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Sample records for fungo sclerotinia sclerotiorum

  1. SOYBEAN STEM LIGNIN CONCENTRATION RELATES TO RESISTANCE TO SCLEROTINIA SCLEROTIORUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an economically important disease of soybean (Glycine max L. Merr.) in the north central United States and other temperate regions throughout the world. The occurrence and severity of SSR in the field is highly depend...

  2. Oxalate-minus mutants of Sclerotinia sclerotiorum via random mutagenesis retain pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is a ubiquitous necrotrophic plant pathogen capable of infecting over 400 plant species including many economically important crops. Oxalic acid production has been shown in numerous studies to be a pathogenicity factor for Sclerotinia sclerotiorum through several mechanisms...

  3. Environmental factors for germination of Sclerotinia sclerotiorum sclerotia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Basal stalk rot of sunflower is an economically important and rather unique disease among crops that are susceptible to Sclerotinia sclerotiorum. This disease is the result of myceliogenic germination of sclerotia whereby the vegetative hyphae infect the sunflower below the soil level. In contrast, ...

  4. Transfection of Sclerotinia sclerotiorum with in vitro transcripts of a naturally occurring interspecific recombinant of Sclerotinia sclerotiorum hypovirus 2 significantly reduces virulence of the fungus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recombinant strain of Sclerotinia sclerotiorum hypovirus 2 (SsHV2) was identified from a North American Sclerotinia sclerotiorum isolate (#328) from lettuce (Lactuca sativa L.) by high-throughput sequencing of total RNA. The 5’ and 3’ terminal regions of the genome were determined by rapid amplifi...

  5. Variation in Biochemical Composition among Indian Isolates of Sclerotinia sclerotiorum

    PubMed Central

    Basha, S. Ameer; Sarma, B. K.; Singh, K. P.

    2006-01-01

    Biochemical variability among 20 Indian isolates of Sclerotinia sclerotiorum collected from different hosts/soil samples from different localities in India is reported. High Performance Liquid Chromatographic (HPLC) analysis of ethyl acetate fraction of culture filtrate, mycelia, sclerotia and sclerotial exudate showed 15~23 peaks but only 11 could be identified. They were tannic, gallic, oxalic, caffeic, vanillic, ferulic, O-coumeric, chlorogenic, cinnamic, salicylic and gentisic acids. The amount of phenolic compounds varied among the culture filtrates, mycelia, sclerotia and sclerotial exudates of S. sclerotiorum. PMID:24039482

  6. Comparison of transcriptomes between Sclerotinia sclerotiorum and S. trifoliorum using 454 Titanium RNA sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum and S. trifoliorum cause Sclerotinia stem and crown rot of chickpea and white mold on many economically important crops. The host range of S. trifoliorum is mainly on cool season forage and grain legumes of about 40 plant species, whereas the host range of S. sclerotiorum ...

  7. Genetic diversity and population differentiation of natural populations of Sclerotinia sclerotiorum on lentils in eastern Washington.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic diversity and population differentiation of natural populations of Sclerotinia sclerotiorum on lentils in eastern Washington. X. Wang and W. Chen. Washington State University, Pullman, WA, and USDA-ARS, Pullman, WA 99163 Sclerotinia sclerotiorum is the causal agent of white mold on lentils....

  8. Effect of water potential on sclerotial production by Sclerotinia sclerotiorum in a culture medium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum causes Sclerotinia blight on peanut. Potato dextrose agar medium was prepared and adjusted to various water potentials (-0.4 to -3.4 MPa) using NaCl. Petri plates (9-cm dia) each containing 15 ml of medium were inoculated with a 4-mm agar plug of S. sclerotiorum. Plates w...

  9. Comparative transcriptome analysis in Sclerotinia sclerotiorum and S. trifoliorum by 454 Titanium RNA sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum and S. trifoliorum are two closely related devastating plant pathogens. Extensive research has been conducted on S. sclerotiorum and its genome sequences are available. To take advantages of the genomic information of S. sclerotiorum, we compared the transcriptome of S. tr...

  10. Activity of a novel strobilurin fungicide benzothiostrobin against Sclerotinia sclerotiorum.

    PubMed

    Xu, Congying; Hou, Yiping; Wang, Jianxin; Yang, Guangfu; Liang, Xiaoyu; Zhou, Mingguo

    2014-10-01

    Benzothiostrobin is a novel strobilurin fungicide. In this study, baseline sensitivity of Sclerotinia sclerotiorum (Lib.) de Bary to benzothiostrobin was determined using 100 strains collected during 2012 and 2013 from different geographical regions in Jiangsu Province of China, and the average EC50 value was 0.0218 (± 0.0111)μg/mL for mycelial growth. After benzothiostrobin treatment, hyphae were contorted with offshoot of top increasing and cell membrane permeability increased markedly, while sclerotial production and oxalic acid content significantly decreased. Benzothiostrobin strongly inhibited mycelial respiration within 12h and the oxygen consumption of the mycelia could not be inhibited after 24h. On detached rapeseed leaves, the protective and curative activity test of benzothiostrobin suggested that benzothiostrobin had good control efficiency against S. sclerotiorum, and protective activity was better than curative activity. These results will contribute to us evaluating the potential of the new strobilurin fungicide benzothiostrobin for management of diseases caused by S. sclerotiorum and understanding the mode of action of benzothiostrobin against S. sclerotiorum.

  11. Sensitivity and biochemical characteristics of Sclerotinia sclerotiorum to propamidine.

    PubMed

    Wang, Yong; Sun, Yang; Zhang, Ying; Zhang, Yinxing; Han, Lirong; Zhang, Xing; Feng, Juntao

    2017-01-01

    Propamidine is an aromatic diamidine compound. In the current study, baseline sensitivity of Sclerotinia sclerotiorum to propamidine was determined using 78 strains collected from the oilseed rape fields without a previous history of propamidine usage. The median effective concentration (EC50) values for propamidine inhibiting mycelial growth ranged from 0.406 to 3.647μg/mL, with a mean of 1.616±0.217μg/mL. There was no correlation between sensitivity to propamidine and sensitivity to dimethachlon or carbendazim. After treated with propamidine, mycelia were thinner with irregular distortion and more branches; cell wall became thicker with uneven distribution of cytoplasm than untreated control. In addition, sclerotia production, cell membrane permeability and oxalic acid content significantly decreased. On detached oilseed rape leaves, propamidine exhibited better control efficacy than carbendazim at the same concentration whether the leaves were inoculated with carbendazim-sensitive or resistant strains. All the results showed that propamidine exhibited strong antifungal activity and potential application in controlling S. sclerotiorum. Importantly, these data will provide more information on understanding the mode of action of propamidine against S. sclerotiorum and should be valuable for development of new antifungal drugs.

  12. Transfection of Sclerotinia sclerotiorum with In Vitro Transcripts of a Naturally Occurring Interspecific Recombinant of Sclerotinia sclerotiorum Hypovirus 2 Significantly Reduces Virulence of the Fungus

    PubMed Central

    Marzano, Shin-Yi Lee; Hobbs, Houston A.; Nelson, Berlin D.; Hartman, Glen L.; Eastburn, Darin M.; McCoppin, Nancy K.

    2015-01-01

    ABSTRACT A recombinant strain of Sclerotinia sclerotiorum hypovirus 2 (SsHV2) was identified from a North American Sclerotinia sclerotiorum isolate (328) from lettuce (Lactuca sativa L.) by high-throughput sequencing of total RNA. The 5′- and 3′-terminal regions of the genome were determined by rapid amplification of cDNA ends. The assembled nucleotide sequence was up to 92% identical to two recently reported SsHV2 strains but contained a deletion near its 5′ terminus of more than 1.2 kb relative to the other SsHV2 strains and an insertion of 524 nucleotides (nt) that was distantly related to Valsa ceratosperma hypovirus 1. This suggests that the new isolate is a heterologous recombinant of SsHV2 with a yet-uncharacterized hypovirus. We named the new strain Sclerotinia sclerotiorum hypovirus 2 Lactuca (SsHV2L) and deposited the sequence in GenBank with accession number KF898354. Sclerotinia sclerotiorum isolate 328 was coinfected with a strain of Sclerotinia sclerotiorum endornavirus 1 and was debilitated compared to cultures of the same isolate that had been cured of virus infection by cycloheximide treatment and hyphal tipping. To determine whether SsHV2L alone could induce hypovirulence in S. sclerotiorum, a full-length cDNA of the 14,538-nt viral genome was cloned. Transcripts corresponding to the viral RNA were synthesized in vitro and transfected into a virus-free isolate of S. sclerotiorum, DK3. Isolate DK3 transfected with SsHV2L was hypovirulent on soybean and lettuce and exhibited delayed maturation of sclerotia relative to virus-free DK3, completing Koch's postulates for the association of hypovirulence with SsHV2L. IMPORTANCE A cosmopolitan fungus, Sclerotinia sclerotiorum infects more than 400 plant species and causes a plant disease known as white mold that produces significant yield losses in major crops annually. Mycoviruses have been used successfully to reduce losses caused by fungal plant pathogens, but definitive relationships between

  13. Inferring outcrossing in the homothallic fungus Sclerotinia sclerotiorum using linkage disequilibrium decay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The occurrence and frequency of outcrossing in homothallic fungal species in nature is an unresolved question. Here we report detection of frequent outcrossing in the homothallic fungus Sclerotinia sclerotiorum. In using multilocus linkage disequilibrium (LD) to infer recombination among microsatell...

  14. Variation in fungicide sensitivity between two field populations of Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum (Lib.) de Bary is a ubiquitous, necrotrophic pathogen. It causes white mold on more than 400 plant species including economically important crops such as potato, canola, soybean, pea, chickpea and lentil. Extensive studies have been carried out on S. sclerotiorum. This study...

  15. Evaluation of Sclerotinia sclerotiorum as a potential mycotoxin producer on soybeans.

    PubMed Central

    Ciegler, A; Burbridge, K A; Ciegler, J; Hesseltine, C W

    1978-01-01

    Solvent extracts of Sclerotinia sclerotiorum sclerotia were nontoxic to mice and chicken embryos; psoralens were not detected. Solvent extracts of soybeans inoculated with 10 strains of S. sclerotiorum were toxic on injection but nontoxic on per os administration to mice. The presence of chlorinated hydrocarbons in the soybeans may partially help explain toxicity by intraperitineal injection. PMID:569464

  16. Lesion expansion of Sclerotinia minor and S. sclerotiorum on two peanut cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inoculation of peanut stems with Sclerotinia minor (SM) or S. sclerotiorum (SS) causes Sclerotinia blight, which is characterized by the formation of tan, water-soaked lesions on infected plant parts, leading to tissue collapse and necrosis of the affected tissue. Significant losses occur in Oklaho...

  17. Sclerotinia wilt of Hop (Humulus lupulus) caused by Sclerotinia sclerotiorum in the Pacific Northwest U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is a widespread, destructive pathogen with an exceptionally broad host range. During June 2011, wilted hop plants (Humulus lupulus cv. Nugget) were observed in a hop yard in Marion County, Oregon. Some affected plants had upward curled leaves with necrotic margins, whereas o...

  18. Degradation of oxalic acid by the mycoparasite Coniothyrium minitans plays an important role in interacting with Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coniothyrium minitans is a mycoparasite of the phytopathogenic fungus Sclerotinia sclerotiorum. Sclerotinia sclerotiorum produces a virulence factor oxalic acid (OA) which is toxic to plants and also to C. minitans, and C. minitans detoxifies OA by degradation. In this study, two oxalate decarboxyla...

  19. Biocontrol potential of Trichoderma harzianum isolate T-aloe against Sclerotinia sclerotiorum in soybean.

    PubMed

    Zhang, Fuli; Ge, Honglian; Zhang, Fan; Guo, Ning; Wang, Yucheng; Chen, Long; Ji, Xiue; Li, Chengwei

    2016-03-01

    Sclerotinia stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary is a major disease of soybean (Glycine max (L.) Merr.). At present, we revealed the three-way interaction between Trichoderma harzianum T-aloe, pathogen S. sclerotiorum and soybean plants in order to demonstrate biocontrol mechanism and evaluate biocontrol potential of T-aloe against S. sclerotiorum in soybean. In our experiments, T-aloe inhibited the growth of S. sclerotiorum with an efficiency of 56.3% in dual culture tests. T-aloe hyphae grew in parallel or intertwined with S. sclerotiorum hyphae and produced hooked contact branches, indicating mycoparasitism. Plate tests showed that T-aloe culture filtrate inhibited S. sclerotiorum growth with an inhibition efficiency of 51.2% and sclerotia production. T-aloe pretreatment showed growth-promoting effect on soybean plants. The activities of peroxidase, superoxide dismutase, and catalase increased, and the hydrogen peroxide (H2O2) as well as the superoxide radical (O2(-)) content in soybean leaves decreased after T-aloe pretreatment in response to S. sclerotiorum pathogen challenge. T-aloe treatment diminished damage caused by pathogen stress on soybean leaf cell membrane, and increased chlorophyll as well as total phenol contents. The defense-related genes PR1, PR2, and PR3 were expressed in the leaves of T-aloe-treated plants. In summary, T-aloe displayed biocontrol potential against S. sclerotiorum. This is the first report of unraveling biocontrol potential of Trichoderma Spp. to soybean sclerotinia stem rot from the three-way interaction between the biocontrol agent, pathogen S. sclerotiorum and soybean plants.

  20. Mycelial compatibility and aggressiveness comparison of Sclerotinia sclerotiorum isolates from Brazil and the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Variability of Sclerotinia sclerotiorum isolates collected in Brazil and the USA were determined by mycelial compatibility grouping (MCG) and inoculations of soybean cultivars. Two experiments for MCGs and two for aggressiveness were conducted with two sets of isolates. The first set included nine i...

  1. Resistance of soybean genotypes to Sclerotinia sclerotiorum isolates in different incubation environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is an important soybean pathogen. The objectives of this study were to evaluate levels of resistance of soybean genotypes to the fungus, and to determine the effects of different incubation environments on host resistance and pathogen aggression. Two experiments were conduct...

  2. Transcriptome analyses of Sclerotinia sclerotiorum infecting chickpea and lentil using RNA sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum causes white mold of many important crops. To elucidate its pathogenic mechanisms, transcriptome analyses were used to study its interactions with chickpea and lentil. Five mRNA libraries were constructed from S. sclertiorum (strain WM-A1), healthy chickpea (cv. Spansih Whit...

  3. Formulations of Bacillus subtilis BY-2 suppress Sclerotinia sclerotiorum on oilseed rape in the field

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are developing a collection of Bacillus strains, isolated from different environments, for use in controlling Sclerotinia sclerotiorum on oilseed rape in China and elsewhere. Strain BY-2, isolated from internal tissues of an oilseed rape root, was demonstrated to be Bacillus subtilis based on bi...

  4. Effect of post-inoculation relative humidity (RH) on peanut infection by Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stems of six-week-old plants of the cv Okrun (susceptible to Sclerotinia blight) were inoculated with S. sclerotiorum, isolated from pumpkin. Two post-inoculation humidity regimes of 100% RH were used. In the first RH regime, one inoculation chamber was kept open for the duration of experiment (DO...

  5. Screening common bean for resistance to four Sclerotinia sclerotiorum isolates collected in northern Spain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mold, caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary, is a serious disease in common bean (Phaseolus vulgaris L.) causing significant yield loss. Few cultivars with high levels of physiological resistance to white mold have been described in common bean. The objectives of this st...

  6. A reevaluation of myceliogenic germination of sclerotia for Sclerotinia sclerotiorum strain Sun-87

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Basal stalk rot of sunflower is an economically important, and rather unique disease, among crops that are susceptible to Sclerotinia sclerotiorum. This disease is the result of myceliogenic germination of sclerotia whereby the vegetative hyphae infect the sunflower below the soil level. In contrast...

  7. New Populations of Sclerotinia sclerotiorum from Lettuce in California and Peas and Lentils in Washington

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four populations of Sclerotinia sclerotiorum in North America were inferred previously, based on analyses of both rapidly evolving markers (DNA fingerprint and mycelial compatiblity), and multilocus DNA sequence spanning the range between fast and slow evolution. Each population was defined as an in...

  8. Defense against Sclerotinia sclerotiorum in Arabidopsis is dependent on jasmonic acid, salicylic acid, and ethylene signaling.

    PubMed

    Guo, Xiaomei; Stotz, Henrik U

    2007-11-01

    Genotypic differences in susceptibility of Arabidopsis thaliana to Sclerotinia sclerotiorum have not been reported due to the extreme susceptibility of this cruciferous plant. To overcome this limitation, we have established inoculation conditions that enable evaluation of differences in susceptibility to S. sclerotiorum among Arabidopsis mutants and ecotypes. Two coil mutant alleles conferred hypersusceptibility to S. sclerotiorum. The plant defensin gene PDF1.2 was no longer induced after challenging the coi1-2 mutant with S. sclerotiorum. Hypersusceptibility of the coi1-2 mutant to S. sclerotiorum was not correlated with oxalate sensitivity. The mutants npr1 and ein2 were also hypersusceptible to S. sclerotiorum. Induction of PDF1.2 and the pathogenesis-related gene PR1 was reduced in ein2 and npr1 mutants, respectively. Actigard, a commercial formulation of the systemic acquired resistance inducer benzothiadiazole, reduced susceptibility to S. sclerotiorum. Based on histochemical analysis of oxalate-deficient and wild-type strains of S. sclerotiorum, oxalate caused a decrease in hydrogen peroxide production but no detectable changes in plant superoxide production or gene expression.

  9. Random T-DNA mutagenesis identifies a Cu-Zn-superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agrobacterium-mediated transformation (AMT) was used to identify potential virulence factors in Sclerotinia sclerotiorum. Screening AMT transformants identified two mutants showing significantly reduced virulence. The mutants showed similar growth rate, colony morphology, and sclerotial and oxalate ...

  10. Pair-wise linkage disequilibrium decay among linked loci suggests meiotic recombination in natural populations of Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both clonal and recombining population structures have been reported in Sclerotinia sclerotiorum populations around the world. Association of independent and putatively unlinked markers indicates clonal population structure, whereas random association of the markers suggests recombination and outcro...

  11. Manipulation of the Xanthophyll Cycle Increases Plant Susceptibility to Sclerotinia sclerotiorum

    PubMed Central

    Zhou, Jun; Zeng, Lizhang; Liu, Jian; Xing, Da

    2015-01-01

    The xanthophyll cycle is involved in dissipating excess light energy to protect the photosynthetic apparatus in a process commonly assessed from non-photochemical quenching (NPQ) of chlorophyll fluorescence. Here, it is shown that the xanthophyll cycle is modulated by the necrotrophic pathogen Sclerotinia sclerotiorum at the early stage of infection. Incubation of Sclerotinia led to a localized increase in NPQ even at low light intensity. Further studies showed that this abnormal change in NPQ was closely correlated with a decreased pH caused by Sclerotinia-secreted oxalate, which might decrease the ATP synthase activity and lead to a deepening of thylakoid lumen acidification under continuous illumination. Furthermore, suppression (with dithiothreitol) or a defect (in the npq1-2 mutant) of violaxanthin de-epoxidase (VDE) abolished the Sclerotinia-induced NPQ increase. HPLC analysis showed that the Sclerotinia-inoculated tissue accumulated substantial quantities of zeaxanthin at the expense of violaxanthin, with a corresponding decrease in neoxanthin content. Immunoassays revealed that the decrease in these xanthophyll precursors reduced de novo abscisic acid (ABA) biosynthesis and apparently weakened tissue defense responses, including ROS induction and callose deposition, resulting in enhanced plant susceptibility to Sclerotinia. We thus propose that Sclerotinia antagonizes ABA biosynthesis to suppress host defense by manipulating the xanthophyll cycle in early pathogenesis. These findings provide a model of how photoprotective metabolites integrate into the defense responses, and expand the current knowledge of early plant-Sclerotinia interactions at infection sites. PMID:25993128

  12. The Microbial Opsin Homolog Sop1 is involved in Sclerotinia sclerotiorum Development and Environmental Stress Response

    PubMed Central

    Lyu, Xueliang; Shen, Cuicui; Fu, Yanping; Xie, Jiatao; Jiang, Daohong; Li, Guoqing; Cheng, Jiasen

    2016-01-01

    Microbial opsins play a crucial role in responses to various environmental signals. Here, we report that the microbial opsin homolog gene sop1 from the necrotrophic phytopathogenic fungus Sclerotinia sclerotiorum was dramatically up-regulated during infection and sclerotial development compared with the vegetative growth stage. Further, study showed that sop1 was essential for growth, sclerotial development and full virulence of S. sclerotiorum. Sop1-silenced transformants were more sensitive to high salt stress, fungicides and high osmotic stress. However, they were more tolerant to oxidative stress compared with the wild-type strain, suggesting that sop1 is involved in different stress responses and fungicide resistance, which plays a role in the environmental adaptability of S. sclerotiorum. Furthermore, a Delta blast search showed that microbial opsins are absent from the genomes of animals and most higher plants, indicating that sop1 is a potential drug target for disease control of S. sclerotiorum. PMID:26779159

  13. Comparative transcriptomic analysis uncovers the complex genetic network for resistance to Sclerotinia sclerotiorum in Brassica napus.

    PubMed

    Wu, Jian; Zhao, Qing; Yang, Qingyong; Liu, Han; Li, Qingyuan; Yi, Xinqi; Cheng, Yan; Guo, Liang; Fan, Chuchuan; Zhou, Yongming

    2016-01-08

    Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most devastating diseases in many important crops including Brassica napus worldwide. Quantitative resistance is the only source for genetic improvement of Sclerotinia-resistance in B. napus, but the molecular basis for such a resistance is largely unknown. Here, we performed dynamic transcriptomic analyses to understand the differential defense response to S. sclerotiorum in a resistant line (R-line) and a susceptible line (S-line) of B. napus at 24, 48 and 96 h post-inoculation. Both the numbers of and fold changes in differentially expressed genes in the R-line were larger than those in the S-line. We identified 9001 relative differentially expressed genes in the R-line compared with the S-line. The differences between susceptibility and resistance were associated with the magnitude of expression changes in a set of genes involved in pathogen recognition, MAPK signaling cascade, WRKY transcription regulation, jasmonic acid/ethylene signaling pathways, and biosynthesis of defense-related protein and indolic glucosinolate. The results were supported by quantitation of defense-related enzyme activity and glucosinolate contents. Our results provide insights into the complex molecular mechanism of the defense response to S. sclerotiorum in B. napus and for development of effective strategies in Sclerotinia-resistance breeding.

  14. Comparative Transcriptome Analysis between the Fungal Plant Pathogens Sclerotinia sclerotiorum and S. trifoliorum Using RNA Sequencing.

    PubMed

    Qiu, Dan; Xu, Liangsheng; Vandemark, George; Chen, Weidong

    2016-03-01

    The fungal plant pathogens Sclerotinia sclerotiorum and S. trifoliorum are morphologically similar, but differ considerably in host range. In an effort to elucidate mechanisms of the host range difference, transcriptomes of the 2 species at vegetative growth stage were compared to gain further insight into commonality and uniqueness in gene expression and pathogenic mechanisms of the 2 closely related pathogens. A total of 23133 and 21043 unique transcripts were obtained from S. sclerotiorum and S. trifoliorum, respectively. Approximately 43% of the transcripts were genes with known functions for both species. Among 1411 orthologous contigs, about 10% (147) were more highly (>3-fold) expressed in S. trifoliorum than in S. sclerotiorum, and about 12% (173) of the orthologs were more highly (>3-fold) expressed in S. sclerotiorum than in S. trifoliorum. The expression levels of genes on the supercontig 30 have the highest correlation coefficient value between the 2 species. Twenty-seven contigs were found to be new and unique for S. trifoliorum. Additionally, differences in expressed genes involved in pathogenesis like oxalate biosynthesis and endopolygalacturonases were detected between the 2 species. The analyses of the transcriptomes not only discovered similarities and uniqueness in gene expression between the 2 closely related species, providing additional information for annotation the S. sclerotiorum genome, but also provided foundation for comparing the transcriptomes with host-infecting transcriptomes.

  15. Calcium oxalate crystals: an integral component of the Sclerotinia sclerotiorum/Brassica carinata pathosystem.

    PubMed

    Uloth, Margaret B; Clode, Peta L; You, Ming Pei; Barbetti, Martin J

    2015-01-01

    Oxalic acid is an important virulence factor for disease caused by the fungal necrotrophic pathogen Sclerotinia sclerotiorum, yet calcium oxalate (CaOx) crystals have not been widely reported. B. carinata stems were infected with S. sclerotiorum and observed using light microscopy. Six hours post inoculation (hpi), CaOx crystals were evident on 46% of stem sections and by 72 hpi on 100%, demonstrating that the secretion of oxalic acid by S. sclerotiorum commences before hyphal penetration. This is the first time CaOx crystals have been reported on B. carinata infected with S. sclerotiorum. The shape of crystals varied as infection progressed. Long tetragonal rods were dominant 12 hpi (68% of crystal-containing samples), but by 72 hpi, 50% of stems displayed bipyramidal crystals, and only 23% had long rods. Scanning electron microscopy from 24 hpi revealed CaOx crystals in all samples, ranging from tiny irregular crystals (< 0.5 μm) to large (up to 40 μm) highly organized arrangements. Crystal morphology encompassed various forms, including tetragonal prisms, oval plates, crystal sand, and druses. Large conglomerates of CaOx crystals were observed in the hyphal mass 72 hpi and these are proposed as a strategy of the fungus to hold and detoxify Ca2+ions. The range of crystal morphologies suggests that S. sclerotiorum growth and infection controls the form taken by CaOx crystals.

  16. Genomic Analysis of the Necrotrophic Fungal Pathogens Sclerotinia sclerotiorum and Botrytis cinerea

    PubMed Central

    Benito, Ernesto P.; Couloux, Arnaud; Coutinho, Pedro M.; de Vries, Ronald P.; Dyer, Paul S.; Fillinger, Sabine; Fournier, Elisabeth; Gout, Lilian; Hahn, Matthias; Kohn, Linda; Lapalu, Nicolas; Plummer, Kim M.; Pradier, Jean-Marc; Quévillon, Emmanuel; Sharon, Amir; Simon, Adeline; ten Have, Arjen; Tudzynski, Bettina; Tudzynski, Paul; Wincker, Patrick; Andrew, Marion; Anthouard, Véronique; Beffa, Rolland; Benoit, Isabelle; Bouzid, Ourdia; Brault, Baptiste; Chen, Zehua; Choquer, Mathias; Collémare, Jérome; Cotton, Pascale; Danchin, Etienne G.; Da Silva, Corinne; Gautier, Angélique; Giraud, Corinne; Giraud, Tatiana; Gonzalez, Celedonio; Grossetete, Sandrine; Güldener, Ulrich; Henrissat, Bernard; Howlett, Barbara J.; Kodira, Chinnappa; Kretschmer, Matthias; Lappartient, Anne; Leroch, Michaela; Levis, Caroline; Mauceli, Evan; Neuvéglise, Cécile; Oeser, Birgitt; Pearson, Matthew; Poulain, Julie; Poussereau, Nathalie; Quesneville, Hadi; Rascle, Christine; Schumacher, Julia; Ségurens, Béatrice; Sexton, Adrienne; Silva, Evelyn; Sirven, Catherine; Soanes, Darren M.; Talbot, Nicholas J.; Templeton, Matt; Yandava, Chandri; Yarden, Oded; Zeng, Qiandong; Rollins, Jeffrey A.; Lebrun, Marc-Henri; Dickman, Marty

    2011-01-01

    Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38–39 Mb genomes include 11,860–14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared to <1% of B. cinerea. The arsenal of genes associated with necrotrophic processes is similar between the species, including genes involved in plant cell wall degradation and oxalic acid production. Analysis of secondary metabolism gene clusters revealed an expansion in number and diversity of B. cinerea–specific secondary metabolites relative to S. sclerotiorum. The potential diversity in secondary metabolism might be involved in adaptation to specific ecological niches. Comparative genome analysis revealed the basis of differing sexual mating compatibility systems between S. sclerotiorum and B. cinerea. The organization of the mating-type loci differs, and their structures provide evidence for the evolution of heterothallism from homothallism. These data shed light on the evolutionary and mechanistic bases of the genetically complex traits of necrotrophic pathogenicity and sexual mating. This resource should facilitate the functional studies designed to better understand what makes these fungi such

  17. Biological management of Sclerotinia sclerotiorum in pea using plant growth promoting microbial consortium.

    PubMed

    Jain, Akansha; Singh, Akanksha; Singh, Surendra; Singh, Harikesh Bahadur

    2015-08-01

    The beneficial plant-microbe interactions play crucial roles in protection against large number of plant pathogens causing disease. The present study aims to investigate the growth promoting traits induced by beneficial microbes namely Pseudomonas aeruginosa PJHU15, Trichoderma harzianum TNHU27, and Bacillus subtilis BHHU100 treated singly and in combinations under greenhouse and field conditions to control Sclerotinia sclerotiorum. Plants treated with three microbe consortium enhanced plant growth maximally both in the presence and absence of the pathogen. Increase in plant length, total biomass, number of leaves, nodules and secondary roots, total chlorophyll and carotenoid content, and yield were recorded in plants treated with microbial consortia. Also, a decrease in plant mortality was observed in plants treated with microbial consortia in comparison to untreated control plants challenged with S. sclerotiorum. Furthermore, the decrease in disease of all the treatments can be associated with differential improvement of growth induced in pea.

