidwarf trees had dramatically reduced growth when in direct competition with wild-type trees, supporting the hypothesis that semidwarfism genes could be effective tools to mitigate the spread of exotic, hybrid, and transgenic plants in wild and feral populations. PMID:22904164

Laboratory and Airborne BRDF Analysis of Vegetation Leaves and Soil Samples

NASA Technical Reports Server (NTRS)

Georgiev, Georgi T.; Gatebe, Charles K.; Butler, James J.; King, Michael D.

2008-01-01

Laboratory-based Bidirectional Reflectance Distribution Function (BRDF) analysis of vegetation leaves, soil, and leaf litter samples is presented. The leaf litter and soil samples, numbered 1 and 2, were obtained from a site located in the savanna biome of South Africa (Skukuza: 25.0degS, 31.5degE). A third soil sample, number 3, was obtained from Etosha Pan, Namibia (19.20degS, 15.93degE, alt. 1100 m). In addition, BRDF of local fresh and dry leaves from tulip tree (Liriodendron tulipifera) and acacia tree (Acacia greggii) were studied. It is shown how the BRDF depends on the incident and scatter angles, sample size (i.e. crushed versus whole leaf,) soil samples fraction size, sample status (i.e. fresh versus dry leaves), vegetation species (poplar versus acacia), and vegetation s biochemical composition. As a demonstration of the application of the results of this study, airborne BRDF measurements acquired with NASA's Cloud Absorption Radiometer (CAR) over the same general site where the soil and leaf litter samples were obtained are compared to the laboratory results. Good agreement between laboratory and airborne measured BRDF is reported.

Conversion from cropland to short rotation coppice willow and poplar: Accumulation of soil organic carbon

NASA Astrophysics Data System (ADS)

Georgiadis, Petros; Stupak, Inge; Vesterdal, Lars; Raulund-Rasmussen, Karsten

2015-04-01

Increased demand for bioenergy has intensified the production of Short Rotation Coppice (SRC) willow and poplar in temperate zones. We used a combined chronosequence and paired plot approach to study the potential of SRC willow and poplar stands to increase the soil carbon stock compared to stocks of the previous arable land-use. The study focused on well-drained soils. We sampled soil from 30 SRC stands in Denmark and southern Sweden including soils from their adjacent arable fields. The 18 willow and 12 poplar stands formed a chronosequence ranging between 4 and 29 years after conversion. The soil was sampled both with soil cores taken by fixed depths of 0-5, 5-10, 10-15, 15-25, and 25-40 cm and by genetic horizons from soil pits to 1m depth. The aim of the study was to estimate the difference and the ratio between soil carbon contents of the SRC and annual crop land and analyze the results as a chronosequence to examine the effect of age after conversion on the difference. Covariates such as soil type, fertilization type and harvest frequency were also taken into account. Preliminary results suggest an overall increase in carbon stocks over time with average accumulation rates ranging from 0.25 to 0.4 Mg ha-1 yr-1 in willow and poplar stands. Poplar stands had higher rates of C gain, probably due to less frequent harvesting. The differences in carbon between the SRC and the paired cropland were initially negative but changed to positive over time, implying loss of carbon after conversion and a later gain in soil carbon with stand age. Pairwise differences ranged from -25 Mg C ha-1 to 37 Mg C ha-1 for the top 40 cm. The carbon stock ratio of the SRC stand to the arable land was estimated to minimize the effect of site-related factors. The results of this analysis suggested that the ratio increased significantly with age after conversion for the top 10 cm of the soil, both for poplar and willow. A slight increase with age was also noticed at the deeper depths, but it was not significant. The increasing soil carbon stocks in SRC stands on former cropland can be attributed to the increased leaf and litter input from the perennial SRC plantations as well as less stimulation of organic matter decomposition after cessation of annual. Initial losses of soil carbon after the land use change have also been reported by other studies, but the soil carbon accumulation high rates suggest that SRC can act as sinks at least for some decades. Our results indicate that a steady state has not yet been reached after 29 years. Key words: Bioenergy,Land Use Change, poplar, Short Rotation Coppice, Soil Organic Carbon, willow,

Practical salinity management for leachate irrigation to poplar trees.

PubMed

Smesrud, Jason K; Duvendack, George D; Obereiner, James M; Jordahl, James L; Madison, Mark F

2012-01-01

Landfill leachate can be beneficially reused for irrigation of fiber crops with appropriate attention to nutrient and salinity management. The Riverbend Landfill in Western Oregon has been effectively practicing irrigation of landfill leachate to poplar trees since 1993. Over that time, the site has been adaptively managed to control salinity impacts to the tree crop while beneficially utilizing the applied water and nutrients during each growing season. Representative leachate irrigation water has ranged in concentration of total dissolved solids from 777 to 6,940 mg/L, chloride from 180 to 1,760 mg/L and boron from 3.2 to 7.3 mg/L. Annual leachate irrigation applications have also ranged between 102 and 812 mm/yr. Important conclusions from this site have included: 1) Appropriate tree clone selection and tree stand spacing, thinning, and harvest rotations are critical to maintaining a productive tree stand that is resilient and resistant to salt stress. The most effective combinations have included clones DN-34, OP-367, 184-411, 49-177, and 15-29 planted at spacing of 3.7-m x 1.8-m to 3.7-m x 3.7-m; 2) Leaf tissue boron levels are closely correlated to soil boron levels and can be managed with leaching. When leaf tissue boron levels exceed 200 to 250 mg/kg, signs of salt stress may emerge and should be monitored closely; 3) Salinity from leachate irrigation can be managed to sustain a healthy tree crop by controlling mass loading rates and providing appropriate irrigation blending if necessary. Providing freshwater irrigation following each leachate irrigation and targeting freshwater irrigation as 30 percent of total irrigation water applied has successfully controlled salt impacts to vegetation; and 4) Drip irrigation generally requires more careful attention to long-term soil salinity management than spray irrigation. Moving drip irrigation tubes periodically to prevent the formation of highly saline zones within the soil profile is important. In this paper, a fifteen year record of monitoring and operational data are presented that can be used by others in managing irrigation of saline water to poplar trees. When salinity is carefully managed, tree systems can help to provide sustainable leachate management solutions for landfills.

Puccinia coronata f. sp. avenae: a threat to global oat production.

PubMed

Nazareno, Eric S; Li, Feng; Smith, Madeleine; Park, Robert F; Kianian, Shahryar F; Figueroa, Melania

2018-05-01

Puccinia coronata f. sp. avenae (Pca) causes crown rust disease in cultivated and wild oat (Avena spp.). The significant yield losses inflicted by this pathogen make crown rust the most devastating disease in the oat industry. Pca is a basidiomycete fungus with an obligate biotrophic lifestyle, and is classified as a typical macrocyclic and heteroecious fungus. The asexual phase in the life cycle of Pca occurs in oat, whereas the sexual phase takes place primarily in Rhamnus species as the alternative host. Epidemics of crown rust happens in areas with warm temperatures (20-25 °C) and high humidity. Infection by the pathogen leads to plant lodging and shrivelled grain of poor quality. Disease symptoms: Infection of susceptible oat varieties gives rise to orange-yellow round to oblong uredinia (pustules) containing newly formed urediniospores. Pustules vary in size and can be larger than 5 mm in length. Infection occurs primarily on the surfaces of leaves, although occasional symptoms develop in the oat leaf sheaths and/or floral structures, such as awns. Symptoms in resistant oat varieties vary from flecks to small pustules, typically accompanied by chlorotic halos and/or necrosis. The pycnial and aecial stages are mostly present in the leaves of Rhamnus species, but occasionally symptoms can also be observed in petioles, young stems and floral structures. Aecial structures display a characteristic hypertrophy and can differ in size, occasionally reaching more than 5 mm in diameter. Taxonomy: Pca belongs to the kingdom Fungi, phylum Basidiomycota, class Pucciniomycetes, order Pucciniales and family Pucciniaceae. Host range: Puccinia coronata sensu lato can infect 290 species of grass hosts. Pca is prevalent in all oat-growing regions and, compared with other cereal rusts, displays a broad telial host range. The most common grass hosts of Pca include cultivated hexaploid oat (Avena sativa) and wild relatives, such as bluejoint grass, perennial ryegrass and fescue. Alternative hosts include several species of Rhamnus, with R. cathartica (common buckthorn) as the most important alternative host in Europe and North America. Most crown rust management strategies involve the use of rust-resistant crop varieties and the application of fungicides. The attainment of the durability of resistance against Pca is difficult as it is a highly variable pathogen with a great propensity to overcome the genetic resistance of varieties. Thus, adult plant resistance is often exploited in oat breeding programmes to develop new crown rust-resistant varieties. Useful website: https://www.ars.usda.gov/midwest-area/st-paul-mn/cereal-disease-lab/docs/cereal-rusts/race-surveys/. © 2017 BSPP AND JOHN WILEY & SONS LTD.

Rust and Thinning Management Effect on Cup Quality and Plant Performance for Two Cultivars of Coffea arabica L.

PubMed

Echeverria-Beirute, Fabian; Murray, Seth C; Klein, Patricia; Kerth, Chris; Miller, Rhonda; Bertrand, Benoit

2018-05-30

Beverage quality is a complex attribute of coffee ( Coffea arabica L.). Genotype (G), environment (E), management (M), postharvest processing, and roasting are all involved. However, little is known about how G × M interactions influence beverage quality. We investigated how yield and coffee leaf rust (CLR) disease (caused by Hemileia vastatrix Berk. et Br.) management affect cup quality and plant performance, in two coffee cultivars. Sensory and chemical analyses revealed that 10 of 70 attributes and 18 of 154 chemical volatile compounds were significantly affected by G and M. Remarkably, acetaminophen was found for the first time in roasted coffee and in higher concentrations under more stressful conditions. A principal component analysis described 87% of the variation in quality and plant overall performance. This study is a first step in understanding the complexity of the physiological, metabolic, and molecular changes in coffee production, which will be useful for the improvement of coffee cultivars.

A systematic review of rye (Secale cereale L.) as a source of resistance to pathogens and pests in wheat (Triticum aestivum L.).

PubMed

Crespo-Herrera, Leonardo A; Garkava-Gustavsson, Larisa; Åhman, Inger

2017-01-01

Wheat is globally one of the most important crops. With the current human population growth rate, there is an increasing need to raise wheat productivity by means of plant breeding, along with development of more efficient and sustainable agricultural systems. Damage by pathogens and pests, in combination with adverse climate effects, need to be counteracted by incorporating new germplasm that makes wheat more resistant/tolerant to such stress factors. Rye has been used as a source for improved resistance to pathogens and pests in wheat during more than 50 years. With new devastating stem and yellow rust pathotypes invading wheat at large acreage globally, along with new biotypes of pest insects, there is renewed interest in using rye as a source of resistance. Currently the proportion of wheat cultivars with rye chromatin varies between countries, with examples of up to 34%. There is mainly one rye source, Petkus, that has been widely exploited and that has contributed considerably to raise yields and increase disease resistance in wheat. Successively, the multiple disease resistances conferred by this source has been overcome by new pathotypes of leaf rust, yellow rust, stem rust and powdery mildew. However, there are several other rye sources reported to make wheat more resistant to various biotic constraints when their rye chromatin has been transferred to wheat. There is also development of knowledge on how to produce new rye translocation, substitution and addition lines. Here we compile information that may facilitate decision making for wheat breeders aiming to transfer resistance to biotic constraints from rye to elite wheat germplasm.

Biotechnology touches the forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powledge, J.M.

1984-09-01

Both the United States and New Zealand are doing research in forest biotechnology and much of the interest is in speedy propagation from seed to mature tree. A number of propagation techniques are discussed, such as tissue culture, the culture of tissue from mature trees and somatic embryo genesis. Much of the tissue culture work has been done on radiata pine. Field testing results are considered. The aims and the advantages of forest biotechnology are discussed under the following headings. 1) Disease resistance: research is being carried out on a loblolly pine which would be resistant to fusiform rust. 2)more » Animal feed: some trees have been discovered to have lower lignin content and similar cellulose and hemicellulose to alfalfa. 3) Specialty chemicals: terpenes, in the tree resin, could be turned into hormones, drugs and other chemicals: the genetic system for the overall biosynthesis of terpenes has been studied. 4) Herbicide resistance. The resistance to glyphosate in poplars is being studied. In conclusion, further research into forest species, using molecular biology is considered essential.« less

Effect of solar radiation on severity of soybean rust.

PubMed

Young, Heather M; George, Sheeja; Narváez, Dario F; Srivastava, Pratibha; Schuerger, Andrew C; Wright, David L; Marois, James J

2012-08-01

Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a damaging fungal disease of soybean (Glycine max). Although solar radiation can reduce SBR urediniospore survival, limited information is available on how solar radiation affects SBR progress within soybean canopies. Such information can aid in developing accurate SBR prediction models. To manipulate light penetration into soybean canopies, structures of shade cloth attenuating 30, 40, and 60% sunlight were constructed over soybean plots. In each plot, weekly evaluations of severity in lower, middle, and upper canopies, and daily temperature and relative humidity were recorded. Final plant height and leaf area index were also recorded for each plot. The correlation between amount of epicuticular wax and susceptibility of leaves in the lower, middle, and upper canopies was assessed with a detached leaf assay. Final disease severity was 46 to 150% greater in the lower canopy of all plots and in the middle canopy of 40 and 60% shaded plots. While daytime temperature within the canopy of nonshaded soybean was greater than shaded soybean by 2 to 3°C, temperatures recorded throughout typical evenings and mornings of the growing season in all treatments were within the range (10 to 28.5°C) for SBR development as was relative humidity. This indicates temperature and relative humidity were not limiting factors in this experiment. Epicuticular wax and disease severity in detached leaf assays from the upper canopy had significant negative correlation (P = 0.009, R = -0.84) regardless of shade treatment. In laboratory experiments, increasing simulated total solar radiation (UVA, UVB, and PAR) from 0.15 to 11.66 MJ m(-2) increased mortality of urediniospores from 2 to 91%. Variability in disease development across canopy heights in early planted soybean may be attributed to the effects of solar radiation not only on urediniospore viability, but also on plant height, leaf area index, and epicuticular wax, which influence disease development of SBR. These results provide an understanding of the effect solar radiation has on the progression of SBR within the soybean canopy.

Gene introgression into Coffea arabica by way of triploid hybrids (C. arabica x C. canephora).

PubMed

Herrera, J C; Combes, M C; Cortina, H; Alvarado, G; Lashermes, P

2002-12-01

Interspecific triploid hybrid plants between the tetraploid species Coffea arabica L. and the diploid species C. canephora P. were backcrossed to C. arabica. Although characterised by a low production and an important fruit dropping, all attempted crosses (ie, 6) generated BC(1) progenies. Flow cytometric analysis of the nuclear DNA content revealed that most of the BC1 individuals were nearly tetraploid. Among the male gametes produced by the interspecific triploid hybrids, those presenting a high number of chromosomes appeared strongly favoured. Only pollen mother cells having nearly 22 chromosomes were effective, the others leading to deficient endosperm and fruit dropping. Molecular markers (ie, microsatellite and AFLP) combined with evaluations of morphological characteristics and resistance to leaf rust were applied to verify the occurrence of gene transfer from C. canephora into C. arabica, and to estimate the amount of introgression present in BC(1) individuals. The results reveal a strong deficiency in the C. canephroa alleles indicating a severe counter-selection against the introgression of genetic material from C. canephora into C. arabica by way of triploid hybrids. However, introgressants displaying desirable traits such as a high resistance to leaf rust were obtained. The low level of introgression could be an advantage by facilitating the recovery of the recurrent parent and possibly reducing the number of required backcrosses. On the other hand, this could be a limitation when attempting the transfer of a complex trait or several simply inherited traits.

Identification, characterization, and gene expression analysis of nucleotide binding site (NB)-type resistance gene homologues in switchgrass

DOE PAGES

Frazier, Taylor P.; Palmer, Nathan A.; Xie, Fuliang; ...

2016-11-08

Switchgrass ( Panicum virgatum L.) is a warm-season perennial grass that can be used as a second generation bioenergy crop. However, foliar fungal pathogens, like switchgrass rust, have the potential to significantly reduce switchgrass biomass yield. Despite its importance as a prominent bioenergy crop, a genome-wide comprehensive analysis of NB-LRR disease resistance genes has yet to be performed in switchgrass. In this study, we used a homology-based computational approach to identify 1011 potential NB-LRR resistance gene homologs (RGHs) in the switchgrass genome (v 1.1). In addition, we identified 40 RGHs that potentially contain unique domains including major sperm protein domain,more » jacalin-like binding domain, calmodulin-like binding, and thioredoxin. RNA-sequencing analysis of leaf tissue from ‘Alamo’, a rust-resistant switchgrass cultivar, and ‘Dacotah’, a rust-susceptible switchgrass cultivar, identified 2634 high quality variants in the RGHs between the two cultivars. RNA-sequencing data from field-grown cultivar ‘Summer’ plants indicated that the expression of some of these RGHs was developmentally regulated. Our results provide useful insight into the molecular structure, distribution, and expression patterns of members of the NB-LRR gene family in switchgrass. These results also provide a foundation for future work aimed at elucidating the molecular mechanisms underlying disease resistance in this important bioenergy crop.« less

Identification, characterization, and gene expression analysis of nucleotide binding site (NB)-type resistance gene homologues in switchgrass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frazier, Taylor P.; Palmer, Nathan A.; Xie, Fuliang

Switchgrass ( Panicum virgatum L.) is a warm-season perennial grass that can be used as a second generation bioenergy crop. However, foliar fungal pathogens, like switchgrass rust, have the potential to significantly reduce switchgrass biomass yield. Despite its importance as a prominent bioenergy crop, a genome-wide comprehensive analysis of NB-LRR disease resistance genes has yet to be performed in switchgrass. In this study, we used a homology-based computational approach to identify 1011 potential NB-LRR resistance gene homologs (RGHs) in the switchgrass genome (v 1.1). In addition, we identified 40 RGHs that potentially contain unique domains including major sperm protein domain,more » jacalin-like binding domain, calmodulin-like binding, and thioredoxin. RNA-sequencing analysis of leaf tissue from ‘Alamo’, a rust-resistant switchgrass cultivar, and ‘Dacotah’, a rust-susceptible switchgrass cultivar, identified 2634 high quality variants in the RGHs between the two cultivars. RNA-sequencing data from field-grown cultivar ‘Summer’ plants indicated that the expression of some of these RGHs was developmentally regulated. Our results provide useful insight into the molecular structure, distribution, and expression patterns of members of the NB-LRR gene family in switchgrass. These results also provide a foundation for future work aimed at elucidating the molecular mechanisms underlying disease resistance in this important bioenergy crop.« less

S-Nitroso-Proteome in Poplar Leaves in Response to Acute Ozone Stress

PubMed Central

Vanzo, Elisa; Ghirardo, Andrea; Merl-Pham, Juliane; Lindermayr, Christian; Heller, Werner; Hauck, Stefanie M.; Durner, Jörg; Schnitzler, Jörg-Peter

2014-01-01

Protein S-nitrosylation, the covalent binding of nitric oxide (NO) to protein cysteine residues, is one of the main mechanisms of NO signaling in plant and animal cells. Using a combination of the biotin switch assay and label-free LC-MS/MS analysis, we revealed the S-nitroso-proteome of the woody model plant Populus x canescens. Under normal conditions, constitutively S-nitrosylated proteins in poplar leaves and calli comprise all aspects of primary and secondary metabolism. Acute ozone fumigation was applied to elicit ROS-mediated changes of the S-nitroso-proteome. This treatment changed the total nitrite and nitrosothiol contents of poplar leaves and affected the homeostasis of 32 S-nitrosylated proteins. Multivariate data analysis revealed that ozone exposure negatively affected the S-nitrosylation status of leaf proteins: 23 proteins were de-nitrosylated and 9 proteins had increased S-nitrosylation content compared to the control. Phenylalanine ammonia-lyase 2 (log2[ozone/control] = −3.6) and caffeic acid O-methyltransferase (−3.4), key enzymes catalyzing important steps in the phenylpropanoid and subsequent lignin biosynthetic pathways, respectively, were de-nitrosylated upon ozone stress. Measuring the in vivo and in vitro phenylalanine ammonia-lyase activity indicated that the increase of the phenylalanine ammonia-lyase activity in response to acute ozone is partly regulated by de-nitrosylation, which might favor a higher metabolic flux through the phenylpropanoid pathway within minutes after ozone exposure. PMID:25192423

Transcript and metabolite profiling for the evaluation of tobacco tree and poplar as feedstock for the bio-based industry.

PubMed

Ruprecht, Colin; Tohge, Takayuki; Fernie, Alisdair; Mortimer, Cara L; Kozlo, Amanda; Fraser, Paul D; Funke, Norma; Cesarino, Igor; Vanholme, Ruben; Boerjan, Wout; Morreel, Kris; Burgert, Ingo; Gierlinger, Notburga; Bulone, Vincent; Schneider, Vera; Stockero, Andrea; Navarro-Aviñó, Juan; Pudel, Frank; Tambuyser, Bart; Hygate, James; Bumstead, Jon; Notley, Louis; Persson, Staffan

2014-05-16

The global demand for food, feed, energy and water poses extraordinary challenges for future generations. It is evident that robust platforms for the exploration of renewable resources are necessary to overcome these challenges. Within the multinational framework MultiBioPro we are developing biorefinery pipelines to maximize the use of plant biomass. More specifically, we use poplar and tobacco tree (Nicotiana glauca) as target crop species for improving saccharification, isoprenoid, long chain hydrocarbon contents, fiber quality, and suberin and lignin contents. The methods used to obtain these outputs include GC-MS, LC-MS and RNA sequencing platforms. The metabolite pipelines are well established tools to generate these types of data, but also have the limitations in that only well characterized metabolites can be used. The deep sequencing will allow us to include all transcripts present during the developmental stages of the tobacco tree leaf, but has to be mapped back to the sequence of Nicotiana tabacum. With these set-ups, we aim at a basic understanding for underlying processes and at establishing an industrial framework to exploit the outcomes. In a more long term perspective, we believe that data generated here will provide means for a sustainable biorefinery process using poplar and tobacco tree as raw material. To date the basal level of metabolites in the samples have been analyzed and the protocols utilized are provided in this article.

Influence of Wind Speed on RGB-D Images in Tree Plantations

PubMed Central

Andújar, Dionisio; Dorado, José; Bengochea-Guevara, José María; Conesa-Muñoz, Jesús; Fernández-Quintanilla, César; Ribeiro, Ángela

2017-01-01

Weather conditions can affect sensors’ readings when sampling outdoors. Although sensors are usually set up covering a wide range of conditions, their operational range must be established. In recent years, depth cameras have been shown as a promising tool for plant phenotyping and other related uses. However, the use of these devices is still challenged by prevailing field conditions. Although the influence of lighting conditions on the performance of these cameras has already been established, the effect of wind is still unknown. This study establishes the associated errors when modeling some tree characteristics at different wind speeds. A system using a Kinect v2 sensor and a custom software was tested from null wind speed up to 10 m·s−1. Two tree species with contrasting architecture, poplars and plums, were used as model plants. The results showed different responses depending on tree species and wind speed. Estimations of Leaf Area (LA) and tree volume were generally more consistent at high wind speeds in plum trees. Poplars were particularly affected by wind speeds higher than 5 m·s−1. On the contrary, height measurements were more consistent for poplars than for plum trees. These results show that the use of depth cameras for tree characterization must take into consideration wind conditions in the field. In general, 5 m·s−1 (18 km·h−1) could be established as a conservative limit for good estimations. PMID:28430119

Comparison of the chemical alteration trajectory of Liriodendron tulipifera L. leaf litter among forests with different earthworm abundance

NASA Astrophysics Data System (ADS)

Filley, Timothy R.; McCormick, Melissa K.; Crow, Susan E.; Szlavecz, Katalin; Whigham, Dennis F.; Johnston, Cliff T.; van den Heuvel, Ronald N.

2008-03-01

To investigate the control of earthworm populations on leaf litter biopolymer decay dynamics, we analyzed the residues of Liriodendron tulipifera L. (tulip poplar) leaves after six months of decay, comparing open surface litter and litter bag experiments among forests with different native and invasive earthworm abundances. Six plots were established in successional tulip poplar forests where sites varied in earthworm density and biomass, roughly 4-10 fold, of nonnative lumbricid species. Analysis of residues by diffuse reflectance Fourier transform infrared spectroscopy and alkaline CuO extraction indicated that open decay in sites with abundant earthworms resulted in residues depleted in cuticular aliphatic and polysaccharide components and enriched in ether-linked lignin relative to open decay in low earthworm abundance plots. Decay within earthworm-excluding litter bags resulted in an increase in aliphatic components relative to initial amendment and similar chemical trajectory to low earthworm open decay experiments. All litter exhibited a decline in cinnamyl-based lignin and an increase in nitrogen content. The influence of earthworm density on the chemical trajectory of litter decay was primarily a manifestation of the physical separation and concentration of lignin-rich and cutin-poor petioles with additional changes promoted by either microorganisms and/or mesofauna resulting in nitrogen addition and polysaccharide loss. These results illustrate how projected increases in invasive earthworm activity in northern North American forests could alter the chemical composition of organic matter in litter residues and potentially organic matter reaching the soil which may result in shifts in the aromatic and aliphatic composition of soils in different systems.

Tracking senescence-induced patterns in leaf litter leachate using parallel factor analysis (PARAFAC) modeling and self-organizing maps

NASA Astrophysics Data System (ADS)

Wheeler, K. I.; Levia, D. F.; Hudson, J. E.

2017-09-01

In autumn, the dissolved organic matter (DOM) contribution of leaf litter leachate to streams in forested watersheds changes as trees undergo resorption, senescence, and leaf abscission. Despite its biogeochemical importance, little work has investigated how leaf litter leachate DOM changes throughout autumn and how any changes might differ interspecifically and intraspecifically. Since climate change is expected to cause vegetation migration, it is necessary to learn how changes in forest composition could affect DOM inputs via leaf litter leachate. We examined changes in leaf litter leachate fluorescent DOM (FDOM) from American beech (Fagus grandifolia Ehrh.) leaves in Maryland, Rhode Island, Vermont, and North Carolina and from yellow poplar (Liriodendron tulipifera L.) leaves from Maryland. FDOM in leachate samples was characterized by excitation-emission matrices (EEMs). A six-component parallel factor analysis (PARAFAC) model was created to identify components that accounted for the majority of the variation in the data set. Self-organizing maps (SOM) compared the PARAFAC component proportions of leachate samples. Phenophase and species exerted much stronger influence on the determination of a sample's SOM placement than geographic origin. As expected, FDOM from all trees transitioned from more protein-like components to more humic-like components with senescence. Percent greenness of sampled leaves and the proportion of tyrosine-like component 1 were found to be significantly different between the two genetic beech clusters, suggesting differences in photosynthesis and resorption. Our results highlight the need to account for interspecific and intraspecific variations in leaf litter leachate FDOM throughout autumn when examining the influence of allochthonous inputs to streams.

Genetic variability among elite popcorn lines based on molecular and morphoagronomic characteristics.

PubMed

Dos Santos, J F; Mangolin, C A; Machado, M F P S; Scapim, C A; Giordani, W; Gonçalves, L S A

2017-06-29

Knowledge of genetic diversity among genotypes and relationships among elite lines is of great importance for the development of breeding programs. Therefore, the objective of this study was to evaluate genetic variability based on the morphoagronomic and molecular characterization of 18 elite popcorn (Zea mays var. everta) lines to be used by Universidade Estadual de Maringá breeding programs. We used 31 microsatellite primers (widely distributed in the genome), and 16 morphological descriptors (including the resistance to maize white spot, common rust, polysora rust of maize, cercospora and leaf blights). The molecular data revealed variability among the lines, which were divided into four groups that were partially concordant with unweighted pair group method with arithmetic mean (UPMGA) and Bayesian clusters. The lines G3, G4, G11, and G13 exhibited favorable morphological characters and low disease incidence rates. The four groups were confirmed using the Gower distance in the UPGMA cluster; however, there was no association with the dissimilarity patterns obtained using the molecular data. The absence of a correlation suggests that both characterizations (morphoagronomic and molecular) are important for discriminating among elite popcorn lines.