  18. Changes in Cell Membrane Permeability in Sunflower Hypocotyls Infected with Sclerotinia sclerotiorum1

    PubMed Central

    Hancock, Joseph G.

    1972-01-01

    Influx and efflux of water and urea and electrolyte leakage are less for sunflower (Helianthus annuus) hypocotyl sections above lesions caused by Sclerotinia sclerotiorum than for those from healthy plants. Urea uptake by sections above lesions is reduced (celery, squash, and tomato) or unchanged (bean) in other hosts after Sclerotinia infection. Efflux of urea from sunflower hypocotyls is biphasic, suggesting diffusion in series from two cellular compartments (cytoplasm and vacuole). Efflux during the fast phase was 7 to 20 times greater than that during the slow phase. No difference was noted in urea efflux from healthy and diseased tissues during the slow phase. However, efflux during the fast phase from diseased tissues was slower than from healthy tissues, suggesting that the increased resistance to diffusion of urea in host cells above lesions resides in the plasmalemma. Water movement across cell membranes of healthy and diseased sunflower hypocotyls was reduced when tissues were treated with p-hydroxymercuribenzoate. PMID:16657961

  19. Changes in Cell Membrane Permeability in Sunflower Hypocotyls Infected with Sclerotinia sclerotiorum.

    PubMed

    Hancock, J G

    1972-03-01

    Influx and efflux of water and urea and electrolyte leakage are less for sunflower (Helianthus annuus) hypocotyl sections above lesions caused by Sclerotinia sclerotiorum than for those from healthy plants. Urea uptake by sections above lesions is reduced (celery, squash, and tomato) or unchanged (bean) in other hosts after Sclerotinia infection. Efflux of urea from sunflower hypocotyls is biphasic, suggesting diffusion in series from two cellular compartments (cytoplasm and vacuole). Efflux during the fast phase was 7 to 20 times greater than that during the slow phase. No difference was noted in urea efflux from healthy and diseased tissues during the slow phase. However, efflux during the fast phase from diseased tissues was slower than from healthy tissues, suggesting that the increased resistance to diffusion of urea in host cells above lesions resides in the plasmalemma. Water movement across cell membranes of healthy and diseased sunflower hypocotyls was reduced when tissues were treated with p-hydroxymercuribenzoate.

  20. The First Report of Postharvest Stem Rot of Kohlrabi Caused by Sclerotinia sclerotiorum in Korea.

    PubMed

    Kim, Joon-Young; Aktaruzzaman, Md; Afroz, Tania; Hahm, Young-Il; Kim, Byung-Sup

    2014-12-01

    In March 2014, a kohlrabi stem rot sample was collected from the cold storage room of Daegwallyong Horticultural Cooperative, Korea. White and fuzzy mycelial growth was observed on the stem, symptomatic of stem rot disease. The pathogen was isolated from the infected stem and cultured on potato dextrose agar for further fungal morphological observation and to confirm its pathogenicity, according to Koch's postulates. Morphological data, pathogenicity test results, and rDNA sequences of internal transcribed spacer regions (ITS 1 and 4) showed that the postharvest stem rot of kohlrabi was caused by Sclerotinia sclerotiorum. This is the first report of postharvest stem rot of kohlrabi in Korea.

  1. Identification of genomic regions involved in resistance against Sclerotinia sclerotiorum from wild Brassica oleracea.

    PubMed

    Mei, Jiaqin; Ding, Yijuan; Lu, Kun; Wei, Dayong; Liu, Yao; Disi, Joseph Onwusemu; Li, Jiana; Liu, Liezhao; Liu, Shengyi; McKay, John; Qian, Wei

    2013-02-01

    The lack of resistant source has greatly restrained resistance breeding of rapeseed (Brassica napus, AACC) against Sclerotinia sclerotiorum which causes severe yield losses in rapeseed production all over the world. Recently, several wild Brassica oleracea accessions (CC) with high level of resistance have been identified (Mei et al. in Euphytica 177:393-400, 2011), bringing a new hope to improve Sclerotinia resistance of rapeseed. To map quantitative trait loci (QTL) for Sclerotinia resistance from wild B. oleracea, an F2 population consisting of 149 genotypes, with several clones of each genotypes, was developed from one F1 individual derived from the cross between a resistant accession of wild B. oleracea (B. incana) and a susceptible accession of cultivated B. oleracea var. alboglabra. The F2 population was evaluated for Sclerotinia reaction in 2009 and 2010 under controlled condition. Significant differences among genotypes and high heritability for leaf and stem reaction indicated that genetic components accounted for a large portion of the phenotypic variance. A total of 12 QTL for leaf resistance and six QTL for stem resistance were identified in 2 years, each explaining 2.2-28.4 % of the phenotypic variation. The combined effect of alleles from wild B. oleracea reduced the relative susceptibility by 22.5 % in leaves and 15 % in stems on average over 2 years. A 12.8-cM genetic region on chromosome C09 of B. oleracea consisting of two major QTL intervals for both leaf and stem resistance was assigned into a 2.7-Mb genomic region on chromosome A09 of B. rapa, harboring about 30 putative resistance-related genes. Significant negative corrections were found between flowering time and relative susceptibility of leaf and stem. The association of flowering time with Sclerotinia resistance is discussed.

  2. Bacillus megaterium A6 suppresses Sclerotinia sclerotiorum on oilseed rape in the field and promotes oilseed rape growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum causes serious yield losses in crops in The People’s Republic of China and other regions of the world. Two formulations of oilseed rape seed containing the plant-growth promoting bacterium Bacillus megaterium A6 were evaluated for suppression of this pathogen on oilseed rap...

  3. Preliminary Analysis of High-Throughput Expression Data and Small RNA in Soybean Stem Tissue Infected with Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We recently published a report on transcriptome changes in soybean stem tissue challenged with Sclerotinia sclerotiorum based on cDNA microarray analysis. We are now advancing this study by examining the differential expression of small RNA (miRNAs and siRNAs) and gene transcripts using the Illumin...

  4. Insertional mutation at the Cu-Zn-superoxide dismutase gene reduces virulence of Sclerotinia sclerotiorum on pea (Pisum sativum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum causes white mold disease on pea and on many other economically important pulse, vegetable and field crops, demonstrating a non-host-specific pathogenic mechanism. Despite extensive studies on this pathogen, its pathogenic mechanisms are still incompletely understood. In ord...

  5. Random T-DNA mutagenesis identifies a Cu-Zn-superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Ascomycetous fungus Sclerotinia sclerotiorum is a devastating pathogen capable of infecting more than 400 plant species including many economically important crops. In order to gain a better mechanistic understanding of its non-specific host-pathogen interactions, random mutagenesis through Agro...

  6. White mould of common bean incited by Sclerotinia sclerotiorum Lib. de Bary in Egypt.

    PubMed

    Amer, M A; Abou-el-Seoud, I; Rasmy, M R; Khater, Manar M

    2009-01-01

    White mould, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is a destructive yield-limiting disease of common bean (Phaseolus vulgaris L.) in Egypt. Forty eight isolate of S. sclerotiorum were isolated from diseased bean tissues taken from 9 geographical regions (Al-Behaira, Alexandria and Assiut governorates) during winter season in 2008. The pathogenicity studies showed that the tested bean cultivars (Bronco, Contender, Giza 6 and Nebraska) varied in disease incidence. Contender bean cultivar was more resistant than other cultivars. Whereas, the more virulent isolates were S5 and S6. Histology investigation of seedlings bean hypocotyls inoculated with S. sclerotiorum after 24, 48, 72 and 96 hours after inoculation indicated that penetration of bean seedlings occurred, during the first 48 hours after inoculation, through the epidermis and the outer layer of the cortex. 72 hours after inoculation, damage extended deeper into the cortical cells. Infection took place inter-and interacellularly after 96 hours more damage occurred. In addition, the invasion of the fungal hyphae through the cortical cells occurred both inter-, and intracellularly. Moreover, the observed of electron microscope both transmission and scanning investigations concluded that penetrating hyphae progressed through bean seedlings tissues leading to complete destruction of epidermis, fully colonization and death of cortical cells, partial invasion of vascular tissues. However, presence of the fungal structures in pith cells was observed.

  7. Effects of ozone treatment on Botrytis cinerea and Sclerotinia sclerotiorum in relation to horticultural product quality.

    PubMed

    Sharpe, Deana; Fan, Lihua; McRae, Ken; Walker, Brad; MacKay, Ron; Doucette, Craig

    2009-08-01

    Botrytis cinerea and Sclerotinia sclerotiorum are fungal pathogens that cause the decay of many fruits and vegetables. Ozone may be used as an antimicrobial agent to control the decay. The effect of gaseous ozone on spore viability of B. cinerea and mycelial growth of B. cinerea and S. sclerotiorum were investigated. Spore viability of B. cinerea was reduced by over 99.5% (P < 0.01) and height of the aerial mycelium was reduced from 4.7 mm in the control to less than 1 mm after exposure to 450 or 600 ppb ozone for 48 h at 20 degrees C. Sporulation of B. cinerea was also substantially inhibited by ozone treatments. However, ozone had no significant effect on mycelial growth of S. sclerotiorum in vitro. Decay and quality parameters including color, chlorophyll fluorescence (CF), and ozone injury were further assessed for various horticultural commodities (apple, grape, highbush blueberry, and carrot) treated with 450 ppb of ozone for 48 h at 20 degrees C over a period of 12 d. Lesion size and height of the aerial mycelium were significantly reduced by the ozone treatment on carrots inoculated with mycelial agar plugs of B. cinerea or S. sclerotiorum. Lesion size was also reduced on treated apples inoculated with 5 x 10(6) spores/mL of B. cinerea, and decay incidence of treated grapes was reduced. The 450 ppb ozone for 48 h treatment had no significant effect on color of carrots and apples or on CF of apples and grapes. Ozone, an environmentally sound antimicrobial agent, inactivates microorganisms through oxidization and residual ozone spontaneously decomposes to nontoxic products. It may be applied to fruits and vegetables to reduce decay and extend shelf life.

  8. Genetic Variation of Sclerotinia sclerotiorum from Multiple Crops in the North Central United States.

    PubMed

    Aldrich-Wolfe, Laura; Travers, Steven; Nelson, Berlin D

    2015-01-01

    Sclerotinia sclerotiorum is an important pathogen of numerous crops in the North Central region of the United States. The objective of this study was to examine the genetic diversity of 145 isolates of the pathogen from multiple hosts in the region. Mycelial compatibility groups (MCG) and microsatellite haplotypes were determined and analyzed for standard estimates of population genetic diversity and the importance of host and distance for genetic variation was examined. MCG tests indicated there were 49 different MCGs in the population and 52 unique microsatellite haplotypes were identified. There was an association between MCG and haplotype such that isolates belonging to the same MCG either shared identical haplotypes or differed at no more than 2 of the 12 polymorphic loci. For the majority of isolates, there was a one-to-one correspondence between MCG and haplotype. Eleven MCGs shared haplotypes. A single haplotype was found to be prevalent throughout the region. The majority of genetic variation in the isolate collection was found within rather than among host crops, suggesting little genetic divergence of S. sclerotiorum among hosts. There was only weak evidence of isolation by distance. Pairwise population comparisons among isolates from canola, dry bean, soybean and sunflower suggested that gene flow between host-populations is more common for some crops than others. Analysis of linkage disequilibrium in the isolates from the four major crops indicated primarily clonal reproduction, but also evidence of genetic recombination for isolates from canola and sunflower. Accordingly, genetic diversity was highest for populations from canola and sunflower. Distribution of microsatellite haplotypes across the study region strongly suggest that specific haplotypes of S. sclerotiorum are often found on multiple crops, movement of individual haplotypes among crops is common and host identity is not a barrier to gene flow for S. sclerotiorum in the north central United

  9. Transcriptomic comparison between Brassica oleracea and rice (Oryza sativa) reveals diverse modulations on cell death in response to Sclerotinia sclerotiorum

    PubMed Central

    Mei, Jiaqin; Ding, Yijuan; Li, Yuehua; Tong, Chaobo; Du, Hai; Yu, Yang; Wan, Huafan; Xiong, Qing; Yu, Jingyin; Liu, Shengyi; Li, Jiana; Qian, Wei

    2016-01-01

    Sclerotinia stem rot caused by Sclerotinia sclerotiorum is a devastating disease of Brassica crops, but not in rice. The leaves of a rice line, a partial resistant (R) and a susceptible (S) Brassica oleracea pool that bulked from a resistance-segregating F2 population were employed for transcriptome sequencing before and after inoculation by S. sclerotiorum for 6 and 12 h. Distinct transcriptome profiles were revealed between B. oleracea and rice in response to S. sclerotiorum. Enrichment analyses of GO and KEGG indicated an enhancement of antioxidant activity in the R B. oleracea and rice, and histochemical staining exhibited obvious lighter reactive oxygen species (ROS) accumulation and cell death in rice and the R B. oleracea as compared to that in the S B. oleracea. Significant enhancement of Ca2+ signalling, a positive regulator of ROS and cell death, were detected in S B. oleracea after inoculation, while it was significantly repressed in the R B. oleracea group. Obvious difference was detected between two B. oleracea groups for WRKY transcription factors, particularly for those regulating cell death. These findings suggest diverse modulations on cell death in host in response to S. sclerotiorum. Our study provides useful insight into the resistant mechanism to S. sclerotiorum. PMID:27647523

  10. Transcriptomic comparison between Brassica oleracea and rice (Oryza sativa) reveals diverse modulations on cell death in response to Sclerotinia sclerotiorum.

    PubMed

    Mei, Jiaqin; Ding, Yijuan; Li, Yuehua; Tong, Chaobo; Du, Hai; Yu, Yang; Wan, Huafan; Xiong, Qing; Yu, Jingyin; Liu, Shengyi; Li, Jiana; Qian, Wei

    2016-09-20

    Sclerotinia stem rot caused by Sclerotinia sclerotiorum is a devastating disease of Brassica crops, but not in rice. The leaves of a rice line, a partial resistant (R) and a susceptible (S) Brassica oleracea pool that bulked from a resistance-segregating F2 population were employed for transcriptome sequencing before and after inoculation by S. sclerotiorum for 6 and 12 h. Distinct transcriptome profiles were revealed between B. oleracea and rice in response to S. sclerotiorum. Enrichment analyses of GO and KEGG indicated an enhancement of antioxidant activity in the R B. oleracea and rice, and histochemical staining exhibited obvious lighter reactive oxygen species (ROS) accumulation and cell death in rice and the R B. oleracea as compared to that in the S B. oleracea. Significant enhancement of Ca(2+) signalling, a positive regulator of ROS and cell death, were detected in S B. oleracea after inoculation, while it was significantly repressed in the R B. oleracea group. Obvious difference was detected between two B. oleracea groups for WRKY transcription factors, particularly for those regulating cell death. These findings suggest diverse modulations on cell death in host in response to S. sclerotiorum. Our study provides useful insight into the resistant mechanism to S. sclerotiorum.

  11. Oxalate-minus mutants of Sclerotinia sclerotiorum via T-DNA insertion accumulate fumarate in culture and retain pathogenicity on plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is a ubiquitous necrotrophic pathogen capable of infecting over 400 plant species including many economically important crops. Oxalic acid production has been shown in numerous studies to be a pathogenicity factor for S. sclerotiorum through several mechanisms. During our ra...

  12. Analyses of Lettuce Drop Incidence and Population Structure of Sclerotinia sclerotiorum and S. minor.

    PubMed

    Wu, B M; Subbarao, K V

    2006-12-01

    ABSTRACT To understand the geographical distribution of lettuce drop incidence and the structure of Sclerotinia minor and S. sclerotiorum populations, commercial lettuce fields were surveyed in the Salinas, San Joaquin, and Santa Maria Valleys in California. Lettuce drop incidence, pathogen species, and mycelial compatibility groups (MCGs) were determined and analyzed using geostatistic and geographical information system tools. Lettuce drop incidence was lowest in the San Joaquin Valley, and not significantly different between the other two valleys. Semivariogram analysis revealed that lettuce drop incidence was not spatially correlated between different fields in the Salinas Valley, suggesting negligible field-to-field spread or influence of inoculum in one field on other fields. Lettuce drop incidence was significantly lower in fields with a surface drip system than in fields with furrow or sprinkler irrigation systems, suggesting that the surface drip system can be a potential management measure for reducing lettuce drop. In the San Joaquin Valley, S. sclerotiorum was the prevalent species, causing drop in 63.5% of the fields, whereas S. minor also was identified in 25.4% of the fields. In contrast, in the Salinas Valley, S. minor was the dominant species (76.1%) whereas S sclerotiorum only observed in only 13.6% fields, in which only a few plants were infected by S. sclerotiorum. In the Santa Maria Valley, both species frequently were identified, with S. minor being slightly more common. Although many MCGs were identified in S. minor, most of them consisted of only one or two isolates. In all, approximately 91.4% of the isolates belonged to four MCGs. Among them, MCG-1 was the most prevalent group in all three valleys, accounting for 49.8% of total isolates. It was distributed all over the surveyed areas, whereas other MCGs were distributed more or less locally. Populations of S. sclerotiorum exhibited greater diversity, with 89 isolates collected from the

  13. Integrated control of white rot disease on beans caused by Sclerotinia sclerotiorum using Contans® and reduced fungicides application.

    PubMed

    Elsheshtawi, Mohamed; Elkhaky, Maged T; Sayed, Shaban R; Bahkali, Ali H; Mohammed, Arif A; Gambhir, Dikshit; Mansour, Aref S; Elgorban, Abdallah M

    2017-02-01

    This study was conducted to determine the compatibility of Contans® (Coniothyrium minitans) with fungicides against Sclerotinia sclerotiorum. Results showed that both Contans® and Topsin® significantly reduced the disease incidence caused by S. sclerotiorum by 90% and 95% survival plants, respectively when they were individually applied and compared to control. While, soil application of Contans® and Sumisclex mixture was the most effective in suppressing the white rot disease incidence that produced 100% survival plants, application of C. minitans combined with the reduced doses of fungicides would be advantageous in saving labor cost, thus increasing production efficiency of bean.

  14. Biocide effects of volatile organic compounds produced by potential biocontrol rhizobacteria on Sclerotinia sclerotiorum

    PubMed Central

    Giorgio, Annalisa; De Stradis, Angelo; Lo Cantore, Pietro; Iacobellis, Nicola S.

    2015-01-01

    Six rhizobacteria isolated from common bean and able to protect bean plants from the common bacterial blight (CBB) causal agent, were in vitro evaluated for their potential antifungal effects toward different plant pathogenic fungi, mostly soil-borne. By dual culture assays, the above bacteria resulted producing diffusible and volatile metabolites which inhibited the growth of the majority of the pathogens under study. In particular, the latter substances highly affected the mycelium growth of Sclerotinia sclerotiorum strains, one of which was selected for further studies either on mycelium or sclerotia. Gas chromatographic analysis of the bacterial volatiles led to the identification of an array of volatile organic compounds (VOCs). Time course studies showed the modification of the VOCs profile along a period of 5 days. In order to evaluate the single detected VOC effects on fungal growth, some of the pure compounds were tested on S. sclerotiorum mycelium and their minimal inhibitory quantities were determined. Similarly, the minimal inhibitory quantities on sclerotia germination were also defined. Moreover, observations by light and transmission electron microscopes highlighted hyphae cytoplasm granulation and ultrastructural alterations at cell organelles, mostly membranes, mitochondria, and endoplasmic reticulum. The membranes appeared one of the primary targets of bacterial volatiles, as confirmed by hemolytic activity observed for the majority of pure VOCs. However, of interest is the alteration observed on mitochondria as well. PMID:26500617

  15. Changes in antioxidant systems in soybean as affected by Sclerotinia sclerotiorum (Lib.) de Bary.

    PubMed

    Malenčić, Djordje; Kiprovski, Biljana; Popović, Milan; Prvulović, Dejan; Miladinović, Jegor; Djordjević, Vuk

    2010-01-01

    Changes in antioxidant systems in soybean [Glycine max (L.) Merr., Fabaceae] genotypes infected with Sclerotinia sclerotiorum were studied 12, 24, 48 and 72h after inoculation. Generation of superoxide and hydroxyl radicals was evaluated together with the production of malonyldialdehyde, main end product of lipid peroxidation. Several enzymatic and non-enzymatic parameters were monitored as well, such as the activity of antioxidant enzymes superoxide dismutase and pyrogallol and guaiacol peroxidases, reduced glutathione, soluble proteins and total carotenoids content. Results showed that genotypes expressed oxidative burst as well as different antioxidant systems in response to biotic stress caused by pathogen invasion. It has been confirmed that, although hypersensitive cell death is efficient against biotrophic pathogens, it does not protect soybean plants against infection by the necrotrophic pathogen such as S. sclerotiorum. Still, some genotypes showed distinctive and combined activity of several biochemical parameters which may point to further directions in exploring host-pathogen relations and lead to selection and production of new genotypes with higher levels of tolerance.

  16. A novel protein elicitor (SsCut) from Sclerotinia sclerotiorum induces multiple defense responses in plants.

    PubMed

    Zhang, Huajian; Wu, Qun; Cao, Shun; Zhao, Tongyao; Chen, Ling; Zhuang, Peitong; Zhou, Xiuhong; Gao, Zhimou

    2014-11-01

    In this study, we report the cloning of the SsCut gene encoding cutinase from Sclerotinia sclerotiorum. We isolated a 609-bp cDNA encoding a polypeptide of 202 amino acids with a molecular weight of 20.4 kDa. Heterologous expression of SsCut in Escherichia coli (His-SsCut) caused the formation of lesions in tobacco that closely resembled hypersensitive response lesions. Mutational analysis identified the C-terminal-half peptide and the same amino acids indispensable for both enzyme and elicitor activity. His-SsCut was caused cell death in Arabidopsis, soybean (Glycine max), oilseed rape (Brassica napus), rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum), indicating that both dicot and monocot species are responsive to the elicitor. Furthermore, the elicitation of tobacco was effective in the induction of the activities of hydrogen peroxide, phenylalanine ammonia-lyase, peroxides, and polyphenol oxidase. His-SsCut-treated plants exhibited enhanced resistance as indicated by a significant reduction in the number and size of S. sclerotiorum, Phytophthora sojae, and P. nicotianae lesions on leaves relative to controls. Real-time PCR results indicated that the expression of defense-related genes and genes involved in signal transduction were induced by His-SsCut. Our results demonstrate that SsCut is an elicitor that triggers defense responses in plants and will help to clarify its relationship to downstream signaling pathways that induce defense responses.

  17. A mutant of the nematophagous fungus Paecilomyces lilacinus (Thom) is a novel biocontrol agent for Sclerotinia sclerotiorum.

    PubMed

    Yang, Fan; Abdelnabby, Hazem; Xiao, Yannong

    2015-12-01

    Sclerotinia sclerotiorum causes severe stem rot and yield loss in oilseed rape (Brassica napus L.) and other crops worldwide. Extensive studies have been conducted on Paecilomyces lilacinus as a nematophagous bioagent. However, no reports stated the effect of P. lilacinus as a biocontrol agent against oilseed rape rot S. sclerotiorum. This study describes such effect in lab and field trials using the new transformant pt361 derived from the wild strain P. lilacinus 36-1. Unlike the wild-type strain, the mutant pt361 showed high antagonistic effect against S. Sclerotiorum A. Under lab conditions, the pt361 inhibited (65%) radial mycelial growth of S. sclerotiorum in dual culture test producing 5.9 mm inhibition zone IZ in front of the S. sclerotiorum colony. Moreover, the cell-free filtrate of pt361 culture showed strong inhibitory effects (60.3-100%) on mycelial growth of S. sclerotiorum. In leaf detached assay, pt361 significantly (p < 0.05) inhibited (40.4-97.9%) the extension of the leaf spots caused by S. sclerotiorum A at all tested concentrations. The genomic DNA sequences of the inserted T-DNA flanking obtained from pt361 strain was cloned, verified as a glycoside hydrolase 31 family by homologous analysis with other fungal strains, and named PGH31 (2556bp). Secondary structure prediction showed a domain (Glycoside hydrolase31). Three years field trial confirmed that the cell-free filtrates or spores suspension of pt361 achieved significant (p < 0.05) suppression of oilseed rape stem rot, promoted growth and increased yield compared to the control and exceeded, at dose 100%, the action of the fungicide procymidone(®). In conclusion, the mutant pt361 of P. lilacinus is a novel and promising biocontrol agent against oilseed rape Sclerotinia stem rot.

  18. The Arabidopsis Mediator Complex Subunit16 Is a Key Component of Basal Resistance against the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum.

    PubMed

    Wang, Chenggang; Yao, Jin; Du, Xuezhu; Zhang, Yanping; Sun, Yijun; Rollins, Jeffrey A; Mou, Zhonglin

    2015-09-01

    Although Sclerotinia sclerotiorum is a devastating necrotrophic fungal plant pathogen in agriculture, the virulence mechanisms utilized by S. sclerotiorum and the host defense mechanisms against this pathogen have not been fully understood. Here, we report that the Arabidopsis (Arabidopsis thaliana) Mediator complex subunit MED16 is a key component of basal resistance against S. sclerotiorum. Mutants of MED16 are markedly more susceptible to S. sclerotiorum than mutants of 13 other Mediator subunits, and med16 has a much stronger effect on S. sclerotiorum-induced transcriptome changes compared with med8, a mutation not altering susceptibility to S. sclerotiorum. Interestingly, med16 is also more susceptible to S. sclerotiorum than coronatine-insensitive1-1 (coi1-1), which is the most susceptible mutant reported so far. Although the jasmonic acid (JA)/ethylene (ET) defense pathway marker gene PLANT DEFENSIN1.2 (PDF1.2) cannot be induced in either med16 or coi1-1, basal transcript levels of PDF1.2 in med16 are significantly lower than in coi1-1. Furthermore, ET-induced suppression of JA-activated wound responses is compromised in med16, suggesting a role for MED16 in JA-ET cross talk. Additionally, MED16 is required for the recruitment of RNA polymerase II to PDF1.2 and OCTADECANOID-RESPONSIVE ARABIDOPSIS ETHYLENE/ETHYLENE-RESPONSIVE FACTOR59 (ORA59), two target genes of both JA/ET-mediated and the transcription factor WRKY33-activated defense pathways. Finally, MED16 is physically associated with WRKY33 in yeast and in planta, and WRKY33-activated transcription of PDF1.2 and ORA59 as well as resistance to S. sclerotiorum depends on MED16. Taken together, these results indicate that MED16 regulates resistance to S. sclerotiorum by governing both JA/ET-mediated and WRKY33-activated defense signaling in Arabidopsis.

  19. Isolation of oxalic acid tolerating fungi and decipherization of its potential to control Sclerotinia sclerotiorum through oxalate oxidase like protein.

    PubMed

    Yadav, Shivani; Srivastava, Alok K; Singh, Dhanajay P; Arora, Dilip K

    2012-11-01

    Oxalic acid plays major role in the pathogenesis by Sclerotinia sclerotiorum; it lowers the pH of nearby environment and creates the favorable condition for the infection. In this study we examined the degradation of oxalic acid through oxalate oxidase and biocontrol of Sclerotinia sclerotiorum. A survey was conducted to collect the rhizospheric soil samples from Indo-Gangetic Plains of India to isolate the efficient fungal strains able to tolerate oxalic acid. A total of 120 fungal strains were isolated from root adhering soils of different vegetable crops. Out of 120 strains a total of 80 isolates were able to grow at 10 mM of oxalic acid whereas only 15 isolates were grow at 50 mM of oxalic acid concentration. Then we examined the antagonistic activity of the 15 isolates against Sclerotinia sclerotiorum. These strains potentially inhibit the growth of the test pathogen. A total of three potential strains and two standard cultures of fungi were tested for the oxalate oxidase activity. Strains S7 showed the maximum degradation of oxalic acid (23 %) after 60 min of incubation with fungal extract having oxalate oxidase activity. Microscopic observation and ITS (internally transcribed spacers) sequencing categorized the potential fungal strains into the Aspergillus, Fusarium and Trichoderma. Trichoderma sp. are well studied biocontrol agent and interestingly we also found the oxalate oxidase type activity in these strains which further strengthens the potentiality of these biocontrol agents.

  20. Mycoparasitism studies of Trichoderma harzianum against Sclerotinia sclerotiorum: evaluation of antagonism and expression of cell wall-degrading enzymes genes.