Tissue- and Cell-Specific Cytokinin Activity in Populus × canescens Monitored by ARR5::GUS Reporter Lines in Summer and Winter.

PubMed

Paul, Shanty; Wildhagen, Henning; Janz, Dennis; Teichmann, Thomas; Hänsch, Robert; Polle, Andrea

2016-01-01

Cytokinins play an important role in vascular development. But knowledge on the cellular localization of this growth hormone in the stem and other organs of woody plants is lacking. The main focus of this study was to investigate the occurrence and cellular localization of active cytokinins in leaves, roots, and along the stem of Populus × canescens and to find out how the pattern is changed between summer and winter. An ARR5::GUS reporter construct was used to monitor distribution of active cytokinins in different tissues of transgenic poplar lines. Three transgenic lines tested under outdoor conditions showed no influence of ARR5::GUS reporter construct on the growth performance compared with the wild-type, but one line lost the reporter activity. ARR5::GUS activity indicated changes in the tissue- and cell type-specific pattern of cytokinin activity during dormancy compared with the growth phase. ARR5::GUS activity, which was present in the root tips in the growing season, disappeared in winter. In the stem apex ground tissue, ARR5::GUS activity was higher in winter than in summer. Immature leaves from tissue-culture grown plants showed inducible ARR5::GUS activity. Leaf primordia in summer showed ARR5::GUS activity, but not the expanded leaves of outdoor plants or leaf primordia in winter. In stem cross sections, the most prominent ARR5::GUS activity was detected in the cortex region and in the rays of bark in summer and in winter. In the cambial zone the ARR5::GUS activity was more pronounced in the dormant than in growth phase. The pith and the ray cells adjacent to the vessels also displayed ARR5::GUS activity. In silico analyses of the tissue-specific expression patterns of the whole PtRR type-A family of poplar showed that PtRR10, the closest ortholog to the Arabidopsis ARR5 gene, was usually the most highly expressed gene in all tissues. In conclusion, gene expression and tissue-localization indicate high activity of cytokinins not only in summer, but also in winter. The presence of the signal in meristematic tissues supports their role in meristem maintenance. The reporter lines will be useful to study the involvement of cytokinins in acclimation of poplar growth to stress.

Effects of defoliation in the developing leaf zone on young Populus Xeuramericana plants. II. Distribution of UC-photosynthate after defoliation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bassman, J.H.; Dickmann, D.I.

Patterns of UC-photosynthate distribution in growth chamber-grown Populus xeuramericana cv. Negrito de Granada were determined 24 h, 3 weeks, and 5 weeks after defoliation in the developing leaf zone. Translocation patterns were determined by exposing leaves below, within, or above the defoliated zone to UCO2 and determining UC distribution within the plant after 48 h. Translocation patterns were altered within 24 h after defoliation. When leaves below or remaining tissue of leaves within the zone of defoliation were exposed to UCO2, a greater percentage of UC-photosynthate was transported to the expanding shoot and lateral branches and less to the rootsmore » in defoliated plants compared to controls. Little difference between defoliated and control plants and UC distribution occurred when new leaves produced subsequent to defoliation were exposed to UCO2. By 5 weeks after defoliation there was little difference in patterns of UC distribution between defoliated and control plants. These results substantiate biomass partitioning data which showed that a single defoliation of young poplar plants did not affect diameter or height growth, whereas leaf growth was stimulated and root growth reduced.« less

Annotation of a hybrid partial genome of the coffee rust (Hemileia vastatrix) contributes to the gene repertoire catalog of the Pucciniales

PubMed Central

Cristancho, Marco A.; Botero-Rozo, David Octavio; Giraldo, William; Tabima, Javier; Riaño-Pachón, Diego Mauricio; Escobar, Carolina; Rozo, Yomara; Rivera, Luis F.; Durán, Andrés; Restrepo, Silvia; Eilam, Tamar; Anikster, Yehoshua; Gaitán, Alvaro L.

2014-01-01

Coffee leaf rust caused by the fungus Hemileia vastatrix is the most damaging disease to coffee worldwide. The pathogen has recently appeared in multiple outbreaks in coffee producing countries resulting in significant yield losses and increases in costs related to its control. New races/isolates are constantly emerging as evidenced by the presence of the fungus in plants that were previously resistant. Genomic studies are opening new avenues for the study of the evolution of pathogens, the detailed description of plant-pathogen interactions and the development of molecular techniques for the identification of individual isolates. For this purpose we sequenced 8 different H. vastatrix isolates using NGS technologies and gathered partial genome assemblies due to the large repetitive content in the coffee rust hybrid genome; 74.4% of the assembled contigs harbor repetitive sequences. A hybrid assembly of 333 Mb was built based on the 8 isolates; this assembly was used for subsequent analyses. Analysis of the conserved gene space showed that the hybrid H. vastatrix genome, though highly fragmented, had a satisfactory level of completion with 91.94% of core protein-coding orthologous genes present. RNA-Seq from urediniospores was used to guide the de novo annotation of the H. vastatrix gene complement. In total, 14,445 genes organized in 3921 families were uncovered; a considerable proportion of the predicted proteins (73.8%) were homologous to other Pucciniales species genomes. Several gene families related to the fungal lifestyle were identified, particularly 483 predicted secreted proteins that represent candidate effector genes and will provide interesting hints to decipher virulence in the coffee rust fungus. The genome sequence of Hva will serve as a template to understand the molecular mechanisms used by this fungus to attack the coffee plant, to study the diversity of this species and for the development of molecular markers to distinguish races/isolates. PMID:25400655

Evaluation of drought response of two poplar clones (Populus x canadensis Monch 'I-214' and P. deltoides Marsh. 'Dvina') through high resolution analysis of stem growth.

PubMed

Giovannelli, Alessio; Deslauriers, Annie; Fragnelli, Giuseppe; Scaletti, Luciano; Castro, Gaetano; Rossi, Sergio; Crivellaro, Alan

2007-01-01

Different irrigation effects on stem radius variation (DeltaR) and maximum daily shrinkage (MDS) in Populus deltoides 'Dvina' and Populusxcanadensis 'I-214' were studied to assess differences in drought tolerance between clones. One-year-old trees growing in concrete tanks were submitted to two irrigation regimes (natural rainfall and irrigation) from 24 June to 10 August, and DeltaR was monitored by automatic point dendrometers. Independently of the irrigation regime, 'Dvina' showed a higher stem radial increment than 'I-214'. In both clones, the first response to changed soil water content was a significant increase in MDS, whilst DeltaR decreased about 20 d later when pre-dawn leaf water potential (Psipd) dropped below -0.4 MPa. However, they displayed different strategies to overcome drought. 'Dvina' maintained a positive DeltaR for longer than 'I-214', which had lower leaf Psipd and greater leaf abscission at the end of the drought period. After irrigation resumed, 'Dvina' showed a higher capacity to restore stem growth. 'I-214' was probably unable to recover secondary growth because of higher leaf abscission during drought stress and the production of newly expanded leaves during recovery. It is concluded that the larger radial growth of 'Dvina' derived from a better water use (carbon uptake versus water loss) than 'I-214' under limited water availability.

Silvical Characteristics of Yellow-Poplar

Treesearch

David F. Olson

1969-01-01

Yellow-poplar (Liriorlentlron tulipifera L.) is also commonly known as tulip poplar, tulip tree, white-poplar, whitewood, and "poplar" (60). It gets its name from the tulip-like flowers which it bears in the late spring. Because of the excellent form and rapid growth of the tree, plus the fine working qualities of the wood, yellow-poplar is one of the most...

Impact of Regionally Distinct Agroecosystem Communities on the Potential for Autonomous Control of the Coffee Leaf Rust.

PubMed

Hajian-Forooshani, Zachary; Rivera Salinas, Iris Saraeny; Jiménez-Soto, Estelí; Perfecto, Ivette; Vandermeer, John

2016-12-01

Recent theoretical work suggests that two ineffective control agents can provide effective biological control when coupled together. We explore the implications of this work with the system of coffee leaf rust (CLR), caused by the fungal agent Hemileiae vastatrix, and two of its natural enemies, a fungal pathogen (Lecanicillium lecanii) and a spore predator (Mycodiplosis hemileiae). Here we report on comparative surveys of the CLR and its two natural enemies in Mexico, where the CLR has been at epidemic status since 2012, and Puerto Rico, where the CLR is present but has not reached epidemic densities. We found that the densities of the two control agents per CLR lesion is higher in Puerto Rico than in Mexico, and we hypothesize that their joint presence at higher densities is contributing to the suppression of the CLR in Puerto Rico but not in Mexico. Furthermore, we found that the presence of Azteca sericeasur, a keystone ant species that occurs in Mexico but not Puerto Rico, significantly reduces the prevalence of M. hemileiae on coffee plants. Our work provides data that allows us to hypothesize that the joint presence of these two control agents may potentially provide control of the CLR and also highlights the importance of regionally specific communities within agroecosystems, and how variation in community composition may lead to varying outcomes for biological control. Additionally, this is the first report of the presence of a potentially important biological control agent, M. hemileiae, in Latin America and the Caribbean. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Matching the best viewing angle in depth cameras for biomass estimation based on poplar seedling geometry.

PubMed

Andújar, Dionisio; Fernández-Quintanilla, César; Dorado, José

2015-06-04

In energy crops for biomass production a proper plant structure is important to optimize wood yields. A precise crop characterization in early stages may contribute to the choice of proper cropping techniques. This study assesses the potential of the Microsoft Kinect for Windows v.1 sensor to determine the best viewing angle of the sensor to estimate the plant biomass based on poplar seedling geometry. Kinect Fusion algorithms were used to generate a 3D point cloud from the depth video stream. The sensor was mounted in different positions facing the tree in order to obtain depth (RGB-D) images from different angles. Individuals of two different ages, e.g., one month and one year old, were scanned. Four different viewing angles were compared: top view (0°), 45° downwards view, front view (90°) and ground upwards view (-45°). The ground-truth used to validate the sensor readings consisted of a destructive sampling in which the height, leaf area and biomass (dry weight basis) were measured in each individual plant. The depth image models agreed well with 45°, 90° and -45° measurements in one-year poplar trees. Good correlations (0.88 to 0.92) between dry biomass and the area measured with the Kinect were found. In addition, plant height was accurately estimated with a few centimeters error. The comparison between different viewing angles revealed that top views showed poorer results due to the fact the top leaves occluded the rest of the tree. However, the other views led to good results. Conversely, small poplars showed better correlations with actual parameters from the top view (0°). Therefore, although the Microsoft Kinect for Windows v.1 sensor provides good opportunities for biomass estimation, the viewing angle must be chosen taking into account the developmental stage of the crop and the desired parameters. The results of this study indicate that Kinect is a promising tool for a rapid canopy characterization, i.e., for estimating crop biomass production, with several important advantages: low cost, low power needs and a high frame rate (frames per second) when dynamic measurements are required.

Elevated ozone affects C, N and P ecological stoichiometry and nutrient resorption of two poplar clones.

PubMed

Shang, Bo; Feng, Zhaozhong; Li, Pin; Calatayud, Vicent

2018-03-01

The effects of elevated ozone on C (carbon), N (nitrogen) and P (phosphorus) ecological stoichiometry and nutrient resorption in different organs including leaves, stems and roots were investigated in poplar clones 546 (P. deltoides cv. '55/56' × P. deltoides cv. 'Imperial') and 107 (P. euramericana cv. '74/76') with a different sensitivity to ozone. Plants were exposed to two ozone treatments, NF (non-filtered ambient air) and NF60 (NF with targeted ozone addition of 60 ppb), for 96 days in open top chambers (OTCs). Significant ozone effects on most variables of C, N and P ecological stoichiometry were found except for the C concentration and the N/P in different organs. Elevated ozone increased both N and P concentrations of individual organs while for C/N and C/P ratios a reduction was observed. On these variables, ozone had a greater effect for clone 546 than for clone 107. N concentrations of different leaf positions ranked in the order upper > middle > lower, showing that N was transferred from the lower senescent leaves to the upper ones. This was also indicative of N resorption processes, which increased under elevated ozone. N resorption of clone 546 was 4 times larger than that of clone 107 under ambient air (NF). However, elevated ozone (NF60) had no significant effect on P resorption for both poplar clones, suggesting that their growth was only limited by N, while available P in the soil was enough to sustain growth. Understanding ecological stoichiometric responses under ozone stress is crucial to predict future effects on ecological processes and biogeochemical cycles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular cytogenetic identification of three rust-resistant wheat-Thinopyrum ponticum partial amphiploids.

PubMed

Pei, Yanru; Cui, Yu; Zhang, Yanping; Wang, Honggang; Bao, Yinguang; Li, Xingfeng

2018-01-01

Thinopyrum ponticum (2n = 10× = 70, J S J S J S J S JJJJJJ) is an important wild perennial Triticeae species that has a unique gene pool with many desirable traits for common wheat. The partial amphiploids derived from wheat- Th. ponticum set up a bridge for transferring valuable genes from Th. ponticum into common wheat. In this study, genomic in situ hybridization (GISH), multicolor GISH (mcGISH) and fluorescence in situ hybridization (FISH) were used to analyze the genomic constitution of SN0389, SN0398 and SN0406, three octoploid accessions with good resistance to rust. The results demonstrated that the three octoploids possessed 42 wheat chromosomes, while SN0389 contained 12 Th. ponticum chromosomes and SN0398 and SN0406 contained 14 Th. ponticum chromosomes. The genomic constitution of SN0389 was 42 W + 12J S , and for SN0398 and SN0406 it was 42 W + 12J S  + 2 J. Chromosomal variation was found in chromosomes 1A, 3A, 6A, 2B, 5B, 6B, 7B, 1D and 5D of SN0389, SN0398 and SN0406 based on the FISH and McGISH pattern. A resistance evaluation showed that SN0389, SN0398 and SN0406 possessed good resistance to stripe and leaf rust at the seedling stage and adult-plant stage. The results indicated that these wheat- Th. ponticum partial amphiploids are new resistant germplasms for wheat improvement.

Diversity of arthropod community in transgenic poplar-cotton ecosystems.

PubMed

Zhang, D J; Lu, Z Y; Liu, J X; Li, C L; Yang, M S

2015-12-02

Poplar-cotton agro-ecosystems are the main agricultural planting modes of plain cotton fields in China. Here, we performed a systematic survey of the diversity and population of arthropod communities in four different combination of poplar-cotton eco-systems, including I) non-transgenic poplar and non-transgenic cotton fields; II) non-transgenic poplar and transgenic cotton fields [Bacillus thuringiensis (Bt) cotton]; III) Bt transgenic poplar (high insect resistant strain Pb29) and non-transgenic cotton; and IV) transgenic poplar and transgenic cotton fields, over a period of 3 years. Based on the statistical methods used to investigate community ecology, the effects of transgenic ecosystems on the whole structure of the arthropod community, on the structure of arthropods in the nutritive layer, and on the similarity of arthropod communities were evaluated. The main results were as follows: the transgenic poplar-cotton ecosystem has a stronger inhibitory effect on insect pests and has no impact on the structure of the arthropod community, and therefore, maintains the diversity of the arthropod community. The character index of the community indicated that the structure of the arthropod community of the transgenic poplar-cotton ecosystem was better than that of the poplar-cotton ecosystem, and that system IV had the best structure. As for the abundance of nutritional classes, the transgenic poplar-cotton ecosystem was also better than that of the non-transgenic poplar-cotton ecosystem. The cluster analysis and similarity of arthropod communities between the four different transgenic poplar-cotton ecosystems illustrated that the structure of the arthropod community excelled in the small sample of the transgenic poplar-cotton ecosystems.

78 FR 27855 - Black Stem Rust; Additions of Rust-Resistant Species and Varieties

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-13

.... APHIS-2012-0108] Black Stem Rust; Additions of Rust-Resistant Species and Varieties AGENCY: Animal and... stem rust quarantine and regulations by adding two varieties to the list of rust-resistant Berberis species and varieties and one variety to the list of rust-resistant Mahonia species and varieties. This...

The use of wooden sticks to assess stream ecosystem functioning: comparison with leaf breakdown rates.

PubMed

Arroita, Maite; Aristi, Ibon; Flores, Lorea; Larrañaga, Aitor; Díez, Joserra; Mora, Juanita; Romaní, Anna M; Elosegi, Arturo

2012-12-01

Breakdown of organic matter is a key process in streams and rivers, and thus, it has potential to assess functional impairment of river ecosystems. Because the litter-bag method commonly used to measure leaf breakdown is time consuming and expensive, several authors proposed to measure breakdown of wooden sticks instead. Nevertheless, currently there is little information on the performance of wooden sticks versus that of leaves. We compared the breakdown of tongue depressors made of untreated poplar wood, to that of six common leaf species in two large streams in the Basque Country (northern Spain), one polluted and the other unpolluted. Breakdown rates ranged from 0.0011 to 0.0120 day(-1), and were significantly lower in the polluted stream. Wooden sticks performed very similarly to leaves, but were less affected by flood-induced physical abrasion. The ranking of the materials according to their breakdown rate was consistent, irrespective of the stream. The experiments with leaves were 10 times more costly for breakdown rate, 4 times if we include the rest of the variables measured. Therefore wooden sticks offer a promising tool to assess river ecosystem functioning, although more research is necessary to define the thresholds for ecosystem functional impairment. Copyright © 2012 Elsevier B.V. All rights reserved.

Ultrastructure of Plant Leaf Cuticles in relation to Sample Preparation as Observed by Transmission Electron Microscopy

PubMed Central

Guzmán, Paula; Fernández, Victoria; García, María Luisa; Fernández, Agustín; Gil, Luis

2014-01-01

The leaf cuticular ultrastructure of some plant species has been examined by transmission electron microscopy (TEM) in only few studies. Attending to the different cuticle layers and inner structure, plant cuticles have been grouped into six general morphological types. With the aim of critically examining the effect of cuticle isolation and preparation for TEM analysis on cuticular ultrastructure, adaxial leaf cuticles of blue-gum eucalypt, grey poplar, and European pear were assessed, following a membrane science approach. The embedding and staining protocols affected the ultrastructure of the cuticles analysed. The solubility parameter, surface tension, and contact angles with water of pure Spurr's and LR-White resins were within a similar range. Differences were however estimated for resin : solvent mixtures, since Spurr's resin is combined with acetone and LR-White resin is mixed with ethanol. Given the composite hydrophilic and lipophilic nature of plant cuticles, the particular TEM tissue embedding and staining procedures employed may affect sample ultrastructure and the interpretation of the results in physicochemical and biological terms. It is concluded that tissue preparation procedures may be optimised to facilitate the observation of the micro- and nanostructure of cuticular layers and components with different degrees of polarity and hydrophobicity. PMID:24895682

Pre-terrestrial origin of rust in the Nakhla meteorite

NASA Technical Reports Server (NTRS)

Wentworth, Susan J.; Gooding, James L.

1990-01-01

The authors present quantative elemental compositions and summarize textural evidence for the pre-terrestrial origin of rust on the Nakhla meteorite. The material in question is called 'rust' because its phase composition remains unknown. Compelling evidence for the pre-terrestrial origin of the rust is found in rust veins truncated by fusion crust and preserved as faults in sutured igneous crystals. Rust veins that approach the meteorite's fusion crust become discontinuous and exhibit vugs that suggest partial decrepitation; no veins that penetrate the fusion crust have been found. Because the rust probably contains volatile compounds, it is reasonable to expect that heating near the ablation surface (formed during atmospheric entry to Earth) would encourage devolatilization of the rust. Hence, the absence of rust veins in fusion crust and vugs in rust veins near fusion crust clearly imply that the rust existed in the meteorite before atmospheric entry.

Observations on a hybrid poplar test planting in West Virginia

Treesearch

Arthur R. Eschner

1960-01-01

Hybrid poplars, crosses between European and American Aigeiros poplars, have been grown in Europe for about 200 years. The rapid growth and high productivity of some of these hybrids on sites to which they are adapted has stimulated interest in poplar growing in this country. And demand for these poplars is developing in many parts of the United States.

An Empirical Assessment of Transgene Flow from a Bt Transgenic Poplar Plantation.

PubMed

Hu, Jianjun; Zhang, Jin; Chen, Xingling; Lv, Jinhui; Jia, Huixia; Zhao, Shutang; Lu, Mengzhu

2017-01-01

To assess the possible impact of transgenic poplar plantations on the ecosystem, we analyzed the frequency and distance of gene flow from a mature male transgenic Populus nigra plantation carrying the Bacillus thuringiensis toxin gene (Bt poplar) and the survival of Bt poplar seeds. The resultant Bt poplar seeds occurred at a frequency of ~0.15% at 0 m to ~0.02% at 500 m from the Bt poplar plantation. The germination of Bt poplar seeds diminished within three weeks in the field (germination rate from 68% to 0%) compared to 48% after three weeks of storage at 4°C. The survival rate of seedlings in the field was 0% without any treatment but increased to 1.7% under the addition of four treatments (cleaning and trimming, watering, weeding, and covering with plastic film to maintain moisture) after being seeded in the field for eight weeks. The results of this study indicate that gene flow originating from the Bt poplar plantation occurred at an extremely low level through pollen or seeds under natural conditions. This study provides first-hand field data on the extent of transgene flow in poplar plantations and offers guidance for the risk assessment of transgenic poplar plantations.

Comparative Physiological and Proteomic Analysis Reveals the Leaf Response to Cadmium-Induced Stress in Poplar (Populus yunnanensis)

PubMed Central

Yang, Shihai; Zhou, Yanli; Dong, Chao; Ren, Jian; Sun, Xudong; Yang, Yongping

2015-01-01

Excess amounts of heavy metals are important environmental pollutants with significant ecological and nutritional effects. Cdmium (Cd) is of particular concern because of its widespread occurrence and high toxicity. We conducted physiological and proteomic analyses to improve our understanding of the responses of Populus yunnanensis to Cd stress. The plantlets experienced two apparent stages in their response to Cd stress. During the first stage, transiently induced defense-response molecules, photosynthesis- and energy-associated proteins, antioxidant enzymes and heat shock proteins (HSPs) accumulated to enhance protein stability and establish a new cellular homeostasis. This activity explains why plant photosynthetic capability during this period barely changed. During the second stage, a decline of ribulose-1, 5-bisphosphate carboxylase (RuBisCO) and HSP levels led to imbalance of the plant photosynthetic system. Additionally, the expression of Mitogen-activated protein kinase 3 (MPK3), Mitogen-activated protein kinase 6 (MPK6) and a homeobox-leucine zipper protein was higher in the second stage. Higher expression of caffeoyl-CoA O-methyltransferase (CCoAOMT) may regulate plant cell wall synthesis for greater Cd storage. These genes may be candidates for further research and use in genetic manipulation of poplar tolerance to Cd stress. PMID:26349064

Genome-Wide Identification of the Invertase Gene Family in Populus.

PubMed

Chen, Zhong; Gao, Kai; Su, Xiaoxing; Rao, Pian; An, Xinmin

2015-01-01

Invertase plays a crucial role in carbohydrate partitioning and plant development as it catalyses the irreversible hydrolysis of sucrose into glucose and fructose. The invertase family in plants is composed of two sub-families: acid invertases, which are targeted to the cell wall and vacuole; and neutral/alkaline invertases, which function in the cytosol. In this study, 5 cell wall invertase genes (PtCWINV1-5), 3 vacuolar invertase genes (PtVINV1-3) and 16 neutral/alkaline invertase genes (PtNINV1-16) were identified in the Populus genome and found to be distributed on 14 chromosomes. A comprehensive analysis of poplar invertase genes was performed, including structures, chromosome location, phylogeny, evolutionary pattern and expression profiles. Phylogenetic analysis indicated that the two sub-families were both divided into two clades. Segmental duplication is contributed to neutral/alkaline sub-family expansion. Furthermore, the Populus invertase genes displayed differential expression in roots, stems, leaves, leaf buds and in response to salt/cold stress and pathogen infection. In addition, the analysis of enzyme activity and sugar content revealed that invertase genes play key roles in the sucrose metabolism of various tissues and organs in poplar. This work lays the foundation for future functional analysis of the invertase genes in Populus and other woody perennials.

Genome-Wide Identification of the Invertase Gene Family in Populus

PubMed Central

Su, Xiaoxing; Rao, Pian; An, Xinmin

2015-01-01

Invertase plays a crucial role in carbohydrate partitioning and plant development as it catalyses the irreversible hydrolysis of sucrose into glucose and fructose. The invertase family in plants is composed of two sub-families: acid invertases, which are targeted to the cell wall and vacuole; and neutral/alkaline invertases, which function in the cytosol. In this study, 5 cell wall invertase genes (PtCWINV1-5), 3 vacuolar invertase genes (PtVINV1-3) and 16 neutral/alkaline invertase genes (PtNINV1-16) were identified in the Populus genome and found to be distributed on 14 chromosomes. A comprehensive analysis of poplar invertase genes was performed, including structures, chromosome location, phylogeny, evolutionary pattern and expression profiles. Phylogenetic analysis indicated that the two sub-families were both divided into two clades. Segmental duplication is contributed to neutral/alkaline sub-family expansion. Furthermore, the Populus invertase genes displayed differential expression in roots, stems, leaves, leaf buds and in response to salt/cold stress and pathogen infection. In addition, the analysis of enzyme activity and sugar content revealed that invertase genes play key roles in the sucrose metabolism of various tissues and organs in poplar. This work lays the foundation for future functional analysis of the invertase genes in Populus and other woody perennials. PMID:26393355

Transgenic upregulation of the condensed tannin pathway in poplar leads to a dramatic shift in leaf palatability for two tree-feeding Lepidoptera.

PubMed

Boeckler, G Andreas; Towns, Megan; Unsicker, Sybille B; Mellway, Robin D; Yip, Lynn; Hilke, Ines; Gershenzon, Jonathan; Constabel, C Peter

2014-02-01

Transgenic hybrid aspen (Populus tremula x tremuloides) overexpressing the MYB134 tannin regulatory gene show dramatically enhanced condensed tannin (proanthocyanidin) levels, as well as shifts in other phenolic metabolites. A series of insect bioassays with forest tent caterpillars (Malacosoma disstria) and gypsy moth (Lymantria dispar) caterpillars was carried out to determine how this metabolic shift affects food preference and performance of generalist tree-feeding lepidopterans. Both species showed a distinct preference for the high-tannin MYB134 overexpressor plants, and L. dispar performance was enhanced relative to controls. L. dispar reached greater pupal weight and showed reduced time to pupation when reared on the MYB134 overexpressing poplar. These results were unexpected since enhanced condensed tannin levels were predicted to act as feeding deterrents. However, the data may be explained by the observed decrease in the salicinoids (phenolic glycosides) salicortin and tremulacin that accompanied the upregulation of the condensed tannins in the transgenics. We conclude that for these two lepidopteran species, condensed tannin levels are unlikely to be a major determinant of caterpillar food preference or performance. However, our experiments show that overexpression of a single regulatory gene in transgenic aspen can have a significant impact on herbivorous insects.

Effects of heat and drought stress on post‐illumination bursts of volatile organic compounds in isoprene‐emitting and non‐emitting poplar

PubMed Central

Jud, Werner; Vanzo, Elisa; Li, Ziru; Ghirardo, Andrea; Zimmer, Ina; Sharkey, Thomas D.; Schnitzler, Jörg‐Peter

2016-01-01

Abstract Over the last decades, post‐illumination bursts (PIBs) of isoprene, acetaldehyde and green leaf volatiles (GLVs) following rapid light‐to‐dark transitions have been reported for a variety of different plant species. However, the mechanisms triggering their release still remain unclear. Here we measured PIBs of isoprene‐emitting (IE) and isoprene non‐emitting (NE) grey poplar plants grown under different climate scenarios (ambient control and three scenarios with elevated CO2 concentrations: elevated control, periodic heat and temperature stress, chronic heat and temperature stress, followed by recovery periods). PIBs of isoprene were unaffected by elevated CO2 and heat and drought stress in IE, while they were absent in NE plants. On the other hand, PIBs of acetaldehyde and also GLVs were strongly reduced in stress‐affected plants of all genotypes. After recovery from stress, distinct differences in PIB emissions in both genotypes confirmed different precursor pools for acetaldehyde and GLV emissions. Changes in PIBs of GLVs, almost absent in stressed plants and enhanced after recovery, could be mainly attributed to changes in lipoxygenase activity. Our results indicate that acetaldehyde PIBs, which recovered only partly, derive from a new mechanism in which acetaldehyde is produced from methylerythritol phosphate pathway intermediates, driven by deoxyxylulose phosphate synthase activity. PMID:26390316

Effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China

PubMed Central

Li, Youzhi; Chen, Xinsheng; Xie, Yonghong; Li, Xu; Li, Feng; Hou, Zhiyong

2014-01-01

This study evaluated the effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China. Poplar plantations resulted in a higher species number and Shannon's diversity. Species compositions were different between areas with poplar and reed populations: a lower ratio of hygrophytes but a higher ratio of mesophytes, and a higher ratio of heliophytes but a lower ratio of neutrophilous or shade plants in poplar areas compared to reed areas. Poplar plantations supported a higher ratio of ligneous plants in the entire Dongting Lake area, but there was no difference in the monitored plots. Unlike reedy areas, poplar plantations had higher light availability but lower soil water content during the growing seasons. These data suggest that young poplar plantations generally increased species richness and plant diversity, but significantly changed species composition due to the reduced soil water and increased light availability. PMID:25208975

75 FR 29191 - Black Stem Rust; Additions of Rust-Resistant Varieties

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-25

.... APHIS-2010-0035] Black Stem Rust; Additions of Rust-Resistant Varieties AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Direct final rule. SUMMARY: We are amending the black stem rust quarantine and regulations by adding 21 varieties to the list of rust-resistant Berberis species or cultivars and...

Qualitative and quantitative trait loci conditioning resistance to Puccinia coronata pathotypes NQMG and LGCG in the oat (Avena sativa L.) cultivars Ogle and TAM O-301.

PubMed

Jackson, E W; Obert, D E; Menz, M; Hu, G; Bonman, J M

2008-02-01

Mapping disease resistance loci relies on the type and precision of phenotypic measurements. For crown rust of oat, disease severity is commonly assessed based on visual ratings of infection types (IT) and/or diseased leaf area (DLA) of infected plants in the greenhouse or field. These data can be affected by several variables including; (i) non-uniform disease development in the field; (ii) atypical symptom development in the greenhouse; (iii) the presence of multiple pathogenic races or pathotypes in the field, and (iv) rating bias. To overcome these limitations, we mapped crown rust resistance to single isolates in the Ogle/TAM O-301 (OT) recombinant inbred line (RIL) population using detailed measurements of IT, uredinia length (UL) and relative fungal DNA (FDNA) estimates determined by q-PCR. Measurements were taken on OT parents and recombinant inbred lines (RIL) inoculated with Puccinia coronata pathotypes NQMG and LGCG in separate greenhouse and field tests. Qualitative mapping identified an allele conferred by TAM O-301 on linkage group (LG) OT-11, which produced a bleached fleck phenotype to both NQMG and LGCG. Quantitative mapping identified two major quantitative trait loci (QTL) originating from TAM O-301 on LGs OT-11 and OT-32 which reduced UL and FDNA of both isolates in all experiments. Additionally, minor QTLs that reduced UL and FDNA were detected on LGs OT-15 and OT-8, originating from TAM O-301, and on LG OT-27, originating from Ogle. Detailed assessments of the OT population using two pathotypes in both the greenhouse and field provided comprehensive information to effectively map the genes responsible for crown rust resistance in Ogle and TAM O-301 to NQMG and LGCG.

An Empirical Assessment of Transgene Flow from a Bt Transgenic Poplar Plantation

PubMed Central

Chen, Xingling; Lv, Jinhui; Jia, Huixia; Zhao, Shutang; Lu, Mengzhu

2017-01-01

To assess the possible impact of transgenic poplar plantations on the ecosystem, we analyzed the frequency and distance of gene flow from a mature male transgenic Populus nigra plantation carrying the Bacillus thuringiensis toxin gene (Bt poplar) and the survival of Bt poplar seeds. The resultant Bt poplar seeds occurred at a frequency of ~0.15% at 0 m to ~0.02% at 500 m from the Bt poplar plantation. The germination of Bt poplar seeds diminished within three weeks in the field (germination rate from 68% to 0%) compared to 48% after three weeks of storage at 4°C. The survival rate of seedlings in the field was 0% without any treatment but increased to 1.7% under the addition of four treatments (cleaning and trimming, watering, weeding, and covering with plastic film to maintain moisture) after being seeded in the field for eight weeks. The results of this study indicate that gene flow originating from the Bt poplar plantation occurred at an extremely low level through pollen or seeds under natural conditions. This study provides first-hand field data on the extent of transgene flow in poplar plantations and offers guidance for the risk assessment of transgenic poplar plantations. PMID:28085955

7 CFR 42.112 - Defects of containers: Tables IV, V, VI, and VII.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Rust (rust stain confined to the top or bottom double seam or rust that can be removed with a soft cloth is not scored a defect): (a) Rust stain (nonmilitary purchases) 206 (b) Rust stain (military purchases) 108 (c) Pitted rust 109 Wet cans (excluding refrigerated containers) 207 Dent: (a) Materially...

7 CFR 42.112 - Defects of containers: Tables IV, V, VI, and VII.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Rust (rust stain confined to the top or bottom double seam or rust that can be removed with a soft cloth is not scored a defect): (a) Rust stain (nonmilitary purchases) 206 (b) Rust stain (military purchases) 108 (c) Pitted rust 109 Wet cans (excluding refrigerated containers) 207 Dent: (a) Materially...

7 CFR 42.112 - Defects of containers: Tables IV, V, VI, and VII.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Rust (rust stain confined to the top or bottom double seam or rust that can be removed with a soft cloth is not scored a defect): (a) Rust stain (nonmilitary purchases) 206 (b) Rust stain (military purchases) 108 (c) Pitted rust 109 Wet cans (excluding refrigerated containers) 207 Dent: (a) Materially...

7 CFR 42.112 - Defects of containers: Tables IV, V, VI, and VII.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Rust (rust stain confined to the top or bottom double seam or rust that can be removed with a soft cloth is not scored a defect): (a) Rust stain (nonmilitary purchases) 206 (b) Rust stain (military purchases) 108 (c) Pitted rust 109 Wet cans (excluding refrigerated containers) 207 Dent: (a) Materially...

Higher photosynthetic capacity from higher latitude: foliar characteristics and gas exchange of southern, central and northern populations of Populus angustifolia.

PubMed

Kaluthota, Sobadini; Pearce, David W; Evans, Luke M; Letts, Matthew G; Whitham, Thomas G; Rood, Stewart B

2015-09-01

Narrowleaf cottonwood (Populus angustifolia James) is an obligate riparian poplar that is a foundation species in river valleys along the Rocky Mountains, spanning 16° of latitude from southern Arizona, USA to southern Alberta, Canada. Its current distribution is fragmented, and genetic variation shows regional population structure consistent with the effects of geographic barriers and past climate. It is thus very well-suited for investigating ecophysiological adaptation associated with latitude. In other section Tacamahaca poplar species, genotypes from higher latitudes show evidence of short-season adaptation with foliar traits that contribute to higher photosynthetic capacity. We tested for similar adaptation in three populations of narrowleaf cottonwoods: from Arizona (south), Alberta (north) and Utah, near the centre of the latitudinal distribution. We propagated 20 genotypes from each population in a common garden in Alberta, and measured foliar and physiological traits after 3 years. Leaves of genotypes from the northern population had higher leaf mass per area (LMA), increased nitrogen (N) content and higher carotenoid and chlorophyll content, and these were associated with higher light-saturated net photosynthesis (Asat). In leaves of all populations the majority of stomata were abaxial, with the proportion of abaxial stomata highest in the southern population. Stomatal conductance (gs) and transpiration rates were higher in the northern population but water-use efficiency (Asat/gs) and leaf carbon isotope composition (δ(13)C) did not differ across the populations. These results (i) establish links between Asat and gs, N, chlorophyll and LMA among populations within this species, (ii) are consistent with the discrimination of populations from prior investigation of genetic variation and (iii) support the concept of latitudinal adaptation, whereby deciduous trees from higher latitudes display higher photosynthetic capacity, possibly compensating for a shorter and cooler growth season and reduced insolation. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ecology and silviculture of poplar plantations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stanturf, John A.; Van Oosten, Cees; Netzer, Daniel A.

2002-07-01

D.I.; Isebrands, J.G.; Eckenwalder, J.E.; Richardson, J., eds. Poplar culture in North America, part A, chapter 5. Ottawa: NRC Research Press, National Research Council of Canada: 153-206. ABSTRACT. Poplars are some of the fastest growing trees in North America and foresters have sought to capitalize on this potential since the 1940s. Interest in growing poplars has fluctuated, and objectives have shifted between producing sawlogs, pulp-wood, or more densely spaced "woodgrass" or biofuels. Currently, most poplar plantations are established for pulpwood or chip production on rotations of 10 years or less, but interest in sawlog production is increasing. Sid McKnight characterizedmore » cottonwood as a prima donna species: under ideal conditions, growth rates are just short of spectacular. Just as this can be applied to all poplars, it is equally true that all poplars are demanding of good sites and careful establishment. Growing poplars in plantations is challenging, and good establishment the first year is critical to long-term success. If a grower lacks the commitment or resources to provide needed treatments at critical times, then species other than poplars should be considered. Our objective in this chapter is to provide growers with current information for establishing and tending poplar plantations, as practiced in North America. Where we have sufficient information, differences between the poplar-growing regions of the United States and Canada will be noted. Mostly information is available on eastern and black cottonwood and their hybrids.« less

Effects of tillage technologies and application of biopreparations on micromycetes in the rhizosphere and rhizoplane of spring wheat

NASA Astrophysics Data System (ADS)

Shirokikh, I. G.; Kozlova, L. M.; Shirokikh, A. A.; Popov, F. A.; Tovstik, E. V.

2017-07-01

The population density and structure of complexes of soil microscopic fungi in the rhizosphere and rhizoplane of spring wheat ( Triticum aestivum L.), plant damage by root rot and leaf diseases, and crop yield were determined in a stationary field experiment on a silty loamy soddy-podzolic soil (Albic Retisol (Loamic, Aric)) in dependence on the soil tillage technique: (a) moldboard plowing to 20-22 cm and (b) non-inversive tillage to 14-16 cm. The results were treated with the two-way ANOVA method. It was shown that the number of fungal propagules in the rhizosphere and rhizoplane of plants in the variant with non-inversive tillage was significantly smaller than that in the variant with plowing. Minimization of the impact on the soil during five years led to insignificant changes in the structure of micromycete complexes in the rhizosphere of wheat. The damage of the plants with root rot and leaf diseases upon non-inversive tillage did not increase in comparison with that upon plowing. Wheat yield in the variant with non-inversive tillage was insignificantly lower than that in the variant with moldboard plowing. The application of biopreparations based on the Streptomyces hygroscopicus A4 and Pseudomonas aureofaciens BS 1393 resulted in a significant decrease of plant damage with leaf rust.

Relationship between the specific surface area of rust and the electrochemical behavior of rusted steel in a wet-dry acid corrosion environment

NASA Astrophysics Data System (ADS)

Liu, Wei; Zhao, Qing-he; Li, Shuan-zhu

2017-01-01

The relationship between the specific surface area (SSA) of rust and the electrochemical behavior of rusted steel under wet-dry acid corrosion conditions was investigated. The results showed that the corrosion current density first increased and then decreased with increasing SSA of the rust during the corrosion process. The structure of the rust changed from single-layer to double-layer, and the γ-FeOOH content decreased in the inner layer of the rust with increasing corrosion time; by contrast, the γ-FeOOH content in the outer layer was constant. When the SSA of the rust was lower than the critical SSA corresponding to the relative humidity during the drying period, condensed water in the micropores of the rust could evaporate, which prompted the diffusion of O2 into the rust and the following formation process of γ-FeOOH, leading to an increase of corrosion current density with increasing corrosion time. However, when the SSA of the rust reached or exceeded the critical SSA, condensate water in the micro-pores of the inner layer of the rust could not evaporate which inhibited the diffusion of O2 and decreased the γ-FeOOH content in the inner rust, leading to a decrease of corrosion current density with increasing corrosion time.

Rust transformation/rust compatible primers

NASA Technical Reports Server (NTRS)

Emeric, Dario A.; Miller, Christopher E.

1993-01-01

Proper surface preparation has been the key to obtain good performance by a surface coating. The major obstacle in preparing a corroded or rusted surface is the complete removal of the contaminants and the corrosion products. Sandblasting has been traditionally used to remove the corrosion products before painting. However, sandblasting can be expensive, may be prohibited by local health regulations and is not applicable in every situation. To get around these obstacles, Industry developed rust converters/rust transformers and rust compatible primers (high solids epoxies). The potential use of these products for military equipment led personnel of the Belvoir Research, Development and Engineering Center (BRDEC) to evaluate the commercially available rust transformers and rust compatible primers. Prior laboratory experience with commercially available rust converters, as well as field studies in Hawaii and Puerto Rico, revealed poor performance, several inherent limitations, and lack of reliability. It was obvious from our studies that the performance of rust converting products was more dependent on the amount and type of rust present, as well as the degree of permeability of the coating, than on the product's ability to form an organometallic complex with the rust. Based on these results, it was decided that the Military should develop their own rust converter formulation and specification. The compound described in the specification is for use on a rusted surface before the application of an organic coating (bituminous compounds, primer or topcoat). These coatings should end the need for sandblasting or the removing of the adherent corrosion products. They also will prepare the surface for the application of the organic coating. Several commercially available rust compatible primers (RCP) were also tested using corroded surfaces. All of the evaluated RCP failed our laboratory tests for primers.

Relation Between Open Circuit Potential and Polarization Resistance with Rust and Corrosion Monitoring of Mild Steel

NASA Astrophysics Data System (ADS)

Choudhary, S.; Garg, A.; Mondal, K.

2016-07-01

The present work discusses continuous corrosion assessment from a unique correlation of open circuit potential (OCP) and linear polarization resistance with rust formation on mild steel after prolong exposure in 3.5% NaCl salt fog environment. The OCP measurement and linear polarization tests were carried out of the rusted samples only without the removal of rust. It also discusses the strong influence of the composition, fraction, and morphology of the rust layers with OCP and linear polarization resistance. The rust characterization was done after the measurement of OCP and linear polarization resistance of the rusted steel samples. Therefore, monitoring of both the OCP and linear polarization resistance of the rusted mild steels coupled with rust characterization could be used for easy and dynamic assessment of the nature of corrosion.

Insect enemies of yellow-poplar

Treesearch

Denver P. Burns; Denver P. Burns

1970-01-01

Yellow-poplar, like the other desirable hardwoods, is attacked by a variety of insects. However, only four species of insects are considered economically important: the tuliptree scale, the yellow-poplar weevil, the root-collar borer, and the Columbian timber beetle. These are native enemies of yellow-poplar (Liriodendvon tzllipifera L.) wherever the tree grows.

Determination of Radiographic Healing: An Assessment of Consistency Using RUST and Modified RUST in Metadiaphyseal Fractures.

PubMed

Litrenta, Jody; Tornetta, Paul; Mehta, Samir; Jones, Clifford; OʼToole, Robert V; Bhandari, Mohit; Kottmeier, Stephen; Ostrum, Robert; Egol, Kenneth; Ricci, William; Schemitsch, Emil; Horwitz, Daniel

2015-11-01

To determine the reliability of the Radiographic Union Scale for Tibia (RUST) score and a new modified RUST score in quantifying healing and to define a value for radiographic union in a large series of metadiaphyseal fractures treated with plates or intramedullary nails. Healing was evaluated using 2 methods: (1) evaluation of interrater agreement in a series of radiographs and (2) analysis of prospectively gathered data from 2 previous large multicenter trials to define thresholds for radiographic union. Part 1: 12 orthopedic trauma surgeons evaluated a series of radiographs of 27 distal femur fractures treated with either plate or retrograde nail fixation at various stages of healing in random order using a modified RUST score. For each radiographic set, the reviewer indicated if the fracture was radiographically healed. Part 2: The radiographic results of 2 multicenter randomized trials comparing plate versus nail fixation of 81 distal femur and 46 proximal tibia fractures were reviewed. Orthopaedic surgeons at 24 trauma centers scored radiographs at 3, 6, and 12 months postoperatively using the modified RUST score above. Additionally, investigators indicated if the fracture was healed or not healed. The intraclass correlation coefficient (ICC) with 95% confidence intervals was determined for each cortex, the standard and modified RUST score, and the assignment of union for part 1 data. The RUST and modified RUST that defined "union" were determined for both parts of the study. ICC: The modified RUST score demonstrated slightly higher ICCs than the standard RUST (0.68 vs. 0.63). Nails had substantial agreement, whereas plates had moderate agreement using both modified and standard RUST (0.74 and 0.67 vs. 0.59 and 0.53). The average standard and modified RUST at union among all fractures was 8.5 and 11.4. Nails had higher standard and modified RUST scores than plates at union. The ICC for union was 0.53 (nails: 0.58; plates: 0.51), which indicates moderate agreement. However, the majority of reviewers assigned union for a standard RUST of 9 and a modified RUST of 11, and >90% considered a score of 10 on the RUST and 13 on the modified RUST united. The ICC for the modified RUST is slightly higher than the standard RUST in metadiaphyseal fractures and had substantial agreement. The ICC for the assessment of union was moderate agreement; however, definite union would be 10 and 13 with over 90% of reviewers assigning union. These are the first data-driven estimates of radiographic union for these scores.

UAV-Based Thermal Imaging for High-Throughput Field Phenotyping of Black Poplar Response to Drought

PubMed Central

Ludovisi, Riccardo; Tauro, Flavia; Salvati, Riccardo; Khoury, Sacha; Mugnozza Scarascia, Giuseppe; Harfouche, Antoine

2017-01-01

Poplars are fast-growing, high-yielding forest tree species, whose cultivation as second-generation biofuel crops is of increasing interest and can efficiently meet emission reduction goals. Yet, breeding elite poplar trees for drought resistance remains a major challenge. Worldwide breeding programs are largely focused on intra/interspecific hybridization, whereby Populus nigra L. is a fundamental parental pool. While high-throughput genotyping has resulted in unprecedented capabilities to rapidly decode complex genetic architecture of plant stress resistance, linking genomics to phenomics is hindered by technically challenging phenotyping. Relying on unmanned aerial vehicle (UAV)-based remote sensing and imaging techniques, high-throughput field phenotyping (HTFP) aims at enabling highly precise and efficient, non-destructive screening of genotype performance in large populations. To efficiently support forest-tree breeding programs, ground-truthing observations should be complemented with standardized HTFP. In this study, we develop a high-resolution (leaf level) HTFP approach to investigate the response to drought of a full-sib F2 partially inbred population (termed here ‘POP6’), whose F1 was obtained from an intraspecific P. nigra controlled cross between genotypes with highly divergent phenotypes. We assessed the effects of two water treatments (well-watered and moderate drought) on a population of 4603 trees (503 genotypes) hosted in two adjacent experimental plots (1.67 ha) by conducting low-elevation (25 m) flights with an aerial drone and capturing 7836 thermal infrared (TIR) images. TIR images were undistorted, georeferenced, and orthorectified to obtain radiometric mosaics. Canopy temperature (Tc) was extracted using two independent semi-automated segmentation techniques, eCognition- and Matlab-based, to avoid the mixed-pixel problem. Overall, results showed that the UAV platform-based thermal imaging enables to effectively assess genotype variability under drought stress conditions. Tc derived from aerial thermal imagery presented a good correlation with ground-truth stomatal conductance (gs) in both segmentation techniques. Interestingly, the HTFP approach was instrumental to detect drought-tolerant response in 25% of the population. This study shows the potential of UAV-based thermal imaging for field phenomics of poplar and other tree species. This is anticipated to have tremendous implications for accelerating forest tree genetic improvement against abiotic stress. PMID:29021803

UAV-Based Thermal Imaging for High-Throughput Field Phenotyping of Black Poplar Response to Drought.

PubMed

Ludovisi, Riccardo; Tauro, Flavia; Salvati, Riccardo; Khoury, Sacha; Mugnozza Scarascia, Giuseppe; Harfouche, Antoine

2017-01-01

Poplars are fast-growing, high-yielding forest tree species, whose cultivation as second-generation biofuel crops is of increasing interest and can efficiently meet emission reduction goals. Yet, breeding elite poplar trees for drought resistance remains a major challenge. Worldwide breeding programs are largely focused on intra/interspecific hybridization, whereby Populus nigra L. is a fundamental parental pool. While high-throughput genotyping has resulted in unprecedented capabilities to rapidly decode complex genetic architecture of plant stress resistance, linking genomics to phenomics is hindered by technically challenging phenotyping. Relying on unmanned aerial vehicle (UAV)-based remote sensing and imaging techniques, high-throughput field phenotyping (HTFP) aims at enabling highly precise and efficient, non-destructive screening of genotype performance in large populations. To efficiently support forest-tree breeding programs, ground-truthing observations should be complemented with standardized HTFP. In this study, we develop a high-resolution (leaf level) HTFP approach to investigate the response to drought of a full-sib F 2 partially inbred population (termed here 'POP6'), whose F 1 was obtained from an intraspecific P. nigra controlled cross between genotypes with highly divergent phenotypes. We assessed the effects of two water treatments (well-watered and moderate drought) on a population of 4603 trees (503 genotypes) hosted in two adjacent experimental plots (1.67 ha) by conducting low-elevation (25 m) flights with an aerial drone and capturing 7836 thermal infrared (TIR) images. TIR images were undistorted, georeferenced, and orthorectified to obtain radiometric mosaics. Canopy temperature ( T c ) was extracted using two independent semi-automated segmentation techniques, eCognition- and Matlab-based, to avoid the mixed-pixel problem. Overall, results showed that the UAV platform-based thermal imaging enables to effectively assess genotype variability under drought stress conditions. T c derived from aerial thermal imagery presented a good correlation with ground-truth stomatal conductance ( g s ) in both segmentation techniques. Interestingly, the HTFP approach was instrumental to detect drought-tolerant response in 25% of the population. This study shows the potential of UAV-based thermal imaging for field phenomics of poplar and other tree species. This is anticipated to have tremendous implications for accelerating forest tree genetic improvement against abiotic stress.

Progress in developing disease control strategies for hybrid poplars

Treesearch

Michael E. Ostry

2000-01-01

Hybrid poplars are being grown throughout many regions of the world for purposes including the production of fiber and energy, ornamental landscape plantings, and soil stabilization. Disease has often been responsible for planting failures resulting in poplars being labeled the universal host to many damaging pathogens. However, many of the poplar species and their...

21st Session of the International Poplar Commission (IPC-2000): poplar and willow culture: meeting the needs of society and the environment; 200 September 24-28; Vancouver, WA.

Treesearch

J.G. Isebrands; J. Richardson

2000-01-01

Research results and ongoing research activities on poplar and willow breeding, diseases, insects, production, and utilization are described in 220 abstracts from the International Poplar Commission meeting in Vancouver, Washington, September 24-28, 2000.

Ecology and silviculture of poplar plantations

Treesearch

John A. Stanturf; Cees van Oosten; Daniel A. Netzer; Mark D. Coleman; C. Jeffrey Portwood

2002-01-01

Poplars are some of the fastest growing trees in North America and foresters have sought to capitalize on this potential since the 1940s. Interest in growing poplars has fluctuated, and objectives have shifted between producing sawlogs, pulp-wood, or more densely spaced "woodgrass" or biofuels. Currently, most poplar plantations are established for pulpwood...

Poplar FT2 Shortens the Juvenile Phase and Promotes Seasonal Flowering[W

PubMed Central

Hsu, Chuan-Yu; Liu, Yunxia; Luthe, Dawn S.; Yuceer, Cetin

2006-01-01

Many woody perennials, such as poplar (Populus deltoides), are not able to form flower buds during the first several years of their life cycle. They must undergo a transition from the juvenile phase to the reproductive phase to be competent to produce flower buds. After this transition, trees begin to form flower buds in the spring of each growing season. The genetic factors that control flower initiation, ending the juvenile phase, are unknown in poplar. The factors that regulate seasonal flower bud formation are also unknown. Here, we report that poplar FLOWERING LOCUS T2 (FT2), a relative of the Arabidopsis thaliana flowering-time gene FT, controls first-time and seasonal flowering in poplar. The FT2 transcript is rare during the juvenile phase of poplar. When juvenile poplar is transformed with FT2 and transcript levels are increased, flowering is induced within 1 year. During the transition between vegetative and reproductive growth in mature trees, FT2 transcripts are abundant during reproductive growth under long days. Subsequently, floral meristems emerge on flanks of the axillary inflorescence shoots. These findings suggest that FT2 is part of the flower initiation pathway in poplar and plays an additional role in regulating seasonal flower initiation that is integrated with the poplar perennial growth habit. PMID:16844908

Apoplastic Sugar Extraction and Quantification from Wheat Leaves Infected with Biotrophic Fungi.

PubMed

Roman-Reyna, Veronica; Rathjen, John P

2017-01-01

Biotrophic fungi such as rusts modify the nutrient status of their hosts by extracting sugars. Hemibiotrophic and biotrophic fungi obtain nutrients from the cytoplasm of host cells and/or the apoplastic spaces. Uptake of nutrients from the cytoplasm is via intracellular hyphae or more complex structures such as haustoria. Apoplastic nutrients are taken up by intercellular hyphae. Overall the infection creates a sink causing remobilization of nutrients from local and distal tissues. The main mobile sugar in plants is sucrose which is absorbed via plant or fungal transporters once unloaded into the cytoplasm or the apoplast. Infection by fungal pathogens alters the apoplastic sugar contents and stimulates the influx of nutrients towards the site of infection as the host tissue transitions to sink. Quantification of solutes in the apoplast can help to understand the allocation of nutrients during infection. However, separation of apoplastic fluids from whole tissue is not straightforward and leakage from damaged cells can alter the results of the extraction. Here, we describe how variation in cytoplasmic contamination and infiltrated leaf volumes must be controlled when extracting apoplastic fluids from healthy and rust-infected wheat leaves. We show the importance of correcting the data for these parameters to measure sugar concentrations accurately.

16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

Code of Federal Regulations, 2010 CFR

2010-01-01

... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

Code of Federal Regulations, 2011 CFR

2011-01-01

... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

Code of Federal Regulations, 2013 CFR

2013-01-01

... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

A green method of diaphragm spring's anti-rusting with high quality and efficiency

NASA Astrophysics Data System (ADS)

Huang, Xinming; Hua, Wenlin

2017-10-01

This paper introduces a green method of diaphragm spring's anti-rusting, which is of high quality, high efficiency and low consumption. It transforms the phosphating way of anti-rusting to physical anti-rusting that directly coat anti-rusting oil on the surface of the spring, and transforms the manual-oiling or oil-immersion to fully-automatically ultrasonic oiling. Hence, this method will completely change the way of diaphgragm spring's anti-rusting.