    PubMed

    Troian, Rogério Fraga; Steindorff, Andrei Stecca; Ramada, Marcelo Henrique Soller; Arruda, Walquiria; Ulhoa, Cirano José

    2014-10-01

    Trichoderma spp. are known for their biocontrol activity against several plant pathogens. A specific isolate of Trichoderma harzianum, 303/02, has the potential to inhibit the growth of Sclerotinia sclerotiorum, an important agent involved in several crop diseases. In this study, the interaction between T. harzianum 303/02 and mycelia, sclerotia and apothecia of S. sclerotiorum was studied by scanning electron microscopy. RT-qPCR was used to examine the expression of 11 genes potentially involved in biocontrol. T. harzianum 303/02 parasitizes S. sclerotiorum by forming branches that coil around the hyphae. The fungus multiplied abundantly at the sclerotia and apothecia surface, forming a dense mycelium that penetrated the inner surface of these structures. The levels of gene expression varied according to the type of structure with which T. harzianum was interacting. The data also showed the presence of synergistic action between the cell-wall degrading enzymes.

  1. Tight regulation of the interaction between Brassica napus and Sclerotinia sclerotiorum at the microRNA level.

    PubMed

    Cao, Jia-Yi; Xu, You-Ping; Zhao, Li; Li, Shuang-Sheng; Cai, Xin-Zhong

    2016-09-01

    MicroRNAs (miRNAs) are multifunctional non-coding short nucleotide molecules. Nevertheless, the role of miRNAs in the interactions between plants and necrotrophic pathogens is largely unknown. Here, we report the identification of the miRNA repertoire of the economically important oil crop oilseed rape (Brassica napus) and those involved in interacting with its most devastating necrotrophic pathogen Sclerotinia sclerotiorum. We identified 280 B. napus miRNA candidates, including 53 novel candidates and 227 canonical members or variants of known miRNA families, by high-throughput deep sequencing of small RNAs from both normal and S. sclerotiorum-inoculated leaves. Target genes of 15 novel candidates and 222 known miRNAs were further identified by sequencing of degradomes from the two types of samples. MiRNA microarray analysis revealed that 68 miRNAs were differentially expressed between S. sclerotiorum-inoculated and uninoculated leaves. A set of these miRNAs target genes involved in plant defense to S. sclerotiorum and/or other pathogens such as nucleotide binding site-leucine-rich repeat (NBS-LRR) R genes and nitric oxygen and reactive oxygen species related genes. Additionally, three miRNAs target AGO1 and AGO2, key components of post-transcriptional gene silencing (PTGS). Expression of several viral PTGS suppressors reduced resistance to S. sclerotiorum. Arabidopsis mutants of AGO1 and AGO2 exhibited reduced resistance while transgenic lines over-expressing AGO1 displayed increased resistance to S. sclerotiorum in an AGO1 expression level-dependent manner. Moreover, transient over-expression of miRNAs targeting AGO1 and AGO2 decreased resistance to S. sclerotiorum in oilseed rape. Our results demonstrate that the interactions between B. napus and S. sclerotiorum are tightly regulated at miRNA level and probably involve PTGS.

  2. An Interspecies Comparative Analysis of the Predicted Secretomes of the Necrotrophic Plant Pathogens Sclerotinia sclerotiorum and Botrytis cinerea

    PubMed Central

    2015-01-01

    Phytopathogenic fungi form intimate associations with host plant species and cause disease. To be successful, fungal pathogens communicate with a susceptible host through the secretion of proteinaceous effectors, hydrolytic enzymes and metabolites. Sclerotinia sclerotiorum and Botrytis cinerea are economically important necrotrophic fungal pathogens that cause disease on numerous crop species. Here, a powerful bioinformatics pipeline was used to predict the refined S. sclerotiorum and B. cinerea secretomes, identifying 432 and 499 proteins respectively. Analyses focusing on S. sclerotiorum revealed that 16% of the secretome encoding genes resided in small, sequence heterogeneous, gene clusters that were distributed over 13 of the 16 predicted chromosomes. Functional analyses highlighted the importance of plant cell hydrolysis, oxidation-reduction processes and the redox state to the S. sclerotiorum and B. cinerea secretomes and potentially host infection. Only 8% of the predicted proteins were distinct between the two secretomes. In contrast to S. sclerotiorum, the B. cinerea secretome lacked CFEM- or LysM-containing proteins. The 115 fungal and oomycete genome comparison identified 30 proteins specific to S. sclerotiorum and B. cinerea, plus 11 proteins specific to S. sclerotiorum and 32 proteins specific to B. cinerea. Expressed sequence tag (EST) and proteomic analyses showed that 246 S. sclerotiorum secretome encoding genes had EST support, including 101 which were only expressed in vitro and 49 which were only expressed in planta, whilst 42 predicted proteins were experimentally proven to be secreted. These detailed in silico analyses of two important necrotrophic pathogens will permit informed choices to be made when candidate effector proteins are selected for function analyses in planta. PMID:26107498

  3. Oxalic acid has an additional, detoxifying function in Sclerotinia sclerotiorum pathogenesis.

    PubMed

    Heller, Annerose; Witt-Geiges, Tanja

    2013-01-01

    The mechanism of the diseases caused by the necrotroph plant pathogen Sclerotinia sclerotiorum is not well understood. To investigate the role of oxalic acid during infection high resolution, light-, scanning-, transmission electron microscopy and various histochemical staining methods were used. Our inoculation method allowed us to follow degradation of host plant tissue around single hyphae and to observe the reaction of host cells in direct contact with single invading hyphae. After penetration the outer epidermal cell wall matrix appeared degraded around subcuticular hyphae (12-24 hpi). Calcium oxalate crystals were detected in advanced (36-48 hpi) and late (72 hpi) infection stages, but not in early stages. In early infection stages, surprisingly, no toxic effect of oxalic acid eventually secreted by S. sclerotiorum was observed. As oxalic acid is a common metabolite in plants, we propose that attacked host cells are able to metabolize oxalic acid in the early infection stage and translocate it to their vacuoles where it is stored as calcium oxalate. The effects, observed on healthy tissue upon external application of oxalic acid to non-infected, living tissue and cell wall degradation of dead host cells starting at the inner side of the walls support this idea. The results indicate that oxalic acid concentrations in the early stage of infection stay below the toxic level. In plant and fungi oxalic acid/calcium oxalate plays an important role in calcium regulation. Oxalic acid likely could quench calcium ions released during cell wall breakdown to protect growing hyphae from toxic calcium concentrations in the infection area. As calcium antimonate-precipitates were found in vesicles of young hyphae, we propose that calcium is translocated to the older parts of hyphae and detoxified by building non-toxic, stable oxalate crystals. We propose an infection model where oxalic acid plays a detoxifying role in late infection stages.

  4. pH Signaling in Sclerotinia sclerotiorum: Identification of a pacC/RIM1 Homolog

    PubMed Central

    Rollins, Jeffrey A.; Dickman, Martin B.

    2001-01-01

    Sclerotinia sclerotiorum acidifies its ambient environment by producing oxalic acid. This production of oxalic acid during plant infection has been implicated as a primary determinant of pathogenicity in this and other phytopathogenic fungi. We found that ambient pH conditions affect multiple processes in S. sclerotiorum. Exposure to increasing alkaline ambient pH increased the oxalic acid accumulation independent of carbon source, sclerotial development was favored by acidic ambient pH conditions but inhibited by neutral ambient pH, and transcripts encoding the endopolygalacturonase gene pg1 accumulated maximally under acidic culture conditions. We cloned a putative transcription factor-encoding gene, pac1, that may participate in a molecular signaling pathway for regulating gene expression in response to ambient pH. The three zinc finger domains of the predicted Pac1 protein are similar in sequence and organization to the zinc finger domains of the A. nidulans pH-responsive transcription factor PacC. The promoter of pac1 contains eight PacC consensus binding sites, suggesting that this gene, like its homologs, is autoregulated. Consistent with this suggestion, the accumulation of pac1 transcripts paralleled increases in ambient pH. Pac1 was determined to be a functional homolog of PacC by complementation of an A. nidulans pacC-null strain with pac1. Our results suggest that ambient pH is a regulatory cue for processes linked to pathogenicity, development, and virulence and that these processes may be under the molecular regulation of a conserved pH-dependent signaling pathway analogous to that in the nonpathogenic fungus A. nidulans. PMID:11133430

  5. Development and application of loop-mediated isothermal amplification for detecting the highly benzimidazole-resistant isolates in Sclerotinia sclerotiorum.

    PubMed

    Duan, Ya Bing; Yang, Ying; Wang, Jian Xin; Liu, Cong Chao; He, Ling Ling; Zhou, Ming Guo

    2015-11-26

    Resistance of benzimidazole fungicides is related to the point mutation of the β-tubulin gene in Sclerotinia sclerotiorum. The point mutation at codon 198 (GAG → GCG, E198A) occurs in more than 90% of field resistant populations in China. Traditional detection methods of benzimidazole-resistant mutants of S. sclerotiorum are time-consuming, tedious and inefficient. To establish a suitable and rapid detection of benzimidazole-resistant mutants of S. sclerotiorum, an efficient and simple method with high specificity was developed based on loop-mediated isothermal amplification (LAMP). Eight sets of LAMP primers were designed and four sets were optimized to specially distinguish benzimidazole-resistant mutants of S. sclerotiorum. With the optimal LAMP primers, the concentration of LAMP components was optimized and the reaction conditions were set as 60-64 °C for 60 min. This method had a good specificity, sensitivity, stability and repeatability. In the 1491 sclerotia, 614 (41.18%) were positive by LAMP, and 629 (42.19%) positive by MIC. Therefore, the LAMP assay is more feasible to detect benzimidazole-resistant mutants of S. sclerotiorum than traditional detection methods.

  6. Involvement of alternative oxidase in the regulation of sensitivity of Sclerotinia sclerotiorum to the fungicides azoxystrobin and procymidone.

    PubMed

    Xu, Ting; Wang, Ya-Ting; Liang, Wu-Sheng; Yao, Fei; Li, Yong-Hong; Li, Dian-Rong; Wang, Hao; Wang, Zheng-Yi

    2013-06-01

    Sclerotinia sclerotiorum is a filamentous fungal pathogen that can infect many economically important crops and vegetables. Alternative oxidase is the terminal oxidase of the alternative respiratory pathway in fungal mitochondria. The function of alternative oxidase was investigated in the regulation of sensitivity of S. sclerotiorum to two commercial fungicides, azoxystrobin and procymidone which have different fungitoxic mechanisms. Two isolates of S. sclerotiorum were sensitive to both fungicides. Application of salicylhydroxamic acid, a specific inhibitor of alternative oxidase, significantly increased the values of effective concentration causing 50% mycelial growth inhibition (EC50) of azoxystrobin to both S. sclerotiorum isolates, whereas notably decreased the EC50 values of procymidone. In mycelial respiration assay azoxystrobin displayed immediate inhibitory effect on cytochrome pathway capacity, but had no immediate effect on alternative pathway capacity. In contrast, procymidone showed no immediate impact on capacities of both cytochrome and alternative pathways in the mycelia. However, alternative oxidase encoding gene (aox) transcript and protein levels, alternative respiration pathway capacity of the mycelia were obviously increased by pre-treatment for 24 h with both azoxystrobin and procymidone. These results indicate that alternative oxidase was involved in the regulation of sensitivity of S. sclerotiorum to the fungicides azoxystrobin and procymidone, and that both fungicides could affect aox gene expression and the alternative respiration pathway capacity development in mycelia of this fungal pathogen.

  7. Disruption of the Gene Encoding Endo-β-1, 4-Xylanase Affects the Growth and Virulence of Sclerotinia sclerotiorum

    PubMed Central

    Yu, Yang; Xiao, Jifen; Du, Jiao; Yang, Yuheng; Bi, Chaowei; Qing, Ling

    2016-01-01

    Sclerotinia sclerotiorum (Lib.) de Bary is a devastating fungal pathogen with worldwide distribution. S. sclerotiorum is a necrotrophic fungus that secretes many cell wall-degrading enzymes (CWDEs) that destroy plant’s cell-wall components. Functional analyses of the genes that encode CWDEs will help explain the mechanisms of growth and pathogenicity of S. sclerotiorum. Here, we isolated and characterized a gene SsXyl1 that encoded an endo-β-1, 4-xylanase in S. sclerotiorum. The SsXyl1 expression showed a slight increase during the development and germination stages of sclerotia and a dramatic increase during infection. The expression of SsXyl1 was induced by xylan. The SsXyl1 deletion strains produce aberrant sclerotia that could not germinate to form apothecia. The SsXyl1 deletion strains also lost virulence to the hosts. This study demonstrates the important roles of endo-β-1, 4-xylanase in the growth and virulence of S. sclerotiorum. PMID:27891117

  8. Development and application of loop-mediated isothermal amplification for detecting the highly benzimidazole-resistant isolates in Sclerotinia sclerotiorum

    PubMed Central

    Duan, Ya Bing; Yang, Ying; Wang, Jian Xin; Liu, Cong Chao; He, Ling Ling; Zhou, Ming Guo

    2015-01-01

    Resistance of benzimidazole fungicides is related to the point mutation of the β-tubulin gene in Sclerotinia sclerotiorum. The point mutation at codon 198 (GAG → GCG, E198A) occurs in more than 90% of field resistant populations in China. Traditional detection methods of benzimidazole-resistant mutants of S. sclerotiorum are time-consuming, tedious and inefficient. To establish a suitable and rapid detection of benzimidazole-resistant mutants of S. sclerotiorum, an efficient and simple method with high specificity was developed based on loop-mediated isothermal amplification (LAMP). Eight sets of LAMP primers were designed and four sets were optimized to specially distinguish benzimidazole-resistant mutants of S. sclerotiorum. With the optimal LAMP primers, the concentration of LAMP components was optimized and the reaction conditions were set as 60–64 °C for 60 min. This method had a good specificity, sensitivity, stability and repeatability. In the 1491 sclerotia, 614 (41.18%) were positive by LAMP, and 629 (42.19%) positive by MIC. Therefore, the LAMP assay is more feasible to detect benzimidazole-resistant mutants of S. sclerotiorum than traditional detection methods. PMID:26606972

  9. Selection of endophytic fungi from comfrey (Symphytum officinale L.) for in vitro biological control of the phytopathogen Sclerotinia sclerotiorum (Lib.)

    PubMed Central

    Rocha, Rafaeli; da Luz, Daniela Eleutério; Engels, Cibelle; Pileggi, Sônia Alvim Veiga; de Souza Jaccoud Filho, David; Matiello, Rodrigo Rodrigues; Pileggi, Marcos

    2009-01-01

    Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM) is a very common strategy. The white mold produced by Sclerotinia sclerotiorum (Lib.) causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytum officinale L.) leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests. PMID:24031320

  10. Selection of endophytic fungi from comfrey (Symphytum officinale L.) for in vitro biological control of the phytopathogen Sclerotinia sclerotiorum (Lib.).

    PubMed

    Rocha, Rafaeli; da Luz, Daniela Eleutério; Engels, Cibelle; Pileggi, Sônia Alvim Veiga; de Souza Jaccoud Filho, David; Matiello, Rodrigo Rodrigues; Pileggi, Marcos

    2009-01-01

    Biological control consists of using one organism to attack another that may cause economic damage to crops. Integrated Pest Management (IPM) is a very common strategy. The white mold produced by Sclerotinia sclerotiorum (Lib.) causes considerable damage to bean crops. This fungus is a soil inhabitant, the symptoms of which are characterized by water-soaked lesions covered by a white cottony fungal growth on the soil surface and/or the host plant. Possible biological control agents taken from plants are being investigated as phytopathogen inhibitors. These are endophytic microorganisms that inhabit the intercellular spaces of vegetal tissues and are often responsible for antimicrobial production. The objective of the present study was to select endophytic fungi isolated from comfrey (Symphytum officinale L.) leaves with in vitro antagonist potential against the phytopathogenic fungus S. sclerotiorum. Twelve isolates of endophytic fungi and a pathogenic strain of S. sclerotiorum were used in the challenge method. With the aid of this method, four endophytes with the best antagonistic activity against S. sclerotiorum were selected. Pathogen growth inhibition zones were considered indicative of antibiosis. The percentages of pathogenic mycelia growth were measured both with and without the antagonist, resulting in growth reductions of 46.7% to 50.0% for S. sclerotiorum. These analyses were performed by evaluating the endophytic/pathogenic mycelia growth in mm/day over an eight-day period of antagonistic tests.

  11. Attack modes and defence reactions in pathosystems involving Sclerotinia sclerotiorum, Brassica carinata, B. juncea and B. napus

    PubMed Central

    Uloth, Margaret B.; Clode, Peta L.; You, Ming Pei; Barbetti, Martin J.

    2016-01-01

    Background and Aims Sclerotinia stem rot (SSR, Sclerotinia sclerotiorum) is a damaging disease of oilseed brassicas world-wide. Host resistance is urgently needed to achieve control, yet the factors that contribute to stem resistance are not well understood. This study investigated the mechanisms of resistance to SSR. Methods Stems of 5-week-old Brassica carinata, B. juncea and B. napus of known resistance were infected via filter paper discs impregnated with S. sclerotiorum mycelium under controlled conditions. Transverse sections of the stem and portions of the stem surface were examined using optical and scanning electron microscopy. The association of anatomical features with the severity of disease (measured by mean lesion length) was determined. Key Results Several distinct resistance mechanisms were recorded for the first time in these Brassica–pathogen interactions, including hypersensitive reactions and lignification within the stem cortex, endodermis and in tissues surrounding the lesions. Genotypes showing a strong lignification response 72 h post-infection (hpi) tended to have smaller lesions. Extensive vascular invasion by S. sclerotiorum was observed only in susceptible genotypes, especially in the vascular fibres and xylem. Mean lesion length was negatively correlated with the number of cell layers in the cortex, suggesting progress of S. sclerotiorum is impeded by more cell layers. Hyphae in the centre of lesions became highly vacuolate 72 hpi, reflecting an ageing process in S. sclerotiorum hyphal networks that was independent of host resistance. The infection process of S. sclerotiorum was analogous in B. carinata and B. napus. Infection cushions of the highly virulent isolate of S. sclerotiorum MBRS-1 were grouped together in dense parallel bundles, while hyphae in the infection cushions of a less aggressive isolate WW-3 were more diffuse, and this was unaffected by host genotype. Conclusions A variety of mechanisms contribute to host

  12. An improved method for the production of fructooligosaccharides by immobilized β-fructofuranosidase from Sclerotinia sclerotiorum.

    PubMed

    Mouelhi, Refka; Abidi, Ferid; Marzouki, Mohamed Nejib

    2016-01-01

    This work is focused on the prebiotic synthesis by a purified immobilized β-fructofuranosidase (FFase) using a by-product molasses as a substrate. When cultivated on wheat bran, the fungus Sclerotinia sclerotiorum produces FFase with interesting transfructosylating activity. The enzyme was purified by gel filtration and anion exchange chromatography to homogeneity. It showed a specific activity of 66.06 U/mg and a molecular mass of 50 kDa. The FFase was immobilized covalently on alginate and chitosan, and the immobilization yield was 90% and 81% respectively, yet the immobilization efficiency was 52% and 93% in that order. The fixed enzymes were stable at a pH varying from 4.0 to 7.0 and at a temperature ranging from 4 to 70 °C. Yet, kinetic parameters and catalytic efficiency were determined for both immobilized and free FFases. Interestingly, chitosan cross-linked enzyme activity was maintained at 89.24% level after 50 reuses during 1 week. Continuous production of fructooligosaccharides (FOS) from beet molasses in chitosan enzyme reactor was improved. The maximum production yield obtained in 12 H was 72.2% (g FOS/g Sucrose). Thin-layer chromatography analysis showed that the major products are kestose and nystose.

  13. Immobilized Sclerotinia sclerotiorum invertase to produce invert sugar syrup from industrial beet molasses by-product.

    PubMed

    Mouelhi, Refka; Abidi, Ferid; Galai, Said; Marzouki, M Nejib

    2014-03-01

    The fungus Sclerotinia sclerotiorum produces invertase activity during cultivation on many agroindustrial residues. The molasses induced invertase was purified by DEAE-cellulose chromatography. The molecular mass of the purified enzyme was estimated at 48 kDa. Optimal temperature was determined at 60 °C and thermal stability up to 65 °C. The enzyme was stable between pH 2.0 and 8.0; optimum pH was about 5.5. Apparent K(m) and V(max) for sucrose were estimated to be respectively 5.8 mM and 0.11 μmol/min. The invertase was activated by β-mercaptoethanol. Free enzyme exhibited 80 % of its original activity after two month's storage at 4 °C and 50 % after 1 week at 25 °C. In order to investigate an industrial application, the enzyme was immobilized on alginate and examined for invert sugar production by molasses hydrolysis in a continuous bioreactor. The yield of immobilized invertase was about 78 % and the activity yield was 59 %. Interestingly the immobilized enzyme hydrolyzed beet molasses consuming nearly all sucrose. It retained all of its initial activity after being used for 4 cycles and about 65 % at the sixth cycle. Regarding productivity; 20 g/l of molasses by-product gave the best invert sugar production 46.21 g/day/100 g substrate related to optimal sucrose conversion of 41.6 %.

  14. Reaction of common bean lines and aggressiveness of Sclerotinia sclerotiorum isolates.

    PubMed

    Silva, P H; Santos, J B; Lima, I A; Lara, L A C; Alves, F C

    2014-11-07

    The aims of this study were to evaluate the reaction of common bean lines to white mold, the aggressiveness of different Sclerotinia sclerotiorum isolates from various common bean production areas in Brazil, and comparison of the diallel and GGE (genotype main effect plus genotype-by-environment interaction) biplot analysis procedures via study of the line-by-isolate interaction. Eleven common bean (Phaseolus vulgaris) lines derived from 3 backcross populations were used. Field experiments were performed in the experimental area of the Departamento de Biologia of the Universidade Federal de Lavras, Lavras, MG, Brazil, in the 2011 and 2012 dry crop season and 2011 winter crop season through a randomized block design with 3 replications. This study was also set up in a greenhouse. Inoculations were performed 28 days after sowing by means of the straw test method. The reaction of the bean lines to white mold was assessed according to a diagrammatic scale from 1 (plant without symptoms) to 9 (dead plant). Estimations of general reaction capacity (lines) and general aggressiveness capacity (isolates) indicated different horizontal levels of resistance in the lines and levels of aggressiveness in the isolates. Therefore, it was possible to select more resistant lines and foresee those crosses that are the most promising for increasing the level of resistance. It was also possible to identify the most aggressive isolates that were more efficient in distinguishing the lines. Both diallel and GGE biplot analyses were useful in identifying the genotypic values of lines and isolates.

  15. Biological control of Sclerotinia sclerotiorum (Lib.) de Bary, the causal agent of white mold, by Pseudomonas species on canola petals.

    PubMed

    Behnam, S; Ahmadzadeh, M; Sharifi Tehrani, A; Hedjaroude, Gh A; Farzaneh, M

    2007-01-01

    Sclerotinia sclerotiorum is an important pathogen on canola. Due to the public concern over pesticide use, alternative methods of disease control, such as biological control, should be considered. Several bacterial strains were isolated from canola and soja plants. Inhibition of S. sclerotiorum by bacterial strains in vitro was assayed on PDA medium in dual culture test. Eight Pseudomonas sp. strains (PB-3, PB-4, PB-5, PB-6, PB-7, PB-8, PB-10 and PB-11) caused inhibition zone against 5. sclerotiorum hyphal growth. The biocontrol potential of the bacteria was tested in a plant assay. Disease suppression was investigated using a petal inoculation technique. Canola petals were pretreated with bacteria, and then inoculated with 5. sclerotiorum ascospores 24 h later. Greenhouse experiment showed that application of Pseudomonas sp. strains (1 x 10(8) cfu ml(-1)) effectively suppressed S. sclerotiorum (1 x 10(5) ascospores ml(-1)) on petals and all of them achieved significant (P<0.01) disease suppression. Fourteen days after inoculation, strain PB-3 had 88/7% disease control and strain PB-4 had 69/9% disease control. Result from all studies indicates PB-3 to be effective biocontrol against S. sclerotiorum of canola. PB-3, PB-4, PB-7, PB-8, PB-10 and PB-11 were identified as Pseudomonas fluorescens biovar III. PB-5 and PB-6 was identified as Pseudomonas fluorescens biovar II. Strains PB-3, PB-4, PB-6, PB-10 and PB-11 produced protease and HCN. Strain PB-5 produce protease; no HCN.

  16. A global study of transcriptome dynamics in canola (Brassica napus L.) responsive to Sclerotinia sclerotiorum infection using RNA-Seq.

    PubMed

    Joshi, Raj Kumar; Megha, Swati; Rahman, Muhammad Hafizur; Basu, Urmila; Kav, Nat N V

    2016-09-15

    The necrotrophic phytopathogen, Sclerotinia sclerotiorum, causes Sclerotinia stem rot, which is a serious constraint to canola (Brassica napus L.) production worldwide. To understand the detailed molecular mechanisms underlying host response to Sclerotinia infection, we analyzed the transcript level changes in canola post-infection with S. sclerotiorum in a time course of a compatible interaction using strand specific whole transcriptome sequencing. Following infection, 161 and 52 genes (P≤0.001) were induced while 24 and 23 genes were repressed at 24h post-inoculation (hpi) and 48hpi, respectively. This suggests that, a gradual increase in host cell lyses and increase virulence of the pathogen led to the expression of only a fewer host specific genes at the later stage of infection. We observed rapid induction of key pathogen responsive genes, including glucanases, chitinases, peroxidases and WRKY Transcription factors (TFs) within 24hpi, indicating early detection of the pathogen by the host. Only 16 genes were significantly induced at both the time points suggesting a coordinated suppression of host responses by the pathogen. In addition to genes involved in plant-pathogen interactions, many novel disease responsive genes, including various TF sand those associated with jasmonate (JA) and ethylene (ET) signalling were identified. This suggests that canola adopts multiple strategies in mediating plant responses to the pathogen attack. Quantitative real time PCR (qRT-PCR) validation of a selected set of genes demonstrated a similar trend as observed by RNA-Seq analysis and highlighted the potential involvement of these genes by the host to defend itself from pathogen attack. Overall, this work presents an in-depth analysis of the interaction between host susceptibility and pathogen virulence in the agriculturally important B. napus-S. sclerotiorum pathosystem.

  17. Enhanced resistance to Sclerotinia sclerotiorum in Brassica napus by co-expression of defensin and chimeric chitinase genes.

    PubMed

    Zarinpanjeh, Nasim; Motallebi, Mostafa; Zamani, Mohammad Reza; Ziaei, Mahboobeh

    2016-11-01

    Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the major fungal diseases of Brassica napus L. To develop resistance against this fungal disease, the defensin gene from Raphanus sativus and chimeric chit42 from Trichoderma atroviride with a C-terminal fused chitin-binding domain from Serratia marcescens were co-expressed in canola via Agrobacterium-mediated transformation. Twenty transformants were confirmed to carry the two transgenes as detected by polymerase chain reaction (PCR), with 4.8 % transformation efficiency. The chitinase activity of PCR-positive transgenic plants were measured in the presence of colloidal chitin, and five transgenic lines showing the highest chitinase activity were selected for checking the copy number of the transgenes through Southern blot hybridisation. Two plants carried a single copy of the transgenes, while the remainder carried either two or three copies of the transgenes. The antifungal activity of two transgenic lines that carried a single copy of the transgenes (T4 and T10) was studied by a radial diffusion assay. It was observed that the constitutive expression of these transgenes in the T4 and T10 transgenic lines suppressed the growth of S. sclerotiorum by 49 % and 47 %, respectively. The two transgenic lines were then let to self-pollinate to produce the T2 generation. Greenhouse bioassays were performed on the transgenic T2 young leaves by challenging with S. sclerotiorum and the results revealed that the expression of defensin and chimeric chitinase from a heterologous source in canola demonstrated enhanced resistance against sclerotinia stem rot disease.

  18. Biocontrol agents-mediated suppression of oxalic acid induced cell death during Sclerotinia sclerotiorum-pea interaction.

    PubMed

    Jain, Akansha; Singh, Akanksha; Singh, Surendra; Sarma, Birinchi Kumar; Singh, Harikesh Bahadur

    2015-05-01

    Oxalic acid (OA) is an important pathogenic factor during early Sclerotinia sclerotiorum-host interaction and might work by reducing hydrogen peroxide production (H2 O2 ). In the present investigation, oxalic acid-induced cell death in pea was studied. Pea plants treated with biocontrol agents (BCAs) viz., Pseudomonas aeruginosa PJHU15, Bacillus subtilis BHHU100, and Trichoderma harzianum TNHU27 either singly and/or in consortium acted on S. sclerotiorum indirectly by enabling plants to inhibit the OA-mediated suppression of oxidative burst via induction of H2 O2 . Our results showed that BCA treated plants upon treatment with culture filtrate of the pathogen, conferred the resistance via. significantly decreasing relative cell death of pea against S. sclerotiorum compared to control plants without BCA treatment but treated with the culture filtrate of the pathogen. The results obtained from the present study indicate that the microbes especially in consortia play significant role in protection against S. sclerotiorum by modulating oxidative burst and partially enhancing tolerance by increasing the H2 O2 generation, which is otherwise suppressed by OA produced by the pathogen.

  19. A new point mutation in the iron-sulfur subunit of succinate dehydrogenase confers resistance to boscalid in Sclerotinia sclerotiorum.

    PubMed

    Wang, Yong; Duan, Yabing; Wang, Jianxin; Zhou, Mingguo

    2015-09-01

    Research has established that mutations in highly conserved amino acids of the succinate dehydrogenase (SDH) complex in various fungi confer SDH inhibitor (SDHI) resistance. For Sclerotinia sclerotiorum (Lib.) de Bary, a necrotrophic fungus with a broad host range and a worldwide distribution, boscalid resistance has been attributed to the mutation H132R in the highly conserved SdhD subunit protein of the SDH complex. In our previous study, however, only one point mutation, A11V in SdhB (GCA to GTA change in SdhB), was detected in S. sclerotiorum boscalid-resistant (BR) mutants. In the current study, replacement of the SdhB gene in a boscalid-sensitive (BS) S. sclerotiorum strain with the mutant SdhB gene conferred resistance. Compared with wild-type strains, BR and GSM (SdhB gene in the wild-type strain replaced by the mutant SdhB gene) mutants were more sensitive to osmotic stress, lacked the ability to produce sclerotia and exhibited lower expression of the pac1 gene. Importantly, the point mutation was not located in the highly conserved sequence of the iron-sulfur subunit of SDH. These results suggest that resistance based on non-conserved vs. conserved protein domains differs in mechanism. In addition to increasing our understanding of boscalid resistance in S. sclerotiorum, the new information will be useful for the development of alternative antifungal drugs.

  20. Mass spectrometry identification of antifungal lipopeptides from Bacillus sp. BCLRB2 against Rhizoctonia solani and Sclerotinia sclerotiorum.

    PubMed

    Elkahoui, S; Djébali, N; Karkouch, I; Ibrahim, A Hadj; Kalai, L; Bachkovel, S; Tabbene, O; Limam, F

    2014-01-01

    This work aims to characterize the bioactive molecules produced by an antagonistic Bacillus sp. strain BCLRB2 isolated from healthy leaves of olive tree against Rhizoctonia solani and Sclerotinia sclerotiorum. The bacterial strain isolated showed a high and persistent antifungal activity against the two pathogens. The free-cell supernatant showed also a high antifungal activity against R. solani and at a lower extent against S. sclerotiorum. The partial purification of the antifungal substances with methanol gradient applied to C18 column binding the Bacillus BCLRB2 culture supernatant showed that the 20% and 60% methanol fractions had a high and specific activity against S. sclerotiorum and R. solani, respectively. The mass spectrometry identification of the compounds in the fraction specifically active against S. sclerotiorum revealed the presence of bacillomycin D C16 as a major lipopeptide. The fraction specifically active against R. solani contained bacillomycin D C15 and 2 unknown lipopeptides. The 80% methanol fraction had a moderate and a broad spectrum activity against the two pathogens and consisted from two iturin D (C13 and C14) as a major lipopeptides.

  1. Emerging Trends in Molecular Interactions between Plants and the Broad Host Range Fungal Pathogens Botrytis cinerea and Sclerotinia sclerotiorum

    PubMed Central

    Mbengue, Malick; Navaud, Olivier; Peyraud, Rémi; Barascud, Marielle; Badet, Thomas; Vincent, Rémy; Barbacci, Adelin; Raffaele, Sylvain

    2016-01-01

    Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum, the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi. PMID:27066056

  2. Metabolic profiles of sunflower genotypes with contrasting response to Sclerotinia sclerotiorum infection.

    PubMed

    Peluffo, Lucila; Lia, Verónica; Troglia, Carolina; Maringolo, Carla; Norma, Paniego; Escande, Alberto; Esteban Hopp, H; Lytovchenko, Anna; Fernie, Alisdair R; Heinz, Ruth; Carrari, Fernando

    2010-01-01

    We report a comprehensive primary metabolite profiling of sunflower (Helianthus annuus) genotypes displaying contrasting behavior to Sclerotinia sclerotiorum infection. Applying a GC-MS-based metabolite profiling approach, we were able to identify differential patterns involving a total of 63 metabolites including major and minor sugars and sugar alcohols, organic acids, amino acids, fatty acids and few soluble secondary metabolites in the sunflower capitulum, the main target organ of pathogen attack. Metabolic changes and disease incidence of the two contrasting genotypes were determined throughout the main infection period (R5.2-R6). Both point-by-point and non-parametric statistical analyses showed metabolic differences between genotypes as well as interaction effects between genotype and time after inoculation. Network correlation analyses suggested that these metabolic changes were synchronized in a time-dependent manner in response to the pathogen. Concerted differential metabolic changes were detected to a higher extent in the susceptible, rather than the resistant genotype, thereby allowing differentiation of modules composed by intermediates of the same pathway which are highly interconnected in the susceptible line but not in the resistant one. Evaluation of these data also demonstrated a genotype specific regulation of distinct metabolic pathways, suggesting the importance of detection of metabolic patterns rather than specific metabolite changes when looking for metabolic markers differentially responding to pathogen infection. In summary, the GC-MS strategy developed in this study was suitable for detection of differences in carbon primary metabolism in sunflower capitulum, a tissue which is the main entry point for this and other pathogens which cause great detrimental impact on crop yield.

  3. Formulations of the endophytic bacterium Bacillus subtilis Tu-100 suppress Sclerotinia sclerotiorum on oilseed rape and improve plant vigor in field trials conducted at separate locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum causes serious yield losses in crops in The People’s Republic of China. Two formulations of oilseed rape seed containing the endophytic bacterium Bacillus subtilis Tu-100 were evaluated for suppression of this pathogen in field trials conducted at two independent locations....

  4. Components of a rice-oilseed rape production system augmented with trichoderma sp. Tri-1 control sclerotinia sclerotiorum on oilseed rape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum causes serious yield losses on many crops throughout the world. In two field trials conducted at the same location in consecutive years, a treatment containing formulated Trichoderma harzianum-1 (Tri-1) resulted in oilseed rape seed yield that was significantly greater than...

  5. pH Dependency of sclerotial development and pathogenicity revealed by using genetically defined oxalate-minus mutants of Sclerotinia sclerotiorum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The devastating plant pathogen Sclerotinia sclerotiorum produces copious (up to 50mM) amounts of oxalic acid, which, for over a quarter century, has been claimed as the pathogenicity determinant based on UV-induced mutants that concomitantly lost oxalate production and pathogenicity. Such a claim wa...

  6. Genome Wide Identification and Functional Prediction of Long Non-Coding RNAs Responsive to Sclerotinia sclerotiorum Infection in Brassica napus

    PubMed Central

    Joshi, Raj Kumar; Megha, Swati; Basu, Urmila; Rahman, Muhammad H.; Kav, Nat N. V.

    2016-01-01

    Sclerotinia stem rot caused by Sclerotinia sclerotiorum affects canola production worldwide. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play important roles in the regulation of gene expression in plants, in response to both abiotic and biotic stress. So far, identification of lncRNAs has been limited to a few model plant species, and their roles in mediating responses to biotic stresses are yet to be characterized in Brassica napus. The present study reports the identification of novel lncRNAs responsive to S. sclerotiorum infection in B. napus at two time points after infection (24 hpi and 48 hpi) using a stranded RNA-Sequencing technique and a detection pipeline for lncRNAs. Of the total 3,181 lncRNA candidates, 2,821 lncRNAs were intergenic, 111 were natural antisense transcripts, 76 possessed exonic overlap with the reference coding transcripts while the remaining 173 represented novel lnc- isoforms. Forty one lncRNAs were identified as the precursors for microRNAs (miRNAs) including miR156, miR169 and miR394, with significant roles in mediating plant responses to fungal phytopathogens. A total of 931 differentially expressed lncRNAs were identified in response to S. sclerotiorum infection and the expression of 12 such lncRNAs was further validated using qRT-PCR. B. napus antisense lncRNA, TCONS_00000966, having 90% overlap with a plant defensin gene, showed significant induction at both infection stages, suggesting its involvement in the transcriptional regulation of defense responsive genes under S. sclerotiorum infection. Additionally, nine lncRNAs showed overlap with cis-regulatory regions of differentially expressed genes of B. napus. Quantitative RT-PCR verification of a set of S. sclerotiorum responsive sense/antisense transcript pairs revealed contrasting expression patterns, supporting the hypothesis that steric clashes of transcriptional machinery may lead to inactivation of sense promoter. Our findings highlight the potential

  7. Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum

    PubMed Central

    Amaradasa, B. Sajeewa

    2016-01-01

    Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor), iprodione (unclear mode of action), thiophanate methyl (inhibition of microtubulin synthesis) and azoxystrobin and pyraclostrobin (quinone outside inhibitors). Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50–100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR) loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs). SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each). Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed) generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA) and discriminant analysis of principal components (DAPC) identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001). Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the experiment

  8. Overexpression of Three Glucosinolate Biosynthesis Genes in Brassica napus Identifies Enhanced Resistance to Sclerotinia sclerotiorum and Botrytis cinerea

    PubMed Central

    Yang, Qingyong; Cheng, Yan; Ma, Ming; Kliebenstein, Daniel J.; Zhou, Yongming

    2015-01-01

    Sclerotinia sclerotiorum and Botrytis cinerea are notorious plant pathogenic fungi with an extensive host range including Brassica crops. Glucosinolates (GSLs) are an important group of secondary metabolites characteristic of the Brassicales order, whose degradation products are proving to be increasingly important in plant protection. Enhancing the defense effect of GSL and their associated degradation products is an attractive strategy to strengthen the resistance of plants by transgenic approaches. We generated the lines of Brassica napus with three biosynthesis genes involved in GSL metabolic pathway (BnMAM1, BnCYP83A1 and BnUGT74B1), respectively. We then measured the foliar GSLs of each transgenic lines and inoculated them with S. sclerotiorum and B. cinerea. Compared with the wild type control, over-expressing BnUGT74B1 in B. napus increased the aliphatic and indolic GSL levels by 1.7 and 1.5 folds in leaves respectively; while over-expressing BnMAM1 or BnCYP83A1 resulted in an approximate 1.5-fold higher only in the aliphatic GSL level in leaves. The results of plant inoculation demonstrated that BnUGT74B1-overexpressing lines showed less severe disease symptoms and tissue damage compared with the wild type control, but BnMAM1 or BnCYP83A1-overexpressing lines showed no significant difference in comparison to the controls. These results suggest that the resistance to S. sclerotiorum and B. cinerea in B. napus could be enhanced through tailoring the GSL profiles by transgenic approaches or molecular breeding, which provides useful information to assist plant breeders to design improved breeding strategies. PMID:26465156

  9. Overexpression of Three Glucosinolate Biosynthesis Genes in Brassica napus Identifies Enhanced Resistance to Sclerotinia sclerotiorum and Botrytis cinerea.

    PubMed

    Zhang, Yuanyuan; Huai, Dongxin; Yang, Qingyong; Cheng, Yan; Ma, Ming; Kliebenstein, Daniel J; Zhou, Yongming

    2015-01-01

    Sclerotinia sclerotiorum and Botrytis cinerea are notorious plant pathogenic fungi with an extensive host range including Brassica crops. Glucosinolates (GSLs) are an important group of secondary metabolites characteristic of the Brassicales order, whose degradation products are proving to be increasingly important in plant protection. Enhancing the defense effect of GSL and their associated degradation products is an attractive strategy to strengthen the resistance of plants by transgenic approaches. We generated the lines of Brassica napus with three biosynthesis genes involved in GSL metabolic pathway (BnMAM1, BnCYP83A1 and BnUGT74B1), respectively. We then measured the foliar GSLs of each transgenic lines and inoculated them with S. sclerotiorum and B. cinerea. Compared with the wild type control, over-expressing BnUGT74B1 in B. napus increased the aliphatic and indolic GSL levels by 1.7 and 1.5 folds in leaves respectively; while over-expressing BnMAM1 or BnCYP83A1 resulted in an approximate 1.5-fold higher only in the aliphatic GSL level in leaves. The results of plant inoculation demonstrated that BnUGT74B1-overexpressing lines showed less severe disease symptoms and tissue damage compared with the wild type control, but BnMAM1 or BnCYP83A1-overexpressing lines showed no significant difference in comparison to the controls. These results suggest that the resistance to S. sclerotiorum and B. cinerea in B. napus could be enhanced through tailoring the GSL profiles by transgenic approaches or molecular breeding, which provides useful information to assist plant breeders to design improved breeding strategies.

  10. Tipping the balance: Sclerotinia sclerotiorum secreted oxalic acid suppresses host defenses by manipulating the host redox environment.

    PubMed

    Williams, Brett; Kabbage, Mehdi; Kim, Hyo-Jin; Britt, Robert; Dickman, Martin B

    2011-06-01

    Sclerotinia sclerotiorum is a necrotrophic ascomycete fungus with an extremely broad host range. This pathogen produces the non-specific phytotoxin and key pathogenicity factor, oxalic acid (OA). Our recent work indicated that this fungus and more specifically OA, can induce apoptotic-like programmed cell death (PCD) in plant hosts, this induction of PCD and disease requires generation of reactive oxygen species (ROS) in the host, a process triggered by fungal secreted OA. Conversely, during the initial stages of infection, OA also dampens the plant oxidative burst, an early host response generally associated with plant defense. This scenario presents a challenge regarding the mechanistic details of OA function; as OA both suppresses and induces host ROS during the compatible interaction. In the present study we generated transgenic plants expressing a redox-regulated GFP reporter. Results show that initially, Sclerotinia (via OA) generates a reducing environment in host cells that suppress host defense responses including the oxidative burst and callose deposition, akin to compatible biotrophic pathogens. Once infection is established however, this necrotroph induces the generation of plant ROS leading to PCD of host tissue, the result of which is of direct benefit to the pathogen. In contrast, a non-pathogenic OA-deficient mutant failed to alter host redox status. The mutant produced hypersensitive response-like features following host inoculation, including ROS induction, callose formation, restricted growth and cell death. These results indicate active recognition of the mutant and further point to suppression of defenses by the wild type necrotrophic fungus. Chemical reduction of host cells with dithiothreitol (DTT) or potassium oxalate (KOA) restored the ability of this mutant to cause disease. Thus, Sclerotinia uses a novel strategy involving regulation of host redox status to establish infection. These results address a long-standing issue involving the

  11. The Arabidopsis Mediator Complex Subunit16 Is a Key Component of Basal Resistance against the Necrotrophic Fungal Pathogen Sclerotinia sclerotiorum1[OPEN

    PubMed Central

    Wang, Chenggang; Yao, Jin; Du, Xuezhu; Zhang, Yanping; Sun, Yijun; Rollins, Jeffrey A.; Mou, Zhonglin

    2015-01-01

    Although Sclerotinia sclerotiorum is a devastating necrotrophic fungal plant pathogen in agriculture, the virulence mechanisms utilized by S. sclerotiorum and the host defense mechanisms against this pathogen have not been fully understood. Here, we report that the Arabidopsis (Arabidopsis thaliana) Mediator complex subunit MED16 is a key component of basal resistance against S. sclerotiorum. Mutants of MED16 are markedly more susceptible to S. sclerotiorum than mutants of 13 other Mediator subunits, and med16 has a much stronger effect on S. sclerotiorum-induced transcriptome changes compared with med8, a mutation not altering susceptibility to S. sclerotiorum. Interestingly, med16 is also more susceptible to S. sclerotiorum than coronatine-insensitive1-1 (coi1-1), which is the most susceptible mutant reported so far. Although the jasmonic acid (JA)/ethylene (ET) defense pathway marker gene PLANT DEFENSIN1.2 (PDF1.2) cannot be induced in either med16 or coi1-1, basal transcript levels of PDF1.2 in med16 are significantly lower than in coi1-1. Furthermore, ET-induced suppression of JA-activated wound responses is compromised in med16, suggesting a role for MED16 in JA-ET cross talk. Additionally, MED16 is required for the recruitment of RNA polymerase II to PDF1.2 and OCTADECANOID-RESPONSIVE ARABIDOPSIS ETHYLENE/ETHYLENE-RESPONSIVE FACTOR59 (ORA59), two target genes of both JA/ET-mediated and the transcription factor WRKY33-activated defense pathways. Finally, MED16 is physically associated with WRKY33 in yeast and in planta, and WRKY33-activated transcription of PDF1.2 and ORA59 as well as resistance to S. sclerotiorum depends on MED16. Taken together, these results indicate that MED16 regulates resistance to S. sclerotiorum by governing both JA/ET-mediated and WRKY33-activated defense signaling in Arabidopsis. PMID:26143252

  12. Structural investigation and homology modeling studies of native and truncated forms of alpha-amylases from Sclerotinia sclerotiorum.

    PubMed

    Ben Abdelmalek, Imen; Urdaci, Maria Camino; Ben Ali, Mamdouh; Denayrolles, Muriel; Chaignepain, Stephane; Limam, Ferid; Bejar, Samir; Marzouki, Mohamed Nejib

    2009-11-01

    The filamentous ascomycete Sclerotinia sclerotiorum is well known for its ability to produce a large variety of hydrolytic enzymes for the degradation of plant polysaccharide material. Two alpha-amylases designated as ScAmy54 and ScAmy43 were biochemically characterized and predicted to play an important role in starch degradation. Those enzymes produce specific oligosaccharides, essentially maltotriose, that have a considerable commercial interest. The primary structures of the two enzymes were analyzed by N-terminal sequencing, MALDI-TOF mass spectrometry, and cDNA cloning, and implied that the two proteins have the same N-terminal catalytic domain and ScAmy43 was produced from ScAmy54 by truncation of 96 amino acids at the carboxyl-terminal region. The result of genomic analysis suggested that the two enzymes originated from the same alpha-amylase gene and that truncation of ScAmy54 to ScAmy43 occurred probably during the S. sclerotiorum cultivation. The structural gene of ScAmy54 consisted of 9 exons and 8 introns, containing a single 1,500-bp open reading frame encoding 499 amino acids including a signal peptide of 21 amino acids. ScAmy54 exhibited high amino acid identity to other liquefying fungal alpha-amylases, essentially in the four conserved regions and in the putative catalytic triad. A 3D structure model of ScAmy54 and ScAmy43 was built using the 3D structure of 2guy from A. niger as template. ScAmy54 with three domains A, B, and C, including the well-known (beta/alpha)8-barrel motif in domain A, has a typical structure of the alpha-amylase family. ScAmy43 composed only of domains A and B constitutes a smallest fungal alpha-amylase with only a catalytic domain.

  13. Detecting the Hormonal Pathways in Oilseed Rape behind Induced Systemic Resistance by Trichoderma harzianum TH12 to Sclerotinia sclerotiorum

    PubMed Central

    Alkooranee, Jawadayn Talib; Aledan, Tamarah Raad; Ali, Ali Kadhim; Lu, Guangyuan; Zhang, Xuekun; Wu, Jiangsheng; Fu, Chunhua

    2017-01-01

    Plants have the ability to resist pathogen attack after infection or treatment with biotic and abiotic elicitors. In oilseed rape plant Brassica napus AACC and in the artificially synthesized Raphanus alboglabra RRCC, the root-colonizing Trichoderma harzianum TH12 fungus triggers induced systemic resistance (ISR), and its culture filtrate (CF) triggers a systemic acquired resistance (SAR) response against infection by the Sclerotinia sclerotiorum. Salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) are plant hormone signals that play important roles in the regulation of ISR and SAR. In this study, at six different time points (1, 2, 4, 6, 8 and 10 days post-infection [dpi]), six resistance genes were used as markers of signaling pathways: JA/ET signaling used AOC3, PDF1.2 and ERF2 genes, while PR-1, TGA5 and TGA6 genes were used as markers of SA signaling. The results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that AOC3, PDF1.2 and ERF2 expression levels in infected leaves of AACC and RRCC increase at 1 and 2 dpi with S. sclerotiorum or inoculation with TH12. PR-1, TGA5 and TGA6 expression levels increased at 8 and 10 dpi in infected leaves. PR-1, TGA5 and TGA6 expression levels increased early in plants treated with CF in both of the healthy genotypes. Furthermore, induction of SA- and JA/ET-dependent defense decreased disease symptoms in infected leaves at different times. The results suggest that the RRCC genotype exhibits resistance to disease and that the ability of TH12 and its CF to induce systemic resistance in susceptible and resistant oilseed rape genotypes exists. In addition, the results indicate for the first time that in RRCC the SA signaling pathway is involved in resistance to necrotrophic pathogens. PMID:28045929

  14. Independently founded populations of Sclerotinia sclerotiorum from a tropical and a temperate region have similar genetic structure

    PubMed Central

    2017-01-01

    Sclerotinia sclerotiorum populations from tropical agricultural zones have been suggested to be more variable compared to those from temperate zones. However, no data were available comparing populations from both zones using the same set of markers. In this study, we compared S. sclerotiorum populations from the United States of America (USA, temperate) and southeast Brazil (tropical) using the frequency of mycelial compatibility groups (MCGs) and 13 microsatellite (SSR) markers. Populations were sourced from diseased plants within leguminous crops in New York, USA (NY; n = 78 isolates), and Minas Gerais State, Brazil (MG; n = 109). Twenty MCGs were identified in NY and 14 were previously reported in MG. The effective number of genotypes based on Hill’s number of order 0, which corresponded to the number of multilocus genotypes (MLGs) were 22 (95% CI = 15.6–28.4) and 24 (95% CI = 18.9–29.1) in NY and MG, respectively. Clonal fractions of MLGs were 71.8% (NY) and 78.0% (MG). The effective number of genotypes based on Hill’s number of orders 1 and 2 in NY were 8.9 (95% CI = 5.2–12.6) and 4.4 (95% CI = 2.6–6.1), respectively. For MG these indices were 11.4 (95% CI = 8.7–14.1) and 7.1 (95% CI = 5.1–9.0), respectively. There were no significant differences of allelic richness, private allelic richness, gene diversity, effective number of alleles and genotype evenness between the NY and MG populations. The populations were differentiated, with 29% of total variance attributed to differences between them and G''ST and Jost’s D indices higher than 0.50. Cluster analysis revealed dissimilarity higher than 80% among most MLGs from both populations. Different alleles segregated in the populations but both had similar levels of genotypic variability. PMID:28296968

  15. Detecting the Hormonal Pathways in Oilseed Rape behind Induced Systemic Resistance by Trichoderma harzianum TH12 to Sclerotinia sclerotiorum.

    PubMed

    Alkooranee, Jawadayn Talib; Aledan, Tamarah Raad; Ali, Ali Kadhim; Lu, Guangyuan; Zhang, Xuekun; Wu, Jiangsheng; Fu, Chunhua; Li, Maoteng

    2017-01-01

    Plants have the ability to resist pathogen attack after infection or treatment with biotic and abiotic elicitors. In oilseed rape plant Brassica napus AACC and in the artificially synthesized Raphanus alboglabra RRCC, the root-colonizing Trichoderma harzianum TH12 fungus triggers induced systemic resistance (ISR), and its culture filtrate (CF) triggers a systemic acquired resistance (SAR) response against infection by the Sclerotinia sclerotiorum. Salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) are plant hormone signals that play important roles in the regulation of ISR and SAR. In this study, at six different time points (1, 2, 4, 6, 8 and 10 days post-infection [dpi]), six resistance genes were used as markers of signaling pathways: JA/ET signaling used AOC3, PDF1.2 and ERF2 genes, while PR-1, TGA5 and TGA6 genes were used as markers of SA signaling. The results of quantitative real-time polymerase chain reaction (qRT-PCR) showed that AOC3, PDF1.2 and ERF2 expression levels in infected leaves of AACC and RRCC increase at 1 and 2 dpi with S. sclerotiorum or inoculation with TH12. PR-1, TGA5 and TGA6 expression levels increased at 8 and 10 dpi in infected leaves. PR-1, TGA5 and TGA6 expression levels increased early in plants treated with CF in both of the healthy genotypes. Furthermore, induction of SA- and JA/ET-dependent defense decreased disease symptoms in infected leaves at different times. The results suggest that the RRCC genotype exhibits resistance to disease and that the ability of TH12 and its CF to induce systemic resistance in susceptible and resistant oilseed rape genotypes exists. In addition, the results indicate for the first time that in RRCC the SA signaling pathway is involved in resistance to necrotrophic pathogens.

  16. Independently founded populations of Sclerotinia sclerotiorum from a tropical and a temperate region have similar genetic structure.

    PubMed

    Lehner, Miller S; de Paula Júnior, Trazilbo J; Del Ponte, Emerson M; Mizubuti, Eduardo S G; Pethybridge, Sarah J

    2017-01-01

    Sclerotinia sclerotiorum populations from tropical agricultural zones have been suggested to be more variable compared to those from temperate zones. However, no data were available comparing populations from both zones using the same set of markers. In this study, we compared S. sclerotiorum populations from the United States of America (USA, temperate) and southeast Brazil (tropical) using the frequency of mycelial compatibility groups (MCGs) and 13 microsatellite (SSR) markers. Populations were sourced from diseased plants within leguminous crops in New York, USA (NY; n = 78 isolates), and Minas Gerais State, Brazil (MG; n = 109). Twenty MCGs were identified in NY and 14 were previously reported in MG. The effective number of genotypes based on Hill's number of order 0, which corresponded to the number of multilocus genotypes (MLGs) were 22 (95% CI = 15.6-28.4) and 24 (95% CI = 18.9-29.1) in NY and MG, respectively. Clonal fractions of MLGs were 71.8% (NY) and 78.0% (MG). The effective number of genotypes based on Hill's number of orders 1 and 2 in NY were 8.9 (95% CI = 5.2-12.6) and 4.4 (95% CI = 2.6-6.1), respectively. For MG these indices were 11.4 (95% CI = 8.7-14.1) and 7.1 (95% CI = 5.1-9.0), respectively. There were no significant differences of allelic richness, private allelic richness, gene diversity, effective number of alleles and genotype evenness between the NY and MG populations. The populations were differentiated, with 29% of total variance attributed to differences between them and G''ST and Jost's D indices higher than 0.50. Cluster analysis revealed dissimilarity higher than 80% among most MLGs from both populations. Different alleles segregated in the populations but both had similar levels of genotypic variability.

  17. Differentially expressed proteins and associated histological and disease progression changes in cotyledon tissue of a resistant and susceptible genotype of brassica napus infected with Sclerotinia sclerotiorum.

    PubMed

    Garg, Harsh; Li, Hua; Sivasithamparam, Krishnapillai; Barbetti, Martin J

    2013-01-01

    Sclerotinia rot caused by Sclerotinia sclerotiorum is one of the most serious diseases of oilseed rape. To understand the resistance mechanisms in the Brassica napus to S. sclerotiorum, comparative disease progression, histological and proteomic studies were conducted of two B. napus genotypes (resistant cv. Charlton, susceptible cv. RQ001-02M2). At 72 and 96 h post inoculation (hpi), lesion size on cotyledons was significantly (P≤0.001) smaller in the resistant Charlton. Anatomical investigations revealed impeded fungal growth (at 24 hpi and onwards) and hyphal disintegration only on resistant Charlton. Temporal changes (12, 24, 48 and 72 hpi) in protein profile showed certain enzymes up-regulated only in resistant Charlton, such as those related to primary metabolic pathways, antioxidant defence, ethylene biosynthesis, pathogenesis related proteins, protein synthesis and protein folding, play a role in mediating defence responses against S. sclerotiorum. Similarly a eukaryotic translation initiation factor 5A enzyme with increased abundance in susceptible RQ001-02M2 and decreased levels in resistant Charlton has a role in increased susceptibility to this pathogen. This is the first time that the expression of these enzymes has been shown to be associated with mediating the defence response against S. sclerotinia in cotyledon tissue of a resistant cultivar of B. napus at a proteomics level. This study not only provides important new insights into the resistance mechanisms within B. napus against S. sclerotiorum, but opens the way for novel engineering of new B. napus varieties that over-express these key enzymes as a strategy to enhance resistance and better manage this devastating pathogen.

  18. Differentially Expressed Proteins and Associated Histological and Disease Progression Changes in Cotyledon Tissue of a Resistant and Susceptible Genotype of Brassica napus Infected with Sclerotinia sclerotiorum

    PubMed Central

    Garg, Harsh; Li, Hua; Sivasithamparam, Krishnapillai; Barbetti, Martin J.