16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

Code of Federal Regulations, 2014 CFR

2014-01-01

... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

16 CFR 23.10 - Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust resistant...

Code of Federal Regulations, 2012 CFR

2012-01-01

... INDUSTRIES § 23.10 Misuse of “corrosion proof,” “noncorrosive,” “corrosion resistant,” “rust proof,” “rust...,” “rust proof,” or any other term of similar meaning to describe an industry product unless all parts of the product will be immune from rust and other forms of corrosion during the life expectancy of the...

New insights into the obligate biotrophic lifestyle of rust fungi through comparative genomics

USDA-ARS?s Scientific Manuscript database

Wheat production continues to be plagued by rust pathogens and with the recent race shifts there is an increased concern regarding world food security. Three distinct rust fungi caused disease in wheat: Puccinia graminis f. sp. tritici (Pgt), stem rust or black stem rust; P. striiformis f. sp. triti...

Long-term response of yellow-poplar to thinning in the Southern Appalachian Mountains

Treesearch

Tara L. Keyser; Peter M. Brown

2015-01-01

Yellow-poplar (Liriodendron tulipifera L.) is the most abundant individual tree species (in terms of volume) in the southern Appalachian Mountains, with Forest Inventory and Analysis (FIA) reports documenting a continuous increase in yellow-poplar over the recent years (Brown 2003, Schweitzer 1999, Thompson 1998). Current management efforts in evenaged yellow-poplar...

Environmental benefits of poplar culture

Treesearch

J. G. Isebrands; D.F. Karnosky.

2001-01-01

Poplars have important values above and beyond wood or fiber production. Poplars have been planted for environmental purposes for centuries. There are reports of poplar plantings dating back to early Chinese history and biblical times in the Middle East, When immigrants came to North America in the 18th and 19th century, they often brought cuttings of their favorite...

The relationship of leaf rust resistance gene Lr13 and hybrid necrosis gene Ne2m on wheat chromosome 2BS.

PubMed

Zhang, Peng; Hiebert, Colin W; McIntosh, Robert A; McCallum, Brent D; Thomas, Julian B; Hoxha, Sami; Singh, Davinder; Bansal, Urmil

2016-03-01

Genetic and mutational analyses of wheat leaf rust resistance gene Lr13 and hybrid necrosis gene Ne2 m indicated that they are the same gene. Hybrid necrosis in wheat characterized by chlorosis and eventual necrosis of plant tissues in certain wheat hybrids is controlled by the interaction of complementary dominant genes Ne1 and Ne2 located on chromosome arms 5BL and 2BS, respectively. Multiple alleles at each locus can be identified by differences in necrotic phenotypes when varieties are crossed with a fixed accession of the other genotype. Some of at least five Ne2 alleles were described as s (strong), m (medium) and w (weak); alleles of Ne1 were similarly described. Ne2m causes moderate necrosis in hybrids with genotypes having Ne1s. Ne2 is located on chromosome arm 2BS in close proximity to Lr13. Most wheat lines with Ne2m carry Lr13, and all wheat lines with Lr13 appear to carry Ne2m. To further dissect the relationship between Lr13 and Ne2m, more than 350 crosses were made between cv. Spica (Triticum aestivum) or Kubanka (T. durum) carrying Ne1s and recombinant inbred lines or doubled haploid lines from three crosses segregating for Lr13. F1 plants from lines carrying Lr13 crossed with Spica (Ne1s) always showed progressive necrosis; those lacking Lr13 did not. Four wheat cultivars/lines carrying Lr13 were treated with the mutagen EMS. Thirty-five susceptible mutants were identified; eight were distinctly less glaucous and late maturing indicative of chromosome 2B or sub-chromosome loss. Hybrids of phenotypically normal Lr13 mutant plants crossed with Spica did not produce symptoms of hybrid necrosis. Thus, Lr13 and one particular Ne2m allele may be the same gene.

Development of COS-SNP and HRM markers for high-throughput and reliable haplotype-based detection of Lr14a in durum wheat (Triticum durum Desf.).

PubMed

Terracciano, Irma; Maccaferri, Marco; Bassi, Filippo; Mantovani, Paola; Sanguineti, Maria C; Salvi, Silvio; Simková, Hana; Doležel, Jaroslav; Massi, Andrea; Ammar, Karim; Kolmer, James; Tuberosa, Roberto

2013-04-01

Leaf rust (Puccinia triticina Eriks. & Henn.) is a major disease affecting durum wheat production. The Lr14a-resistant gene present in the durum wheat cv. Creso and its derivative cv. Colosseo is one of the best characterized leaf-rust resistance sources deployed in durum wheat breeding. Lr14a has been mapped close to the simple sequence repeat markers gwm146, gwm344 and wmc10 in the distal portion of the chromosome arm 7BL, a gene-dense region. The objectives of this study were: (1) to enrich the Lr14a region with single nucleotide polymorphisms (SNPs) and high-resolution melting (HRM)-based markers developed from conserved ortholog set (COS) genes and from sequenced Diversity Array Technology (DArT(®)) markers; (2) to further investigate the gene content and colinearity of this region with the Brachypodium and rice genomes. Ten new COS-SNP and five HRM markers were mapped within an 8.0 cM interval spanning Lr14a. Two HRM markers pinpointed the locus in an interval of <1.0 cM and eight COS-SNPs were mapped 2.1-4.1 cM distal to Lr14a. Each marker was tested for its capacity to predict the state of Lr14a alleles (in particular, Lr14-Creso associated to resistance) in a panel of durum wheat elite germplasm including 164 accessions. Two of the most informative markers were converted into KASPar(®) markers. Single assay markers ubw14 and wPt-4038-HRM designed for agarose gel electrophoresis/KASPar(®) assays and high-resolution melting analysis, respectively, as well as the double-marker combinations ubw14/ubw18, ubw14/ubw35 and wPt-4038-HRM-ubw35 will be useful for germplasm haplotyping and for molecular-assisted breeding.

Comparative Temporal Transcriptome Profiling of Wheat near Isogenic Line Carrying Lr57 under Compatible and Incompatible Interactions

PubMed Central

Yadav, Inderjit S.; Sharma, Amandeep; Kaur, Satinder; Nahar, Natasha; Bhardwaj, Subhash C.; Sharma, Tilak R.; Chhuneja, Parveen

2016-01-01

Leaf rust caused by Puccinia triticina (Pt) is one of the most important diseases of bread wheat globally. Recent advances in sequencing technologies have provided opportunities to analyse the complete transcriptomes of the host as well as pathogen for studying differential gene expression during infection. Pathogen induced differential gene expression was characterized in a near isogenic line carrying leaf rust resistance gene Lr57 and susceptible recipient genotype WL711. RNA samples were collected at five different time points 0, 12, 24, 48, and 72 h post inoculation (HPI) with Pt 77-5. A total of 3020 transcripts were differentially expressed with 1458 and 2692 transcripts in WL711 and WL711+Lr57, respectively. The highest number of differentially expressed transcripts was detected at 12 HPI. Functional categorization using Blast2GO classified the genes into biological processes, molecular function and cellular components. WL711+Lr57 showed much higher number of differentially expressed nucleotide binding and leucine rich repeat genes and expressed more protein kinases and pathogenesis related proteins such as chitinases, glucanases and other PR proteins as compared to susceptible genotype. Pathway annotation with KEGG categorized genes into 13 major classes with carbohydrate metabolism being the most prominent followed by amino acid, secondary metabolites, and nucleotide metabolism. Gene co-expression network analysis identified four and eight clusters of highly correlated genes in WL711 and WL711+Lr57, respectively. Comparative analysis of the differentially expressed transcripts led to the identification of some transcripts which were specifically expressed only in WL711+Lr57. It was apparent from the whole transcriptome sequencing that the resistance gene Lr57 directed the expression of different genes involved in building the resistance response in the host to combat invading pathogen. The RNAseq data and differentially expressed transcripts identified in present study is a genomic resource which can be used for further studying the host pathogen interaction for Lr57 and wheat transcriptome in general. PMID:28066494

Repression of gibberellin biosynthesis or signaling produces striking alterations in poplar growth, morphology, and flowering.

PubMed

Zawaski, Christine; Kadmiel, Mahita; Pickens, Jim; Ma, Cathleen; Strauss, Steven; Busov, Victor

2011-12-01

We modified gibberellin (GA) metabolism and signaling in transgenic poplars using dominant transgenes and studied their effects for 3 years under field conditions. The transgenes that we employed either reduced the bioactive GAs, or attenuated their signaling. The majority of transgenic trees had significant and in many cases dramatic changes in height, crown architecture, foliage morphology, flowering onset, floral structure, and vegetative phenology. Most transgenes elicited various levels of height reduction consistent with the roles of GA in elongation growth. Several other growth traits were proportionally reduced, including branch length, internode distance, and leaf length. In contrast to elongation growth, stem diameter growth was much less affected, suggesting that semi-dwarf trees in dense stands might provide high levels of biomass production and carbon sequestration. The severity of phenotypic effects was strongly correlated with transgene expression among independent transgenic events, but often in a non-linear manner, the form of which varied widely among constructs. The majority of semi-dwarfed, transgenic plants showed delayed bud flush and early bud set, and expression of a native GAI transgene accelerated first time flowering in the field. All of the phenotypic changes observed in multiple years were stable over the 3 years of field study. Our results suggest that transgenic modification of GA action may be useful for producing semi-dwarf trees with modified growth and morphology for horticulture and other uses.

Effects of heat and drought stress on post-illumination bursts of volatile organic compounds in isoprene-emitting and non-emitting poplar.

PubMed

Jud, Werner; Vanzo, Elisa; Li, Ziru; Ghirardo, Andrea; Zimmer, Ina; Sharkey, Thomas D; Hansel, Armin; Schnitzler, Jörg-Peter

2016-06-01

Over the last decades, post-illumination bursts (PIBs) of isoprene, acetaldehyde and green leaf volatiles (GLVs) following rapid light-to-dark transitions have been reported for a variety of different plant species. However, the mechanisms triggering their release still remain unclear. Here we measured PIBs of isoprene-emitting (IE) and isoprene non-emitting (NE) grey poplar plants grown under different climate scenarios (ambient control and three scenarios with elevated CO2 concentrations: elevated control, periodic heat and temperature stress, chronic heat and temperature stress, followed by recovery periods). PIBs of isoprene were unaffected by elevated CO2 and heat and drought stress in IE, while they were absent in NE plants. On the other hand, PIBs of acetaldehyde and also GLVs were strongly reduced in stress-affected plants of all genotypes. After recovery from stress, distinct differences in PIB emissions in both genotypes confirmed different precursor pools for acetaldehyde and GLV emissions. Changes in PIBs of GLVs, almost absent in stressed plants and enhanced after recovery, could be mainly attributed to changes in lipoxygenase activity. Our results indicate that acetaldehyde PIBs, which recovered only partly, derive from a new mechanism in which acetaldehyde is produced from methylerythritol phosphate pathway intermediates, driven by deoxyxylulose phosphate synthase activity. © 2016 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Increasing atmospheric CO2 reduces metabolic and physiological differences between isoprene- and non-isoprene-emitting poplars.

PubMed

Way, Danielle A; Ghirardo, Andrea; Kanawati, Basem; Esperschütz, Jürgen; Monson, Russell K; Jackson, Robert B; Schmitt-Kopplin, Philippe; Schnitzler, Jörg-Peter

2013-10-01

Isoprene, a volatile organic compound produced by some plant species, enhances abiotic stress tolerance under current atmospheric CO2 concentrations, but its biosynthesis is negatively correlated with CO2 concentrations. We hypothesized that losing the capacity to produce isoprene would require stronger up-regulation of other stress tolerance mechanisms at low CO2 than at higher CO2 concentrations. We compared metabolite profiles and physiological performance in poplars (Populus × canescens) with either wild-type or RNAi-suppressed isoprene emission capacity grown at pre-industrial low, current atmospheric, and future high CO2 concentrations (190, 390 and 590 ppm CO2 , respectively). Suppression of isoprene biosynthesis led to significant rearrangement of the leaf metabolome, increasing stress tolerance responses such as xanthophyll cycle pigment de-epoxidation and antioxidant levels, as well as altering lipid, carbon and nitrogen metabolism. Metabolic and physiological differences between isoprene-emitting and suppressed lines diminished as growth CO2 concentrations rose. The CO2 dependence of our results indicates that the effects of isoprene biosynthesis are strongest at pre-industrial CO2 concentrations. Rising CO2 may reduce the beneficial effects of biogenic isoprene emission, with implications for species competition. This has potential consequences for future climate warming, as isoprene emitted from vegetation has strong effects on global atmospheric chemistry. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Characterization of molecular diversity and genome-wide mapping of loci associated with resistance to stripe rust and stem rust in Ethiopian bread wheat accessions.

PubMed

Muleta, Kebede T; Rouse, Matthew N; Rynearson, Sheri; Chen, Xianming; Buta, Bedada G; Pumphrey, Michael O

2017-08-04

The narrow genetic basis of resistance in modern wheat cultivars and the strong selection response of pathogen populations have been responsible for periodic and devastating epidemics of the wheat rust diseases. Characterizing new sources of resistance and incorporating multiple genes into elite cultivars is the most widely accepted current mechanism to achieve durable varietal performance against changes in pathogen virulence. Here, we report a high-density molecular characterization and genome-wide association study (GWAS) of stripe rust and stem rust resistance in 190 Ethiopian bread wheat lines based on phenotypic data from multi-environment field trials and seedling resistance screening experiments. A total of 24,281 single nucleotide polymorphism (SNP) markers filtered from the wheat 90 K iSelect genotyping assay was used to survey Ethiopian germplasm for population structure, genetic diversity and marker-trait associations. Upon screening for field resistance to stripe rust in the Pacific Northwest of the United States and Ethiopia over multiple growing seasons, and against multiple races of stripe rust and stem rust at seedling stage, eight accessions displayed resistance to all tested races of stem rust and field resistance to stripe rust in all environments. Our GWAS results show 15 loci were significantly associated with seedling and adult plant resistance to stripe rust at false discovery rate (FDR)-adjusted probability (P) <0.10. GWAS also detected 9 additional genomic regions significantly associated (FDR-adjusted P < 0.10) with seedling resistance to stem rust in the Ethiopian wheat accessions. Many of the identified resistance loci were mapped close to previously identified rust resistance genes; however, three loci on the short arms of chromosomes 5A and 7B for stripe rust resistance and two on chromosomes 3B and 7B for stem rust resistance may be novel. Our results demonstrate that considerable genetic variation resides within the landrace accessions that can be utilized to broaden the genetic base of rust resistance in wheat breeding germplasm. The molecular markers identified in this study should be useful in efficiently targeting the associated resistance loci in marker-assisted breeding for rust resistance in Ethiopia and other countries.

Cadmium accumulation and growth responses of a poplar (Populus deltoidsxPopulus nigra) in cadmium contaminated purple soil and alluvial soil.

PubMed

Wu, Fuzhong; Yang, Wanqin; Zhang, Jian; Zhou, Liqiang

2010-05-15

To characterize the phytoextraction efficiency of a hybrid poplar (Populus deltoidsxPopulus nigra) in cadmium contaminated purple soil and alluvial soil, a pot experiment in field was carried out in Sichuan basin, western China. After one growing period, the poplar accumulated the highest of 541.98+/-19.22 and 576.75+/-40.55 microg cadmium per plant with 110.77+/-12.68 and 202.54+/-19.12 g dry mass in these contaminated purple soil and alluvial soil, respectively. Higher phytoextraction efficiency with higher cadmium concentration in tissues was observed in poplar growing in purple soil than that in alluvial soil at relative lower soil cadmium concentration. The poplar growing in alluvial soil had relative higher tolerance ability with lower reduction rates of morphological and growth characters than that in purple soil, suggesting that the poplar growing in alluvial soil might display the higher phytoextraction ability when cadmium contamination level increased. Even so, the poplars exhibited obvious cadmium transport from root to shoot in both soils regardless of cadmium contamination levels. It implies that this examined poplar can extract more cadmium than some hyperaccumulators. The results indicated that metal phytoextraction using the poplar can be applied to clean up soils moderately contaminated by cadmium in these purple soil and alluvial soil. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Numerical Analysis of the Bending Properties of Cathay Poplar Glulam

PubMed Central

Gao, Ying; Wu, Yuxuan; Zhu, Xudong; Zhu, Lei; Yu, Zhiming; Wu, Yong

2015-01-01

This paper presents the formulae and finite element analysis models for predicting the Modulus of Elastic (MOE) and Modulus of Rupture (MOR) of Cathay poplar finger-jointed glulam. The formula of the MOE predicts the MOE of Cathay poplar glulam glued with one-component polyurethane precisely. Three formulae are used to predict the MOR, and Equation (12) predicts the MOR of Cathay poplar glulam precisely. The finite element analysis simulation results of both the MOE and MOR are similar to the experimental results. The predicted results of the finite element analysis are shown to be more accurate than those of the formulae, because the finite element analysis considers the glue layers, but the formulae do not. Three types of typical failure modes due to bending were summarized. The bending properties of Cathay poplar glulam were compared to those of Douglas fir glulam. The results show that Cathay poplar glulam has a lower stiffness, but a marginally higher strength. One-component polyurethane adhesive is shown to be more effective than resorcinol formaldehyde resin adhesive for Cathay poplar glulam. This study shows that Cathay poplar has the potential to be a glulam material in China. PMID:28793619

The partitioning of litter carbon during litter decomposition under different rainfall patterns: a laboratory study

NASA Astrophysics Data System (ADS)

Yang, X.; Szlavecz, K. A.; Langley, J. A.; Pitz, S.; Chang, C. H.

2017-12-01

Quantifying litter C into different C fluxes during litter decomposition is necessary to understand carbon cycling under changing climatic conditions. Rainfall patterns are predicted to change in the future, and their effects on the fate of litter carbon are poorly understood. Soils from deciduous forests in Smithsonian Environmental Research Center (SERC) in Maryland, USA were collected to reconstruct soil columns in the lab. 13C labeled tulip poplar leaf litter was used to trace carbon during litter decomposition. Top 1% and the mean of 15-minute historical precipitation data from nearby weather stations were considered as extreme and control rainfall intensity, respectively. Both intensity and frequency of rainfall were manipulated, while the total amount was kept constant. A pulse of CO2 efflux was detected right after each rainfall event in the soil columns with leaf litter. After the first event, CO2 efflux of the control rainfall treatment soils increased to threefold of the CO2 efflux before rain event and that of the extreme treatment soils increased to fivefold. However, in soils without leaf litter, CO2 efflux was suppressed right after rainfall events. After each rainfall event, the leaf litter contribution to CO2 efflux first showed an increase, decreased sharply in the following two days, and then stayed relatively constant. In soil columns with leaf litter, the order of cumulative CO2 efflux was control > extreme > intermediate. The order of cumulative CO2 efflux in the bare soil treatment was extreme > intermediate > control. The order of volume of leachate from different treatments was extreme > intermediate > control. Our initial results suggest that more intense rainfall events result in larger pulses of CO2, which is rarely measured in the field. Additionally, soils with and without leaf litter respond differently to precipitation events. This is important to consider in temperate regions where leaf litter cover changes throughout the year. Including the rainfall pattern as a parameter to the partitioning of litter carbon could help better project soil carbon cycling in the Mid-Atlantic region.

Field-to-Fuel Performance Testing of Lignocellulosic Feedstocks: An Integrated Study of the Fast Pyrolysis/Hydrotreating Pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howe, Daniel T.; Westover, Tyler; Carpenter, Daniel

2015-05-21

Feedstock composition can affect final fuel yields and quality for the fast pyrolysis and hydrotreatment upgrading pathway. However, previous studies have focused on individual unit operations rather than the integrated system. In this study, a suite of six pure lignocellulosic feedstocks (clean pine, whole pine, tulip poplar, hybrid poplar, switchgrass, and corn stover) and two blends (equal weight percentages whole pine/tulip poplar/switchgrass and whole pine/clean pine/hybrid poplar) were prepared and characterized at Idaho National Laboratory. These blends then underwent fast pyrolysis at the National Renewable Energy Laboratory and hydrotreatment at Pacific Northwest National Laboratory. Although some feedstocks showed a highmore » fast pyrolysis bio-oil yield such as tulip poplar at 57%, high yields in the hydrotreater were not always observed. Results showed overall fuel yields of 15% (switchgrass), 18% (corn stover), 23% (tulip poplar, Blend 1, Blend 2), 24% (whole pine, hybrid poplar) and 27% (clean pine). Simulated distillation of the upgraded oils indicated that the gasoline fraction varied from 39% (clean pine) to 51% (corn stover), while the diesel fraction ranged from 40% (corn stover) to 46% (tulip poplar). Little variation was seen in the jet fuel fraction at 11 to 12%. Hydrogen consumption during hydrotreating, a major factor in the economic feasibility of the integrated process, ranged from 0.051 g/g dry feed (tulip poplar) to 0.070 g/g dry feed (clean pine).« less

Antifungal activities of Bacillus thuringiensis isolates on barley and cucumber powdery mildews.

PubMed

Choi, Gyung Ja; Kim, Jin-Cheol; Jang, Kyoung Soo; Lee, Dong-Hyun

2007-12-01

Fourteen Bacillus thuringiensis isolates having both insecticidal activity and in vitro antifungal activity were selected and tested for in vivo antifungal activity against tomato late blight, wheat leaf rust, tomato gray mold, and barley powdery mildew in growth chambers. All the isolates represented more than 70% disease control efficacy against at least one of four plant diseases. Specifically, 12 isolates exhibited strong control activity against barley powdery mildew. Under glasshouse conditions, four (50-02, 52-08, 52-16, and 52- 18) of the isolates also displayed potent control efficacy against cucumber powdery mildew. To our knowledge, this is the first report of B. thuringiensis isolates that have disease control efficacy against powdery mildew of barley and cucumber as well as insecticidal activity.

Effect of Genetically Modified Poplars on Soil Microbial Communities during the Phytoremediation of Waste Mine Tailings▿†

PubMed Central

Hur, Moonsuk; Kim, Yongho; Song, Hae-Ryong; Kim, Jong Min; Choi, Young Im; Yi, Hana

2011-01-01

The application of transgenic plants to clean up environmental pollution caused by the wastes of heavy metal mining is a promising method for removing metal pollutants from soils. However, the effect of using genetically modified organisms for phytoremediation is a poorly researched topic in terms of microbial community structures, despite the important role of microorganisms in the health of soil. In this study, a comparative analysis of the bacterial and archaeal communities found in the rhizosphere of genetically modified (GM) versus wild-type (WT) poplar was conducted on trees at different growth stages (i.e., the rhizospheres of 1.5-, 2.5-, and 3-year-old poplars) that were cultivated on contaminated soils together with nonplanted control soil. Based on the results of DNA pyrosequencing, poplar type and growth stages were associated with directional changes in the structure of the microbial community. The rate of change was faster in GM poplars than in WT poplars, but the microbial communities were identical in the 3-year-old poplars. This phenomenon may arise because of a higher rate and greater extent of metal accumulation in GM poplars than in naturally occurring plants, which resulted in greater changes in soil environments and hence the microbial habitat. PMID:21890678

Novel rust resistance in wheat (Triticum aestivum L.)

USDA-ARS?s Scientific Manuscript database

The Puccinia fungi that cause wheat rust diseases are among the most globally destructive agricultural pathogens. The most effective and utilized defense against rust is genetic resistance. The vast majority of rust resistance is racespecific conferred by single genes rapidly overcome by the pathoge...

Inheritance of resistance to orange rust in sugarcane

USDA-ARS?s Scientific Manuscript database

Orange rust, caused by Puccinia kuehnii, is an economically important disease in the Florida sugarcane industry. In this study, orange rust reactions of seedlings in progenies originating from 12 crosses between female and male parents with differing resistance to orange rust (three of each categor...

Inheritance of resistance to orange rust in sugarcane

USDA-ARS?s Scientific Manuscript database

Orange rust, caused by Puccinia kuehnii, is an economically important disease in the Florida sugarcane industry. In this study, orange rust reactions of seedlings in progenies originating from 12 crosses between female and male parents with differing resistance to orange rust (three of each category...

Screening and incorporation of rust resistance from Allium cepa into bunching onion (Allium fistulosum) via alien chromosome addition.

PubMed

Wako, Tadayuki; Yamashita, Ken-ichiro; Tsukazaki, Hikaru; Ohara, Takayoshi; Kojima, Akio; Yaguchi, Shigenori; Shimazaki, Satoshi; Midorikawa, Naoko; Sakai, Takako; Yamauchi, Naoki; Shigyo, Masayoshi

2015-04-01

Bunching onion (Allium fistulosum L.; 2n = 16), bulb onion (Allium cepa L. Common onion group), and shallot (Allium cepa L. Aggregatum group) cultivars were inoculated with rust fungus, Puccinia allii, isolated from bunching onion. Bulb onions and shallots are highly resistant to rust, suggesting they would serve as useful resources for breeding rust resistant bunching onions. To identify the A. cepa chromosome(s) related to rust resistance, a complete set of eight A. fistulosum - shallot monosomic alien addition lines (MAALs) were inoculated with P. allii. At the seedling stage, FF+1A showed a high level of resistance in controlled-environment experiments, suggesting that the genes related to rust resistance could be located on shallot chromosome 1A. While MAAL, multi-chromosome addition line, and hypoallotriploid adult plants did not exhibit strong resistance to rust. In contrast to the high resistance of shallot, the addition line FF+1A+5A showed reproducibly high levels of rust resistance.

Carbon budget and its response to environmental factors in young and mature poplar plantations along the middle and lower reaches of the Yangtze River, China

Treesearch

Jinxing Zhou; Yuan Wei; Jun Yang; Xiaohui Yang; Zeping Jiang; Jiquan Chen; Asko Noormets; Xiaosong Zhao

2012-01-01

Although poplar forest is the dominant plantation type in China, there is uncertainty about the carbon budget of these forests across the country. The observations, performed in 2006, of two eddy covariance flux towers on a young poplar plantation (Yueyang, Hunan province) and a mature poplar plantation (Huaining, Anhui province) provide an opportunity to understand...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landry, L.G.; Pell, E.J.

Hybrid poplar clones exposed to ozone exhibit symptoms of accelerated senescence, including early decline in activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco). The authors examined the hypothesis that ozone-induced reduction in rubisco occurred as a result of increased protease activity. To test this hypothesis, saplings of Populus maximowizii x trichocarpa were exposed to 0.08 {mu}l/l ozone, 4 h/day, from initiation of sample leaf expansion to foliar abscission. Periodically throughout the treatment the sample leaf was analyzed for chlorophyll content, total protein content, rubisco activity, and proteolytic activity at pH 4.5 and 7.8. At the time of peak rubisco activity, protein was subjectmore » to SDS-PAGE to quantify rubisco. Total protein content of sample leaves was unaffected by ozone treatment. Proteolysis measured under acidic conditions was lower in ozone-treated than control plants throughout the exposure. Proteolysis determined under alkaline conditions only revealed decreases in the second half of the experiment. Ozone induced a more rapid decline in rubisco activity than occurred in control tissue. Quantitative effects of rubisco reflected results of activity assays. It did not appear that enhanced proteolysis could explain the ozone-induced accelerated decline in rubisco.« less

Differential ecophysiological responses and resilience to heat wave events in four co-occurring temperate tree species

NASA Astrophysics Data System (ADS)

Guha, Anirban; Han, Jimei; Cummings, Cadan; McLennan, David A.; Warren, Jeffrey M.