    2013-01-01

    Sclerotinia rot caused by Sclerotinia sclerotiorum is one of the most serious diseases of oilseed rape. To understand the resistance mechanisms in the Brassica napus to S. sclerotiorum, comparative disease progression, histological and proteomic studies were conducted of two B. napus genotypes (resistant cv. Charlton, susceptible cv. RQ001-02M2). At 72 and 96 h post inoculation (hpi), lesion size on cotyledons was significantly (P≤0.001) smaller in the resistant Charlton. Anatomical investigations revealed impeded fungal growth (at 24 hpi and onwards) and hyphal disintegration only on resistant Charlton. Temporal changes (12, 24, 48 and 72 hpi) in protein profile showed certain enzymes up-regulated only in resistant Charlton, such as those related to primary metabolic pathways, antioxidant defence, ethylene biosynthesis, pathogenesis related proteins, protein synthesis and protein folding, play a role in mediating defence responses against S. sclerotiorum. Similarly a eukaryotic translation initiation factor 5A enzyme with increased abundance in susceptible RQ001-02M2 and decreased levels in resistant Charlton has a role in increased susceptibility to this pathogen. This is the first time that the expression of these enzymes has been shown to be associated with mediating the defence response against S. sclerotinia in cotyledon tissue of a resistant cultivar of B. napus at a proteomics level. This study not only provides important new insights into the resistance mechanisms within B. napus against S. sclerotiorum, but opens the way for novel engineering of new B. napus varieties that over-express these key enzymes as a strategy to enhance resistance and better manage this devastating pathogen. PMID:23776450

  19. Degradation of oxalic acid by the mycoparasite Coniothyrium minitans plays an important role in interacting with Sclerotinia sclerotiorum.

    PubMed

    Zeng, Li-Mei; Zhang, Jing; Han, Yong-Chao; Yang, Long; Wu, Ming-de; Jiang, Dao-Hong; Chen, Weidong; Li, Guo-Qing

    2014-08-01

    Coniothyrium minitans (Cm) is a mycoparasite of the phytopathogenic fungus Sclerotinia sclerotiorum (Ss). Ss produces a virulence factor oxalic acid (OA) which is toxic to plants and also to Cm, and Cm detoxifies OA by degradation. In this study, two oxalate decarboxylase genes, Cmoxdc1 and Cmoxdc2, were cloned from Cm strain Chy-1. OA and low pH induced expression of Cmoxdc1, but not Cmoxdc2. Cmoxdc1 was partially responsible for OA degradation, whereas Cmoxdc2 had no effect on OA degradation. Disruption of Cmoxdc1 in Cm reduced its ability to infect Ss in dual cultures where OA accumulated. Compared with Chy-1, the Cmoxdc1-disrupted mutants had reduced expression levels of two mycoparasitism-related genes chitinase (Cmch1) and β-1,3-glucanase (Cmg1), and had no detectable activity of extracellular proteases in the presence of OA. On the other hand, the cultural filtrates of the Cmoxdc1-disrupted mutants in OA-amended media showed enhanced antifungal activity, possibly because of increased production of antifungal substances under acidic pH condition resulted from reduced Cmoxdc1-mediated OA degradation. This study provides direct genetic evidence of OA degradation regulating mycoparasitism and antibiosis of Cm against Ss, and sheds light on the sophisticated strategies of Cm in interacting with metabolically active mycelia and dormant sclerotia of Ss.

  20. Oxaloacetate acetylhydrolase gene mutants of Sclerotinia sclerotiorum do not accumulate oxalic acid, but do produce limited lesions on host plants.

    PubMed

    Liang, Xiaofei; Liberti, Daniele; Li, Moyi; Kim, Young-Tae; Hutchens, Andrew; Wilson, Ron; Rollins, Jeffrey A

    2015-08-01

    The oxaloacetate acetylhydrolase (OAH, EC 3.7.1.1)-encoding gene Ss-oah1 was cloned and functionally characterized from Sclerotinia sclerotiorum. Ss-oah1 transcript accumulation mirrored oxalic acid (OA) accumulation with neutral pH induction dependent on the pH-responsive transcriptional regulator Ss-Pac1. Unlike previously characterized ultraviolet (UV)-induced oxalate-deficient mutants ('A' mutants) which retain the capacity to accumulate OA, gene deletion Δss-oah1 mutants did not accumulate OA in culture or during plant infection. This defect in OA accumulation was fully restored on reintroduction of the wild-type (WT) Ss-oah1 gene. The Δss-oah1 mutants were also deficient in compound appressorium and sclerotium development and exhibited a severe radial growth defect on medium buffered at neutral pH. On a variety of plant hosts, the Δss-oah1 mutants established very restricted lesions in which the infectious hyphae gradually lost viability. Cytological comparisons of WT and Δss-oah1 infections revealed low and no OA accumulation, respectively, in subcuticular hyphae. Both WT and mutant hyphae exhibited a transient association with viable host epidermal cells at the infection front. In summary, our experimental data establish a critical requirement for OAH activity in S. sclerotiorum OA biogenesis and pathogenesis, but also suggest that factors independent of OA contribute to the establishment of primary lesions.

  1. Effectiveness and residues of procymidone applied on celery and fennel in the control of Sclerotinia sclerotiorum (Lib.) de Bary.

    PubMed

    Pompi, V; Galli, M; Leandri, A; Forchielli, L

    2005-01-01

    A biennial experimentation has been led using the active ingredient (a.i.) procymidone, for the control of Sclerotinia sclerotiorum (Lib.) De Bary on fennel and celery. At present this utilizathion it is not authorized, even though this "minor use" is considered essential for the control of the various phytopathologies. For every test, both in field and in greenhouse, two treatments to the dose of 40 g/hl of a.i. have been made. After the second treatment two assessments were led to check effectiveness of a.i. and subsequent vegetable samplings have been made to determine the entity and the persistence of the residues of the used active ingredient. At the end of the agricultural cycle, in all the tests a good control of the infection caused by the fungus has been found; statistically significant differences of the infection between treated plots and the control. At harvesting (21 days from the 2nd treatment) we have found a residue average value of 0.1-0.2 mg/kg (field) and 0.3-0.4 mg/kg (greenhouse) on fennel and of: 1.0-1.5 mg/kg (field) e 3.0-3.5 mg/kg (greenhouse) on celery.

  2. pH dependency of sclerotial development and pathogenicity revealed by using genetically defined oxalate-minus mutants of Sclerotinia sclerotiorum.

    PubMed

    Xu, Liangsheng; Xiang, Meichun; White, David; Chen, Weidong

    2015-08-01

    The devastating plant pathogen Sclerotinia sclerotiorum produces copious (up to 50 mM) amounts of oxalic acid, which, for over a quarter century, has been claimed as the pathogenicity determinant based on UV-induced mutants that concomitantly lost oxalate production and pathogenicity. Such a claim was made without fulfilling the molecular Koch's postulates because the UV mutants are genetically undefined and harbour a developmental defect in sclerotial production. Here, we generated oxalate-minus mutants of S. sclerotiorum using two independent mutagenesis techniques, and tested the resulting mutants for growth at different pHs and for pathogenicity on four host plants. The oxalate-minus mutants accumulated fumaric acid, produced functional sclerotia and have reduced ability to acidify the environment. The oxalate-minus mutants retained pathogenicity on plants, but their virulence varied depending on the pH and buffering capacity of host tissue. Acidifying the host tissue enhanced virulence of the oxalate-minus mutants, whereas supplementing with oxalate did not. These results suggest that it is low pH, not oxalic acid itself, that establishes the optimum conditions for growth, reproduction, pathogenicity and virulence expression of S. sclerotiorum. Exonerating oxalic acid as the primary pathogenicity determinant will stimulate research into identifying additional candidates as pathogenicity factors towards better understanding and managing Sclerotinia diseases.

  3. The Complete Genome Sequence of the Phytopathogenic Fungus Sclerotinia sclerotiorum Reveals Insights into the Genome Architecture of Broad Host Range Pathogens

    PubMed Central

    Denton-Giles, Matthew; Hegedus, Dwayne; Seifbarghy, Shirin; Rollins, Jeffrey; van Kan, Jan; Seidl, Michael F.; Faino, Luigi; Mbengue, Malick; Navaud, Olivier; Raffaele, Sylvain; Hammond-Kosack, Kim; Heard, Stephanie; Oliver, Richard

    2017-01-01

    Sclerotinia sclerotiorum is a phytopathogenic fungus with over 400 hosts including numerous economically important cultivated species. This contrasts many economically destructive pathogens that only exhibit a single or very few hosts. Many plant pathogens exhibit a “two-speed” genome. So described because their genomes contain alternating gene rich, repeat sparse and gene poor, repeat-rich regions. In fungi, the repeat-rich regions may be subjected to a process termed repeat-induced point mutation (RIP). Both repeat activity and RIP are thought to play a significant role in evolution of secreted virulence proteins, termed effectors. We present a complete genome sequence of S. sclerotiorum generated using Single Molecule Real-Time Sequencing technology with highly accurate annotations produced using an extensive RNA sequencing data set. We identified 70 effector candidates and have highlighted their in planta expression profiles. Furthermore, we characterized the genome architecture of S. sclerotiorum in comparison to plant pathogens that exhibit “two-speed” genomes. We show that there is a significant association between positions of secreted proteins and regions with a high RIP index in S. sclerotiorum but we did not detect a correlation between secreted protein proportion and GC content. Neither did we detect a negative correlation between CDS content and secreted protein proportion across the S. sclerotiorum genome. We conclude that S. sclerotiorum exhibits subtle signatures of enhanced mutation of secreted proteins in specific genomic compartments as a result of transposition and RIP activity. However, these signatures are not observable at the whole-genome scale. PMID:28204478

  4. Comparative proteomic analysis in pea treated with microbial consortia of beneficial microbes reveals changes in the protein network to enhance resistance against Sclerotinia sclerotiorum.

    PubMed

    Jain, Akansha; Singh, Akanksha; Singh, Surendra; Singh, Vinay; Singh, Harikesh Bahadur

    2015-06-15

    Microbial consortia may provide protection against pathogenic ingress via enhancing plant defense responses. Pseudomonas aeruginosa PJHU15, Trichoderma harzianum TNHU27 and Bacillus subtilis BHHU100 were used either singly or in consortia in the pea rhizosphere to observe proteome level changes upon Sclerotinia sclerotiorum challenge. Thirty proteins were found to increase or decrease differentially in 2-DE gels of pea leaves, out of which 25 were identified by MALDI-TOF MS or MS/MS. These proteins were classified into several functional categories including photosynthesis, respiration, phenylpropanoid metabolism, protein synthesis, stress regulation, carbohydrate and nitrogen metabolism and disease/defense-related processes. The respective homologue of each protein identified was trapped in Pisum sativum and a phylogenetic tree was constructed to check the ancestry. The proteomic view of the defense response to S. sclerotiorum in pea, in the presence of beneficial microbes, highlights the enhanced protection that can be provided by these microbes in challenged plants.

  5. Evidence of ectopic recombination and a repeat-induced point (RIP) mutation in the genome of Sclerotinia sclerotiorum, the agent responsible for white mold

    PubMed Central

    Goldfarb, Míriam; Santana, Mateus Ferreira; Salomão, Tânia Maria Fernandes; de Queiroz, Marisa Vieira; de Barros, Everaldo Gonçalves

    2016-01-01

    Abstract Two retrotransposons from the superfamilies Copia and Gypsy named as Copia-LTR_SS and Gypsy-LTR_SS, respectively, were identified in the genomic bank of Sclerotinia sclerotiorum. These transposable elements (TEs) contained direct and preserved long terminal repeats (LTR). Domains related to codified regions for gag protein, integrase, reverse transcriptase and RNAse H were identified in Copia-LTR_SS, whereas in Gypsy-LTR_SS only domains for gag, reverse transcriptase and RNAse H were found. The abundance of identified LTR-Solo suggested possible genetic recombination events in the S. sclerotiorum genome. Furthermore, alignment of the sequences for LTR elements from each superfamily suggested the presence of a RIP (repeat-induced point mutation) silencing mechanism that may directly affect the evolution of this species. PMID:27560652

  6. Structural and functional characterization of the GalNAc/Gal-specific lectin from the phytopathogenic ascomycete Sclerotinia sclerotiorum (Lib.) de Bary.

    PubMed

    Candy, Laure; Van Damme, Els J M; Peumans, Willy J; Menu-Bouaouiche, Laurence; Erard, Monique; Rougé, Pierre

    2003-08-22

    The lectin found in mycelium and sclerotes of the phytopathogenic fungus Sclerotinia sclerotiorum is a homodimer consisting of two identical non-covalently bound subunits of 16,000 Da. CD spectra analysis revealed that the S. sclerotiorum agglutinin (SSA) contains predominantly beta-sheet structures. SSA exhibits specificity towards GalNAc whereby the hydroxyls at positions 4 and 6 of the pyranose ring play a key role in the interaction with simple sugars. The carbohydrate-binding site of SSA can also accommodate disaccharides. The N-terminal sequence of SSA shares no significant similarity with any other protein except a lectin from the Sclerotiniaceae species Ciborinia camelliae. A comparison of SSA and the lectins from C. camelliae and some previously characterized lectins indicates that the Sclerotiniaceae lectins form a homogeneous family of fungal lectins. This newly identified lectin family, which is structurally unrelated to any other family of fungal lectins, is most probably confined to the Ascomycota.

  7. A Small Secreted Virulence-Related Protein Is Essential for the Necrotrophic Interactions of Sclerotinia sclerotiorum with Its Host Plants

    PubMed Central

    Lyu, Xueliang; Shen, Cuicui; Fu, Yanping; Xie, Jiatao; Jiang, Daohong; Li, Guoqing; Cheng, Jiasen

    2016-01-01

    Small, secreted proteins have been found to play crucial roles in interactions between biotrophic/hemi-biotrophic pathogens and plants. However, little is known about the roles of these proteins produced by broad host-range necrotrophic phytopathogens during infection. Here, we report that a cysteine-rich, small protein SsSSVP1 in the necrotrophic phytopathogen Sclerotinia sclerotiorum was experimentally confirmed to be a secreted protein, and the secretion of SsSSVP1 from hyphae was followed by internalization and cell-to-cell movement independent of a pathogen in host cells. SsSSVP1∆SP could induce significant plant cell death and targeted silencing of SsSSVP1 resulted in a significant reduction in virulence. Through yeast two-hybrid (Y2H), coimmunoprecipitation (co-IP) and bimolecular fluorescence complementation (BiFC) assays, we demonstrated that SsSSVP1∆SP interacted with QCR8, a subunit of the cytochrome b-c1 complex of mitochondrial respiratory chain in plants. Double site-directed mutagenesis of two cysteine residues (C38 and C44) in SsSSVP1∆SP had significant effects on its homo-dimer formation, SsSSVP1∆SP-QCR8 interaction and plant cell death induction, indicating that partial cysteine residues surely play crucial roles in maintaining the structure and function of SsSSVP1. Co-localization and BiFC assays showed that SsSSVP1∆SP might hijack QCR8 to cytoplasm before QCR8 targeting into mitochondria, thereby disturbing its subcellular localization in plant cells. Furthermore, virus induced gene silencing (VIGS) of QCR8 in tobacco caused plant abnormal development and cell death, indicating the cell death induced by SsSSVP1∆SP might be caused by the SsSSVP1∆SP-QCR8 interaction, which had disturbed the QCR8 subcellular localization and hence disabled its biological functions. These results suggest that SsSSVP1 is a potential effector which may manipulate plant energy metabolism to facilitate the infection of S. sclerotiorum. Our findings

  8. Microsatellite markers used for genome-wide association mapping of partial resistance to Sclerotinia sclerotiorum in a world collection of Brassica napus.

    PubMed

    Gyawali, Sanjaya; Harrington, Myrtle; Durkin, Jonathan; Horner, Kyla; Parkin, Isobel A P; Hegedus, Dwayne D; Bekkaoui, Diana; Buchwaldt, Lone

    The fungal pathogen Sclerotinia sclerotiorum causes stem rot of oilseed rape (Brassica napus) worldwide. In preparation for genome-wide association mapping (GWAM) of sclerotinia resistance in B. napus, 152 accessions from diverse geographical regions were screened with a single Canadian isolate, #321. Plants were inoculated by attaching mycelium plugs to the main stem at full flower. Lesion lengths measured 7, 14 and 21 days after inoculation were used to calculate the area under the disease progress curve (AUDPC). Depth of penetration was noted and used to calculate percent soft and collapsed lesions (% s + c). The two disease traits were highly correlated (r = 0.93). Partially resistant accessions (AUDPC <7 and % s + c <2) were identified primarily from South Korea and Japan with a few from Pakistan, China and Europe. Genotyping of accessions with 84 simple sequence repeat markers provided 690 polymorphic loci for GWAM. The general linear model in TASSEL best fitted the data when adjusted for population structure (STRUCTURE), GLM + Q. After correction for positive false discovery rate, 34 loci were significantly associated with both disease traits of which 21 alleles contributed to resistance, while the remaining enhanced susceptibility. The phenotypic variation explained by the loci ranged from 6 to 25 %. Five loci mapped to published quantitative trait loci conferring sclerotinia resistance in Chinese lines.

  9. Members of the germin-like protein family in Brassica napus are candidates for the initiation of an oxidative burst that impedes pathogenesis of Sclerotinia sclerotiorum.

    PubMed

    Rietz, Steffen; Bernsdorff, Friederike E M; Cai, Daguang

    2012-09-01

    Germin-like proteins (GLPs) are defined by their sequence homology to germins from barley and are present ubiquitously in plants. Analyses of corresponding genes have revealed diverse functions of GLPs in plant development and biotic and abiotic stresses. This study describes the identification of a family of 14 germin-like genes from Brassica napus (BnGLP) designated BnGLP1-BnGLP14 and investigated potential functions of BnGLPs in plant defense against the necrotrophic fungus Sclerotinia sclerotiorum. Sequence alignment and phylogenetic analyses classify the 14 BnGLPs into four groups, which were clearly distinguished from known germin oxalic acid oxidases. Transcriptional responses of the BnGLP genes to S. sclerotiorum infection was determined by comparing cultivars of susceptible B. napus 'Falcon' and partially resistant B. napus 'Zhongshuang 9'. Of the 14 BnGLP genes tested, BnGLP3 was transcriptionally upregulated in both B. napus cultivars at 6h after S. sclerotiorum infection, while upregulation of BnGLP12 was restricted to resistant B. napus 'Zhongshuang 9'. Biochemical analysis of five representative BnGLP members identified a H(2)O(2)-generating superoxide dismutase activity only for higher molecular weight complexes of BnGLP3 and BnGLP12. By analogy, H(2)O(2) formation at infected leaf sites increased after 6h, with even higher H(2)O(2) production in B. napus 'Zhongshuang 9' compared with B. napus 'Falcon'. Conversely, exogenous application of H(2)O(2) significantly reduced the susceptibility of B. napus 'Falcon'. These data suggest that early induction of BnGLP3 and BnGLP12 participates in an oxidative burst that may play a pivotal role in defence of B. napus against S. sclerotiorum.

  10. Characterization of a Novel Megabirnavirus from Sclerotinia sclerotiorum Reveals Horizontal Gene Transfer from Single-Stranded RNA Virus to Double-Stranded RNA Virus

    PubMed Central

    Wang, Minghong; Wang, Yong; Sun, Xiangzhong; Cheng, Jiasen; Fu, Yanping; Liu, Huiquan; Jiang, Daohong; Ghabrial, Said A.

    2015-01-01

    ABSTRACT Mycoviruses have been detected in all major groups of filamentous fungi, and their study represents an important branch of virology. Here, we characterized a novel double-stranded RNA (dsRNA) mycovirus, Sclerotinia sclerotiorum megabirnavirus 1 (SsMBV1), in an apparently hypovirulent strain (SX466) of Sclerotinia sclerotiorum. Two similarly sized dsRNA segments (L1- and L2-dsRNA), the genome of SsMBV1, are packaged in rigid spherical particles purified from strain SX466. The full-length cDNA sequence of L1-dsRNA/SsMBV1 comprises two large open reading frames (ORF1 and ORF2), which encode a putative coat protein and an RNA-dependent RNA polymerase (RdRp), respectively. Phylogenetic analysis of the RdRp domain clearly indicates that SsMBV1 is related to Rosellinia necatrix megabirnavirus 1 (RnMBV1). L2-dsRNA/SsMBV1 comprises two nonoverlapping ORFs (ORFA and ORFB) encoding two hypothetical proteins with unknown functions. The 5′-terminal regions of L1- and L2-dsRNA/SsMBV1 share strictly conserved sequences and form stable stem-loop structures. Although L2-dsRNA/SsMBV1 is dispensable for replication, genome packaging, and pathogenicity of SsMBV1, it enhances transcript accumulation of L1-dsRNA/SsMBV1 and stability of virus-like particles (VLPs). Interestingly, a conserved papain-like protease domain similar to a multifunctional protein (p29) of Cryphonectria hypovirus 1 was detected in the ORFA-encoded protein of L2-dsRNA/SsMBV1. Phylogenetic analysis based on the protease domain suggests that horizontal gene transfer may have occurred from a single-stranded RNA (ssRNA) virus (hypovirus) to a dsRNA virus, SsMBV1. Our results reveal that SsMBV1 has a slight impact on the fundamental biological characteristics of its host regardless of the presence or absence of L2-dsRNA/SsMBV1. IMPORTANCE Mycoviruses are widespread in all major fungal groups, and they possess diverse genomes of mostly ssRNA and dsRNA and, recently, circular ssDNA. Here, we have characterized

  11. A Model for Sclerotinia sclerotiorum Infection and Disease Development in Lettuce, Based on the Effects of Temperature, Relative Humidity and Ascospore Density

    PubMed Central

    Clarkson, John P.; Fawcett, Laura; Anthony, Steven G.; Young, Caroline

    2014-01-01

    The plant pathogen Sclerotinia sclerotiorum can cause serious losses on lettuce crops worldwide and as for most other susceptible crops, control relies on the application of fungicides, which target airborne ascospores. However, the efficacy of this approach depends on accurate timing of these sprays, which could be improved by an understanding of the environmental conditions that are conducive to infection. A mathematical model for S. sclerotiorum infection and disease development on lettuce is presented here for the first time, based on quantifying the effects of temperature, relative humidity (RH) and ascospore density in multiple controlled environment experiments. It was observed that disease can develop on lettuce plants inoculated with dry ascospores in the absence of apparent leaf wetness (required for spore germination). To explain this, the model conceptualises an infection court area containing microsites (in leaf axils and close to the stem base) where conditions are conducive to infection, the size of which is modified by ambient RH. The model indicated that minimum, maximum and optimum temperatures for ascospore germination were 0.0, 29.9 and 21.7°C respectively and that maximum rates of disease development occurred at spore densities >87 spores cm−2. Disease development was much more rapid at 80–100% RH at 20°C, compared to 50–70% RH and resulted in a greater proportion of lettuce plants infected. Disease development was also more rapid at 15–27°C compared to 5–10°C (85% RH). The model was validated by a further series of independent controlled environment experiments where both RH and temperature were varied and generally simulated the pattern of disease development well. The implications of the results in terms of Sclerotinia disease forecasting are discussed. PMID:24736409

  12. Brassica napus Genome Possesses Extraordinary High Number of CAMTA Genes and CAMTA3 Contributes to PAMP Triggered Immunity and Resistance to Sclerotinia sclerotiorum.

    PubMed

    Rahman, Hafizur; Xu, You-Ping; Zhang, Xuan-Rui; Cai, Xin-Zhong

    2016-01-01

    Calmodulin-binding transcription activators (CAMTAs) play important roles in various plant biological processes including disease resistance and abiotic stress tolerance. Oilseed rape (Brassica napus L.) is one of the most important oil-producing crops worldwide. To date, compositon of CAMTAs in genomes of Brassica species and role of CAMTAs in resistance to the devastating necrotrophic fungal pathogen Sclerotinia sclerotiorum are still unknown. In this study, 18 CAMTA genes were identified in oilseed rape genome through bioinformatics analyses, which were inherited from the nine copies each in its progenitors Brassica rapa and Brassica oleracea and represented the highest number of CAMTAs in a given plant species identified so far. Gene structure, protein domain organization and phylogentic analyses showed that the oilseed rape CAMTAs were structurally similar and clustered into three major groups as other plant CAMTAs, but had expanded subgroups CAMTA3 and CAMTA4 genes uniquely in rosids species occurring before formation of oilseed rape. A large number of stress response-related cis-elements existed in the 1.5 kb promoter regions of the BnCAMTA genes. BnCAMTA genes were expressed differentially in various organs and in response to treatments with plant hormones and the toxin oxalic acid (OA) secreted by S. sclerotiorum as well as the pathogen inoculation. Remarkably, the expression of BnCAMTA3A1 and BnCAMTA3C1 was drastically induced in early phase of S. sclerotiorum infection, indicating their potential role in the interactions between oilseed rape and S. sclerotiorum. Furthermore, inoculation analyses using Arabidopsis camta mutants demonstrated that Atcamta3 mutant plants exhibited significantly smaller disease lesions than wild-type and other Atcamta mutant plants. In addition, compared with wild-type plants, Atcamta3 plants accumulated obviously more hydrogen peroxide in response to the PAMP chitin and exhibited much higher expression of the CGCG

  13. Biocontrol Potentials of Antimicrobial Peptide Producing Bacillus Species: Multifaceted Antagonists for the Management of Stem Rot of Carnation Caused by Sclerotinia sclerotiorum

    PubMed Central

    Vinodkumar, S.; Nakkeeran, S.; Renukadevi, P.; Malathi, V. G.

    2017-01-01

    Bacillus species are widely exploited as biocontrol agents because of their efficiency in impeding various plant pathogens with multifaceted approach. In this study, Bacillus species were isolated from rhizosphere of various plants viz., carnations, cotton, turmeric, and bananas in Tamil Nadu state of India. Their potential to control the mycelial growth of Sclerotinia sclerotiorum was assessed in vitro by dual plate and partition plate techniques. B. amyloliquefaciens strain VB7 was much effective in inhibiting mycelial growth (45% inhibition of over control) and sclerotial production (100%). PCR detection of AMP genes revealed that B. amyloliquefaciens (VB7) had a maximum of 10 diverse antibiotic biosynthesis genes, namely, ituD, ipa14, bacA, bacD, bamC, sfP, spaC, spaS, alba, and albF, that resulted in production of the antibiotics iturin, bacilysin, bacillomycin, surfactin, subtilin, and subtilosin. Further, metabolites from B. amyloliquefaciens strains VB2 and VB7, associated with inhibition of S. sclerotiorum, were identified as phenols and fatty acids by gas chromatography mass spectrometry (GC-MS). Delivery of bacterial suspension of the effective strains of Bacillus spp. as root dip was found promising for the management of stem rot of cultivated carnations. Minimal percent disease incidence (4.6%) and maximum plant growth promotion was observed in the plants treated with B. amyloliquefaciens (VB7). PMID:28392780

  14. Transcriptional reprogramming underpins enhanced plant growth promotion by the biocontrol fungus Trichoderma hamatum GD12 during antagonistic interactions with Sclerotinia sclerotiorum in soil.

    PubMed

    Shaw, Sophie; Le Cocq, Kate; Paszkiewicz, Konrad; Moore, Karen; Winsbury, Rebecca; de Torres Zabala, Marta; Studholme, David J; Salmon, Deborah; Thornton, Christopher R; Grant, Murray R

    2016-12-01

    The free-living soil fungus Trichoderma hamatum strain GD12 is notable amongst Trichoderma strains in both controlling plant diseases and stimulating plant growth, a property enhanced during its antagonistic interactions with pathogens in soil. These attributes, alongside its markedly expanded genome and proteome compared with other biocontrol and plant growth-promoting Trichoderma strains, imply a rich potential for sustainable alternatives to synthetic pesticides and fertilizers for the control of plant disease and for increasing yields. The purpose of this study was to investigate the transcriptional responses of GD12 underpinning its biocontrol and plant growth promotion capabilities during antagonistic interactions with the pathogen Sclerotinia sclerotiorum in soil. Using an extensive mRNA-seq study capturing different time points during the pathogen-antagonist interaction in soil, we show that dynamic and biphasic signatures in the GD12 transcriptome underpin its biocontrol and plant (lettuce) growth-promoting activities. Functional predictions of differentially expressed genes demonstrate the enrichment of transcripts encoding proteins involved in transportation and oxidation-reduction reactions during both processes and an over-representation of siderophores. We identify a biphasic response during biocontrol characterized by a significant induction of transcripts encoding small-secreted cysteine-rich proteins, secondary metabolite-producing gene clusters and genes unique to GD12. These data support the hypothesis that Sclerotinia biocontrol is mediated by the synthesis and secretion of antifungal compounds and that GD12's unique reservoir of uncharacterized genes is actively recruited during the effective biological control of a plurivorous plant pathogen.

  15. Electrocatalytic oxidation of phytohormone salicylic acid at copper nanoparticles-modified gold electrode and its detection in oilseed rape infected with fungal pathogen Sclerotinia sclerotiorum.