2018-06-01

Extreme summer heat waves are known to induce foliar and stem mortality in temperate forest ecosystems, yet our mechanistic knowledge of physiological thresholds for damage is lacking. Current spatiotemporal simulations of forest growth responses to climate change fail to explain the variability between co-occurring tree species to climate extremes, indicating a need for new model frameworks that include mechanistic understanding of trait-specific responses. In this context, using manipulative heat wave (hw) experiments we investigated ecophysiological responses and physiological recovery in four co-occurring temperate tree species of the southeastern United States including three deciduous angiosperms: southern red oak (Quercus falcata Michx.), shumard oak (Q. shumardii Buckl.) and, tulip-poplar (Liriodendron tulipifera L.) and one evergreen conifer: eastern white pine (Pinus strobus L.). The objectives were to investigate inter-specific differences in ecophysiological responses to hw events to understand mechanistic differences in resilience that may be useful for future model development. Two-year-old, well-irrigated potted saplings were exposed to progressively increasing extreme hw diurnal cycles followed by a recovery cycle, with peak midday air temperature increasing from 37 °C to a maximum of 51 °C on the third day of the hw. Plants were assessed for various photosynthetic and water use responses, chlorophyll fluorescence and photosystem-II (PSII) activity, leaf temperature and foliar pigments. Intense heat caused progressive down-regulation in net photosynthesis, but the stomata remained operational, which helped cool leaves through loss of latent heat. Even though whole plant transpiration increased for all species, the rate plateaued at higher hw events that allowed leaf temperature to exceed 45 °C, well beyond the optimal range. A significant increase in non-photochemical quenching over the hw cycles was evident in all species though indications of both transient and chronic PSII damage were evident in the most heat sensitive species, pine and tulip poplar. The oaks, especially Q. falcata, showed greater thermotolerance than other species with a higher threshold for photodamage to PSII, rapid overnight recovery of photoinhibition and minimal heat-induced canopy necrosis. We conclude that these co-occurring tree species exhibit large variability in thermotolerance and in their capability to repair both transient and chronic photodamage. Our results indicate that extreme heat induced damage to PSII within the leaf chloroplasts may be a mechanistic trait that can be used to project how different species respond to extreme weather events.

The Big Rust and the Red Queen: Long-Term Perspectives on Coffee Rust Research.

PubMed

McCook, Stuart; Vandermeer, John

2015-09-01

Since 2008, there has been a cluster of outbreaks of the coffee rust (Hemileia vastatrix) across the coffee-growing regions of the Americas, which have been collectively described as the Big Rust. These outbreaks have caused significant hardship to coffee producers and laborers. This essay situates the Big Rust in a broader historical context. Over the past two centuries, coffee farmers have had to deal with the "curse of the Red Queen"-the need to constantly innovate in the face of an increasing range of threats, which includes the rust. Over the 20th century, particularly after World War II, national governments and international organizations developed a network of national, regional, and international coffee research institutions. These public institutions played a vital role in helping coffee farmers manage the rust. Coffee farmers have pursued four major strategies for managing the rust: bioprospecting for resistant coffee plants, breeding resistant coffee plants, chemical control, and agroecological control. Currently, the main challenge for researchers is to develop rust control strategies that are both ecologically and economically viable for coffee farmers, in the context of a volatile, deregulated coffee industry and the emergent challenges of climate change.

Effector proteins of rust fungi.

PubMed

Petre, Benjamin; Joly, David L; Duplessis, Sébastien

2014-01-01

Rust fungi include many species that are devastating crop pathogens. To develop resistant plants, a better understanding of rust virulence factors, or effector proteins, is needed. Thus far, only six rust effector proteins have been described: AvrP123, AvrP4, AvrL567, AvrM, RTP1, and PGTAUSPE-10-1. Although some are well established model proteins used to investigate mechanisms of immune receptor activation (avirulence activities) or entry into plant cells, how they work inside host tissues to promote fungal growth remains unknown. The genome sequences of four rust fungi (two Melampsoraceae and two Pucciniaceae) have been analyzed so far. Genome-wide analyses of these species, as well as transcriptomics performed on a broader range of rust fungi, revealed hundreds of small secreted proteins considered as rust candidate secreted effector proteins (CSEPs). The rust community now needs high-throughput approaches (effectoromics) to accelerate effector discovery/characterization and to better understand how they function in planta. However, this task is challenging due to the non-amenability of rust pathosystems (obligate biotrophs infecting crop plants) to traditional molecular genetic approaches mainly due to difficulties in culturing these species in vitro. The use of heterologous approaches should be promoted in the future.

An analysis of the risk of introduction of additional strains of the rust puccinia psidii Winter ('Ohi'a Rust) to Hawai'i

USGS Publications Warehouse

Loope, Lloyd; La Rosa, Anne Marie

2010-01-01

In April 2005, the rust fungus Puccinia psidii (most widely known as guava rust or eucalyptus rust) was found in Hawai'i. This was the first time this rust had been found outside the Neotropics (broadly-defined, including subtropical Florida, where the rust first established in the 1970s). First detected on a nursery-grown 'ohi'a plant, it became known as ''ohi'a rust'in Hawai'i. The rust spread rapidly and by August 2005 had been found throughout the main Hawaiian Islands. The rust probably reached Hawai'i via the live plant trade or via the foliage trade. In Hawai'i, the rust has infected three native plant species and at least eight non-native species. Effects have been substantial on the endangered endemic plant Eugenia koolauensis and the introduced rose apple, Syzygium jambos. Billions of yellow, asexual urediniospores are produced on rose apple, but a complete life cycle (involving sexual reproduction) has not yet been observed. The rust is autoecious (no alternate host known) on Myrtaceae. The strain introduced into Hawai'i is found sparingly on 'ohi'a (Metrosideros polymorpha), the dominant tree of Hawai'i's forests, with sporadic damage detected to date. The introduction of a rust strain that causes widespread damage to 'ohi'a would be catastrophic for Hawai'i's native biodiversity. Most imports of material potentially contaminated with rust are shipped to Hawai'i from Florida and California (from which P. psidii was reported in late 2005 by Mellano, 2006). Florida is known to have multiple strains. The identity of the strain or strains in California is unclear, but one of them is known to infect myrtle, Myrtus communis, a species commonly imported into Hawai'i. It is important to ecosystem conservation and commercial forestry that additional rust strains or genotypes be prevented from establishing in Hawai'i. The purpose of this analysis of risk is to evaluate the need for an interim rule by the Hawai'i Department of Agriculture to regulate plant material of Myrtaceae arriving from the continental United States and to clarify consequences of such a rule, especially implications for possible eventual action by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, to assist in protection of Hawai'i's native and non-native Myrtaceae from plant pests.

Comparative Proteomic Analysis of Mature Pollen in Triploid and Diploid Populus deltoides

PubMed Central

Zhang, Xiao-Ling; Zhang, Jin; Guo, Ying-Hua; Sun, Pei; Jia, Hui-Xia; Fan, Wei; Lu, Meng-Zhu; Hu, Jian-Jun

2016-01-01

Ploidy affects plant growth vigor and cell size, but the relative effects of pollen fertility and allergenicity between triploid and diploid have not been systematically examined. Here we performed comparative analyses of fertility, proteome, and abundances of putative allergenic proteins of pollen in triploid poplar ‘ZhongHuai1’ (‘ZH1’, triploid) and ‘ZhongHuai2’ (‘ZH2’, diploid) generated from the same parents. The mature pollen was sterile in triploid poplar ‘ZH1’. By applying two-dimensional gel electrophoresis (2-DE), a total of 72 differentially expressed protein spots (DEPs) were detected in triploid poplar pollen. Among them, 24 upregulated and 43 downregulated proteins were identified in triploid poplar pollen using matrix-assisted laser desorption/ionisation coupled with time of-flight tandem mass spectrometer analysis (MALDI-TOF/TOF MS/MS). The main functions of these DEPs were related with “S-adenosylmethionine metabolism”, “actin cytoskeleton organization”, or “translational elongation”. The infertility of triploid poplar pollen might be related to its abnormal cytoskeletal system. In addition, the abundances of previously identified 28 putative allergenic proteins were compared among three poplar varieties (‘ZH1’, ‘ZH2’, and ‘2KEN8‘). Most putative allergenic proteins were downregulated in triploid poplar pollen. This work provides an insight into understanding the protein regulation mechanism of pollen infertility and low allergenicity in triploid poplar, and gives a clue to improving poplar polyploidy breeding and decreasing the pollen allergenicity. PMID:27598155

The Atlantic-Mediterranean watershed, river basins and glacial history shape the genetic structure of Iberian poplars.

PubMed

Macaya-Sanz, D; Heuertz, M; López-de-Heredia, U; De-Lucas, A I; Hidalgo, E; Maestro, C; Prada, A; Alía, R; González-Martínez, S C

2012-07-01

Recent phylogeographic studies have elucidated the effects of Pleistocene glaciations and of Pre-Pleistocene events on populations from glacial refuge areas. This study investigates those effects in riparian trees (Populus spp.), whose particular features may convey enhanced resistance to climate fluctuations. We analysed the phylogeographic structure of 44 white (Populus alba), 13 black (Populus nigra) and two grey (Populus x canescens) poplar populations in the Iberian Peninsula using plastid DNA microsatellites and sequences. We also assessed fine-scale spatial genetic structure and the extent of clonality in four white and one grey poplar populations using nuclear microsatellites and we determined quantitative genetic differentiation (Q(ST) ) for growth traits in white poplar. Black poplar displayed higher regional diversity and lower differentiation than white poplar, reflecting its higher cold-tolerance. The dependence of white poplar on phreatic water was evidenced by strong differentiation between the Atlantic and Mediterranean drainage basins and among river basins, and by weaker isolation by distance within than among river basins. Our results suggest confinement to the lower river courses during glacial periods and moderate interglacial gene exchange along coastlines. In northern Iberian river basins, white poplar had lower diversity, fewer private haplotypes and larger clonal assemblies than in southern basins, indicating a stronger effect of glaciations in the north. Despite strong genetic structure and frequent asexual propagation in white poplar, some growth traits displayed adaptive divergence between drainage and river basins (Q(ST) >F(ST)), highlighting the remarkable capacity of riparian tree populations to adapt to regional environmental conditions. © 2012 Blackwell Publishing Ltd.

Ecosystem development on terraces along the Kugururok River, northwest Alaska

USGS Publications Warehouse

Binkley, Dan; Suarez, F.; Stottlemyer, R.; Caldwell, B.

1997-01-01

Riverside terraces along the Kugururok River in the Noatak National Preserve provided an opportunity to study primary succession, considering general trends that apply across all terraces, and unique events that influence individual terraces. The 30-year-old willow/poplar (Salix spp., Populus balsamifera L.) terrace had no trees taller than 1.5 m; the abundant spruce trees were not tall enough to emerge from the canopy height of the willows and poplars, and moose (Alces alces [Clinton]) browsing limited the canopy height of these plants. The 75-year-old poplar/spruce (Picea glauca [Moench] Voss) terrace had a high density of poplars (> 1000/ha) and low density of spruce (125/ha); heavy browsing by moose reduced the density of poplar by about one-half. The removal of the poplar by moose in this stand resulted in sustained increases in growth of individual spruce trees. The 100-year-old younger spruce/poplar terrace had about twice as many spruce trees (1250/ha) as poplar trees (500/ha), and the spruce trees were larger on average than the poplar trees. In the 220+ year-old older spruce/poplar type, only a few poplars remained (about 25/ha), and the number of spruce trees (600/ha) was only half that of the younger stage, either from lower initial spruce density on this terrace, or increased mortality of spruce. The 240+ year-old spruce type was a second-generation forest, characterized by a high density (1950/ha) of small spruce trees, some of which were tilted, indicating discontinuous permafrost. Plant litterfall mass showed no strong trend with terrace age, although N content of litterfall appeared to decline by about 1/3 in the spruce-dominated stages. Fungal biomass increased with ecosystem age, whereas bacterial biomass and microfauna declined. We found no evidence of declining soil N supply in older stages, but fertilization experiments would be needed to determine if N limitation of productivity changed with ecosystem development. We conclude that the general successional trend of increased spruce dominance is robust for this location, but that unique events play important roles in determining tree densities and the timing of the shift in dominance from poplar to spruce. The arrival of moose in the 1970s accelerated dominance by spruce on young terraces.

DIVERSITY OF PUCCINIA KUEHNII AND P. MELANOCEPHALA CAUSING RUST DISEASES ON BRAZILIAN SUGARCANE

USDA-ARS?s Scientific Manuscript database

Sugarcane industry in Brazil suffers yield loss due to brown rust (Puccinia melanocephala) since 1986 and orange rust (P. kuehnii) as recent as 2009. The main control measure for both diseases has been cultivar resistance. Nevertheless, recent onsets of orange rust on previously resistant cultivars ...

Glyphosate Control of Orange and Brown Rusts in Glyphosate-Sensitive Sugarcane Cultivars

USDA-ARS?s Scientific Manuscript database

Technical Abstract: Brown and orange rust diseases cause substantial yield reductions on sugarcane (Saccharum spp.) in Florida and other regions where sugarcane is grown. Brown rust caused by Puccinia melanocephala Syd. & P. Syd has been present in Florida since 1978 and orange rust caused by Pucci...

Diseases Which Challenge Global Wheat Production - The Cereal Rusts

USDA-ARS?s Scientific Manuscript database

The rusts of wheat are common and widespread diseases in the US and throughout the world. Wheat rusts have been important throughout the history of wheat cultivation and are currently important diseases that are responsible for regularly occurring yield losses in wheat. The wheat rust fungi are obli...

Role of alternate hosts in epidemiology and pathogen variation of cereal rusts

USDA-ARS?s Scientific Manuscript database

Cereal rusts, caused by obligate and biotrophic fungi in the genus Puccinia of basidiomycete are an important group of diseases threatening the world food security. With the recent discovery of alternate hosts for the stripe rust fungus (Puccinia striiformis), all cereal rust fungi are now known ...

7 CFR 301.38-1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Black Stem Rust § 301.38-1 Definitions. In this subpart... Agriculure. Black stem rust. The disease commonly known as the black stem rust of grains (Puccinia graminis... clonally propagated only if its parent stock is, or was derived from, a seed-propagated black stem rust...

77 FR 65840 - Chrysanthemum White Rust Regulatory Status and Restrictions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-31

... Inspection Service 7 CFR Part 319 [Docket No. APHIS-2012-0001] RIN 0579-AD67 Chrysanthemum White Rust... should amend our process for responding to domestic chrysanthemum white rust (CWR) outbreaks and the... whether and how we should amend our process for responding to domestic chrysanthemum white rust (CWR...

Epidemiology for hazard rating of white pine blister rust

Treesearch

Eugene P. Van Arsdel; Brian W. Geils; Paul J. Zambino

2006-01-01

The ability to assess the potential for a severe infestation of white pine blister rust is an important management tool. Successful hazard rating requires a proper understanding of blister rust epidemiology, including environmental and genetic factors. For the blister rust caused by Cronartium ribicola, climate and meteorology, and the ecology,...

7 CFR 301.38-1 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Black Stem Rust § 301.38-1 Definitions. In this subpart... Agriculure. Black stem rust. The disease commonly known as the black stem rust of grains (Puccinia graminis... clonally propagated only if its parent stock is, or was derived from, a seed-propagated black stem rust...

7 CFR 301.38-1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Black Stem Rust § 301.38-1 Definitions. In this subpart... Agriculure. Black stem rust. The disease commonly known as the black stem rust of grains (Puccinia graminis... clonally propagated only if its parent stock is, or was derived from, a seed-propagated black stem rust...

7 CFR 301.38-1 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Black Stem Rust § 301.38-1 Definitions. In this subpart... Agriculure. Black stem rust. The disease commonly known as the black stem rust of grains (Puccinia graminis... clonally propagated only if its parent stock is, or was derived from, a seed-propagated black stem rust...

7 CFR 301.38-1 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Black Stem Rust § 301.38-1 Definitions. In this subpart... Agriculure. Black stem rust. The disease commonly known as the black stem rust of grains (Puccinia graminis... clonally propagated only if its parent stock is, or was derived from, a seed-propagated black stem rust...

Epidemiology and control of rusts of wheat and barley

USDA-ARS?s Scientific Manuscript database

Rusts of wheat and barley were monitored throughout the Pacific Northwest (PNW) using trap plots and through field surveys during the 2008 growing season. Through collaborators in other states, stripe rusts of wheat and barley were monitored throughout the US. In 2008, stripe rust occurred in 18 st...

A preliminary model of yellow-poplar seedling establishment two years after a growing season prescribed fire in southern Appalachian oak stands

Treesearch

Henry McNab

2016-01-01

Factors affecting the density and distribution of yellow-poplar regeneration after a single growing season prescribed fire were studied in mature upland oak stands in the southern Appalachian Mountains. In burned and unburned stands, density of one and two year old yellow-poplar seedlings was inventoried within 50 m from isolated yellow-poplar canopy seed trees in...

Sealing and anti-corrosive action of tannin rust converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gust, J.; Bobrowicz, J.

1993-01-01

A possibility of the application of mercury porosimetry in the investigation on porosity in corrosion products of the carbon steel along with the degree of sealing by the use of tannin rust converters is presented. The effect of the atmospheric humidity on the rust conversion including the time of that conversion on the degree of rust sealing is discussed. The results of the corrosion investigation of carbon steel covered with a layer of the rust converted with tannin-containing agents are presented.

La Roya naranja de la caña de azúcar, una enfermedad emergente: su impacto y comparación con la roya marrón English Translation: Orange rust of sugarcane, an emerging disease: its impact and comparison to brown rust.

USDA-ARS?s Scientific Manuscript database

Sugarcane orange rust, caused by Puccinia kuehnii, was first detected in Florida in 2007, the first for Western Hemisphere. Subsequently, it has spread to the majority of sugarcane producing countries in the hemisphere. Orange rust is distinguished from brown rust its pustule size which is slightl...

Potential Rapid Effects on Soil Organic Matter Characteristics and Chemistry Following a Change in Dominant Litter Inputs

NASA Astrophysics Data System (ADS)

Crow, S. E.; Filley, T.; Conyers, G.; Stott, D.; McCormick, M.; Whigham, D.; Taylor, D.

2006-12-01

Changes in vegetation structure are expected in forests globally under predicted future climate scenarios. Shifts in type or quantity of litter inputs, which will be associated with changes in plant community, may influence soil organic matter (SOM) characteristics. We altered litter inputs in a mixed-deciduous forest at the Smithsonian Environmental Research Center beginning in May 2004: litter removal, leaf amendment, and wood amendment plots were established in three old (120-150 y) and three young (50-70 y) forests. Plots were amended with wood and leaves collected locally from the dominant tree species, tulip poplar (Lirodendron tulipifera). 0-5 cm A horizon soil was collected in November 2005, 18 months after initial treatment, and physically fractionated first by dispersal in HMP and size separation (53 μm) to remove silts and clays then the >53 μm fraction by density (1.4 g cm-3) in SPT to separate the organic debris (light fraction, LF) from the mineral material. Soil with the greatest amount of C present within the LF came from the wood amendment treatment (35.2 ± 0.1%), followed by the leaf amendment (27.7 ± 0.0%) and the litter removal (24.5 ± 0.0%) treatments. In a pattern opposite of the other treatments, leaf amended soil from the old sites had less C within LF than the young. Potentially, a priming effect from the leaf addition at the old sites resulted in increased decomposition of soil LF. While at the young sites, invasive earthworms potentially provided a rapid, direct mode for incorporation of fresh leaf inputs into LF. Preliminary data indicate differences in lignin and cutin/suberin decay rates during litter decomposition between old and young sites. An investigation into the biopolymer composition of LF will determine whether altering litter inputs will ultimately influence SOM dynamics at both the old and young forest sites.

Adaptive mechanisms and genomic plasticity for drought tolerance identified in European black poplar (Populus nigra L.)

PubMed Central

Viger, Maud; Smith, Hazel K.; Cohen, David; Dewoody, Jennifer; Trewin, Harriet; Steenackers, Marijke; Bastien, Catherine; Taylor, Gail

2016-01-01

Summer droughts are likely to increase in frequency and intensity across Europe, yet long-lived trees may have a limited ability to tolerate drought. It is therefore critical that we improve our understanding of phenotypic plasticity to drought in natural populations for ecologically and economically important trees such as Populus nigra L. A common garden experiment was conducted using ∼500 wild P. nigra trees, collected from 11 river populations across Europe. Phenotypic variation was found across the collection, with southern genotypes from Spain and France characterized by small leaves and limited biomass production. To examine the relationship between phenotypic variation and drought tolerance, six genotypes with contrasting leaf morphologies were subjected to a water deficit experiment. ‘North eastern’ genotypes were collected at wet sites and responded to water deficit with reduced biomass growth, slow stomatal closure and reduced water use efficiency (WUE) assessed by Δ13C. In contrast, ‘southern’ genotypes originating from arid sites showed rapid stomatal closure, improved WUE and limited leaf loss. Transcriptome analyses of a genotype from Spain (Sp2, originating from an arid site) and another from northern Italy (Ita, originating from a wet site) revealed dramatic differences in gene expression response to water deficit. Transcripts controlling leaf development and stomatal patterning, including SPCH, ANT, ER, AS1, AS2, PHB, CLV1, ERL1–3 and TMM, were down-regulated in Ita but not in Sp2 in response to drought. PMID:27174702

Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level

NASA Astrophysics Data System (ADS)

Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

2016-09-01

The emission of isoprene and other biogenic volatile organic compounds from vegetation plays an important role in tropospheric ozone (O3) formation. The potentially large expansion of isoprene emitting species (e.g., poplars) for bioenergy production might, therefore, impact tropospheric O3 formation. Using the eddy covariance technique we have simultaneously measured fluxes isoprene, O3 and of CO2 from a poplar (Populus) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground level O3 concentrations. Our findings suggest that isoprene emissions from existing poplar-for-bioenergy plantations do not significantly affect the ground level of O3 concentration. Indeed the overall land in Europe covered with poplar plantations has not significantly changed over the last two decades despite policy incentives to produce bioenergy crops. The current surface area of isoprene emitting poplars-for-bioenergy remains too limited to significantly enhance O3 concentrations and thus to be considered a potential threat for air quality and human health.

Interaction between isoprene and ozone fluxes in a poplar plantation and its impact on air quality at the European level.

PubMed

Zenone, Terenzio; Hendriks, Carlijn; Brilli, Federico; Fransen, Erik; Gioli, Beniamio; Portillo-Estrada, Miguel; Schaap, Martijn; Ceulemans, Reinhart

2016-09-12

The emission of isoprene and other biogenic volatile organic compounds from vegetation plays an important role in tropospheric ozone (O3) formation. The potentially large expansion of isoprene emitting species (e.g., poplars) for bioenergy production might, therefore, impact tropospheric O3 formation. Using the eddy covariance technique we have simultaneously measured fluxes isoprene, O3 and of CO2 from a poplar (Populus) plantation grown for bioenergy production. We used the chemistry transport model LOTOS-EUROS to scale-up the isoprene emissions associated with the existing poplar plantations in Europe, and we assessed the impact of isoprene fluxes on ground level O3 concentrations. Our findings suggest that isoprene emissions from existing poplar-for-bioenergy plantations do not significantly affect the ground level of O3 concentration. Indeed the overall land in Europe covered with poplar plantations has not significantly changed over the last two decades despite policy incentives to produce bioenergy crops. The current surface area of isoprene emitting poplars-for-bioenergy remains too limited to significantly enhance O3 concentrations and thus to be considered a potential threat for air quality and human health.

Determination of the role of Berberis spp. in wheat stem rust in China

USDA-ARS?s Scientific Manuscript database

Previous studies on the relationship of barberry (Berberis spp.) and wheat stem rust suggested that although some barberry species can serve as alternate hosts for the stem rust fungus Puccinia graminis f. sp. tritici (Pgt), barberry plants play no role in wheat stem rust development and virulence v...

77 FR 46339 - Chrysanthemum White Rust Regulatory Status and Restrictions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-03

... Inspection Service 7 CFR Part 319 [Docket No. APHIS-2012-0001] RIN 0579-AD67 Chrysanthemum White Rust... whether and how we should amend our process for responding to domestic chrysanthemum white rust (CWR... INFORMATION: Background Puccinia horiana P. Henn. is a filamentous rust fungus and obligate parasite that is...

Unveiling common responses of Medicago truncatula to appropriate and inappropriate rust species

PubMed Central

Vaz Patto, Maria Carlota; Rubiales, Diego

2014-01-01

Little is known about the nature of effective defense mechanisms in legumes to pathogens of remotely related plant species. Some rust species are among pathogens with broad host range causing dramatic losses in various crop plants. To understand and compare the different host and nonhost resistance (NHR) responses of legume species against rusts, we characterized the reaction of the model legume Medicago truncatula to one appropriate (Uromyces striatus) and two inappropriate (U. viciae-fabae and U. lupinicolus) rusts. We found that similar pre and post-haustorial mechanisms of resistance appear to be operative in M. truncatula against appropriate and inappropriate rust fungus. The appropriate U. striatus germinated better on M. truncatula accessions then the inappropriate U. viciae-fabae and U. lupinicolus, but once germinated, germ tubes of the three rusts had a similar level of success in finding stomata and forming an appressoria over a stoma. However, responses to different inappropriate rust species also showed some specificity, suggesting a combination of non-specific and specific responses underlying this legume NHR to rust fungi. Further genetic and expression analysis studies will contribute to the development of the necessary molecular tools to use the present information on host and NHR mechanisms to breed for broad-spectrum resistance to rust in legume species. PMID:25426128

Physical Localization of a Locus from Agropyron cristatum Conferring Resistance to Stripe Rust in Common Wheat

PubMed Central

Song, Liqiang; Han, Haiming; Zhou, Shenghui; Zhang, Jinpeng; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

2017-01-01

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. Agropyron cristatum (L.) Gaertn. (2n = 28, PPPP), one of the wild relatives of wheat, exhibits resistance to stripe rust. In this study, wheat-A. cristatum 6P disomic addition line 4844-12 also exhibited resistance to stripe rust. To identify the stripe rust resistance locus from A. cristatum 6P, ten translocation lines, five deletion lines and the BC2F2 and BC3F2 populations of two wheat-A. cristatum 6P whole-arm translocation lines were tested with a mixture of two races of Pst in two sites during 2015–2016 and 2016–2017, being genotyped with genomic in situ hybridization (GISH) and molecular markers. The result indicated that the locus conferring stripe rust resistance was located on the terminal 20% of 6P short arm’s length. Twenty-nine 6P-specific sequence-tagged-site (STS) markers mapped on the resistance locus have been acquired, which will be helpful for the fine mapping of the stripe rust resistance locus. The stripe rust-resistant translocation lines were found to carry some favorable agronomic traits, which could facilitate their use in wheat improvement. Collectively, the stripe rust resistance locus from A. cristatum 6P could be a novel resistance source and the screened stripe rust-resistant materials will be valuable for wheat disease breeding. PMID:29137188

Physical Localization of a Locus from Agropyron cristatum Conferring Resistance to Stripe Rust in Common Wheat.

PubMed

Zhang, Zhi; Song, Liqiang; Han, Haiming; Zhou, Shenghui; Zhang, Jinpeng; Yang, Xinming; Li, Xiuquan; Liu, Weihua; Li, Lihui

2017-11-13

Stripe rust, caused by Puccinia striiformis f. sp. tritici ( Pst ), is one of the most destructive diseases of wheat ( Triticum aestivum L.) worldwide. Agropyron cristatum (L.) Gaertn. (2 n = 28, PPPP), one of the wild relatives of wheat, exhibits resistance to stripe rust. In this study, wheat- A . cristatum 6P disomic addition line 4844-12 also exhibited resistance to stripe rust. To identify the stripe rust resistance locus from A . cristatum 6P, ten translocation lines, five deletion lines and the BC₂F₂ and BC₃F₂ populations of two wheat- A . cristatum 6P whole-arm translocation lines were tested with a mixture of two races of Pst in two sites during 2015-2016 and 2016-2017, being genotyped with genomic in situ hybridization (GISH) and molecular markers. The result indicated that the locus conferring stripe rust resistance was located on the terminal 20% of 6P short arm's length. Twenty-nine 6P-specific sequence-tagged-site (STS) markers mapped on the resistance locus have been acquired, which will be helpful for the fine mapping of the stripe rust resistance locus. The stripe rust-resistant translocation lines were found to carry some favorable agronomic traits, which could facilitate their use in wheat improvement. Collectively, the stripe rust resistance locus from A . cristatum 6P could be a novel resistance source and the screened stripe rust-resistant materials will be valuable for wheat disease breeding.