    PubMed

    Wang, Zhan; Wei, Fang; Liu, Sheng-Yi; Xu, Qiao; Huang, Jun-Yan; Dong, Xu-Yan; Yu, Jiu-Hong; Yang, Qin; Zhao, Yuan-Di; Chen, Hong

    2010-01-15

    Salicylic acid (SA) is a biological substance that acts as a phytohormone and plays an important role in signal transduction in plants. It is important to accurately and sensitively detect SA levels. A gold electrode modified with copper nanoparticles was used to assay the electrocatalytic oxidation of salicylic acid. It was found that the electrochemical behavior of salicylic acid was greatly improved at copper nanoparticles, indicating that anodic oxidation could be catalyzed at copper nanoparticles. And the pH had remarkable effect on the electrochemical process, a very well-defined oxidation peak appeared at pH 13.3 (0.2M NaOH). The kinetics parameters of this process were calculated and the heterogeneous electron transfer rate constant (k) was determined to be 1.34x10(-3)cms(-1), and (1-alpha)n(alpha) was 1.22. The gold electrode modified with copper nanoparticles could detect SA at a higher sensitivity than common electrodes. The electrode was used to detect the SA levels in oilseed rape infected with the fungal pathogen Sclerotinia sclerotiorum. The results showed that the SA concentration reached a maximum during the 10th-25th hours after infection. This result was very similar to that determined by HPLC, indicating that the gold electrodes modified with copper nanoparticles could be used as salicylic acid sensors.

  16. Characterization of an extracellularly derived α-mannosidase from the liquid exudate of the sclerotia of Sclerotinia sclerotiorum (Lib.) de Bary.

    PubMed

    Liu, Zhengli; Wei, Ran; He, Wen; Ruan, Ying; Liu, Chunlin

    2015-07-01

    Class I α-mannosidases play an important role in co- and post-translational N-glycosylation modification of proteins, and also in glycoprotein glycan hydrolysis. Herein, we investigated a protein named Man-41, from liquid exudate droplets secreted on the surface of developing sclerotia by Sclerotinia sclerotiorum. The protein was identified by MALDI-TOF mass spectrometry to be a α-mannosidase. The full-length open reading frame of Man-41 consists of 1581 bp, encoding 526 amino acid residues and containing a putative signal peptide at amino acid residues 1-20, and a conserved sequence at residues 50-521. Man-41 was classified into glycoside hydrolase family 47 (GH47) by clustering analysis. The catalytic residues include Glu(125), Arg(129), Asp(270), Ser(271), Glu(274), Arg(420), Glu(422), Glu(425), Glu(485), Thr(514), and Glu(515), which are conserved in all Class I α-1,2-mannosidases. Recombinant Man-41 protein had 26.67 ± 2.18 U/mg of α-mannosidase activity, about one-half of intracellular mannosidase activity of sclerotia. In conclusion, this is the first time that mannosidase has been identified in an extracellular fluid and Man-41 is also a new member of GH47 with Ca(2+)-dependent characteristics. This work lays the foundation for further study of the function of Man-41 in sclerotial development.

  17. Expression and validation of PvPGIP genes for resistance to white mold (Sclerotinia sclerotiorum) in common beans (Phaseolus vulgaris L.).

    PubMed

    Vasconcellos, R C C; Lima, T F C; Fernandes-Brum, C N; Chalfun-Junior, A; Santos, J B

    2016-08-19

    The interaction between polygalacturonase-inhibiting proteins (PGIPs), produced by plants, and endopolygalacturonases (PGs), produced by fungi, limits the destructive potential of PGs and can trigger plant defense responses. This study aimed to i) investigate variation in the expression of different common bean (Phaseolus vulgaris L.) genotypes and its relationship with resistance to white mold (Sclerotinia sclerotiorum); ii) determine the expression levels of PvPGIP genes at different time points after inoculation with white mold; and iii) investigate differences in PvPGIP gene expression between two white mold isolates with different levels of aggressiveness. Four bean lines were analyzed, including two lines from a recurrent selection for white mold (50/5 and 84/6), one resistant line that was not adapted to Brazilian conditions (Cornell 605), and one susceptible line (Corujinha). Gene expression was investigated at 0, 1, 2, 3, and 5 days after inoculation. The isolate UFLA 03 caused no significant difference in the relative expression of any gene examined, and was inefficient in discriminating among the genotypes. For the isolate UFLA 116, all of the genes were differentially expressed, as they were associated with resistance to white mold, and the expressions increased until the third day after inoculation. The 50/5 line was not significantly different from the Corujinha line for all of the genes analyzed. However, this line had a resistance level that was similar to that of Cornell 605, according to the straw test. Therefore, the incorporation of PvPGIP genes can increase the resistance of lines derived from recurrent selection.

  18. Purification, characterization, and partial primary sequence of a major-maltotriose-producing alpha-amylase, ScAmy43, from Sclerotinia sclerotiorum.

    PubMed

    Ben Abdelmalek-Khedher, Imen; Urdaci, Maria Camino; Limam, Ferid; Schmitter, Jean Marie; Marzouki, M Nejib; Bressollier, Philippe

    2008-09-01

    A novel alpha-amylase (alpha-1,4-alpha-D-glucan glucanohydrolase, E.C. 3.2.1.1), ScAmy43, was found in the culture medium of the phytopathogenic fungus Sclerotinia sclerotiorum grown on oats flour. Purified to homogeneity, ScAmy43 appeared as a 43 kDa monomeric enzyme, as estimated by SDS-PAGE and Superdex 75 gel filtration. The MALDI peptide mass fingerprint of ScAmy43 tryptic digest as well as internal sequence analyses indicate that the enzyme has an original primary structure when compared with other fungal alpha- amylases. However, the sequence of the 12 N-terminal residues is homologous with those of Aspergillus awamori and Aspergillus kawachii amylases, suggesting that the new enzyme belongs to the same GH13 glycosyl hydrolase family. Assayed with soluble starch as substrate, this enzyme displayed optimal activity at pH 4 and 55oC with an apparent Km value of 1.66 mg/ml and Vmax of 0.1 micromol glucose x min-1 x ml-1. ScAmy43 activity was strongly inhibited by Cu2+, Mn2+, and Ba2+, moderately by Fe2+, and was only weakly affected by Ca2+ addition. However, since EDTA and EGTA did not inhibit ScAmy43 activity, this enzyme is probably not a metalloprotein. DTT and beta-mercaptoethanol strongly increased the enzyme activity. Starting with soluble starch as substrate, the end products were mainly maltotriose, suggesting for this enzyme an endo action.

  19. Genome-Wide Identification of Dicer-Like, Argonaute, and RNA-Dependent RNA Polymerase Gene Families in Brassica Species and Functional Analyses of Their Arabidopsis Homologs in Resistance to Sclerotinia sclerotiorum

    PubMed Central

    Cao, Jia-Yi; Xu, You-Ping; Li, Wen; Li, Shuang-Sheng; Rahman, Hafizur; Cai, Xin-Zhong

    2016-01-01

    RNA silencing is an important mechanism to regulate gene expression and antiviral defense in plants. Nevertheless, RNA silencing machinery in the important oil crop Brassica napus and function in resistance to the devastating fungal pathogen Sclerotinia sclerotiorum are not well-understood. In this study, gene families of RNA silencing machinery in B. napus were identified and their role in resistance to S. sclerotiorum was revealed. Genome of the allopolyploid species B. napus possessed 8 Dicer-like (DCL), 27 Argonaute (AGO), and 16 RNA-dependent RNA polymerase (RDR) genes, which included almost all copies from its progenitor species B. rapa and B. oleracea and three extra copies of RDR5 genes, indicating that the RDR5 group in B. napus appears to have undergone further expansion through duplication during evolution. Moreover, compared with Arabidopsis, some AGO and RDR genes such as AGO1, AGO4, AGO9, and RDR5 had significantly expanded in these Brassica species. Twenty-one out of 51 DCL, AGO, and RDR genes were predicted to contain calmodulin-binding transcription activators (CAMTA)-binding site (CGCG box). S. sclerotiorum inoculation strongly induced the expression of BnCAMTA3 genes while significantly suppressed that of some CGCG-containing RNA silencing component genes, suggesting that RNA silencing machinery might be targeted by CAMTA3. Furthermore, Arabidopsis mutant analyses demonstrated that dcl4-2, ago9-1, rdr1-1, rdr6-11, and rdr6-15 mutants were more susceptible to S. sclerotiorum, while dcl1-9 was more resistant. Our results reveal the importance of RNA silencing in plant resistance to S. sclerotiorum and imply a new mechanism of CAMTA function as well as RNA silencing regulation. PMID:27833632

  20. Genome-Wide Identification of Dicer-Like, Argonaute, and RNA-Dependent RNA Polymerase Gene Families in Brassica Species and Functional Analyses of Their Arabidopsis Homologs in Resistance to Sclerotinia sclerotiorum.

    PubMed

    Cao, Jia-Yi; Xu, You-Ping; Li, Wen; Li, Shuang-Sheng; Rahman, Hafizur; Cai, Xin-Zhong

    2016-01-01

    RNA silencing is an important mechanism to regulate gene expression and antiviral defense in plants. Nevertheless, RNA silencing machinery in the important oil crop Brassica napus and function in resistance to the devastating fungal pathogen Sclerotinia sclerotiorum are not well-understood. In this study, gene families of RNA silencing machinery in B. napus were identified and their role in resistance to S. sclerotiorum was revealed. Genome of the allopolyploid species B. napus possessed 8 Dicer-like (DCL), 27 Argonaute (AGO), and 16 RNA-dependent RNA polymerase (RDR) genes, which included almost all copies from its progenitor species B. rapa and B. oleracea and three extra copies of RDR5 genes, indicating that the RDR5 group in B. napus appears to have undergone further expansion through duplication during evolution. Moreover, compared with Arabidopsis, some AGO and RDR genes such as AGO1, AGO4, AGO9, and RDR5 had significantly expanded in these Brassica species. Twenty-one out of 51 DCL, AGO, and RDR genes were predicted to contain calmodulin-binding transcription activators (CAMTA)-binding site (CGCG box). S. sclerotiorum inoculation strongly induced the expression of BnCAMTA3 genes while significantly suppressed that of some CGCG-containing RNA silencing component genes, suggesting that RNA silencing machinery might be targeted by CAMTA3. Furthermore, Arabidopsis mutant analyses demonstrated that dcl4-2, ago9-1, rdr1-1, rdr6-11, and rdr6-15 mutants were more susceptible to S. sclerotiorum, while dcl1-9 was more resistant. Our results reveal the importance of RNA silencing in plant resistance to S. sclerotiorum and imply a new mechanism of CAMTA function as well as RNA silencing regulation.

  1. Multiplex PCR for four Sclerotinia species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia homeocarpa, S. minor, S. sclerotiorum, and S. trifoliorum are common species within the genus Sclerotinia, where the morphological identification is challenging, especially when one crop hosts multiple species. The objective of this study was to design species specific primers compatibl...

  2. Narrow-Leafed Lupin (Lupinus angustifolius) β1- and β6-Conglutin Proteins Exhibit Antifungal Activity, Protecting Plants against Necrotrophic Pathogen Induced Damage from Sclerotinia sclerotiorum and Phytophthora nicotianae

    PubMed Central

    Jimenez-Lopez, Jose C.; Melser, Su; DeBoer, Kathleen; Thatcher, Louise F.; Kamphuis, Lars G.; Foley, Rhonda C.; Singh, Karam B.

    2016-01-01

    Vicilins (7S globulins) are seed storage proteins and constitute the main protein family in legume seeds, particularly in narrow-leafed lupin (Lupinus angustifolius L.; NLL), where seven vicilin genes, called β1- to β7-conglutin have been identified. Vicilins are involved in germination processes supplying amino acids for seedling growth and plant development, as well as in some cases roles in plant defense and protection against pathogens. The roles of NLL β-conglutins in plant defense are unknown. Here the potential role of five NLL β-conglutin family members in protection against necrotrophic fungal pathogens was investigated and it was demonstrated that recombinant purified 6xHis-tagged β1- and β6-conglutin proteins exhibited the strongest in vitro growth inhibitory activity against a range of necrotrophic fungal pathogens compared to β2, β3, and β4 conglutins. To examine activity in vivo, two representative necrotrophic pathogens, the fungus Sclerotinia sclerotiorum and oomycete Phytophthora nicotianae were used. Transient expression of β1- and β6-conglutin proteins in Nicotiana benthamiana leaves demonstrated in vivo growth suppression of both of these pathogens, resulting in low percentages of hyphal growth and elongation in comparison to control treated leaves. Cellular studies using β1- and β6-GFP fusion proteins showed these conglutins localized to the cell surface including plasmodesmata. Analysis of cellular death following S. sclerotiorum or P. nicotianae revealed both β1- and β6-conglutins suppressed pathogen induced cell death in planta and prevented pathogen induced suppression of the plant oxidative burst as determined by protein oxidation in infected compared to mock-inoculated leaves. PMID:28018392

  3. Spatiotemporal characterization of Sclerotinia crown rot epidemics in pyrethrum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia crown rot, caused by Sclerotinia minor and S. sclerotiorum is a disease of pyrethrum in Australia that may cause substantial decline in plant density. The spatiotemporal characteristics of the disease were quantified in 14 fields spread across three growing seasons. Fitting the binary ...

  4. A polymerase chain reaction assay for ascosporic inoculum of Sclerotinia species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A PCR assay was developed which amplified a 170-bp fragment of the intergenic spacer region of Sclerotinia sclerotiorum, the cause of white mould. Sensitivity was 10 S. sclerotiorum ascospores per DNA extraction (0.2 ascospores per PCR reaction). The presence of soil did not affect sensitivity a...

  5. Identification and functional analysis of candidate Sclerotinia defense genes in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have conducted a series of microarray studies that enabled us to identify genes that are significantly differentially expressed in soybean plants in response to Sclerotinia sclerotiorum. We are expanding these studies to include effects of oxalic acid, a major virulence factor of S. sclerotiorum....

  6. Greenhouse evaluation of wild sunflower species for resistance to Sclerotinia wilt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wild sunflowers have been a frequent source of genes for disease resistance for cultivated sunflowers, but are largely unexplored in terms of resistance to Sclerotinia wilt, caused by the fungus Sclerotinia sclerotiorum. The initial goal of this project was to develop a reliable greenhouse screening...

  7. Crop damage from Sclerotinia crown rot and risk factors in pyrethrum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia crown rot, caused by Sclerotinia sclerotiorum and S. minor, is a prevalent disease in pyrethrum fields in Australia. Management involves the application of fungicides during the rosette stage of plant development during autumn to early spring in fields approaching first-harvest, althoug...

  8. Genomic analysis of soybean resistance to Sclerotinia sclerotiorm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that infects soybean causing white mold disease. Oxalic acid is considered to be its major virulence factor. Plants from the oxalate oxidase (OxO) transgenic line (80(30)1) which showed resistance to the pathogen and its susceptible parent l...

  9. Genotyping-by-sequencing uncovers the introgression alien segments associated with Sclerotinia basal stalk rot resistance from wild species—I. Helianthus argophyllus and H. petiolaris

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Basal stalk rot (BSR), caused by Sclerotinia Sclerotiorum, is a devastating disease in sunflower worldwide. The progress of breeding for Sclerotinia BSR resistance has been hampered due to the lack of effective sources of resistance for cultivated sunflower. Our objective was to transfer BSR resista...

  10. Progress on the introgression of Sclerotinia resistance genes from wild perennial Helianthus species into cultivated sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The necrotrophic fungus Sclerotinia sclerotiorum (Lib.) de Bary attacks sunflower (Helianthus annuus L.) causing root, stalk, and head rot, and is one of the most damaging and difficult-to-control sunflower diseases. Some wild perennial Helianthus species have been identified to contain abundant res...

  11. SNP discovery and QTL mapping of Sclerotinia basal stalk rot resistance in sunflower using genotyping-by-sequencing (GBS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Basal stalk rot (BSR) caused by the ascomycete fungus Sclerotinia sclerotiorum (Lib.) de Bary is a serious disease of sunflower (Helianthus annuus L.) in the cool and humid production areas of the world. Quantitative trait loci (QTL) for BSR resistance were identified in a sunflower recombinant inbr...

  12. Discriminatory simplex and multiplex PCR for four species of the genus Sclerotinia.

    PubMed

    Abd-Elmagid, Ahmed; Garrido, Patricia A; Hunger, Robert; Lyles, Justin L; Mansfield, Michele A; Gugino, Beth K; Smith, Damon L; Melouk, Hassan A; Garzon, Carla D

    2013-03-01

    Sclerotinia sclerotiorum (Lib.) de Bary, S. minor Jagger, S. trifoliorum Eriks, and S. homoeocarpa F.T. Benn are the most relevant plant pathogenic species within the genus Sclerotinia because of their large range of economically important hosts, including tomato, peanut, alfalfa, and turfgrass, among others. Species identification based on morphological characteristics is challenging and time demanding, especially when one crop hosts multiple species. The objective of this study was to design specific primers compatible with multiplexing, for rapid, sensitive and accurate detection and discrimination among four Sclerotinia species. Specific primers were designed for the aspartyl protease gene of S. sclerotiorum, the calmodulin gene of S. trifoliorum, the elongation factor-1 alpha gene of S. homoeocarpa, and the laccase 2 gene of S. minor. The specificity and sensitivity of each primer set was tested individually and in multiplex against isolates of each species and validated using genomic DNA from infected plants. Each primer set consistently amplified DNA of its target gene only. DNA fragments of different sizes were amplified: a 264 bp PCR product for S. minor, a 218 bp product for S. homoeocarpa, a 171 bp product for S. sclerotiorum, and a 97 bp product for S. trifoliorum. These primer sets can be used individually or in multiplex for identification of Sclerotinia spp. in pure culture or from infected plants. The multiplex assay had a lower sensitivity limit than the simplex assays (0.0001 pg/μL DNA of each species). The multiplex assay developed is an accurate and rapid tool to differentiate between the most relevant plant pathogenic Sclerotinia species in a single PCR reaction.

  13. Use of formulated Trichoderma sp. Tri-1 in combination with reduced rates of chemical pesticide for control of Sclerotinia sclerotiorium on oilseed rape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable strategies for control of Sclerotinia sclerotiorum on oilseed rape are needed. Here we tested combinations of Trichoderma sp. Tri-1, formulated with oilseed rape seedcake and straw, with reduced application rates of the chemical pesticide Carbendazim for control of this pathogen on oils...

  14. Association mapping in sunflower for sclerotinia head rot resistance

    PubMed Central

    2012-01-01

    Background Sclerotinia Head Rot (SHR) is one of the most damaging diseases of sunflower in Europe, Argentina, and USA, causing average yield reductions of 10 to 20 %, but leading to total production loss under favorable environmental conditions for the pathogen. Association Mapping (AM) is a promising choice for Quantitative Trait Locus (QTL) mapping, as it detects relationships between phenotypic variation and gene polymorphisms in existing germplasm without development of mapping populations. This article reports the identification of QTL for resistance to SHR based on candidate gene AM. Results A collection of 94 sunflower inbred lines were tested for SHR under field conditions using assisted inoculation with the fungal pathogen Sclerotinia sclerotiorum. Given that no biological mechanisms or biochemical pathways have been clearly identified for SHR, 43 candidate genes were selected based on previous transcript profiling studies in sunflower and Brassica napus infected with S. sclerotiorum. Associations among SHR incidence and haplotype polymorphisms in 16 candidate genes were tested using Mixed Linear Models (MLM) that account for population structure and kinship relationships. This approach allowed detection of a significant association between the candidate gene HaRIC_B and SHR incidence (P < 0.01), accounting for a SHR incidence reduction of about 20 %. Conclusions These results suggest that AM will be useful in dissecting other complex traits in sunflower, thus providing a valuable tool to assist in crop breeding. PMID:22708963

  15. Genome-wide association analysis and differential expression analysis of resistance to Sclerotinia stem rot in Brassica napus.

    PubMed

    Wei, Lijuan; Jian, Hongju; Lu, Kun; Filardo, Fiona; Yin, Nengwen; Liu, Liezhao; Qu, Cunmin; Li, Wei; Du, Hai; Li, Jiana

    2016-06-01

    Brassica napus is one of the most important oil crops in the world, and stem rot caused by the fungus Sclerotinia sclerotiorum results in major losses in yield and quality. To elucidate resistance genes and pathogenesis-related genes, genome-wide association analysis of 347 accessions was performed using the Illumina 60K Brassica SNP (single nucleotide polymorphism) array. In addition, the detached stem inoculation assay was used to select five highly resistant (R) and susceptible (S) B. napus lines, 48 h postinoculation with S. sclerotiorum for transcriptome sequencing. We identified 17 significant associations for stem resistance on chromosomes A8 and C6, five of which were on A8 and 12 on C6. The SNPs identified on A8 were located in a 409-kb haplotype block, and those on C6 were consistent with previous QTL mapping efforts. Transcriptome analysis suggested that S. sclerotiorum infection activates the immune system, sulphur metabolism, especially glutathione (GSH) and glucosinolates in both R and S genotypes. Genes found to be specific to the R genotype related to the jasmonic acid pathway, lignin biosynthesis, defence response, signal transduction and encoding transcription factors. Twenty-four genes were identified in both the SNP-trait association and transcriptome sequencing analyses, including a tau class glutathione S-transferase (GSTU) gene cluster. This study provides useful insight into the molecular mechanisms underlying the plant's response to S. sclerotiorum.

  16. Genomic evaluation of oxalate-degrading transgenic soybean in response to Sclerotinia sclerotiorum infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxalate oxidases catalyze the degradation of oxalic acid (OA). Highly resistant transgenic soybean carrying an oxalate oxidase (OxO) gene and its susceptible parent soybean line, AC Colibri, were tested for genome-wide gene expression in response to the necrotrophic, OA producing pathogen Sclerotini...

  17. Interference and Mechanism of Dill Seed Essential Oil and Contribution of Carvone and Limonene in Preventing Sclerotinia Rot of Rapeseed

    PubMed Central

    Huang, Bo; He, Jingsheng; Tian, Jun; Zeng, Hong; Chen, Yuxin; Wang, Youwei

    2015-01-01

    This study aimed to evaluate the inhibitory effects of dill (Anethum graveolens L.) seed essential oil against Sclerotinia sclerotiorum and its mechanism of action. The antifungal activities of the two main constituents, namely carvone and limonene, were also measured. Mycelial growth and sclerotial germination were thoroughly inhibited by dill seed essential oil at the 1.00 μL/mL under contact condition and 0.125μL/mL air under vapor condition. Carvone also contributed more than limonene in inhibiting the growth of S. sclerotiorum. Carvone and limonene synergistically inhibited the growth of the fungus. In vivo experiments, the essential oil remarkably suppressed S. sclerotiorum, and considerable morphological alterations were observed in the hyphae and sclerotia. Inhibition of ergosterol synthesis, malate dehydrogenase, succinate dehydrogenase activities, and external medium acidification were investigated to elucidate the antifungal mechanism of the essential oil. The seed essential oil of A. graveolens can be extensively used in agriculture for preventing the oilseed crops fungal disease. PMID:26133771

  18. Interference and Mechanism of Dill Seed Essential Oil and Contribution of Carvone and Limonene in Preventing Sclerotinia Rot of Rapeseed.

    PubMed

    Ma, Bingxin; Ban, Xiaoquan; Huang, Bo; He, Jingsheng; Tian, Jun; Zeng, Hong; Chen, Yuxin; Wang, Youwei

    2015-01-01

    This study aimed to evaluate the inhibitory effects of dill (Anethum graveolens L.) seed essential oil against Sclerotinia sclerotiorum and its mechanism of action. The antifungal activities of the two main constituents, namely carvone and limonene, were also measured. Mycelial growth and sclerotial germination were thoroughly inhibited by dill seed essential oil at the 1.00 μL/mL under contact condition and 0.125μL/mL air under vapor condition. Carvone also contributed more than limonene in inhibiting the growth of S. sclerotiorum. Carvone and limonene synergistically inhibited the growth of the fungus. In vivo experiments, the essential oil remarkably suppressed S. sclerotiorum, and considerable morphological alterations were observed in the hyphae and sclerotia. Inhibition of ergosterol synthesis, malate dehydrogenase, succinate dehydrogenase activities, and external medium acidification were investigated to elucidate the antifungal mechanism of the essential oil. The seed essential oil of A. graveolens can be extensively used in agriculture for preventing the oilseed crops fungal disease.

  19. Inhibitory effect and enzymatic analysis of E-cinnamaldehyde against sclerotinia carrot rot.

    PubMed

    Ojaghian, Mohammad Reza; Wang, Qi; Li, Xiaolin; Sun, Xiaoting; Xie, Guan-Lin; Zhang, Jingze; Hai-Wei, Fan; Wang, Li

    2016-02-01

    This study was conducted to determine the inhibitory effect of E-cinnamaldehyde (EC) against causal agent of storage carrot rot, Sclerotinia sclerotiorum, under in vivo and in vitro conditions. Based on the results, EC was able to completely inhibit mycelial growth of three isolates (P>0.05) in both volatile and contact phases after 6days at the concentrations 200μl and 1μl/ml, respectively. In addition, EC at concentrations 1 and 10μl/ml completely inhibited carpogenic germination of three isolates. The results of in vivo trials showed that EC at the concentration of 10μl/ml was able to control the disease caused by isolates 1 and 3. However the disease caused by isolate 2 was inhibited with the concentration of 20μl/ml. In enzyme analyses, the activity of polyphenoloxidase and peroxidase did not change in the inoculated carrots after application of EC. Furthermore, the level of phenylalanine ammonia lyase decreased. These results indicated that EC does not have any potential to be considered as resistance inducers against sclerotinia carrot rot.

  20. Common protein sequence signatures associate with Sclerotinia borealis lifestyle and secretion in fungal pathogens of the Sclerotiniaceae

    PubMed Central

    Badet, Thomas; Peyraud, Rémi; Raffaele, Sylvain

    2015-01-01

    Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases. PMID:26442085

  1. Analysis of genes that are differentially expressed during the Sclerotinia sclerotiorum–Phaseolus vulgaris interaction

    PubMed Central

    Oliveira, Marília B.; de Andrade, Rosângela V.; Grossi-de-Sá, Maria F.; Petrofeza, Silvana

    2015-01-01

    The fungus Sclerotinia sclerotiorum (Lib.) de Bary, one of the most important plant pathogens, causes white mold on a wide range of crops. Crop yield can be dramatically decreased due to this disease, depending on the plant cultivar and environmental conditions. In this study, a suppression subtractive hybridization cDNA library approach was used for the identification of pathogen and plant genes that were differentially expressed during infection of the susceptible cultivar BRS Pérola of Phaseolus vulgaris L. A total of 979 unigenes (430 contigs and 549 singletons) were obtained and classified according to their functional categories. The transcriptional profile of 11 fungal genes related to pathogenicity and virulence were evaluated by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). Additionally, the temporal expression profile obtained by RT-qPCR was evaluated for the following categories of plant defense-related genes: pathogenesis-related genes (PvPR1, PvPR2, and PvPR3), phenylpropanoid pathway genes (PvIsof, PvFPS1, and 4CL), and genes involved in defense and stress-related categories (PvLox, PvHiprp, PvGST, PvPod, and PvDox). Data obtained in this study provide a starting point for achieving a better understanding of the pathosystem S. sclerotiorum–P. vulgaris. PMID:26579080

  2. HERITABILITY OF CLOVER ROT RESISTANCE (SCLEROTINIA SPP.) IN RED CLOVER (TRIFOLIUM PRATENSE) POPULATIONS.

    PubMed

    Vleugels, T; Van Bockstaele, E

    2014-01-01

    European red clover (Trifolium pratense) crops are susceptible to clover rot, a destructive disease caused by Sclerotinia trifoliorum or S. sclerotiorum. The lack of knowledge on the heritability of clover rot resistance is, among other reasons, responsible for the slow progress of resistance breeding. In this paper, we acquired insight in the heritability of clover rot resistance through divergent selection by our high-throughput bio-test on an experimental diploid population. The disease susceptibility indices of the first generation after selection for susceptibility and the first and the second generation after selection for resistance were compared with the susceptibility of the original population. The susceptible population (79.2%), the original population (70.5%) and the first generation resistant population (62.3%) differed significantly in susceptibility (p < 0.001). The first (62.3%) and second generation resistant population (60.0%) did not differ significantly in susceptibility. The heritability (h2) of clover rot resistance was low: 0.34 and 0.07 in the first and second cycle of selection respectively. This indicates that mass selection is not suitable to improve clover rot resistance. Family selection may allow a sustained increase in resistance for multiple generations.

  3. Transferring Sclerotinia Resistance Genes from Wild Helianthus into Cultivated Sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To enhance resistance to Sclerotinia head and stalk rot in cultivated sunflower, mining and introgression of Sclerotinia resistance genes from diverse wild Helianthus accessions into cultivated sunflower has been conducted using backcrossing method since 2004. During the last four years, numerous in...

  4. Developing Sclerotinia Resistant Sunflower Germplasm Utilizing Wild Perennial Helianthus Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivated sunflower lacks a sufficient level of resistance to both Sclerotinia stalk and head rot, but abundant resistance in perennial Helianthus species has been confirmed. The objectives of this project were to transfer Sclerotinia head and stalk rot resistance genes from wild perennial hexaploi...

  5. Responses of high O/L peanut cultivars to fungicide for control of Sclerotinia blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia blight, caused by Sclerotinia minor, remains an important disease of peanuts in Oklahoma where it causes severe damage when prolonged periods of wet weather occur during mid to late season. Progress has been made in increasing the resistance of peanut cultivars to Sclerotinia blight. S...

  6. Response to oxalic acid as a resistance assay for Sclerotinia minor in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Response to oxalic acid was evaluated as a potential assay for screening peanut breeding lines for resistance to Sclerotinia blight caused by Sclerotinia minor. Detached stems of seven Spanish- and six runner-type peanut cultivars and advanced breeding lines, varying in resistance to Sclerotinia bl...

  7. A taxonomic and phylogenetic revision of the Penicillium sclerotiorum complex

    PubMed Central

    Rivera, K.G.; Seifert, K.A.

    2011-01-01

    The morphological concept of Penicillium sclerotiorum (subgenus Aspergilloides) includes strains with monoverticillate, vesiculate conidiophores, and vivid orange to red colony colours, with colourful sclerotia sometimes produced. Multigene phylogenetic analyses with the nuclear ribosomal internal transcribed spacer (ITS) region, cytochrome c oxidase subunit 1 (cox1), β-tubulin (benA), translation elongation factor 1-α (tef1-α), and calmodulin (cmd), reveal that the P. sclerotiorum morphospecies is a complex of seven phylogenetically distinct species, three of which were recently described, namely P. guanacastense, P. mallochii, and P. viticola. Three previously unidentified species are described here as P. cainii, P. jacksonii, and P. johnkrugii. The phylogenetic species are morphologically similar, but differ in combinations of colony characters, sclerotium production, conidiophore stipe roughening and branching, and conidial shape. Ecological characters and differences in geographical distribution further characterise some of the species, but increased sampling is necessary to confirm these differences. The fungal DNA barcode, the ITS, and the animal DNA barcode, cox1, have lower species resolving ability in our phylogenetic analyses, but still allow identification of all the species. Tef1-α and cmd were superior in providing fully resolved, statistically well-supported phylogenetic trees for this species complex, whereas benA resolved all species but had some issues with paraphyly. Penicillium adametzioides and P. multicolor, considered synonyms of P. sclerotiorum by some previous authors, do not belong to the P. sclerotiorum complex. Taxonomic novelties: New species: Penicillium cainii K.G. Rivera, Malloch & Seifert, P. jacksonii K.G. Rivera, Houbraken & Seifert, P. johnkrugii K.G. Rivera, Houbraken & Seifert. PMID:22308047

  8. Genome Sequencing and Analysis of the Filamentous Fungus Penicillium sclerotiorum 113, Isolated after Hurricane Sandy.

    PubMed

    Yin, Guohua; Zhang, Yuliang; Pennerman, Kayla K; Hua, Sui Sheng T; Huang, Qixing; Guo, Anping; Liu, Zhixin; Bennett, Joan W

    2016-11-23

    Penicillium sclerotiorum is a distinctive species within the genus Penicillium that usually produces vivid orange to red colonies, sometimes with colorful sclerotia. Here, we report the first draft genome sequence of P. sclerotiorum strain 113, isolated in 2013 in the aftermath of Hurricane Sandy from a flooded home in New Jersey.

  9. Genome Sequencing and Analysis of the Filamentous Fungus Penicillium sclerotiorum 113, Isolated after Hurricane Sandy

    PubMed Central

    Zhang, Yuliang; Pennerman, Kayla K.; Hua, Sui Sheng T.; Huang, Qixing; Guo, Anping; Liu, Zhixin; Bennett, Joan W.

    2016-01-01

    Penicillium sclerotiorum is a distinctive species within the genus Penicillium that usually produces vivid orange to red colonies, sometimes with colorful sclerotia. Here, we report the first draft genome sequence of P. sclerotiorum strain 113, isolated in 2013 in the aftermath of Hurricane Sandy from a flooded home in New Jersey. PMID:27881534

  10. Draft Genome Sequences of the Turfgrass Pathogen Sclerotinia homoeocarpa

    PubMed Central

    Sang, Hyunkyu; Chang, Taehyun; Allan-Perkins, Elisha; Petit, Elsa

    2016-01-01

    Sclerotinia homoeocarpa (F. T. Bennett) is one of the most economically important pathogens on high-amenity cool-season turfgrasses, where it causes dollar spot. To understand the genetic mechanisms of fungicide resistance, which has become highly prevalent, the whole genomes of two isolates with varied resistance levels to fungicides were sequenced. PMID:26868400

  11. Three inoculation methods for evaluating Sclerotinia blight resistance in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory-based assays for screening germplasm for resistance to Sclerotinia blight in peanuts can be conducted year-round, and thus may accelerate progress in breeding for resistant plants. Three previously proposed inoculation methods (using main stems of intact plants, detached main stems, or de...

  12. Breeding and quantitative genetics advances in sunflower Sclerotinia research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic research of the sunflower research unit, USDA-ARS, in Fargo, ND, was discussed in a presentation to a group of producers, industry representatives, and scientists. The need for sunflower quantitative genetics research to find and capture Sclerotinia resistance is increasing with every year t...

  13. Genotyping-by-Sequencing Uncovers the Introgression Alien Segments Associated with Sclerotinia Basal Stalk Rot Resistance from Wild Species-I. Helianthus argophyllus and H. petiolaris.

    PubMed

    Qi, Lili; Long, Yunming; Talukder, Zahirul I; Seiler, Gerald J; Block, Charles C; Gulya, Thomas J

    2016-01-01

    Basal stalk rot (BSR), caused by Sclerotinia sclerotiorum, is a devastating disease in sunflower worldwide. The progress of breeding for Sclerotinia BSR resistance has been hampered due to the lack of effective sources of resistance for cultivated sunflower. Our objective was to transfer BSR resistance from wild annual Helianthus species into cultivated sunflower and identify the introgressed alien segments associated with BSR resistance using a genotyping-by-sequencing (GBS) approach. The initial crosses were made between the nuclear male sterile HA 89 with the BSR resistant plants selected from wild Helianthus argophyllus and H. petiolaris populations in 2009. The selected resistant F1 plants were backcrossed to HA 458 and HA 89, respectively. Early generation evaluations of BSR resistance were conducted in the greenhouse, while the BC2F3 and subsequent generations were evaluated in the inoculated field nurseries. Eight introgression lines; six from H. argophyllus (H.arg 1 to H.arg 6), and two from H. petiolaris (H.pet 1 and H.pet 2), were selected. These lines consistently showed high levels of BSR resistance across seven environments from 2012 to 2015 in North Dakota and Minnesota, USA. The mean BSR disease incidence (DI) for H.arg 1 to H.arg 6, H.pet 1, and H.pet 2 was 3.0, 3.2, 0.8, 7.2, 7.7, 1.9, 2.5, and 4.4%, compared to a mean DI of 36.1% for Cargill 270 (susceptible hybrid), 31.0% for HA 89 (recurrent parent), 19.5% for HA 441 (resistant inbred), and 11.6% for Croplan 305 (resistant hybrid). Genotyping of the highly BSR resistant introgression lines using GBS revealed the presence of the H. argophyllus segments in linkage groups (LGs) 3, 8, 9, 10, and 11 of the sunflower genome, and the H. petiolaris segments only in LG8. The shared polymorphic SNP loci in the introgression lines were detected in LGs 8, 9, 10, and 11, indicating the common introgression regions potentially associated with BSR resistance. Additionally, a downy mildew resistance gene, Pl17

  14. Genotyping-by-Sequencing Uncovers the Introgression Alien Segments Associated with Sclerotinia Basal Stalk Rot Resistance from Wild Species—I. Helianthus argophyllus and H. petiolaris

    PubMed Central

    Qi, Lili; Long, Yunming; Talukder, Zahirul I.; Seiler, Gerald J.; Block, Charles C.; Gulya, Thomas J.

    2016-01-01

    Basal stalk rot (BSR), caused by Sclerotinia sclerotiorum, is a devastating disease in sunflower worldwide. The progress of breeding for Sclerotinia BSR resistance has been hampered due to the lack of effective sources of resistance for cultivated sunflower. Our objective was to transfer BSR resistance from wild annual Helianthus species into cultivated sunflower and identify the introgressed alien segments associated with BSR resistance using a genotyping-by-sequencing (GBS) approach. The initial crosses were made between the nuclear male sterile HA 89 with the BSR resistant plants selected from wild Helianthus argophyllus and H. petiolaris populations in 2009. The selected resistant F1 plants were backcrossed to HA 458 and HA 89, respectively. Early generation evaluations of BSR resistance were conducted in the greenhouse, while the BC2F3 and subsequent generations were evaluated in the inoculated field nurseries. Eight introgression lines; six from H. argophyllus (H.arg 1 to H.arg 6), and two from H. petiolaris (H.pet 1 and H.pet 2), were selected. These lines consistently showed high levels of BSR resistance across seven environments from 2012 to 2015 in North Dakota and Minnesota, USA. The mean BSR disease incidence (DI) for H.arg 1 to H.arg 6, H.pet 1, and H.pet 2 was 3.0, 3.2, 0.8, 7.2, 7.7, 1.9, 2.5, and 4.4%, compared to a mean DI of 36.1% for Cargill 270 (susceptible hybrid), 31.0% for HA 89 (recurrent parent), 19.5% for HA 441 (resistant inbred), and 11.6% for Croplan 305 (resistant hybrid). Genotyping of the highly BSR resistant introgression lines using GBS revealed the presence of the H. argophyllus segments in linkage groups (LGs) 3, 8, 9, 10, and 11 of the sunflower genome, and the H. petiolaris segments only in LG8. The shared polymorphic SNP loci in the introgression lines were detected in LGs 8, 9, 10, and 11, indicating the common introgression regions potentially associated with BSR resistance. Additionally, a downy mildew resistance gene, Pl17

  15. Draft genomes of Amanita jacksonii, Ceratocystis albifundus, Fusarium circinatum, Huntiella omanensis, Leptographium procerum, Rutstroemia sydowiana, and Sclerotinia echinophila

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The draft nuclear genomes of Sclerotinia echinophila and Rutstroemia sydowiana are presented. Sclerotinia echinophila is a member of the Sclerotiniaceae family, which includes many destructive necrotrophic plant pathogens. Rutstroemia sydowiana is a member of the Rutstroemiaceae, a cosmopolitan fam...

  16. Resistance to Sclerotinia blight in the U.S. Peanut Mini-Core Collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seventy-one of the 112 accessions comprising the U.S. Peanut Mini-Core Collection were evaluated in 2013 and 2014 for resistance to Sclerotinia blight, caused by Sclerotinia minor. Susceptible cultivar Okrun, and resistant cultivars Southwest Runner, Tamnut OL06, and Tamspan 90, were included for r...

  17. Greenhouse-based inoculation methods for Sclerotinia blight resistance in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse-based assays for screening germplasm for resistance to Sclerotinia blight in peanuts can be conducted year-round, and thus may accelerate progress in breeding for resistant plants. Several techniques for assaying Sclerotinia blight resistance in the greenhouse have been proposed including...

  18. Transferring Sclerotinia Resistance Genes from Wild Helianthus Species into Cultivated Sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivated sunflower lacks a sufficient level of resistance to both Sclerotinia stalk and head rot, but abundant resistance in perennial Helianthus species has been confirmed. The objectives of this project were to transfer Sclerotinia head and stalk rot resistance from resistant wild perennial hexa...

  19. Transferring Sclerotinia Resistance Genes from Wild Helianthus Species into Cultivated Sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eight Sclerotinia-resistant diploid accessions, one hexaploid, and five interspecific amphiploids have been successfully crossed with Sclerotinia-tolerant cultivated lines, backcrossed and selfed to produce progeny families for field evaluation. In 2009, replicated field screening of 163 and 316 pro...

  20. Transferring sclerotinia resistance genes from wild perennial Helianthus species into cultivated sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the lack of highly tolerant cultivated sunflower germplasm, new sources of Sclerotinia resistance from wild Helianthus species need to be identified and incorporated into a cultivated background. Wild perennial Helianthus species are highly resistant to Sclerotinia and have provided good sou...

  1. Epidemiology and Resistance to Sclerotinia Head Rot in Wild Sunflower Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field trials were conducted in 2002-2008 to establish methodology for infecting and assessing the reaction of wild perennial sunflower species to sclerotinia, to understand the epidemiology of the Sclerotinia infections to wild sunflower heads and stems, and to identify sources of resistance. In 200...

  2. Population structure and genetic diversity of Sclerotinia minor from peanut research plots in Oklahoma

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia minor is the causal agent of Sclerotinia blight, a disease that significantly reduces peanut (Arachis hypogea) productivity. This study analyzed the diversity and population structure of 164 S. minor isolates from Oklahoma. Isolates were obtained from infected stems of peanut plants fr...

  3. Low carbon amendment rates during anaerobic soil disinfestation (ASD) at moderate soil temperatures do not decrease viability of Sclerotinia sclerotiorum sclerotia or Fusarium root rot of common bean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic soil disinfestation (ASD; also termed biological soil disinfestation) is a non-chemical process which includes 1) soil incorporation of a labile carbon (C) source, 2) mulching with polyethylene film to limit gas exchange, and 3) drip irrigation to saturation of the topsoil or bedded area. ...

  4. Effect of post-inoculation relative humidity on peanut infection by Sclerotinia minor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stems of six-week-old plants of the cv Okrun (susceptible to Sclerotinia blight) were inoculated with S. minor. Two post-inoculation humidity regimes of 100% RH were used. In the first RH regime, one inoculation chamber was kept open for the duration of experiment (DOE), and five were closed for d...

  5. Quantification of Sclerotinia homoeocarpa overwintering in planta and detection in commercial seed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dollar spot is the most economically important disease of amenity turf grasses in the United States, yet little is known about the source of primary inoculum for this disease. With the exception of a few isolates from the United Kingdom, Sclerotinia homoeocarpa, the causal agent of dollar spot, does...

  6. Identifying resistance to Sclerotinia stalk and root rot in perennial sunflower germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of the research was to identify resistance to Sclerotinia stalk and root rot in perennial sunflower species from the USDA germplasm collection. Two diploid species, Helianthus grosseserratus and H. salicifolius, and four hexaploid species, H. californicus, H. pauciflorus, H. resinosus,...

  7. Carpogenic germination of sclerotia of Sclerotinia minor and ascosporic infection of pyrethrum flowers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evidence for carpogenic germination of sclerotia and infection of flowers by ascospores of Sclerotinia minor is rare. During 2007 to 2009, isolates with morphological characteristics consistent with S. minor were obtained from surface-sterilized pyrethrum flowers collected from fields in Tasmania, ...

  8. Biologically Active Tetranorditerpenoids from Fungus Sclerotinia homoeocarpa Causal Agent of Dollar Spot in Turfgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nine new tetranorditerpenoid dilactones (2-10), together with four previously reported norditerpenoids dilactones (1, 11), and two known putative biosynthetic intermediates oidiolactone-E (12) and 13 were isolated from the ethyl acetate extract of the culture medium of Sclerotinia homoeocarpa. Struc...

  9. Candidate gene association mapping of Sclerotinia stalk rot resistance in sunflower (Helianthus annuus L.) uncovers the importance of COI1 homologs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia stalk rot is one of the most destructive diseases of sunflower (Helianthus annuus L.) worldwide. Markers based on the Sclerotinia disease resistance gene will enable efficient marker-assisted selection (MAS). We sequenced eight candidate genes homologus to Arabidopsis thaliana defense ge...

  10. Assessment of peanut quality and compositional characteristics among transgenic sclerotinia blight-resistant and non-transgenic susceptible cultivars.

    PubMed

    Hu, Jiahuai; Telenko, Darcy E P; Phipps, Patrick M; Grabau, Elizabeth A

    2014-08-06

    This study presents the results of a comparison that includes an analysis of variance and a canonical discriminant analysis to determine compositional equivalence and similarity between transgenic, sclerotinia blight-resistant and non-transgenic, susceptible cultivars of peanut in 3 years of field trials. Three Virginia-type cultivars (NC 7, Wilson, and Perry) and their corresponding transgenic lines (N70, W73, and P39) with a barley oxalate oxidase gene were analyzed for differences in key mineral nutrients, fatty acid components, hay constituents, and grade characteristics. Results from both analyses demonstrated that transgenic lines were compositionally similar to their non-transgenic parent cultivar in all factors as well as market-grade characteristics and nutritional value. Transgenic lines expressing oxalate oxidase for resistance to sclerotinia blight were substantially equivalent to their non-transgenic parent cultivar in quality and compositional characteristics.

  11. Evaluation of a diverse red clover collection for clover rot resistance (Sclerotinia trifoliorum).

    PubMed

    Vleugels, T; Baert, J; Van Bockstaele, E

    2013-01-01

    Sclerotinia trifoliorum Erikks. causes clover rot (clover cancer, Sclerotinia crown and root rot), an important disease in European red clover crops (Trifolium pratense L). The fungus infects plants in autumn through ascospores and entire fields can be destroyed by early spring. Although previous studies have evaluated various red clover populations for clover rot resistance, screening was often performed with one local isolate on just a few local varieties, often cultivars. Until today, no large collections of diverse red clover accessions have been screened. In this study, we studied the variation in clover rot susceptibility among 122 red clover accessions, including 85 accessions from the NPGS-USDA core collection. Cultivars (both diploid and tetraploid), landraces and wild accessions were included and different S. trifoliorum isolates were used. In a field experiment, plant yield, branching and susceptibility to mildew, rust and virus disease were scored for 122 red clover accessions. A similar collection of germplasm was screened for clover rot resistance by a bio-test on young plants using a mixture of five aggressive S. trifoliorum isolates. The effects of the variety type, ploidy level, growth habit, resistance to other diseases and levels of isoflavones (available for the NPGS-USDA collection) on clover rot susceptibility were determined. Possible sources of resistance were identified. Our red clover accessions differed significantly in susceptibility but no accession was completely resistant Three accessions (Maro, Tedi and No. 292) were significantly less susceptible than the other accessions. Intensive branching or a prostrate growth habit did not render plants more resistant. Accessions resistant to mildew or viruses were not more resistant to clover rot and accessions with high levels of isoflavones were not better protected against clover rot. On the other hand, tetraploid cultivars were on average 10% less susceptible than diploid cultivars

  12. Sclerotinia homoeocarpa Overwinters in Turfgrass and Is Present in Commercial Seed

    PubMed Central

    Rioux, Renée A.; Shultz, Jeanette; Garcia, Michelle; Willis, David Kyle; Casler, Michael; Bonos, Stacy; Smith, Damon; Kerns, James

    2014-01-01

    Dollar spot is the most economically important disease of amenity turfgrasses in the United States, yet little is known about the source of primary inoculum for this disease. With the exception of a few isolates from the United Kingdom, Sclerotinia homoeocarpa, the causal agent of dollar spot, does not produce spores. Consequently, it was assumed that overwintering of this organism in soil, thatch, and plant debris provides primary inoculum for dollar spot epidemics. Overwintering of S. homoeocarpa in roots and shoots of symptomatic and asymptomatic creeping bentgrass turfgrass was quantified over the course of a three-year field experiment. Roots did not consistently harbor S. homoeocarpa, whereas S. homoeocarpa was isolated from 30% of symptomatic shoots and 10% of asymptomatic shoots in the spring of two out of three years. The presence of stroma-like pathogen material on leaf blades was associated with an increase in S. homoeocarpa isolation and colony diameter at 48 hpi. Commercial seed has also been hypothesized to be a potential source of initial inoculum for S. homoeocarpa. Two or more commercial seed lots of six creeping bentgrass cultivars were tested for contamination with S. homoeocarpa using culture-based and molecular detection methods. A viable, pathogenic isolate of S. homoeocarpa was isolated from one commercial seed lot and contamination of this lot was confirmed with nested PCR using S. homoeocarpa specific primers. A sensitive nested PCR assay detected S. homoeocarpa contamination in eight of twelve (75%) commercial seed lots. Seed source, but not cultivar or resistance to dollar spot, influenced contamination by S. homoeocarpa. Overall, this research suggests that seeds are a potential source of initial inoculum for dollar spot epidemics and presents the need for further research in this area. PMID:25333928

  13. RNA-Seq Analysis of the Sclerotinia homoeocarpa – Creeping Bentgrass Pathosystem

    PubMed Central

    Opiyo, Stephen O.; Reddyvari-Channarayappa, Venu; Mitchell, Thomas K.; Boehm, Michael J.

    2012-01-01

    Sclerotinia homoeocarpa causes dollar spot disease, the predominate disease on highly-maintained turfgrass. Currently, there are major gaps in our understanding of the molecular interactions between S. homoeocarpa and creeping bentgrass. In this study, 454 sequencing technology was used in the de novo assembly of S. homoeocarpa and creeping bentgrass transcriptomes. Transcript sequence data obtained using Illumina's first generation sequencing-by-synthesis (SBS) were mapped to the transcriptome assemblies to estimate transcript representation in different SBS libraries. SBS libraries included a S. homoeocarpa culture control, a creeping bentgrass uninoculated control, and a library for creeping bentgrass inoculated with S. homoeocarpa and incubated for 96 h. A Fisher's exact test was performed to determine transcripts that were significantly different during creeping bentgrass infection with S. homoeocarpa. Fungal transcripts of interest included glycosyl hydrolases, proteases, and ABC transporters. Of particular interest were the large number of glycosyl hydrolase transcripts that target a wide range of plant cell wall compounds, corroborating the suggested wide host range and saprophytic abilities of S. homoeocarpa. Several of the multidrug resistance ABC transporters may be important for resistance to both fungicides and plant defense compounds. Creeping bentgrass transcripts of interest included germins, ubiquitin transcripts involved in proteasome degradation, and cinnamoyl reductase, which is involved in lignin production. This analysis provides an extensive overview of the S. homoeocarpa-turfgrass pathosystem and provides a starting point for the characterization of potential virulence factors and host defense responses. In particular, determination of important host defense responses may assist in the development of highly resistant creeping bentgrass varieties. PMID:22905098

  14. Evidence for Genetic Similarity of Vegetative Compatibility Groupings in Sclerotinia homoeocarpa

    PubMed Central

    Chang, Seog Won; Jo, Young-Ki; Chang, Taehyun; Jung, Geunhwa

    2014-01-01

    Vegetative compatibility groups (VCGs) are determined for many fungi to test for the ability of fungal isolates to undergo heterokaryon formation. In several fungal plant pathogens, isolates belonging to a VCG have been shown to share significantly higher genetic similarity than those of different VCGs. In this study we sought to examine the relationship between VCG and genetic similarity of an important cool season turfgrass pathogen, Sclerotinia homoeocarpa. Twenty-two S. homoeocarpa isolates from the Midwest and Eastern US, which were previously characterized in several studies, were all evaluated for VCG using an improved nit mutant assay. These isolates were also genotyped using 19 microsatellites developed from partial genome sequence of S. homoeocarpa. Additionally, partial sequences of mitochondrial genes cytochrome oxidase II and mitochondrial small subunit (mtSSU) rRNA, and the atp6-rns intergenic spacer, were generated for isolates from each nit mutant VCG to determine if mitochondrial haplotypes differed among VCGs. Of the 22 isolates screened, 15 were amenable to the nit mutant VCG assay and were grouped into six VCGs. The 19 microsatellites gave 57 alleles for this set. Unweighted pair group methods with arithmetic mean (UPGMA) tree of binary microsatellite data were used to produce a dendrogram of the isolate genotypes based on microsatellite alleles, which showed high genetic similarity of nit mutant VCGs. Analysis of molecular variance of microsatellite data demonstrates that the current nit mutant VCGs explain the microsatellite genotypic variation among isolates better than the previous nit mutant VCGs or the conventionally determined VCGs. Mitochondrial sequences were identical among all isolates, suggesting that this marker type may not be informative for US populations of S. homoeocarpa. PMID:25506303

  15. Progress in sunflower Sclerotinia research: Pyramiding head rot resistance into elite lines and association mapping of stalk rot resistance using candidate genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The need for sunflower quantitative genetics research to find and capture Sclerotinia resistance is increasing with every year that this disease results in widespread losses in yield and crop quality. Our efforts to perform association mapping with the 260 Plant Introductions (PIs) obtained from the...

  16. Antifungal mechanisms of ZnO and Ag nanoparticles to Sclerotinia homoeocarpa.

    PubMed

    Li, Junli; Sang, Hyunkyu; Guo, Huiyuan; Popko, James T; He, Lili; White, Jason C; Parkash Dhankher, Om; Jung, Geunhwa; Xing, Baoshan

    2017-04-18

    Fungicides have extensively been used to effectively combat fungal diseases on a range of plant species, but resistance to multiple active ingredients has developed in pathogens such as Sclerotinia homoeocarpa, the causal agent of dollar spot on cool-season turfgrasses. Recently, ZnO and Ag nanoparticles (NPs) have received increased attention due to their antimicrobial activities. In this study, the NPs' toxicity and mechanisms of action were investigated as alternative antifungal agents against S. homoeocarpa isolates that varied in their resistance to demethylation inhibitor (DMI) fungicides. S. homoeocarpa isolates were treated with ZnO NPs and ZnCl2 (25-400 μg ml(-1)) and Ag NPs and AgNO3 (5-100 μg ml(-1)) to test antifungal activity of the NPs and ions. The mycelial growth of S. homoeocarpa isolates regardless of their DMI sensitivity was significantly inhibited on ZnO NPs (≥200 μg ml(-1)), Ag NPs (≥25 μg ml(-1)), Zn(2+) ions (≥200 μg ml(-1)), and Ag(+) ions (≥10 μg ml(-1)) amended media. Expression of stress response genes, glutathione S-transferase (Shgst1) and superoxide dismutase 2 (ShSOD2), was significantly induced in the isolates by exposure to the NPs and ions. In addition, a significant increase in the nucleic acid contents of fungal hyphae, which may be due to stress response, was observed upon treatment with Ag NPs using Raman spectroscopy. We further observed that a zinc transporter (Shzrt1) might play an important role in accumulating ZnO and Ag NPs into the cells of S. homoeocarpa due to overexpression of Shzrt1 significantly induced by ZnO or Ag NPs within 3 h of exposure. Yeast mutants complemented with Shzrt1 became more sensitive to ZnO and Ag NPs as well as Zn(2+) and Ag(+) ions than the control strain and resulted in increased Zn or Ag content after exposure. This is the first report of involvement of the zinc transporter in the accumulation of Zn and Ag from NP exposure in filamentous plant pathogenic fungi. Understanding

  17. Mechanisms of Subsurface Drip Irrigation-Mediated Suppression of Lettuce Drop Caused by Sclerotinia minor.

    PubMed

    Bell, A A; Liu, L; Reidy, B; Davis, R M; Subbarao, K V

    1998-03-01

    ABSTRACT Subsurface drip irrigation and associated mandatory minimum tillage practices significantly reduced the incidence of lettuce drop (Sclerotinia minor) and the severity of corky root on lettuce compared with furrow irrigation and conventional tillage. Three possible mechanisms for the drip irrigation-mediated disease suppression were examined in this study: qualitative and quantitative differences in the soil microflora under furrow and subsurface drip irrigation; their antagonism and potential bio-control effects on S. minor; and the physical distribution of soil moisture and temperature relative to the two irrigation methods. To determine if the suppressive effects under subsurface drip irrigation were related to changes in soil microflora, soils were assayed for actinomycetes, bacteria, and fungi during the spring and fall seasons. The effects of the irrigation methods on microbial populations were nearly identical during both seasons. In the spring season, the total number of fungal colonies recovered on potato dextrose agar amended with rose Bengal generally was greater in soils under drip irrigation than under furrow irrigation, but no such differences were observed during the fall. Numbers of actinomycetes and bacteria were not significantly different between irrigation methods during either season. No interaction between sampling time and irrigation methods was observed for any of the microbial populations during both seasons. Thus, the significant effect of sampling time observed for actinomycete and bacterial populations during the spring was most likely not caused by the irrigation treatments. There were also no qualitative differences in the three groups of soil microflora between the irrigation treatments. Even though some fungal, actinomycete, and bacterial isolates suppressed mycelial growth of S. minor in in vitro assays, the isolates came from both subsurface drip- and furrow-irrigated soils. In in planta assays, selected isolates failed to

  18. Antifungal mechanisms of ZnO and Ag nanoparticles to Sclerotinia homoeocarpa

    NASA Astrophysics Data System (ADS)

    Li, Junli; Sang, Hyunkyu; Guo, Huiyuan; Popko, James T.; He, Lili; White, Jason C.; Parkash Dhankher, Om; Jung, Geunhwa; Xing, Baoshan

    2017-04-01

    Fungicides have extensively been used to effectively combat fungal diseases on a range of plant species, but resistance to multiple active ingredients has developed in pathogens such as Sclerotinia homoeocarpa, the causal agent of dollar spot on cool-season turfgrasses. Recently, ZnO and Ag nanoparticles (NPs) have received increased attention due to their antimicrobial activities. In this study, the NPs’ toxicity and mechanisms of action were investigated as alternative antifungal agents against S. homoeocarpa isolates that varied in their resistance to demethylation inhibitor (DMI) fungicides. S. homoeocarpa isolates were treated with ZnO NPs and ZnCl2 (25–400 μg ml‑1) and Ag NPs and AgNO3 (5–100 μg ml‑1) to test antifungal activity of the NPs and ions. The mycelial growth of S. homoeocarpa isolates regardless of their DMI sensitivity was significantly inhibited on ZnO NPs (≥200 μg ml‑1), Ag NPs (≥25 μg ml‑1), Zn2+ ions (≥200 μg ml‑1), and Ag+ ions (≥10 μg ml‑1) amended media. Expression of stress response genes, glutathione S-transferase (Shgst1) and superoxide dismutase 2 (ShSOD2), was significantly induced in the isolates by exposure to the NPs and ions. In addition, a significant increase in the nucleic acid contents of fungal hyphae, which may be due to stress response, was observed upon treatment with Ag NPs using Raman spectroscopy. We further observed that a zinc transporter (Shzrt1) might play an important role in accumulating ZnO and Ag NPs into the cells of S. homoeocarpa due to overexpression of Shzrt1 significantly induced by ZnO or Ag NPs within 3 h of exposure. Yeast mutants complemented with Shzrt1 became more sensitive to ZnO and Ag NPs as well as Zn2+ and Ag+ ions than the control strain and resulted in increased Zn or Ag content after exposure. This is the first report of involvement of the zinc transporter in the accumulation of Zn and Ag from NP exposure in filamentous plant pathogenic fungi. Understanding the

  19. Diseases and Their Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Important diseases and their management practices of lentil were reviewed. The diseases reveiwed include Ascochyta blight (Ascochyta lentis), Anthracnose (Colletotrichum truncatum), White mold (Sclerotinia sclerotiorum), rust (Uromyces viciae-fabae), Botrytis gray mold (Botrytis cinerea and B. faba...