Duplications and losses in gene families of rust pathogens highlight putative effectors.

PubMed

Pendleton, Amanda L; Smith, Katherine E; Feau, Nicolas; Martin, Francis M; Grigoriev, Igor V; Hamelin, Richard; Nelson, C Dana; Burleigh, J Gordon; Davis, John M

2014-01-01

Rust fungi are a group of fungal pathogens that cause some of the world's most destructive diseases of trees and crops. A shared characteristic among rust fungi is obligate biotrophy, the inability to complete a lifecycle without a host. This dependence on a host species likely affects patterns of gene expansion, contraction, and innovation within rust pathogen genomes. The establishment of disease by biotrophic pathogens is reliant upon effector proteins that are encoded in the fungal genome and secreted from the pathogen into the host's cell apoplast or within the cells. This study uses a comparative genomic approach to elucidate putative effectors and determine their evolutionary histories. We used OrthoMCL to identify nearly 20,000 gene families in proteomes of 16 diverse fungal species, which include 15 basidiomycetes and one ascomycete. We inferred patterns of duplication and loss for each gene family and identified families with distinctive patterns of expansion/contraction associated with the evolution of rust fungal genomes. To recognize potential contributors for the unique features of rust pathogens, we identified families harboring secreted proteins that: (i) arose or expanded in rust pathogens relative to other fungi, or (ii) contracted or were lost in rust fungal genomes. While the origin of rust fungi appears to be associated with considerable gene loss, there are many gene duplications associated with each sampled rust fungal genome. We also highlight two putative effector gene families that have expanded in Cqf that we hypothesize have roles in pathogenicity.

Analyzing the impact of climate and management factors on the productivity and soil carbon sequestration of poplar plantations.

PubMed

Wang, Dan; Fan, Jiazhi; Jing, Panpan; Cheng, Yong; Ruan, Honghua

2016-01-01

It is crucial to investigate how climate and management factors impact poplar plantation production and soil carbon sequestration interactively. We extracted above-ground net primary production (ANPP), climate and management factors from peer-reviewed journal articles and analyzed impact of management factor and climate on the mean annual increment (MAI) of poplar ANPP statistically. Previously validated mechanistic model (ED) is used to perform case simulations for managed poplar plantations under different harvesting rotations. The meta-analysis indicate that the dry matter MAI was 6.3 Mg ha(-1) yr(-1) (n=641, sd=4.9) globally, and 5.1 (n=292, sd=4.0), 8.1 (n=224, sd=4.7) and 4.4 Mg ha(-1) yr(-1) (n=125, sd=3.2) in Europe, the US and China, respectively. Poplar MAI showed a significant response to GDD, precipitation and planting density and formed a quadratic relationship with stand age. The low annual production for poplar globally was probably caused by suboptimal water availability, rotation length and planting density. SEM attributes the variance of poplar growth rate more to climate than to management effects. Case simulations indicated that longer rotation cycle significantly increased soil carbon storage. Findings of this work suggests that management factor of rotation cycle alone could have dramatic impact on the above ground growth, as well as on the soil carbon sequestration of poplar plantations and will be helpful to quantify the long-term carbon sequestration through short rotation plantation. The findings of this study are useful in guiding further research, policy and management decisions towards sustainable poplar plantations. Copyright © 2015 Elsevier Inc. All rights reserved.

Biochemical response of hybrid black poplar tissue culture (Populus × canadensis) on water stress.

PubMed

Popović, B M; Štajner, D; Ždero-Pavlović, R; Tari, I; Csiszár, J; Gallé, Á; Poór, P; Galović, V; Trudić, B; Orlović, S

2017-05-01

In this study, poplar tissue culture (hybrid black poplar, M1 genotype) was subjected to water stress influenced by polyethyleneglycol 6000 (100 and 200 mOsm PEG 6000). The aim of the research was to investigate the biochemical response of poplar tissue culture on water deficit regime. Antioxidant status was analyzed including antioxidant enzymes, superoxide-dismutase (SOD), catalase (CAT), guiacol-peroxidase (GPx), glutathione-peroxidase (GSH-Px), glutathione-reductase, reduced glutathione, total phenol content, Ferric reducing antioxidant power and DPPH radical antioxidant power. Polyphenol oxidase and phenylalanine-ammonium-lyase were determined as enzymatic markers of polyphenol metabolism. Among oxidative stress parameters lipid peroxidation, carbonyl-proteins, hydrogen-peroxide, reactive oxygen species, nitric-oxide and peroxynitrite were determined. Proline, proline-dehydrogenase and glycinebetaine were measured also as parameters of water stress. Cell viability is finally determined as a biological indicator of osmotic stress. It was found that water stress induced reactive oxygen and nitrogen species and lipid peroxidation in leaves of hybrid black poplar and reduced cell viability. Antioxidant enzymes including SOD, GPx, CAT and GSH-Px were induced but total phenol content and antioxidant capacity were reduced by PEG 6000 mediated osmotic stress. The highest biochemical response and adaptive reaction was the increase of proline and GB especially by 200 mOsm PEG. While long term molecular analysis will be necessary to fully address the poplar potentials for water stress adaptation, our results on hybrid black poplar suggest that glycine-betaine, proline and PDH enzyme might be the most important markers of poplar on water stress and that future efforts should be focused on these markers and strategies to enhance their concentration in poplar.

Assessment of imperfect detection of blister rust in whitebark pine within the Greater Yellowstone Ecosystem

USGS Publications Warehouse

Wright, Wilson J.; Irvine, Kathryn M.

2017-01-01

We examined data on white pine blister rust (blister rust) collected during the monitoring of whitebark pine trees in the Greater Yellowstone Ecosystem (from 2004-2015). Summaries of repeat observations performed by multiple independent observers are reviewed and discussed. These summaries show variability among observers and the potential for errors being made in blister rust status. Based on this assessment, we utilized occupancy models to analyze blister rust prevalence while explicitly accounting for imperfect detection. Available covariates were used to model both the probability of a tree being infected with blister rust and the probability of an observer detecting the infection. The fitted model provided strong evidence that the probability of blister rust infection increases as tree diameter increases and decreases as site elevation increases. Most importantly, we found evidence of heterogeneity in detection probabilities related to tree size and average slope of a transect. These results suggested that detecting the presence of blister rust was more difficult in larger trees. Also, there was evidence that blister rust was easier to detect on transects located on steeper slopes. Our model accounted for potential impacts of observer experience on blister rust detection probabilities and also showed moderate variability among the different observers in their ability to detect blister rust. Based on these model results, we suggest that multiple observer sampling continue in future field seasons in order to allow blister rust prevalence estimates to be corrected for imperfect detection. We suggest that the multiple observer effort be spread out across many transects (instead of concentrated at a few each field season) while retaining the overall proportion of trees with multiple observers around 5-20%. Estimates of prevalence are confounded with detection unless it is explicitly accounted for in an analysis and we demonstrate how an occupancy model can be used to do account for this source of observation error.

Correlation between RUST assessments of fracture healing to structural and biomechanical properties.

PubMed

Cooke, Margaret E; Hussein, Amira I; Lybrand, Kyle E; Wulff, Alexander; Simmons, Erin; Choi, Jeffrey H; Litrenta, Jody; Ricci, William M; Nascone, Jason W; O'Toole, Robert V; Morgan, Elise F; Gerstenfeld, Louis C; Tornetta, Paul

2018-03-01

Radiographic Union Score for Tibia (RUST) and modified RUST (mRUST) are radiographic tools for quantitatively evaluating fracture healing using a cortical scoring system. This tool has high intra-class correlation coefficients (ICCs); however, little evidence has evaluated the scores against the physical properties of bone healing. Closed, stabilized fractures were made in the femora of C3H/HeJ male mice (8-12 week-old) of two dietary groups: A control and a phosphate restricted diet group. Micro-computed tomography (µCT) and torsion testing were carried out at post-operative days (POD) 14, 21, 35, and 42 (n = 10-16) per group time-point. Anteroposterior and lateral radiographic views were constructed from the µCT scans and scored by five raters. The raters also indicated if the fracture were healed. ICCs were 0.71 (mRUST) and 0.63 (RUST). Both RUST scores were positively correlated with callus bone mineral density (BMD) (r = 0.85 and 0.80, p < 0.001) and bone volume fraction (BV/TV) (r = 0.86 and 0.80, p < 0.001). Both RUST scores positively correlated with callus strength (r = 0.35 and 0.26, p < 0.012) and rigidity (r = 0.50 and 0.39, p < 0.001). Radiographically healed calluses had a mRUST ≥13 and a RUST ≥10 and had excellent relationship to structural and biomechanical metrics. Effect of delayed healing due to phosphate dietary restrictions was found at later time points with all mechanical properties (p < 0.011), however no differences found in the RUST scores (p > 0.318). Clinical relevance of this study is both RUST scores showed high correlation to physical properties of healing and generally distinguished healed vs. non-healed fractures. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:945-953, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Yellow-poplar seedfall pattern

Treesearch

LaMont G. Engle

1960-01-01

Knowing the pattern of seedfall can be helpful when trying to regenerate yellow-poplar. This is especially true if the stand contains only scattered yellow-poplar seed trees. Information obtained from seed collections in Indiana shows that most of the seed falls north and northeast of seed trees.

7. GENERAL VIEW EAST FROM ROOFTOP OF POPLAR FOREST TOWARDS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. GENERAL VIEW EAST FROM ROOFTOP OF POPLAR FOREST TOWARDS SUMMER KITCHEN (FOREGROUND) AND DAIRY; CHIMNEY OF SOUTH TENANT HOUSE BARELY VISIBLE THROUGH TREES; EAST PRIVY RARELY VISIBLE OVER EAST MOUND (1987) - Poplar Forest, Summer Kitchen, State Route 661, Forest, Bedford County, VA

[Canopy conductance characteristics of poplar in agroforestry system in west Liaoning Province of Northeast China].

PubMed

Li, Zheng; Niu, Li-Hua; Yuan, Feng-Hui; Guan, De-Xin; Wang, An-Zhi; Jin, Chang-Jie; Wu, Jia-Bing

2012-11-01

By using Granier' s thermal dissipation probe, the sap flow of poplar in a poplar-maize agroforestry system in west Liaoning was continuously measured, and as well, the environmental factors such as air temperature, air humidity, net radiation, wind speed, soil temperature, and soil moisture content were synchronically measured. Based on the sap flow data, the canopy conductance of poplar was calculated with simplified Penman-Monteith equation. In the study area, the diurnal variation of poplar' s canopy conductance showed a "single peak" curve, whereas the seasonal variation showed a decreasing trend. There was a negative logarithm relationship between the canopy conductance and vapor pressure deficit, with the sensitivity of canopy conductance to vapor pressure deficit change decreased gradually from May to September. The canopy conductance had a positive relationship with solar radiation. In different months, the correlation degree of canopy conductance with environmental factors differed. The vapor pressure deficit in the whole growth period of poplar was the most significant environmental factor correlated with the canopy conductance.

Over-expression of bacterial gamma-glutamylcysteine synthetase (GSH1) in plastids affects photosynthesis, growth and sulphur metabolism in poplar (Populus tremula x Populus alba) dependent on the resulting gamma-glutamylcysteine and glutathione levels.

PubMed

Herschbach, Cornelia; Rizzini, Luca; Mult, Susanne; Hartmann, Tanja; Busch, Florian; Peuke, Andreas D; Kopriva, Stanislav; Ensminger, Ingo

2010-07-01

We compared three transgenic poplar lines over-expressing the bacterial gamma-glutamylcysteine synthetase (GSH1) targeted to plastids. Lines Lggs6 and Lggs12 have two copies, while line Lggs20 has three copies of the transgene. The three lines differ in their expression levels of the transgene and in the accumulation of gamma-glutamylcysteine (gamma-EC) and glutathione (GSH) in leaves, roots and phloem exudates. The lowest transgene expression level was observed in line Lggs6 which showed an increased growth, an enhanced rate of photosynthesis and a decreased excitation pressure (1-qP). The latter typically represents a lower reduction state of the plastoquinone pool, and thereby facilitates electron flow along the electron transport chain. Line Lggs12 showed the highest transgene expression level, highest gamma-EC accumulation in leaves and highest GSH enrichment in phloem exudates and roots. This line also exhibited a reduced growth, and after a prolonged growth of 4.5 months, symptoms of leaf injury. Decreased maximum quantum yield (F(v)/F(m)) indicated down-regulation of photosystem II reaction centre (PSII RC), which correlates with decreased PSII RC protein D1 (PsbA) and diminished light-harvesting complex (Lhcb1). Potential effects of changes in chloroplastic and cytosolic GSH contents on photosynthesis, growth and the whole-plant sulphur nutrition are discussed for each line.

Spread, genetic variation and methods for the detection of Puccinia kuehnii, the causal agent of sugarcane orange rust.

USDA-ARS?s Scientific Manuscript database

Sugarcane is susceptible to infection by two rust pathogens, Puccinia melanocephala and P. kuehnii, causing brown and orange rust, respectively. Orange rust of sugarcane was first reported in the Western hemisphere in Florida in July 2007. The pathogen was found to be distributed widely throughout t...

Genetic characterization of stem rust resistance in a global spring wheat germplasm collection

USDA-ARS?s Scientific Manuscript database

Stem rust is considered one of the most damaging diseases of wheat. The recent emergence of the stem rust Ug99 race group poses a serious threat to world wheat production. Utilization of genetic resistance in cultivar development is the optimal way to control stem rust. Here we report association ma...

Aecidium kalanchoe sp. nov., a new rust on Kalanchoe blossfeldiana (Crassulaceae).

PubMed

Hernádez, José R; Aime, M Catherine; Newbry, Brad

2004-07-01

A rust fungus found on cultivars of Kalanchoe blossfeldiana (Crassulaceae) is described as a new species, Aecidium kalanchoe sp. nov., and compared to the other described rusts on members of the Crassulaceae. Only one other rust is known to parasitize Kalanchoe spp. A DNA sequence of A. kalanchoe suggests that the teleomorph is related to Puccinia.

Geographic Variation in Melampsora Rust Resistance in Eastern Cottonwood in the Lower Mississippi Valley

Treesearch

D. T. Cooper; T. H. Filer

1976-01-01

Eastern cottonwood clones originating from 36 young natural stands along the Mississippi River from Memphis, Tennessee, to Baton Rouge, Louisiana, were evaluated in a nursery near Greenville, Mississippi for resistance to Melampsora rust. In general, the northern sources had more rust and were more variable in rust susceptibility than the southern sources. Eleven...

76 FR 13970 - Notice of Request for Extension of Approval of an Information Collection; Black Stem Rust...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-15

...] Notice of Request for Extension of Approval of an Information Collection; Black Stem Rust; Identification Requirements for Addition of Rust-Resistant Varieties AGENCY: Animal and Plant Health Inspection Service, USDA... black stem rust quarantine and regulations. DATES: We will consider all comments that we receive on or...

Major Chromosomal Rearrangements Distinguish Willow and Poplar After the Ancestral “Salicoid” Genome Duplication

PubMed Central

Hou, Jing; Ye, Ning; Dong, Zhongyuan; Lu, Mengzhu; Li, Laigeng; Yin, Tongming

2016-01-01

Populus (poplar) and Salix (willow) are sister genera in the Salicaceae family. In both lineages extant species are predominantly diploid. Genome analysis previously revealed that the two lineages originated from a common tetraploid ancestor. In this study, we conducted a syntenic comparison of the corresponding 19 chromosome members of the poplar and willow genomes. Our observations revealed that almost every chromosomal segment had a parallel paralogous segment elsewhere in the genomes, and the two lineages shared a similar syntenic pinwheel pattern for most of the chromosomes, which indicated that the two lineages diverged after the genome reorganization in the common progenitor. The pinwheel patterns showed distinct differences for two chromosome pairs in each lineage. Further analysis detected two major interchromosomal rearrangements that distinguished the karyotypes of willow and poplar. Chromosome I of willow was a conjunction of poplar chromosome XVI and the lower portion of poplar chromosome I, whereas willow chromosome XVI corresponded to the upper portion of poplar chromosome I. Scientists have suggested that Populus is evolutionarily more primitive than Salix. Therefore, we propose that, after the “salicoid” duplication event, fission and fusion of the ancestral chromosomes first give rise to the diploid progenitor of extant Populus species. During the evolutionary process, fission and fusion of poplar chromosomes I and XVI subsequently give rise to the progenitor of extant Salix species. This study contributes to an improved understanding of genome divergence after ancient genome duplication in closely related lineages of higher plants. PMID:27352946

Yellow-Poplar Site Index Curves

Treesearch

Donald E. Beck

1962-01-01

Yellow-poplar (Liriodendron tulipifera L.) occurs naturally throughout the eastern and central United States from southern New England west to Michigan and south to Florida and Louisiana. Because of its wide occurrence, yellow-poplar grows under a variety of climatic, edaphic, and biotic conditions. Combinations of these different environmental...

Identification of Alfalfa Leaf Diseases Using Image Recognition Technology

PubMed Central

Qin, Feng; Liu, Dongxia; Sun, Bingda; Ruan, Liu; Ma, Zhanhong; Wang, Haiguang

2016-01-01

Common leaf spot (caused by Pseudopeziza medicaginis), rust (caused by Uromyces striatus), Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana) and Cercospora leaf spot (caused by Cercospora medicaginis) are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering) and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis). After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection), disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM) and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features) was the optimal model. For this SVM model, the recognition accuracies of the training set and the testing set were 97.64% and 94.74%, respectively. Semi-supervised models for disease recognition were built based on the 45 effective features that were used for building the optimal SVM model. For the optimal semi-supervised models built with three ratios of labeled to unlabeled samples in the training set, the recognition accuracies of the training set and the testing set were both approximately 80%. The results indicated that image recognition of the four alfalfa leaf diseases can be implemented with high accuracy. This study provides a feasible solution for lesion image segmentation and image recognition of alfalfa leaf disease. PMID:27977767

Identification of Alfalfa Leaf Diseases Using Image Recognition Technology.

PubMed

Qin, Feng; Liu, Dongxia; Sun, Bingda; Ruan, Liu; Ma, Zhanhong; Wang, Haiguang

2016-01-01

Common leaf spot (caused by Pseudopeziza medicaginis), rust (caused by Uromyces striatus), Leptosphaerulina leaf spot (caused by Leptosphaerulina briosiana) and Cercospora leaf spot (caused by Cercospora medicaginis) are the four common types of alfalfa leaf diseases. Timely and accurate diagnoses of these diseases are critical for disease management, alfalfa quality control and the healthy development of the alfalfa industry. In this study, the identification and diagnosis of the four types of alfalfa leaf diseases were investigated using pattern recognition algorithms based on image-processing technology. A sub-image with one or multiple typical lesions was obtained by artificial cutting from each acquired digital disease image. Then the sub-images were segmented using twelve lesion segmentation methods integrated with clustering algorithms (including K_means clustering, fuzzy C-means clustering and K_median clustering) and supervised classification algorithms (including logistic regression analysis, Naive Bayes algorithm, classification and regression tree, and linear discriminant analysis). After a comprehensive comparison, the segmentation method integrating the K_median clustering algorithm and linear discriminant analysis was chosen to obtain lesion images. After the lesion segmentation using this method, a total of 129 texture, color and shape features were extracted from the lesion images. Based on the features selected using three methods (ReliefF, 1R and correlation-based feature selection), disease recognition models were built using three supervised learning methods, including the random forest, support vector machine (SVM) and K-nearest neighbor methods. A comparison of the recognition results of the models was conducted. The results showed that when the ReliefF method was used for feature selection, the SVM model built with the most important 45 features (selected from a total of 129 features) was the optimal model. For this SVM model, the recognition accuracies of the training set and the testing set were 97.64% and 94.74%, respectively. Semi-supervised models for disease recognition were built based on the 45 effective features that were used for building the optimal SVM model. For the optimal semi-supervised models built with three ratios of labeled to unlabeled samples in the training set, the recognition accuracies of the training set and the testing set were both approximately 80%. The results indicated that image recognition of the four alfalfa leaf diseases can be implemented with high accuracy. This study provides a feasible solution for lesion image segmentation and image recognition of alfalfa leaf disease.

Wheat: Its water use, production and disease detection and prediction. [Kansas

NASA Technical Reports Server (NTRS)

Kanemasu, E. T. (Principal Investigator); Lenhert, D.; Niblett, C.; Manges, H.; Eversmeyer, M. G.

1974-01-01

The author has identified the following significant results. Discussed in this report are: (1) the effects of wheat disease on water use and yield; and (2) the use of ERTS-1 imagery in the evaluation of wheat growth and in the detection of disease severity. Leaf area index was linearly correlated with ratios MSS4:MSS5 and MSS5:MSS6. In an area of severe wheat streak mosaic virus infected fields, correlations of ERTS-1 digital counts with wheat yields and disease severity levels were significant at the 5% level for MSS bands 4 and 5 and band ratios 4/6 and 4/7. Data collection platforms were used to gather meteorological data for the early prediction of rust severity and economic loss.

Genotype-by-sequencing facilitates genetic mapping of a stem rust resistance locus in Aegilops umbellulata, a wild relative of cultivated wheat.

PubMed

Edae, Erena A; Olivera, Pablo D; Jin, Yue; Poland, Jesse A; Rouse, Matthew N

2016-12-15

Wild relatives of wheat play a significant role in wheat improvement as a source of genetic diversity. Stem rust disease of wheat causes significant yield losses at the global level and stem rust pathogen race TTKSK (Ug99) is virulent to most previously deployed resistance genes. Therefore, the objective of this study was to identify loci conferring resistance to stem rust pathogen races including Ug99 in an Aegilops umbelluata bi-parental mapping population using genotype-by-sequencing (GBS) SNP markers. A bi-parental F 2:3 population derived from a cross made between stem rust resistant accession PI 298905 and stem rust susceptible accession PI 542369 was used for this study. F 2 individuals were evaluated with stem rust race TTTTF followed by testing F 2:3 families with races TTTTF and TTKSK. The segregation pattern of resistance to both stem rust races suggested the presence of one resistance gene. A genetic linkage map, comprised 1,933 SNP markers, was created for all seven chromosomes of Ae. umbellulata using GBS. A major stem rust resistance QTL that explained 80% and 52% of the phenotypic variations for TTTTF and TTKSK, respectively, was detected on chromosome 2U of Ae. umbellulata. The novel resistance gene for stem rust identified in this study can be transferred to commercial wheat varieties assisted by the tightly linked markers identified here. These markers identified through our mapping approach can be a useful strategy to identify and track the resistance gene in marker-assisted breeding in wheat.

Genome-wide association study of rust traits in orchardgrass using SLAF-seq technology.

PubMed

Zeng, Bing; Yan, Haidong; Liu, Xinchun; Zang, Wenjing; Zhang, Ailing; Zhou, Sifan; Huang, Linkai; Liu, Jinping

2017-01-01

While orchardgrass ( Dactylis glomerata L.) is a well-known perennial forage species, rust diseases cause serious reductions in the yield and quality of orchardgrass; however, genetic mechanisms of rust resistance are not well understood in orchardgrass. In this study, a genome-wide association study (GWAS) was performed using specific-locus amplified fragment sequencing (SLAF-seq) technology in orchardgrass. A total of 2,334,889 SLAF tags were generated to produce 2,309,777 SNPs. ADMIXTURE analysis revealed unstructured subpopulations for 33 accessions, indicating that this orchardgrass population could be used for association analysis. Linkage disequilibrium (LD) analysis revealed an average r 2 of 0.4 across all SNP pairs, indicating a high extent of LD in these samples. Through GWAS, a total of 4,604 SNPs were found to be significantly ( P  < 0.01) associated with the rust trait. The bulk analysis discovered a number of 5,211 SNPs related to rust trait. Two candidate genes, including cytochrome P450, and prolamin were implicated in disease resistance through prediction of functional genes surrounding each high-quality SNP ( P  < 0.01) associated with rust traits based on GWAS analysis and bulk analysis. The large number of SNPs associated with rust traits and these two candidate genes may provide the basis for further research on rust resistance mechanisms and marker-assisted selection (MAS) for rust-resistant lineages.

Genome-Wide Association Mapping of Crown Rust Resistance in Oat Elite Germplasm.

PubMed

Klos, Kathy Esvelt; Yimer, Belayneh A; Babiker, Ebrahiem M; Beattie, Aaron D; Bonman, J Michael; Carson, Martin L; Chong, James; Harrison, Stephen A; Ibrahim, Amir M H; Kolb, Frederic L; McCartney, Curt A; McMullen, Michael; Fetch, Jennifer Mitchell; Mohammadi, Mohsen; Murphy, J Paul; Tinker, Nicholas A

2017-07-01

Oat crown rust, caused by f. sp. , is a major constraint to oat ( L.) production in many parts of the world. In this first comprehensive multienvironment genome-wide association map of oat crown rust, we used 2972 single-nucleotide polymorphisms (SNPs) genotyped on 631 oat lines for association mapping of quantitative trait loci (QTL). Seedling reaction to crown rust in these lines was assessed as infection type (IT) with each of 10 crown rust isolates. Adult plant reaction was assessed in the field in a total of 10 location-years as percentage severity (SV) and as infection reaction (IR) in a 0-to-1 scale. Overall, 29 SNPs on 12 linkage groups were predictive of crown rust reaction in at least one experiment at a genome-wide level of statistical significance. The QTL identified here include those in regions previously shown to be linked with seedling resistance genes , , , , , and and also with adult-plant resistance and adaptation-related QTL. In addition, QTL on linkage groups Mrg03, Mrg08, and Mrg23 were identified in regions not previously associated with crown rust resistance. Evaluation of marker genotypes in a set of crown rust differential lines supported as the identity of . The SNPs with rare alleles associated with lower disease scores may be suitable for use in marker-assisted selection of oat lines for crown rust resistance. Copyright © 2017 Crop Science Society of America.

Properties and utilization of poplar wood

Treesearch

John J. Balatinecz; David E. Kretschmann

2001-01-01

Hybrid poplars are fast-growing, moisture-loving, full-sun-loving large trees that can be a rapid source of wood fiber. With the introduction of waferboard, oriented strandboard (OSB), and laminated strand lumber (LSL), aspen utilization has dramatically increased. Indigenous and hybrid poplars, however, present their own challenges, such as high discoloration...

Survey of twenty-six hybrid poplar lines for poplar borer

Treesearch

W. Doug Stone; T. Keith Beatty; T. Evan Nebeker

2006-01-01

An insect survey was completed on 26 lines of hybrid poplar (Populus nigra x P. maximowiczii) that had the Roundup® Ready and Bt (Bacillus thuringiensis) genes. The survey was conducted in Kentucky in cooperation with MeadWestvaco. A total of 260 trees were evaluated. Survival rate averaged...

Yield of Unthinned Yellow-Poplar

Treesearch

Donald E. Beck; Lino Della-Bianca

1970-01-01

Cubic-foot and board-foot yields of unthinned yellow-poplar (Liriodendron Tulipiferi L.) stands are described in relation to stand age, site index, and number of trees per acre. The yield tables are based on analysis of diameter distributions and height-diameter relationships obtained from 141 natural, unthinned yellow-poplar stands in the...

Case history development of a hybrid poplar nursery at Reynolds Metals Company, Massena, New York. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marler, R.L.

1981-11-01

Intensive cultivation of fast-growing hardwoods, such as hybrid poplars, is a promising method of assuring adequate supplies of biomass for energy purposes. This report details the establishment of a hybrid poplar nursery on formerly unused land at the Reynolds Metals Company's reduction plant in Massena, NY and presents the results obtained during the first growing season. Cuttings from the nursery replanted during the Spring of 1982 are the first phase of a 600-acre hybrid poplar plantation at the Reynolds site.

Molecular Analysis of Primary Vapor and Char Products during Stepwise Pyrolysis of Poplar Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Roger W.; Reinot, Tonu; McClelland, John F.

2010-08-03

Pyrolysis of biomass produces both pyrolysis oil and solid char. In this study, poplar has been pyrolyzed in a stepwise fashion over a series of temperatures from 200 to 500°C, and both the primary products contributing to pyrolysis oil and the changes in the pyrolyzing poplar surface leading toward char have been characterized at each step. The primary products were identified by direct analysis in real time (DART) mass spectrometry, and the changes in the poplar surface were monitored using Fourier transform infrared (FTIR) photoacoustic spectroscopy, with a sampling depth of a few micrometers. The primary products from pyrolyzing cellulose,more » xylan, and lignin under similar conditions were also characterized to identify the sources of the poplar products.« less

Molecular Analysis of Primary Vapor and Char Products during Stepwise Pyrolysis of Poplar Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Roger W.; Reinot, Tonu; McClelland, John F.

2010-08-30

Pyrolysis of biomass produces both pyrolysis oil and solid char. In this study, poplar has been pyrolyzed in a stepwise fashion over a series of temperatures from 200 to 500 C, and both the primary products contributing to pyrolysis oil and the changes in the pyrolyzing poplar surface leading toward char have been characterized at each step. The primary products were identified by direct analysis in real time (DART) mass spectrometry, and the changes in the poplar surface were monitored using Fourier transform infrared (FTIR) photoacoustic spectroscopy, with a sampling depth of a few micrometers. The primary products from pyrolyzingmore » cellulose, xylan, and lignin under similar conditions were also characterized to identify the sources of the poplar products.« less

Frequency of comandra blister rust infection episodes on lodgepole pine

Treesearch

William R. Jacobi; Brian W. Geils; Jane E. Taylor

2002-01-01

Comandra blister rust is a damaging canker disease of lodgepole pine in the Central Rocky Mountains. Our knowledge of previous blister rust outbreaks and the effects of weather and climate on rust epidemiology has not been sufficient to explain the frequency and severity of disease outbreaks. Thus, we sought to describe the seasonal and annual frequency and duration of...

Environment in relation to white pine blister rust infection

Treesearch

E.P. Van Arsdel

1972-01-01

Pine trees can be free of blister rust infection either because they are growing in a climate unfavorable to rust or because they are genetically resistant to the rust. The climatic escape is hundreds of times more common than genetic resistance in the American white pines. The minimum time and temperature required for penetration by an isolate of the rice blast fungus...

Study of Rust Effect on the Corrosion Behavior of Reinforcement Steel Using Impedance Spectroscopy

NASA Astrophysics Data System (ADS)

Bensabra, Hakim; Azzouz, Noureddine

2013-12-01

Most studies on corrosion of steel reinforcement in concrete are conducted on steel samples with polished surface (free of all oxides) in order to reproduce the same experimental conditions. However, before embedding in concrete, the steel bars are often covered with natural oxides (rust), which are formed during exposure to the atmosphere. The presence of this rust may affect the electrochemical behavior of steel rebar in concrete. In order to understand the effect of rust on the corrosion behavior of reinforcement steel, potentiodynamic and electrochemical impedance spectroscopy (EIS) tests were carried out in a simulated concrete pore solution using steel samples with two different surface conditions: polished and rusted samples. The obtained results have shown that the presence of rust on the steel bar has a negative effect on its corrosion behavior, with or without the presence of chlorides. This detrimental effect can be explained by the fact that the rust provokes a decrease of the electrolyte resistance at the metal-concrete interface and reduces the repassivating ability. In addition, the rust layer acts as a barrier against the hydroxyl ion diffusion, which prevents the realkalinization phenomenon.

Host jumps shaped the diversity of extant rust fungi (Pucciniales).

PubMed

McTaggart, Alistair R; Shivas, Roger G; van der Nest, Magriet A; Roux, Jolanda; Wingfield, Brenda D; Wingfield, Michael J

2016-02-01

The aim of this study was to determine the evolutionary time line for rust fungi and date key speciation events using a molecular clock. Evidence is provided that supports a contemporary view for a recent origin of rust fungi, with a common ancestor on a flowering plant. Divergence times for > 20 genera of rust fungi were studied with Bayesian evolutionary analyses. A relaxed molecular clock was applied to ribosomal and mitochondrial genes, calibrated against estimated divergence times for the hosts of rust fungi, such as Acacia (Fabaceae), angiosperms and the cupressophytes. Results showed that rust fungi shared a most recent common ancestor with a mean age between 113 and 115 million yr. This dates rust fungi to the Cretaceous period, which is much younger than previous estimations. Host jumps, whether taxonomically large or between host genera in the same family, most probably shaped the diversity of rust genera. Likewise, species diversified by host shifts (through coevolution) or via subsequent host jumps. This is in contrast to strict coevolution with their hosts. Puccinia psidii was recovered in Sphaerophragmiaceae, a family distinct from Raveneliaceae, which were regarded as confamilial in previous studies. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Development of Rust Stripping System using High Power Laser

NASA Astrophysics Data System (ADS)

Shirakawa, Kazuomi; Ohashi, Katsuaki; Ashidate, Shuichi; Kurosawa, Kiyoshi; Nakayama, Michio; Uchida, Yutaka; Nobusada, Yuuji

The repainting cycle depends on removal of rust in maintenance of outdoor steel-frame structural facilities. However existing stripping process, which is usually made by hands with brushes, cannot strip the rust completely in maintenance of power transmission towers, for example. To solve this problem, we investigated laser fluence and pulse width for removal of rust using DPSSL (Diode Pumped Solid State Laser), and selected optimum laser supply. Then we checked the effect of laser stripping on prolongation of the repainting cycle compared with the conventional stripping process. Utilizing results of the research, we developed rust stripping system using DPSSL. From the results of field trial of rust removal operation using this system at high places of a power transmission tower, possibility of practical use of the system for the maintenance was confirmed.

A system for diagnosis of wheat leaf diseases based on Android smartphone

NASA Astrophysics Data System (ADS)

Xie, Xinhua; Zhang, Xiangqian; He, Bing; Liang, Dong; Zhang, Dongyang; Huang, Linsheng

2016-10-01

Owing to the shortages of inconvenience, expensive and high professional requirements etc. for conventional recognition devices of wheat leaf diseases, it does not satisfy the requirements of uploading and releasing timely investigation data in the large-scale field, which may influence the effectiveness of prevention and control for wheat diseases. In this study, a fast, accurate, and robust diagnose system of wheat leaf diseases based on android smartphone was developed, which comprises of two parts—the client and the server. The functions of the client include image acquisition, GPS positioning, corresponding, and knowledge base of disease prevention and control. The server includes image processing, feature extraction, and selection, and classifier establishing. The recognition process of the system goes as follow: when disease images were collected in fields and sent to the server by android smartphone, and then image processing of disease spots was carried out by the server. Eighteen larger weight features were selected by algorithm relief-F and as the input of Relevance Vector Machine (RVM), and the automatic identification of wheat stripe rust and powdery mildew was realized. The experimental results showed that the average recognition rate and predicted speed of RVM model were 5.56% and 7.41 times higher than that of Support Vector Machine (SVM). And application discovered that it needs about 1 minute to get the identification result. Therefore, it can be concluded that the system could be used to recognize wheat diseases and real-time investigate in fields.

Duplications and losses in gene families of rust pathogens highlight putative effectors

Treesearch

Amanda L. Pendleton; Katherine E. Smith; Nicolas Feau; Francis M. Martin; Igor V. Grigoriev; Richard Hamelin; C.Dana Nelson; J.Gordon Burleigh; John M. Davis

2014-01-01

Rust fungi are a group of fungal pathogens that cause some of the world’s most destructive diseases of trees and crops . A shared characteristic among rust fungi is obligate biotrophy, the inability to complete a lifecycle without a host. This dependence on a host species likely affects patterns of gene expansion, contraction, and innovation within rust pathogen...

Strategies for managing whitebark pine in the presence of white pine blister rust [Chapter 17

Treesearch

Raymond J. Hoff; Dennis E. Ferguson; Geral I. McDonald; Robert E. Keane

2001-01-01

Whitebark pine (Pinus albicaulis) is one of many North American white pine species (Pinus subgenus Strobus) susceptible to the fungal disease white pine blister rust (Cronartium ribicola). Blister rust has caused severe mortality (often reaching nearly 100 percent) in many stands of white bark pine north of 45° latitude in western North America. The rust is slowly...

Two distinct classes of QTL determine rust resistance in sorghum.

PubMed

Wang, Xuemin; Mace, Emma; Hunt, Colleen; Cruickshank, Alan; Henzell, Robert; Parkes, Heidi; Jordan, David

2014-12-31

Agriculture is facing enormous challenges to feed a growing population in the face of rapidly evolving pests and pathogens. The rusts, in particular, are a major pathogen of cereal crops with the potential to cause large reductions in yield. Improving stable disease resistance is an on-going major and challenging focus for many plant breeding programs, due to the rapidly evolving nature of the pathogen. Sorghum is a major summer cereal crop that is also a host for a rust pathogen Puccinia purpurea, which occurs in almost all sorghum growing areas of the world, causing direct and indirect yield losses in sorghum worldwide, however knowledge about its genetic control is still limited. In order to further investigate this issue, QTL and association mapping methods were implemented to study rust resistance in three bi-parental populations and an association mapping set of elite breeding lines in different environments. In total, 64 significant or highly significant QTL and 21 suggestive rust resistance QTL were identified representing 55 unique genomic regions. Comparisons across populations within the current study and with rust QTL identified previously in both sorghum and maize revealed a high degree of correspondence in QTL location. Negative phenotypic correlations were observed between rust, maturity and height, indicating a trend for both early maturing and shorter genotypes to be more susceptible to rust. The significant amount of QTL co-location across traits, in addition to the consistency in the direction of QTL allele effects, has provided evidence to support pleiotropic QTL action across rust, height, maturity and stay-green, supporting the role of carbon stress in susceptibility to rust. Classical rust resistance QTL regions that did not co-locate with height, maturity or stay-green QTL were found to be significantly enriched for the defence-related NBS-encoding gene family, in contrast to the lack of defence-related gene enrichment in multi-trait effect rust resistance QTL. The distinction of disease resistance QTL hot-spots, enriched with defence-related gene families from QTL which impact on development and partitioning, provides plant breeders with knowledge which will allow for fast-tracking varieties with both durable pathogen resistance and appropriate adaptive traits.

Tagging and mapping of SSR marker for rust resistance gene in lentil (Lens culinaris Medikus subsp. culinaris).

PubMed

Dikshit, H K; Singh, Akanksha; Singh, D; Aski, M; Jain, Neelu; Hegde, V S; Basandrai, A K; Basandrai, D; Sharma, T R

2016-06-01

Lentil, as an economical source of protein, minerals and vitamins, plays important role in nutritional security of the common man. Grown mainly in West Asia, North Africa (WANA) region and South Asia, it suffers from several biotic stresses such as wilt, rust, blight and broomrape. Lentil rust caused by autoecious fungus Uromyces viciae fabae (Pers.) Schroet is a serious lentil disease in Algeria, Bangladesh, Ethiopia, India, Italy, Morocco, Pakistan and Nepal. The disease symptoms are observed during flowering and early podding stages. Rust causes severe yield losses in lentil. It can only be effectively controlled by identifying the resistant source, understanding its inheritance and breeding for host resistance. The obligate parasitic nature of pathogen makes it difficult to maintain the pathogen in culture and to apply it to screen segregating progenies under controlled growth conditions. Hence, the use of molecular markers will compliment in identification of resistant types in different breeding programs. Here, we studied the inheritance of resistance to rust in lentil using F₁, F₂ and F₂:₃ from cross PL 8 (susceptible) x L 4149 (resistant) varieties. The phenotyping of lentil population was carried out at Sirmour, India. The result of genetic analysis revealed that a single dominant gene controls rust resistance in lentil genotype L 4149. The F2 population from this cross was used to tag and map the rust resistance gene using SSR and SRAP markers. Markers such as 270 SRAP and 162 SSR were studied for polymorphism and 101 SRAP and 33 SSRs were found to be polymorphic between the parents. Two SRAP and two SSR markers differentiated the resistant and susceptible bulks. SSR marker Gllc 527 was estimated to be linked to rust resistant locus at a distance of 5.9 cM. The Gllc 527 marker can be used for marker assisted selection for rust resistance; however, additional markers closer to rust resistant locus are required. The markers linked to the rust resistance gene can serve as starting points for map-based cloning of the rust resistance gene.

Effect of sterilizing treatments on survival and growth of hybrid poplar cuttings

Treesearch

Harold F. Ford

1954-01-01

Fungus diseases of poplars might be spread to new locations if hybrid poplar cuttings (now being test-planted in various parts of the northeast) were not sterilized before shipment. Among these diseases are the canker-producing fungi Septoria musiva and Dothichiza populea and the leafblotch fungus Septotinia populiperda.

Dimension yields from yellow-poplar lumber

Treesearch

R. C. Gilmore; J. D. Danielson

1984-01-01

The available supply of yellow poplar (Liriodendron tulipifera L.), its potential for new uses, and its continuing importance to the furniture industry have created a need to accumulate additional information about this species. As an aid to better utilization of this species, charts for determining cutting stock yields from yellow poplar lumber are presented for each...

A comprehensive database of poplar research in North America from 1980 - 2010

Treesearch

David R. Coyle; Jill A. Zalesny; Ronald S. Jr. Zalesny

2010-01-01

Short rotation woody crops such as Populus species and hybrids (hereafter referred to as poplars) are renewable energy feedstocks that can potentially be used to offset electricity generation and natural gas use in many temperature regions. Highly productive poplars grown primarily on marginal agricultural sites are an important component of the...

WUS and STM-based reporter genes for studying meristem development in poplar

USDA-ARS?s Scientific Manuscript database

We describe the development of a reporter system for monitoring meristem initiation in poplar using promoters of poplar homologs to the meristem-active regulatory genes WUSCHEL (WUS) and SHOOTMERISTEMLESS (STM). When ~3 kb of the 5’ flanking regions of close homologs were used to drive expression o...

Harvesting systems and costs for short rotation poplar

Treesearch

B. Rummer; D. Mitchell

2013-01-01

The objective of this review is to compare the cost of coppice and longer rotation poplar harvesting technology. Harvesting technology for short rotation poplar has evolved over the years to address both coppice harvest and single-stem harvest systems. Two potential approaches for coppice harvesting are modified forage harvesters and modified mulcher-balers. Both of...

Methods of rapid, early selection of poplar clones for maximum yield potential: a manual of procedures.

Treesearch

USDA FS

1982-01-01

Instructions, illustrated with examples and experimental results, are given for the controlled-environment propagation and selection of poplar clones. Greenhouse and growth-room culture of poplar stock plants and scions are described, and statistical techniques for discriminating among clones on the basis of growth variables are emphasized.

Potential Utilization of Sweetgum and Yellow-Poplar for Structural Lumber

Treesearch

Timothy D. Faust; Robert H. McAlister; Stanley J. Zarnoch; Christopher B. Stephens

1991-01-01

The forest resource base in the Southeast is rapidly changing. Dwindling reserves of high quality pine sawlogs will provide incentive to utilize low-density hardwoods such as yellow-poplar and sweetgum for structural lumber. Inventories of sweetgum (Liquidambar styraciflua, L.) and yellow-poplar (Liriodendron tulipifera, L.) are currently high and growth is exceeding...

Expression of Multiple Resistance Genes Enhances Tolerance to Environmental Stressors in Transgenic Poplar (Populus × euramericana ‘Guariento’)

PubMed Central

Su, Xiaohua; Chu, Yanguang; Li, Huan; Hou, Yingjie; Zhang, Bingyu; Huang, Qinjun; Hu, Zanmin; Huang, Rongfeng; Tian, Yingchuan

2011-01-01

Commercial and non-commercial plants face a variety of environmental stressors that often cannot be controlled. In this study, transgenic hybrid poplar (Populus × euramericana ‘Guariento’) harboring five effector genes (vgb, SacB, JERF36, BtCry3A and OC-I) were subjected to drought, salinity, waterlogging and insect stressors in greenhouse or laboratory conditions. Field trials were also conducted to investigate long-term effects of transgenic trees on insects and salt tolerance in the transformants. In greenhouse studies, two transgenic lines D5-20 and D5-21 showed improved growth, as evidenced by greater height and basal diameter increments and total biomass relative to the control plants after drought or salt stress treatments. The improved tolerance to drought and salt was primarily attributed to greater instantaneous water use efficiency (WUEi) in the transgenic trees. The chlorophyll concentrations tended to be higher in the transgenic lines under drought or saline conditions. Transformed trees in drought conditions accumulated more fructan and proline and had increased Fv/Fm ratios (maximum quantum yield of photosystem II) under waterlogging stress. Insect-feeding assays in the laboratory revealed a higher total mortality rate and lower exuviation index of leaf beetle [Plagiodera versicolora (Laicharting)] larvae fed with D5-21 leaves, suggesting enhanced insect resistance in the transgenic poplar. In field trials, the dominance of targeted insects on 2-year-old D5-21 transgenic trees was substantially lower than that of the controls, indicating enhanced resistance to Coleoptera. The average height and DBH (diameter at breast height) of 2.5-year-old transgenic trees growing in naturally saline soil were 3.80% and 4.12% greater than those of the control trees, but these increases were not significant. These results suggested that multiple stress-resistance properties in important crop tree species could be simultaneously improved, although additional research is needed to fully understand the relationships between the altered phenotypes and the function of each transgene in multigene transformants. PMID:21931776

Creation and validation of a simulator for corneal rust ring removal.

PubMed

Mednick, Zale; Tabanfar, Reza; Alexander, Ashley; Simpson, Sarah; Baxter, Stephanie

2017-10-01

To create and validate a simulation model for corneal rust ring removal. Rust rings were created on cadaveric eyes with the use of small particles of metal. The eyes were mounted on suction plates at slit lamps and the trainees practiced rust ring removal. An inexperienced cohort of medical students and first year ophthalmology residents (n=11), and an experienced cohort of senior residents and faculty (n=11) removed the rust rings from the eyes with the use of a burr. Rust ring removal was evaluated based on removal time, percentage of rust removed and incidence of corneal perforation. A survey was administered to participants to determine face validity. Time for rust ring removal was longer in the inexperienced group at 187±93 seconds (range of 66-408 seconds), compared to the experienced group at 117±54 seconds (range of 55-240 seconds) (p=0.046). Removal speed was similar between groups, at 4847±4355 pixels/minute and 7206±5181 pixels/minute in the inexperienced and experienced groups, respectively (p=0.26). Removal percentage values were similar between groups, at 61±15% and 69±18% (p=0.38). There were no corneal perforations. 100% (22/22) of survey respondents believed the simulator would be a valuable practice tool, and 89% (17/19) felt the simulation was a valid representation of the clinical correlate. The corneal rust ring simulator presented here is a valid training tool that could be used by early trainees to gain greater comfort level before attempting rust ring removal on a live patient. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Characterization of Brachypodium distachyon as a nonhost model against switchgrass rust pathogen Puccinia emaculata.

PubMed

Gill, Upinder S; Uppalapati, Srinivasa R; Nakashima, Jin; Mysore, Kirankumar S

2015-05-08

Switchgrass rust, caused by Puccinia emaculata, is an important disease of switchgrass, a potential biofuel crop in the United States. In severe cases, switchgrass rust has the potential to significantly affect biomass yield. In an effort to identify novel sources of resistance against switchgrass rust, we explored nonhost resistance against P. emaculata by characterizing its interactions with six monocot nonhost plant species. We also studied the genetic variations for resistance among Brachypodium inbred accessions and the involvement of various defense pathways in nonhost resistance of Brachypodium. We characterized P. emaculata interactions with six monocot nonhost species and identified Brachypodium distachyon (Bd21) as a suitable nonhost model to study switchgrass rust. Interestingly, screening of Brachypodium accessions identified natural variations in resistance to switchgrass rust. Brachypodium inbred accessions Bd3-1 and Bd30-1 were identified as most and least resistant to switchgrass rust, respectively, when compared to tested accessions. Transcript profiling of defense-related genes indicated that the genes which were induced in Bd21after P. emaculata inoculation also had higher basal transcript abundance in Bd3-1 when compared to Bd30-1 and Bd21 indicating their potential involvement in nonhost resistance against switchgrass rust. In the present study, we identified Brachypodium as a suitable nonhost model to study switchgrass rust which exhibit type I nonhost resistance. Variations in resistance response were also observed among tested Brachypodium accessions. Brachypodium nonhost resistance against P. emaculata may involve various defense pathways as indicated by transcript profiling of defense related genes. Overall, this study provides a new avenue to utilize novel sources of nonhost resistance in Brachypodium against switchgrass rust.

Effects of drought on leaf gas exchange in an eastern broadleaf deciduous forest

NASA Astrophysics Data System (ADS)

Roman, D. T.; Brzostek, E. R.; Dragoni, D.; Rahman, A. F.; Novick, K. A.; Phillips, R.

2013-12-01

Understanding plant physiological adaptations to drought is critical for predicting changes in ecosystem productivity that result from climate variability and future climate change. From 2011-2013, southern Indiana experienced a late growing season drought in 2011, a severe early season drought in 2012, and a wet growing season in 2013 characterized by an absence of water stress with frequent precipitation and milder temperatures. The 2012 drought was unique due to the severity and early onset drought conditions (compared to the more frequent late season drought) and was characterized by a Palmer Drought severity index below -4 and precipitation totals from May - July that were 70% less than the long-term (2000 - 2010) mean. During the 2012 drought, an 11% decline in net ecosystem productivity relative to the long-term mean was observed at the AmeriFlux tower in Morgan Monroe State Forest despite a growing season that started ~25 days earlier. Thus, the objective of this study is to evaluate species-specific contributions to the canopy-scale response to inter-annual variability in water stress. We investigated differences between tree species in their response to climate variability using weekly leaf gas exchange and leaf water potential measurements during the growing seasons of 2011-2013. We used this unique dataset, collected at the top of the canopy with a 25 m boom lift, to evaluate changes in leaf water status and maximum assimilation capacity in the drought versus non-drought years. The leaf-level physiology of oak (Quercus) species appears to be less sensitive to drought than other species (tulip poplar [Liriodendron tulipifera], sassafras [Sassafras albidum] and sugar maple [Acer saccharum]). Preliminary data shows mean canopy leaf water potential for oaks was 30.5% more negative in May-July 2012 versus the same time period in 2013. During these same periods the rate of C assimilation in oaks was reduced by only 3%, whereas other species were reduced by closer to 10-20% in the drought year. We then assess how assimilation capacity and leaf water potential relate to marginal water use efficiency across species and years. Given that this region is predicted to experience more water stress over the coming decades, these results will inform predictions as to how species composition will drive ecosystem responses to climate variability.

Improved diffusivity of NaOH solution in autohydrolyzed poplar sapwood chips for chemi-mechanical pulp production.

PubMed

Zhang, Honglei; Hou, Qingxi; Liu, Wei; Yue, Zhen; Jiang, Xiaoya; Ma, Xixi

2018-07-01

This work investigated the changes in the physical structure of autohydrolyzed poplar sapwood chips and the effect on the subsequent alkali liquor diffusion properties for chemi-mechanical pulping (CMP). An alkali impregnation process was conducted by using the autohydrolyzed poplar sapwood with different levels of autohydrolysis intensity. The results showed that the volume porosity, water constraint capacity, and saturated water absorption of the autohydrolyzed poplar sapwood chips increased. Also, the effective capillary cross-sectional area (ECCSA) in the radial direction and the diffusion coefficients of NaOH solution in both the radial and axial directions all increased. Autohydrolysis pretreatment enhanced the alkali liquor diffusion properties in poplar sapwood chips, and the diffusion coefficient was increased more greatly in the radial direction than that in the axial direction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rust-Inhibited Nonreactive Perfluorinated Polymer Greases

DTIC Science & Technology

Perfluoroalkylpolyether fluids thickened with polytetrafluoroethylene were studied in connection with the development of rust-inhibited chemically...dimethyloctadecylbenzyl ammonium bentonite + sodium nitrate imparts very effective rust-preventive properties to perfluoro polymer grease mixtures. Data are

Identification of a novel hydroxylated metabolite of 2,2′,3,5′,6-pentachlorobiphenyl formed in whole poplar plants

PubMed Central

Ma, Cunxian; Zhai, Guangshu; Wu, Huimin; Kania-Korwel, Izabela; Lehmler, Hans-Joachim; Schnoor, Jerald L

2015-01-01

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants consisting of 209 congeners. Oxidation of several PCB congeners to hydroxylated PCBs (OH-PCBs) in whole poplar plants has been reported before. Moreover, 2,2′,3,5′,6-pentachlorobiphenyl (PCB95), as a chiral congener, has been previously shown to be atropselectively taken up and transformed in whole poplar plants. The objective of this study was to determine if PCB95 is atropselectively metabolized to OH-PCBs in whole poplar plants. Two hydroxylated PCB95s were detected by high performance liquid chromatography-mass spectrometry in the roots of whole poplar plants exposed to racemic PCB95 for 30 days. The major metabolite was confirmed to be 4′-hydroxy-2,2′,3,5′,6-pentachlorobiphenyl (4′-OH-PCB95) by gas chromatography-mass spectrometry (GC-MS) using an authentic reference standard. Enantioselective analysis showed that 4′-OH-PCB95 was formed atropselectively, with the atropisomer eluting second on the Nucleodex β-PM column (E2-4′-OH-PCB95) being slightly more abundant in the roots of whole poplar plants. Therefore, PCB95 can at least be metabolized into 4′-OH-PCB95 and another unknown hydroxylated PCB95 (as a minor metabolite) in whole poplar plants. Both atropisomers of 4′-OH-PCB95 are formed, but E2-4′-OH-PCB95 has greater atropisomeric enrichment in the roots of whole poplar plants. A comparison with mammalian biotransformation studies indicates a distinctively different metabolite profile of OH-PCB95 metabolites in whole poplar plants. Our observations suggest that biotransformation of chiral PCBs to OH-PCBs by plants may represent an important source of enantiomerically enriched OH-PCBs in the environment. PMID:26676542

White pine blister rust in northern ldaho and western Montana: alternatives for integrated management

Treesearch

Susan K. Hagle; Geral I. McDonald; Eugene A. Norby

1989-01-01

This report comprises a handbook for managing western white pine in northern ldaho and western Montana, under the threat of white pine blister rust. Various sections cover the history of the disease and efforts to combat it, the ecology of the white pine and Ribes, alternate host of the rust, and techniques for evaluating the rust hazard and attenuating it. The authors...

Relationship between sugarcane rust severity and soil properties in louisiana.

PubMed

Johnson, Richard M; Grisham, Michael P; Richard, Edward P

2007-06-01

ABSTRACT The extent of spatial and temporal variability of sugarcane rust (Puccinia melanocephala) infestation was related to variation in soil properties in five commercial fields of sugarcane (interspecific hybrids of Saccharum spp., cv. LCP 85-384) in southern Louisiana. Sugarcane fields were grid-soil sampled at several intensities and rust ratings were collected at each point over 6 to 7 weeks. Soil properties exhibited significant variability (coefficients of variation = 9 to 70.1%) and were spatially correlated in 39 of 40 cases with a range of spatial correlation varying from 39 to 201 m. Rust ratings were spatially correlated in 32 of 33 cases, with a range varying from 29 to 241 m. Rust ratings were correlated with several soil properties, most notably soil phosphorus (r = 0.40 to 0.81) and soil sulfur (r = 0.36 to 0.68). Multiple linear regression analysis resulted in coefficients of determination that ranged from 0.22 to 0.73, and discriminant analysis further improved the overall predictive ability of rust models. Finally, contour plots of soil properties and rust levels clearly suggested a link between these two parameters. These combined data suggest that sugarcane growers that apply fertilizer in excess of plant requirements will increase the incidence and severity of rust infestations in their fields.

A reassessment of the risk of rust fungi developing resistance to fungicides.

PubMed

Oliver, Richard P

2014-11-01

Rust fungi are major pathogens of many annual and perennial crops. Crop protection is largely based on genetic and chemical control. Fungicide resistance is a significant issue that has affected many crop pathogens. Some pathogens have rapidly developed resistance and hence are regarded as high-risk species. Rust fungi have been classified as being low risk, in spite of sharing many relevant features with high-risk pathogens. An examination of the evidence suggests that rust fungi may be wrongly classified as low risk. Of the nine classes of fungicide to which resistance has developed, six are inactive against rusts. The three remaining classes are quinone outside inhibitors (QoIs), demethylation inhibitors (DMIs) and succinate dehydrogenase inhibitors (SDHIs). QoIs have been protected by a recently discovered intron that renders resistant mutants unviable. Low levels of resistance have developed to DMIs, but with limited field significance. Older SDHI fungicides were inactive against rusts. Some of the SDHIs introduced since 2003 are active against rusts, so it may be that insufficient time has elapsed for resistance to develop, especially as SDHIs are generally sold in mixtures with other actives. It would therefore seem prudent to increase the level of vigilance for possible cases of resistance to established and new fungicides in rusts. © 2014 Society of Chemical Industry.

Aegilops tauschii Accessions with Geographically Diverse Origin Show Differences in Chromosome Organization and Polymorphism of Molecular Markers Linked to Leaf Rust and Powdery Mildew Resistance Genes.

PubMed

Majka, Maciej; Kwiatek, Michał T; Majka, Joanna; Wiśniewska, Halina

2017-01-01

Aegilops tauschii (2n = 2x = 14) is a diploid wild species which is reported as a donor of the D-genome of cultivated bread wheat. The main goal of this study was to examine the differences and similarities in chromosomes organization among accessions of Ae. tauschii with geographically diversed origin, which is believed as a potential source of genes, especially determining resistance to fungal diseases (i.e., leaf rust and powdery mildew) for breeding of cereals. We established and compared the fluorescence in situ hybridization patterns of 21 accessions of Ae. tauschii using various repetitive sequences mainly from the BAC library of wheat cultivar Chinese Spring. Results obtained for Ae. tauschii chromosomes revealed many similarities between analyzed accessions, however, some hybridization patterns were specific for accessions, which become from cognate regions of the World. The most noticeable differences were observed for accessions from China which were characterized by presence of distinct signals of pTa-535 in the interstitial region of chromosome 3D, less intensity of pTa-86 signals in chromosome 2D, as well as lack of additional signals of pTa-86 in chromosomes 1D, 5D, or 6D. Ae. tauschii of Chinese origin appeared homogeneous and separate from landraces that originated in western Asia. Ae. tauschii chromosomes showed similar hybridization patterns to wheat D-genome chromosomes, but some differences were also observed among both species. What is more, we identified reciprocal translocation between short arm of chromosome 1D and long arm of chromosome 7D in accession with Iranian origin. High polymorphism between analyzed accessions and extensive allelic variation were revealed using molecular markers associated with resistance genes. Majority of the markers localized in chromosomes 1D and 2D showed the diversity of banding patterns between accessions. Obtained results imply, that there is a moderate or high level of polymorphism in the genome of Ae . tauschii determined by a geographical origin, which we proved by cytogenetic and molecular markers analysis. Therefore, selected accessions might constitute an accessible source of variation for improvement of Triticeae species like wheat and triticale.

Epigenetic Diversity of Clonal White Poplar (Populus alba L.) Populations: Could Methylation Support the Success of Vegetative Reproduction Strategy?

PubMed

Guarino, Francesco; Cicatelli, Angela; Brundu, Giuseppe; Heinze, Berthold; Castiglione, Stefano

2015-01-01

The widespread poplar populations of Sardinia are vegetatively propagated and live in different natural environments forming large monoclonal stands. The main goals of the present study were: i) to investigate/measure the epigenetic diversity of the poplar populations by determining their DNA methylation status; ii) to assess if and how methylation status influences population clustering; iii) to shed light on the changes that occur in the epigenome of ramets of the same poplar clone. To these purposes, 83 white poplar trees were sampled at different locations on the island of Sardinia. Methylation sensitive amplified polymorphism analysis was carried out on the genomic DNA extracted from leaves at the same juvenile stage. The study showed that the genetic biodiversity of poplars is quite limited but it is counterbalanced by epigenetic inter-population molecular variability. The comparison between MspI and HpaII DNA fragmentation profiles revealed that environmental conditions strongly influence hemi-methylation of the inner cytosine. The variable epigenetic status of Sardinian white poplars revealed a decreased number of population clusters. Landscape genetics analyses clearly demonstrated that ramets of the same clone were differentially methylated in relation to their geographic position. Therefore, our data support the notion that studies on plant biodiversity should no longer be restricted to genetic aspects, especially in the case of vegetatively propagated plant species.

Quantitative characterization of the atomic-scale structure of oxyhydroxides in rusts formed on steel surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saito, M.; Suzuki, S.; Kimura, M.

Quantitative X-ray structural analysis coupled with anomalous X-ray scattering has been used for characterizing the atomic-scale structure of rust formed on steel surfaces. Samples were prepared from rust layers formed on the surfaces of two commercial steels. X-ray scattered intensity profiles of the two samples showed that the rusts consisted mainly of two types of ferric oxyhydroxide, {alpha}-FeOOH and {gamma}-FeOOH. The amounts of these rust components and the realistic atomic arrangements in the components were estimated by fitting both the ordinary and the environmental interference functions with a model structure calculated using the reverse Monte Carlo simulation technique. The twomore » rust components were found to be the network structure formed by FeO{sub 6} octahedral units, the network structure itself deviating from the ideal case. The present results also suggest that the structural analysis method using anomalous X-ray scattering and the reverse Monte Carlo technique is very successful in determining the atomic-scale structure of rusts formed on the steel surfaces.« less

Use of Sulfometuron in Hybrid Poplar Energy Plantations

Treesearch

Daniel A. Netzer

1995-01-01

Reports that low rates of sulfometuron, 70 grams per hactare (1 ounce product or 0.75 ounces active ingredient per acre), applied when hybrid poplars are completely dormant, can provide season-long weed control and increase hybrid poplar growth. If plantation access is not possible before growth activity begins in the spring, late fall application of this herbicide...

75 FR 30799 - Notice of a Waiver of Section 1605 of the American Recovery and Reinvestment Act of 2009 (ARRA...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-02

... DEPARTMENT OF EDUCATION Notice of a Waiver of Section 1605 of the American Recovery and... 1605 of the American Recovery and Reinvestment Act of 2009 (ARRA) for Poplar School District, Poplar... Buy American requirements in section 1605(a) of the ARRA (Buy American Requirements) for the Poplar...

Gene and enhancer trap tagging of vascular-expressed genes in poplar trees

Treesearch

Andrew Groover; Joseph R. Fontana; Gayle Dupper; Caiping Ma; Robert Martienssen; Steven Strauss; Richard Meilan

2004-01-01

We report a gene discovery system for poplar trees based on gene and enhancer traps. Gene and enhancer trap vectors carrying the β-glucuronidase (GUS) reporter gene were inserted into the poplar genome via Agrobacterium tumefaciens transformation, where they reveal the expression pattern of genes at or near the insertion sites. Because GUS...

An approach for siting poplar energy production systems to increase productivity and associated ecosystem services

Treesearch

R.S. Jr. Zalesny; D.M. Donner; D.R. Coyle; W.L. Headlee; R.B. Hall

2010-01-01

Short rotation woody crops (SRWC) such as Populus species and hybrids (i.e., poplars) are renewable energy feedstocks that are vital to reducing our dependence on non-renewable and foreign sources of energy used for heat, power, and transportation fuels. Highly productive poplars grown primarily on marginal agricultural sites are an important...

Contribution factor of wood properties of three poplar clones to strength of laminated veneer lumber

Treesearch

Fucheng Bao; Feng Fu; Elvin Choong; Chung-Yun Hse

2001-01-01

The term "Contribution Factor" (c.) was introduced in this paper to indicate the contribution ratio of solid wood properties to laminated veneer lumber (LVL) strength. Three poplar (Populus sp.) clones were studied, and the results showed that poplar with good solid wood properties has high Contribution Factor. The average Contribution...

Board-Foot and Diameter Growth of Yellow-Poplar After Thinning

Treesearch

Donald E. Beck; Lino Della-Bianca

1975-01-01

Board-foot growth and yield of thinned yellow-poplar stands (Liriodendron tulipifera L.)is related to age, site index, residual basal area, and residual quadratic mean stand diameter after thinning. Diameter growth of individual trees is increased considerably by thinning. Equations describing growth and yield are based on data from 141 natura1 yellow-poplar stands in...

Environmental applications of poplars and willows

Treesearch

J.G. Isebrands; P. Aronsson; M. Carlson; R. Ceulemans; M. Coleman; N. Dickinson; J. Dimitriou; S. Doty; E. Gardiner; K. Heinsoo; J.D. Johnson; Y.B. Koo; J. Kort; J. Kuzovkina; L. Licht; A.R. McCracken; I. McIvor; P. Mertens; K. Perttu; D. Riddell-Black; B. Robins; G. Scarascia-Mugnozza; W.R. Schroeder; John Stanturf; T.A. Volk; M. Weih

2014-01-01

Poplars and willows have been planted for environmental purposes for millennia. There are reports that poplars were planted to improve the human environment 4000 years ago in the third dynasty of Ur, for streamside stabilization 2000 years ago in what is now the south-western USA by native North Americans and for urban amenities by the early Chinese dynasties (see...

Low temperatures are required to induce the development of fertile flowers in transgenic male and female early flowering poplar (Populus tremula L.)

PubMed Central

Hoenicka, Hans; Lehnhardt, Denise; Briones, Valentina; Nilsson, Ove; Fladung, Matthias

2016-01-01

Until now, artificial early flowering poplar systems have mostly led to the development of sterile flowers. In this study, several strategies aimed at inducting fertile flowers in pHSP::AtFT transgenic poplar were evaluated, in particular the influence of temperature and photoperiod. Our results provide evidence that temperature, and not photoperiod, is the key factor required for the development of fertile flowers in early flowering poplar. Fertile flowers were only obtained when a cold treatment phase of several weeks was used after the heat treatment phase. Heat treatments induced AtFT gene activity through activation of the heat-shock promoter (pHSP). Photoperiod did not show a similar influence on flower fertility as pollen grains were obtained under both long- and short-day conditions. Fertility was confirmed in flowers of both male and female plants. For the first time, crosses were successfully performed with transgenic female early flowering poplar. All mature flowers obtained after 8 weeks of inductive treatments were fertile. Gene expression studies also confirmed that cold temperatures influenced expression of poplar genes homologous to ‘pollen development genes’ from Arabidopsis thaliana (L.) Heynh. Homology and expression patterns suggested a role for PtTDF1, PtBAM1, PtSERK1/2 and PtMS1 on anther and pollen development in poplar flowers. The system developed in this study allows a fast and very reliable induction of fertile poplar flowers in a very short period of time. The non-reproductive phase, usually 7–10 years, can now be shortened to 6–10 months, and fertile flowers can be obtained independently of the season. This system is a reliable tool for breeding purposes (high-speed breeding technology), genomics and biosafety research. PMID:27052434

Phylogeographic patterns of the desert poplar in Northwest China shaped by both geology and climatic oscillations.

PubMed

Zeng, Yan-Fei; Zhang, Jian-Guo; Abuduhamiti, Bawerjan; Wang, Wen-Ting; Jia, Zhi-Qing

2018-05-25

The effects of historical geology and climatic events on the evolution of plants around the Qinghai-Tibetan Plateau region have been at the center of debate for years. To identify the influence of the uplift of the Tianshan Mountains and/or climatic oscillations on the evolution of plants in arid northwest China, we investigated the phylogeography of the Euphrates poplar (Populus euphratica) using chloroplast DNA (cpDNA) sequences and nuclear microsatellites, and estimated its historical distribution using Ecological Niche Modeling (ENM). We found that the Euphrates poplar differed from another desert poplar, P. pruinosa, in both nuclear and chloroplast DNA. The low clonal diversity in both populations reflected the low regeneration rate by seed/seedlings in many locations. Both cpDNA and nuclear markers demonstrated a clear divergence between the Euphrates poplar populations from northern and southern Xinjiang regions. The divergence time was estimated to be early Pleistocene based on cpDNA, and late Pleistocene using an Approximate Bayesian Computation analysis based on microsatellites. Estimated gene flow was low between these two regions, and the limited gene flow occurred mainly via dispersal from eastern regions. ENM analysis supported a wider distribution of the Euphrates poplar at 3 Ma, but a more constricted distribution during both the glacial period and the interglacial period. These results indicate that the deformation of the Tianshan Mountains has impeded gene flow of the Euphrates poplar populations from northern and southern Xinjiang, and the distribution constriction due to climatic oscillations further accelerated the divergence of populations from these regions. To protect the desert poplars, more effort is needed to encourage seed germination and seedling establishment, and to conserve endemic gene resources in the northern Xinjiang region.

Ozone curbs crown rust

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1970-01-01

Crown rust, the most destructive disease of oats, was suppressed in laboratory fumigation chambers by ozone air pollution levels commonly surpassed in many areas. Whether the effects of air pollution on crown rust are of economic importance under field conditions is yet to be determined. Crown rust, caused by the fungus Puccinia coronata, is particularly destructive in Southern and North Central States, often reducing yields 20 percent or more. Rust pustules on oats were significantly smaller when plants were exposed to 10 parts per hundred million ozone for 6 hours in the light on the 10 days after infection. Aboutmore » half as many rust spores were produced in the ozone chamber as in one protected by carbon filters. Exposure to 10 pphm ozone did not affect viability of spores. Spores produced on exposed plants germinated and penetrated stomates of oat leaves as well as spores produced on unexposed leaves.« less

Mechanical properties of the rust layer induced by impressed current method in reinforced mortar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Care, S.; Nguyen, Q.T.; L'Hostis, V.

This paper describes the mechanical effects of rust layer formed in reinforced mortar through accelerated tests of corrosion. The morphological and physico-chemical properties (composition, structures) of the corrosion system were characterized at different stages by using optical microscope and scanning electron microscope coupled with energy dispersive spectroscopy. The corrosion pattern was mainly characterized by a rust layer confined at the interface between the steel and the mortar. Expansion coefficient of rust products was determined from the rust thickness and the Faraday's law. Furthermore, in order to understand the mechanical effects of corrosion on the damage of mortar, displacement field measurementsmore » were obtained by using digital image correlation. An analytical model (hollow cylinder subjected to inner and outer pressures) was used with a set of experimental data to deduce the time of cracking and the order of magnitude of the mechanical properties of the rust layer.« less

Recent progress in the study of protective rust-layer formation on weathering steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamashita, M.; Misawa, T.

Latest understanding of protective rust layer on weathering steel and its application for structural steels is discussed. Phase transformation of the weathering steel rust layer during long-time exposure brings {alpha}-(Fe{sub 1{minus}x},Cr{sub x})OOH, Cr-substituted goethite, as the final protective rust layer. It is said that the Cr content in the Cr-substituted goethite layer increases gradiently with reaching the rust-steel interface. This increase in the Cr content gives densely packed fine crystal structure end cation selective ability, which impedes the penetration of aggressive corrosives including anions such as Cl{sup {minus}} and SO{sub 4}{sup 2{minus}}. Quite recently, new surface-treatment technique employing Cr{sub 2}(SO{submore » 4}){sub 3}, was proposed, which provides a possibility for obtaining the protective rust layer in a relatively short period even in the severe environment such as coastal region.« less

Morphological measurements and ITS sequences show that the new alder rust in Europe is conspecific with Melampsoridium hiratsukanum in eastern Asia.

PubMed

Hantula, J; Kurkela, T; Hendry, S; Yamaguchi, T

2009-01-01

Three species of Melampsoridium have been reported to infect hosts in genus Alnus. An epidemic of foliar rust affecting A. glutinosa and A. incana began in Europe in the mid-1990s, and the associated pathogen was identified as Melampsoridium hiratsukanum based on morphology. In this investigation we analyzed the morphology and genetic variation of alder rusts from Europe and Japan and the host specificity of the European epidemic rust. Our results showed that two rusts occur on the leaves of alders native to northern Europe; in Scotland an endemic rust indistinguishable from M. betulinum occurs, whereas alders in areas of Europe affected by the current epidemic were infected by M. hiratsukanum. M. hiratsukanum from naturally infected alder in Finland produced aecia on all Larix species tested but did not infect Betula leaves.

Structure and vascular tissue expression of duplicated TERMINAL EAR1-like paralogues in poplar.

PubMed

Charon, Céline; Vivancos, Julien; Mazubert, Christelle; Paquet, Nicolas; Pilate, Gilles; Dron, Michel

2010-02-01

TERMINAL EAR1-like (TEL) genes encode putative RNA-binding proteins only found in land plants. Previous studies suggested that they may regulate tissue and organ initiation in Poaceae. Two TEL genes were identified in both Populus trichocarpa and the hybrid aspen Populus tremula x P. alba, named, respectively, PoptrTEL1-2 and PtaTEL1-2. The analysis of the organisation around the PoptrTEL genes in the P. trichocarpa genome and the estimation of the synonymous substitution rate for PtaTEL1-2 genes indicate that the paralogous link between these two Populus TEL genes probably results from the Salicoid large-scale gene-duplication event. Phylogenetic analyses confirmed their orthology link with the other TEL genes. The expression pattern of both PtaTEL genes appeared to be restricted to the mother cells of the plant body: leaf founder cells, leaf primordia, axillary buds and root differentiating tissues, as well as to mother cells of vascular tissues. Most interestingly, PtaTEL1-2 transcripts were found in differentiating cells of secondary xylem and phloem, but probably not in the cambium itself. Taken together, these results indicate specific expression of the TEL genes in differentiating cells controlling tissue and organ development in Populus (and other Angiosperm species).

Climate-resilient agroforestry: physiological responses to climate change and engineering of crassulacean acid metabolism (CAM) as a mitigation strategy.

PubMed

Borland, Anne M; Wullschleger, Stan D; Weston, David J; Hartwell, James; Tuskan, Gerald A; Yang, Xiaohan; Cushman, John C

2015-09-01

Global climate change threatens the sustainability of agriculture and agroforestry worldwide through increased heat, drought, surface evaporation and associated soil drying. Exposure of crops and forests to warmer and drier environments will increase leaf:air water vapour-pressure deficits (VPD), and will result in increased drought susceptibility and reduced productivity, not only in arid regions but also in tropical regions with seasonal dry periods. Fast-growing, short-rotation forestry (SRF) bioenergy crops such as poplar (Populus spp.) and willow (Salix spp.) are particularly susceptible to hydraulic failure following drought stress due to their isohydric nature and relatively high stomatal conductance. One approach to sustaining plant productivity is to improve water-use efficiency (WUE) by engineering crassulacean acid metabolism (CAM) into C3 crops. CAM improves WUE by shifting stomatal opening and primary CO2 uptake and fixation to the night-time when leaf:air VPD is low. CAM members of the tree genus Clusia exemplify the compatibility of CAM performance within tree species and highlight CAM as a mechanism to conserve water and maintain carbon uptake during drought conditions. The introduction of bioengineered CAM into SRF bioenergy trees is a potentially viable path to sustaining agroforestry production systems in the face of a globally changing climate. © 2014 John Wiley & Sons Ltd.

Actual and potential transpiration and carbon assimilation in an irrigated poplar plantation.

PubMed

Kim, Hyun-Seok; Oren, Ram; Hinckley, Thomas M

2008-04-01

We examined the tradeoffs between stand-level water use and carbon uptake that result when biomass production of trees in plantations is maximized by removing nutrient and water limitations. A Populus trichocarpa Torr. x P. deltoides Bartr. & Marsh. plantation was irrigated and received frequent additions of nutrients to optimize biomass production. Sap flux density was measured continuously over four of the six growing-season months, supplemented with periodic measurements of leaf gas exchange and water potential. Measurements of tree diameter and height were used to estimate leaf area and biomass production based on allometric relationships. Sap flux was converted to canopy conductance and analyzed with an empirical model to isolate the effects of water limitation. Actual and soil-water-unlimited potential CO(2) uptakes were estimated with a canopy conductance constrained carbon assimilation (4C-A) scheme, which couples actual or potential canopy conductance with vertical gradients of light distribution, leaf-level conductance, maximum Rubisco capacity and maximum electron transport. Net primary production (NPP) was about 43% of gross primary production (GPP); when estimated for individual trees, this ratio was independent of tree size. Based on the NPP/GPP ratio, we found that current irrigation reduced growth by about 18% compared with growth with no water limitation. To achieve maximum growth, however, would require 70% more water for transpiration, and would reduce water-use efficiency by 27%, from 1.57 to 1.15 g stem wood C kg(-1) water. Given the economic and social values of water, plantation managers appear to have optimized water use.

[Prediction model of meteorological grade of wheat stripe rust in winter-reproductive area, Sichuan Basin, China].

PubMed

Guo, Xiang; Wang, Ming Tian; Zhang, Guo Zhi

2017-12-01

The winter reproductive areas of Puccinia striiformis var. striiformis in Sichuan Basin are often the places mostly affected by wheat stripe rust. With data on the meteorological condition and stripe rust situation at typical stations in the winter reproductive area in Sichuan Basin from 1999 to 2016, this paper classified the meteorological conditions inducing wheat stripe rust into 5 grades, based on the incidence area ratio of the disease. The meteorological factors which were biologically related to wheat stripe rust were determined through multiple analytical methods, and a meteorological grade model for forecasting wheat stripe rust was created. The result showed that wheat stripe rust in Sichuan Basin was significantly correlated with many meteorological factors, such as the ave-rage (maximum and minimum) temperature, precipitation and its anomaly percentage, relative humidity and its anomaly percentage, average wind speed and sunshine duration. Among these, the average temperature and the anomaly percentage of relative humidity were the determining factors. According to a historical retrospective test, the accuracy of the forecast based on the model was 64% for samples in the county-level test, and 89% for samples in the municipal-level test. In a meteorological grade forecast of wheat stripe rust in the winter reproductive areas in Sichuan Basin in 2017, the prediction was accurate for 62.8% of the samples, with 27.9% error by one grade and only 9.3% error by two or more grades. As a result, the model could deliver satisfactory forecast results, and predicate future wheat stripe rust from a meteorological point of view.

Functional and DNA-protein binding studies of WRKY transcription factors and their expression analysis in response to biotic and abiotic stress in wheat (Triticum aestivum L.).

PubMed

Satapathy, Lopamudra; Kumar, Dhananjay; Kumar, Manish; Mukhopadhyay, Kunal

2018-01-01

WRKY, a plant-specific transcription factor family, plays vital roles in pathogen defense, abiotic stress, and phytohormone signalling. Little is known about the roles and function of WRKY transcription factors in response to rust diseases in wheat. In the present study, three TaWRKY genes encoding complete protein sequences were cloned. They belonged to class II and III WRKY based on the number of WRKY domains and the pattern of zinc finger structures. Twenty-two DNA-protein binding docking complexes predicted stable interactions of WRKY domain with W-box. Quantitative real-time-PCR using wheat near-isogenic lines with or without Lr28 gene revealed differential up- or down-regulation in response to biotic and abiotic stress treatments which could be responsible for their functional divergence in wheat. TaWRKY62 was found to be induced upon treatment with JA, MJ, and SA and reduced after ABA treatments. Maximum induction of six out of seven genes occurred at 48 h post inoculation due to pathogen inoculation. Hence, TaWRKY (49, 50 , 52 , 55 , 57, and 62 ) can be considered as potential candidate genes for further functional validation as well as for crop improvement programs for stress resistance. The results of the present study will enhance knowledge towards understanding the molecular basis of mode of action of WRKY transcription factor genes in wheat and their role during leaf rust pathogenesis in particular.

International surveillance of wheat rust pathogens: progress and challenges

USDA-ARS?s Scientific Manuscript database

Surveillance of wheat rust pathogens, including assessments of rust incidence and virulence characterization via either trap plots or race (pathotype) surveys, has provided information fundamental in formulating and adopting appropriate national and international policies, investments and strategies...

Influence of Rust Permeability on Corrosion of E690 Steel in Industrial and Non-industrial Marine Splash Zones

NASA Astrophysics Data System (ADS)

Chen, Mindong; Pang, Kun; Liu, Zhiyong; Wu, Junsheng; Li, Xiaogang

2018-05-01

The corrosion behaviour of E690 steel in industrial and non-industrial marine splash environments was studied by environmental testing, morphology analysis, electrochemical measurements, and scanning Kelvin probe microscopy. Chloride and sulphide anions were found to diffuse across the rust layer following the evaporation of seawater splashed on the steel's surface. The cation-selective permeability of the rust layer resulted in an anion concentration gradient across the rust layer, which was more significant in the presence of sulphur dioxide. In addition, sulphur dioxide enhanced the formation of α-FeOOH, which led to the formation of distinct anode and cathode areas at the rust/steel interface.

Hybrid poplars: fast-growing, disease-resistant species has multiple uses

Treesearch

Ronald S., Jr. Zalesny

2004-01-01

The production of alternative fuels as a source of energy is a focus of concern in the United States. Intensively cultured hybrid poplar plantations have been used to supplement industrial fiber supplies in several areas of the United States, and have therefore gained attention in the North Central region. Attention is focused on poplars because they are fast growing...

Hybrid poplar planting in the Lake States

Treesearch

Paul O. Rudolf

1948-01-01

Poplars are among our fastest growing trees. Many of them are also relatively easy to grow from cuttings and to hybridize by means of cut flower-bearing twigs. Their wood is in demand for pulpwood, veneer for match and crate production, boxboards, and other uses. For these reasons there has been interest in many countries in selecting and breeding poplars. The tree...

Early root development of poplars ( Populus spp.) in relation to moist and saturated soil conditions

Treesearch

Rebecka Mc Carthy; Magnus Löf; Emile S. Gardiner

2017-01-01

Poplars (Populus spp.) are among the fastest growing trees raised in temperate regions of the world. Testing of newly developed cultivars informs assessment of potential planting stock for local environments. Initial rooting by nine poplar clones was tested in moist and saturated soil conditions during an 18-day greenhouse experiment. Clones responded differently to...

Clonal variation in survival and growth of hybrid poplar and willow in an in situ trial on soils heavily contaminated with petroleum hydrocarbons

Treesearch

Ronald S., Jr. Zalesny; Edmund O. Bauer; Richard B. Hall; Jill A. Zalesny; Joshua Kunzman; Chris J. Rog; Don E. Riemenschneider

2005-01-01

Species and hybrids between species belonging to the genera Populus (poplar) and Salix (willow) have been used successfully for phytoremediation of contaminated soils. Our objectives were to: 1) evaluate the potential for establishing genotypes of poplar and willow on soils heavily contaminated with petroleum hydrocarbons and 2)...

Bedding Improves Yellow-Poplar Growth on Fragipan Soils

Treesearch

John K. Francis

1979-01-01

Yellow-poplar can be grown on soils that have a shallow fragipan--but unless such sites are bedded, growth is likely to be extremely poor. In a Tennessee study, bedding increased height of planted yellow-poplar over 5 years, but fertilizer did not. Because of the cost of bedding and the availability of nonfragipan sites, it would ordinarily be better not to plant...