  20. Dose response of soilborne plant pathogens and Meloidogyne incognita to citrus-based experimental compounds.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two novel citrus-based compounds have been tested in vitro against Colletotrichum gleosporioides, Fusarium oxysporum, Sclerotinia sclerotiorum, Sclerotium rolfsii, Rhizoctonia solani, Verticillium albo-atrum, Pythium aphanidermatum, P. myriotilum, Phytophthora nicotianae and P. capsici. One of the...

  1. Proteometabolomic Study of Compatible Interaction in Tomato Fruit Challenged with Sclerotinia rolfsii Illustrates Novel Protein Network during Disease Progression

    PubMed Central

    Ghosh, Sudip; Narula, Kanika; Sinha, Arunima; Ghosh, Rajgourab; Jawa, Priyanka; Chakraborty, Niranjan; Chakraborty, Subhra

    2016-01-01

    Fruit is an assimilator of metabolites, nutrients, and signaling molecules, thus considered as potential target for pathogen attack. In response to patho-stress, such as fungal invasion, plants reorganize their proteome, and reconfigure their physiology in the infected organ. This remodeling is coordinated by a poorly understood signal transduction network, hormonal cascades, and metabolite reallocation. The aim of the study was to explore organ-based proteomic alterations in the susceptibility of heterotrophic fruit to necrotrophic fungal attack. We conducted time-series protein profiling of Sclerotinia rolfsii invaded tomato (Solanum lycopersicum) fruit. The differential display of proteome revealed 216 patho-stress responsive proteins (PSRPs) that change their abundance by more than 2.5-fold. Mass spectrometric analyses led to the identification of 56 PSRPs presumably involved in disease progression; regulating diverse functions viz. metabolism, signaling, redox homeostasis, transport, stress-response, protein folding, modification and degradation, development. Metabolome study indicated differential regulation of organic acid, amino acids, and carbohydrates paralleling with the proteomics analysis. Further, we interrogated the proteome data using network analysis that identified two significant functional protein hubs centered around malate dehydrogenase, T-complex protein 1 subunit gamma, and ATP synthase beta. This study reports, for the first-time, kinetically controlled patho-stress responsive protein network during post-harvest storage in a sink tissue, particularly fruit and constitute the basis toward understanding the onset and context of disease signaling and metabolic pathway alterations. The network representation may facilitate the prioritization of candidate proteins for quality improvement in storage organ. PMID:27507973

  2. A single recessive gene conferring short leaves in romaine x Latin type lettuce (Lactuca sativa L.) crosses, and its effect on plant morphology and resistance to lettuce drop caused by Sclerotinia minor Jagger.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the relationship between plant morphology and disease resistance is crucial to successful breeding, particularly resistance to lettuce drop caused by Sclerotinia minor. Latin type lettuce cultivars are small plants with upright leaves longer than they are wide, similar to romaine type...

  3. A Satellite RNA of Ophiostoma novo-ulmi Mitovirus 3a in Hypovirulent Isolates of Sclerotinia homoeocarpa.

    PubMed

    Deng, F; Boland, G J

    2004-09-01

    ABSTRACT Two genetically distinct double-stranded RNA (dsRNA) elements were identified in hypovirulent isolates of Sclerotinia homoeocarpa, the causal agent of dollar spot of turfgrass. The large dsRNA (L-dsRNA) was consistently present in all hypovirulent isolates, whereas the small dsRNA (S-dsRNA) was found only in some hypovirulent isolates. Virulence comparisons revealed that there was no significant difference between isolates containing one or both dsRNAs. Therefore, the L-dsRNA appears to be the genetic determinant of hypovirulence, while the S-dsRNA is not essential for hypovirulence in S. homoeocarpa. The L-dsRNA in hypovirulent isolate Sh12B of S. homoeocarpa was previously characterized as a fungal mitochondrial virus and designated Ophiostoma novo-ulmi mitovirus 3a-Sh12B (OnuMV3a-Sh12B) because it was conspecific with O. novo-ulmi mitovirus 3a-Ld from O. novo-ulmi, the causal agent of Dutch elm disease. In the present study, the nucleotide sequences of the S-dsRNAs (738 to 767 nucleotides) in hypovirulent isolates Sh12B, Sh279B, and Sh286B were determined. Nucleotide sequence analysis indicated that the S-dsRNA was not derived from the OnuMV3a dsRNA and it could not encode an RNA-dependent RNA polymerase. These results are consistent with biological data that the S-dsRNA was always associated with the L-dsRNA and was never found independently. Therefore, the S-dsRNA can be regarded as a satellite RNA of OnuMV3a in S. homoeocarpa. Northern blotting analysis indicated that nucleic acid extracts from isolate Sh12B of S. homoeocarpa contained more single (+) stranded RNA than dsRNA for this satellite RNA. The 5'- and 3'-terminal sequences of the positive strand of the S-dsRNA each could be folded into a stem-loop structure and the terminal 21 nucleotides were complementary to each other, potentially forming a panhandle structure.

  4. Effects of Irrigation and Tillage on Temporal and Spatial Dynamics of Sclerotinia minor Sclerotia and Lettuce Drop Incidence.

    PubMed

    Wu, B M; Subbarao, K V

    2003-12-01

    ABSTRACT The temporal and spatial dynamics of Sclerotinia minor sclerotia and the resulting incidence of lettuce drop were studied under furrow irrigation with conventional tillage and subsurface-drip irrigation with minimum tillage during 1993-95. Lettuce crops were grown each year during the spring and fall seasons. All plants were inoculated immediately after thinning in the spring of 1993. Grids of 24 contiguous quadrats (1 by 1 m(2)) were demarcated in the centers of each 150-m(2) plot. Lettuce drop incidence in each quadrat was evaluated each season prior to harvest. One soil sample (100 cm(3)) was collected from each quadrat at harvest and after tillage prior to planting of the next crop for both spring and fall crops and assayed for S. minor sclerotia using wet sieving. Lloyd's index of patchiness, the beta-binomial distribution, and variance of moving window averages were used to evaluate the spatial patterns of sclerotia and lettuce drop incidence under the two irrigation systems and associated tillage treatments. Disease incidence remained significantly higher under furrow irrigation than under subsurface-drip irrigation throughout the study period, and was significantly higher on fall crops than on spring crops. Under furrow irrigation, the number of sclerotia at the end of a crop season increased significantly over that at the beginning of the season, but no significant changes were detected over years. In contrast, the number of sclerotia within a single season did not increase significantly under subsurface drip irrigation, nor was year-to-year accumulation of sclerotia statistically significant. The degree of aggregation of sclerotia increased significantly during a cropping season under furrow irrigation, but not under subsurface drip irrigation. The conventional tillage after harvest under furrow irrigation decreased the degree of aggregation of sclerotia after each season, but the distribution pattern of sclerotia under subsurface-drip irrigation

  5. IMA Genome-F 3: Draft genomes of Amanita jacksonii, Ceratocystis albifundus, Fusarium circinatum, Huntiella omanensis, Leptographium procerum, Rutstroemia sydowiana, and Sclerotinia echinophila.

    PubMed

    van der Nest, Magriet A; Beirn, Lisa A; Crouch, Jo Anne; Demers, Jill E; de Beer, Z Wilhelm; De Vos, Lieschen; Gordon, Thomas R; Moncalvo, Jean-Marc; Naidoo, Kershney; Sanchez-Ramirez, Santiago; Roodt, Danielle; Santana, Quentin C; Slinski, Stephanie L; Stata, Matt; Taerum, Stephen J; Wilken, P Markus; Wilson, Andrea M; Wingfield, Michael J; Wingfield, Brenda D

    2014-12-01

    The genomes of fungi provide an important resource to resolve issues pertaining to their taxonomy, biology, and evolution. The genomes of Amanita jacksonii, Ceratocystis albifundus, a Fusarium circinatum variant, Huntiella omanensis, Leptographium procerum, Sclerotinia echinophila, and Rutstroemia sydowiana are presented in this genome announcement. These seven genomes are from a number of fungal pathogens and economically important species. The genome sizes range from 27 Mb in the case of Ceratocystis albifundus to 51.9 Mb for Rutstroemia sydowiana. The latter also encodes for a predicted 17 350 genes, more than double that of Ceratocystis albifundus. These genomes will add to the growing body of knowledge of these fungi and provide a value resource to researchers studying these fungi.

  6. Overexpression of ShCYP51B and ShatrD in Sclerotinia homoeocarpa isolates exhibiting practical field resistance to a demethylation inhibitor fungicide.

    PubMed

    Hulvey, Jon; Popko, James T; Sang, Hyunkyu; Berg, Andrew; Jung, Geunhwa

    2012-09-01

    We investigated genetic factors that govern the reduced propiconazole sensitivity of Sclerotinia homoeocarpa field isolates collected during a 2-year field efficacy study on dollar spot disease of turf in five New England sites. These isolates displayed a >50-fold range of in vitro sensitivity to a sterol demethylation inhibitor (DMI) fungicide, propiconazole, making them ideal for investigations of genetic mechanisms of reduced DMI sensitivity. The CYP51 gene homolog in S. homoeocarpa (ShCYP51B), encoding the enzyme target of DMIs, is likely a minor genetic factor for reduced propiconazole sensitivity, since there were no differences in constitutive relative expression (RE) values and only 2-fold-higher induced RE values for insensitive than for sensitive isolate groups. Next, we mined RNA-Seq transcriptome data for additional genetic factors and found evidence for the overexpression of a homolog of Botrytis cinerea atrD (BcatrD), ShatrD, a known efflux transporter of DMI fungicides. The ShatrD gene showed much higher constitutive and induced RE values for insensitive isolates. Several polymorphisms were found upstream of ShatrD but were not definitively linked to overexpression. The screening of constitutive RE values of ShCYP51B and ShatrD in isolates from two golf courses that exhibited practical field resistance to propiconazole uncovered evidence for significant population-specific overexpression of both genes. However, linear regression demonstrated that the RE of ShatrD displays a more significant relationship with propiconazole sensitivity than that of ShCYP51B. In summary, our results suggest that efflux is a major determinant of the reduced DMI sensitivity of S. homoeocarpa genotypes in New England, which may have implications for the emergence of practical field resistance in this important turfgrass pathogen.

  7. D-erythroascorbic acid: Its preparations, chemistry, and metabolism (fungi and plants). Second year [annual] report, [May 23, 1988--May 22, 1990

    SciTech Connect

    Loewus, F.A.; Seib, P.A.

    1990-12-31

    Sclerotinia sclerotiorum contains D-erythroascorbic acid (EAA) and a closely related reducing acid, possibly the open-chain form of EAA. The organism cleaves one of these products or possibly both to yield OA and D-glyceric acid. The OA is rapidly secreted into the medium. An analogy can be made between AA-linked OA biosynthesis in higher plants and EAA-linked OA biosynthesis in fungi as exemplified by S. sclerotiorum.

  8. D-erythroascorbic acid: Its preparations, chemistry, and metabolism (fungi and plants)

    SciTech Connect

    Loewus, F.A. . Inst. of Biological Chemistry); Seib, P.A. . Dept. of Grain Science and Industry)

    1990-01-01

    Sclerotinia sclerotiorum contains D-erythroascorbic acid (EAA) and a closely related reducing acid, possibly the open-chain form of EAA. The organism cleaves one of these products or possibly both to yield OA and D-glyceric acid. The OA is rapidly secreted into the medium. An analogy can be made between AA-linked OA biosynthesis in higher plants and EAA-linked OA biosynthesis in fungi as exemplified by S. sclerotiorum.

  9. Synthesis and evaluation of antifungal activity of C21-steroidal derivatives.

    PubMed

    Huang, Lie-Jun; Wang, Bin; Zhang, Jian-Xin; Yuan, Chun-Mao; Gu, Wei; Mu, Shu-Zhen; Hao, Xiao-Jiang

    2016-04-15

    The antifungal activities of eleven C21-steroidal compounds isolated from Cynanchum wilfordii, together with thirty-six derivatives of caudatin and qingyangshengenin were evaluated on Sclerotinia sclerotiorum and other five fungal strains by the mycelium growth rate method. Four derivatives 1k, 1y, 10d, and 10j exhibited much stronger inhibitions on growth of S. sclerotiorum with IC50 values of 0.0084, 0.0049, 0.0053, and 0.0034 μM, respectively.

  10. Registration of partial white mold resistant pinto bean germplasm line USPT-WM-12

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pinto bean (Phaseolus vulgaris L.), the most widely grown dry bean market class across the United States, is highly susceptible to white mold disease caused by the fungal pathogen Sclerotinia sclerotiorum Lib deBary. The Agricultural Research Service, Michigan State University AgBioResearch, and the...

  11. Site-specific risk factors of white mould epidemics in bean (Phaseolus vulgaris) in Tasmania

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Tasmania, Australia, if more than 5% of bean pods are found to be affected by white mould (caused by Sclerotinia sclerotiorum) entire crops can be rejected by contracting processors. This strict quality standard is one of the main reasons for prophylactic application of fungicides over flowering...

  12. Comparative QTL map for white mold resistance in common bean, and characterization of partial resistance in dry bean lines VA19 and I9365-31

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mold caused by the necrotrophic fungus Sclerotinia sclerotiorum (Lib.) de Bary limits common bean (Phaseolus vulgaris L.) production in temperate climates. Disease resistance has been identified, but breeding is hampered by a paucity of resistance sources and complex inheritance, as numerous ...

  13. Analysis of variation for white mold resistance in the BeanCAP snap bean panel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mold disease caused by Sclerotinia sclerotiorum Lib. de Bary, is one of the most devastated diseases that infect snap and dry beans (Miklas et al. 2013). The USDA-NIFA supported Bean Coordinated Agricultural Project (CAP) has assembled and genotyped dry and a snap bean panels. The snap bean pa...

  14. Sources of resistance to sunflower diseases in a global collection of domesticated USDA plant introductions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Basal stalk rot (BSR) and head rot (HR) caused by Sclerotinia sclerotiorum (Lib.) de Bary are traditionally major diseases of sunflower (Helianthus annuus L.) in the United States, while Phomopsis stem canker (PSC) caused by Phomopsis helianthi Munt.-Cvet. et. al. has increasingly become damaging in...

  15. Genome Sequence of Pseudomonas chlororaphis Strain PA23

    PubMed Central

    Loewen, Peter C.; Villenueva, Jacylyn; Fernando, W. G. Dilantha

    2014-01-01

    Pseudomonas chlororaphis strain PA23 is a plant-beneficial bacterium that is able to suppress disease caused by the fungal pathogen Sclerotinia sclerotiorum through a process known as biological control. Here we present a 7.1-Mb assembly of the PA23 genome. PMID:25035328

  16. Transcriptome analyses suggest a disturbance of iron homeostasis in soybean leaves during white mould disease establishment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sclerotinia sclerotiorum is a serious pathogen of numerous crops around the world. The major virulence factor of this pathogen is oxalic acid (OA). Mutants that cannot produce OA do not cause disease, and plants that express enzymes that degrade OA, such as oxalate oxidase (OxO) are very resistant t...

  17. Sequence-based introgression mapping identifies candidate white mold tolerance genes in common bean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mold disease, caused by the necrotrophic fungus Sclerotinia sclerotiorum (Lib.) de Bary, is a major pathogen of common bean (Phaseolus vulgaris L.). More than 20 QTL were reported using multiple bi-parental populations. To study the disease in more detail, advanced back-cross populations seg...

  18. Spatial characteristics of white mould epidemics and the development of sequential sampling plans in Australian bean fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mould, caused by Sclerotinia sclerotiorum, causes losses to bean through reducing the marketable yield of pods by flower infections and stem rot. In Australia, entire fields may be rejected due to high disease incidence. The spatial characteristics of white mould epidemics were characterised...

  19. Effect of neem (Azardirachta indica A. Juss) seeds and leaves extract on some plant pathogenic fungi.

    PubMed

    Moslem, M A; El-Kholie, E M

    2009-07-15

    In this study plant pathogenic fungi Alternaria solani, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum were chosen to study the effect of ethanolic, hexane and methanolic extracts of neem seeds and leaves. Antifungal effects of neem leave and seed extracts obtained by ethanol, hexane and ptrolium ether were examined separately in vitro against Fusarium oxysporum, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum. Results indicated that seeds and leaves extracts could cause growth inhibition of tested fungi, although the rate of inhibition of tested fungi varied with different extracts and concentrations. But all these extracts and concentrations of extract inhibited the growth of pathogenic fungi at a significant level. Azadirachtin, nimonol and expoxyazdirodione were detected from neem extract by using High Performance Liquid Chromatography (HPLC). We can conclude that neem leave and seed extracts were effective as antifungal against all tested fungi but F. oxysporum and R. solani were the most sensitive fungi.

  20. Isolation and characterization of rhizosphere bacteria for the biocontrol of the damping-off disease of tomatoes in Tunisia.

    PubMed

    Hammami, Inés; Ben Hsouna, Anis; Hamdi, Naceur; Gdoura, Radhouane; Triki, Mohamed Ali

    2013-01-01

    Fluorescent Pseudomonas spp., isolated from tomato and pepper plants rhizosphere soil, was evaluated in vitro as a potential antagonist of fungal pathogens. Pseudomonas strains were tested against the causal agents of tomatoes damping-off (Sclerotinia sclerotiorum), root rot (Fusarium solani), and causal agents of stem canker and leaf blight (Alternaria alternata). For this purpose, dual culture antagonism assays were carried out on 25% tryptic soy agar, King B medium and potato dextrose agar to determine the effect of the strains on mycelial growth of the pathogens. In addition, strains were screened for their ability to produce exoenzymes and siderophores. All the strains significantly inhibited Alternaria alternata, particularly in 25% TSA medium. Antagonistic effect on Sclerotinia sclerotiorum and Fusarium solani was greater on King B medium. Protease was produced by 30% of the strains, but no strain produced cellulase or chitinase. Finally, the selected Pseudomonas strain, Psf5, was evaluated on tomato seedling development and as a potential candidate for controlling tomato damping-off caused by Sclerotinia sclerotiorum, under growth chamber conditions. In vivo studies resulted in significant increases in plant stand as well as in root dry weight. Psf5 was able to establish and survive in tomato plants rhizosphere after 40days following the planting of bacterized seeds.

  1. Biogenic silver nanoparticles based on trichoderma harzianum: synthesis, characterization, toxicity evaluation and biological activity

    PubMed Central

    Guilger, Mariana; Pasquoto-Stigliani, Tatiane; Bilesky-Jose, Natália; Grillo, Renato; Abhilash, P. C.; Fraceto, Leonardo Fernandes; Lima, Renata de

    2017-01-01

    White mold is an agricultural disease caused by the fungus Sclerotinia sclerotiorum, which affects important crops. There are different ways of controlling this organism, but none provides inhibition of its resistance structures (sclerotia). Nanotechnology offers promising applications in agricultural area. Here, silver nanoparticles were biogenically synthesized using the fungus Trichoderma harzianum and characterized. Cytotoxicity and genotoxicity were evaluated, and the nanoparticles were initially tested against white mold sclerotia. Their effects on soybean were also investigated with no effects observed. The nanoparticles showed potential against S. sclerotiorum, inhibiting sclerotia germination and mycelial growth. Nanoparticle characterization data indicated spherical morphology, satisfactory polydispersity and size distribution. Cytotoxicity and genotoxicity assays showed that the nanoparticles caused both the effects, although, the most toxic concentrations were above those applied for white mold control. Given the potential of the nanoparticles against S. sclerotiorum, we conclude that this study presents a first step for a new alternative in white mold control. PMID:28300141

  2. Biogenic silver nanoparticles based on trichoderma harzianum: synthesis, characterization, toxicity evaluation and biological activity

    NASA Astrophysics Data System (ADS)

    Guilger, Mariana; Pasquoto-Stigliani, Tatiane; Bilesky-Jose, Natália; Grillo, Renato; Abhilash, P. C.; Fraceto, Leonardo Fernandes; Lima, Renata De

    2017-03-01

    White mold is an agricultural disease caused by the fungus Sclerotinia sclerotiorum, which affects important crops. There are different ways of controlling this organism, but none provides inhibition of its resistance structures (sclerotia). Nanotechnology offers promising applications in agricultural area. Here, silver nanoparticles were biogenically synthesized using the fungus Trichoderma harzianum and characterized. Cytotoxicity and genotoxicity were evaluated, and the nanoparticles were initially tested against white mold sclerotia. Their effects on soybean were also investigated with no effects observed. The nanoparticles showed potential against S. sclerotiorum, inhibiting sclerotia germination and mycelial growth. Nanoparticle characterization data indicated spherical morphology, satisfactory polydispersity and size distribution. Cytotoxicity and genotoxicity assays showed that the nanoparticles caused both the effects, although, the most toxic concentrations were above those applied for white mold control. Given the potential of the nanoparticles against S. sclerotiorum, we conclude that this study presents a first step for a new alternative in white mold control.

  3. Synthesis and antifungal activity evaluation of new heterocycle containing amide derivatives.

    PubMed

    Wang, Xuesong; Gao, Sumei; Yang, Jian; Gao, Yang; Wang, Ling; Tang, Xiaorong

    2016-01-01

    A series of heterocycle containing amide derivatives (1-28) were synthesised by the combination of acyl chlorides (1a, 2a) and heterocyclic/homocyclic ring containing amines, and their in vitro antifungal activity was evaluated against five plant pathogenic fungi, namely Gibberella zeae, Helminthosporium maydis, Rhizoctonia solani, Botrytis cinerea and Sclerotinia sclerotiorum. Results of antifungal activity analysis indicated that some of the products showed good to excellent antifungal activity, as compound 2 showed excellent activity against G. zeae and R. solani and potent activity against H. maydi, B. cinerea and S. sclerotiorum, and compounds 1, 8 and 10 also displayed excellent antifungal potential against H. maydi, B. cinerea and S. sclerotiorum and good activity against R. solani when compared with the standard carbendazim.

  4. Chaetomium globosum CDW7, a potential biological control strain and its antifungal metabolites.

    PubMed

    Zhao, Shuang-Shuang; Zhang, Ying-Ying; Yan, Wei; Cao, Ling-Ling; Xiao, Yu; Ye, Yong-Hao

    2016-12-22

    Screening for endophytic fungi with antifungal activity is an effective strategy for the discovery of novel biopesticides. Our previous work indicated that Chaetomium globosum CDW7, an endophyte from Ginkgo biloba, exhibited strong inhibitory activity against plant pathogenic fungi in vitro In this study, we evaluated the CDW7 strain for its antifungal activities against nine phytopathogenic fungi and its biocontrol potential against rape sclerotinia rot caused by Sclerotinia sclerotiorum The fermentation broth of CDW7 could successfully inhibit disease development in S. sclerotiorum-infected rape in vivo with 57.8% protective efficiency, which is comparable to that of carbendazim (59.8%) at 250 μg mL(-1) The fermentation broth also expressed significant activity-stability when exposed to 60°C, UV illumination or when stored at 4°C. Furthermore, we found that 10% fermentation broth can promote the germination and growth of rape seedlings. Followed by the bioassay-guided approach, seven known metabolites were isolated and identified by spectroscopic analyses. Among them, chaetoglobosins A and D exhibited inhibitory activity against S. sclerotiorum with IC50 values of 0.35 μg mL(-1) and 0.62 μg mL(-1), respectively, compared with carbendazim (0.17 μg mL(-1)). Therefore, our study demonstrated that CDW7 is a promising biocontrol fungus against S. sclerotiorum in agriculture.

  5. Arabidopsis receptor-like protein30 and receptor-like kinase suppressor of BIR1-1/EVERSHED mediate innate immunity to necrotrophic fungi.

    PubMed

    Zhang, Weiguo; Fraiture, Malou; Kolb, Dagmar; Löffelhardt, Birgit; Desaki, Yoshitake; Boutrot, Freddy F G; Tör, Mahmut; Zipfel, Cyril; Gust, Andrea A; Brunner, Frédéric

    2013-10-01

    Effective plant defense strategies rely in part on the perception of non-self determinants, so-called microbe-associated molecular patterns (MAMPs), by transmembrane pattern recognition receptors leading to MAMP-triggered immunity. Plant resistance against necrotrophic pathogens with a broad host range is complex and yet not well understood. Particularly, it is unclear if resistance to necrotrophs involves pattern recognition receptors. Here, we partially purified a novel proteinaceous elicitor called sclerotinia culture filtrate elicitor1 (SCFE1) from the necrotrophic fungal pathogen Sclerotinia sclerotiorum that induces typical MAMP-triggered immune responses in Arabidopsis thaliana. Analysis of natural genetic variation revealed five Arabidopsis accessions (Mt-0, Lov-1, Lov-5, Br-0, and Sq-1) that are fully insensitive to the SCFE1-containing fraction. We used a forward genetics approach and mapped the locus determining SCFE1 sensitivity to receptor-like protein30 (RLP30). We also show that SCFE1-triggered immune responses engage a signaling pathway dependent on the regulatory receptor-like kinases brassinosteroid insensitive1-associated receptor kinase1 (BAK1) and Suppressor of BIR1-1/evershed (SOBIR1/EVR). Mutants of RLP30, BAK1, and SOBIR1 are more susceptible to S. sclerotiorum and the related fungus Botrytis cinerea. The presence of an elicitor in S. sclerotiorum evoking MAMP-triggered immune responses and sensed by RLP30/SOBIR1/BAK1 demonstrates the relevance of MAMP-triggered immunity in resistance to necrotrophic fungi.

  6. Fungistatic activity of Zanthoxylum rhoifolium Lam. bark extracts against fungal plant pathogens and investigation on mechanism of action in Botrytis cinerea.

    PubMed

    Carotenuto, Gennaro; Carrieri, Raffaele; Tarantino, Paola; Alfieri, Mariaevelina; Leone, Antonella; De Tommasi, Nunziatina; Lahoz, Ernesto

    2015-01-01

    Plant-derived compounds are emerging as an alternative choice to synthetic fungicides. Chloroform-methanol extract, obtained from the bark of Zanthoxylum rhoifolium, a member of Rutaceae, showed a fungistatic effect on Botrytis cinerea, Sclerotinia sclerotiorum, Alternaria alternata, Colletotrichum gloeosporioides and Clonostachys rosea, when added to the growth medium at different concentrations. A fraction obtained by gel separation and containing the alkaloid O-Methylcapaurine showed significant fungistatic effect against B. cinerea and S. sclerotiorum, two of the most destructive phytopathogenic fungi. The underlying mechanism of such an inhibition was further investigated in B. cinerea, a fungus highly prone to develop fungicide resistance, by analysing the expression levels of a set of genes (BcatrB, P450, CYP51 and TOR). O-Methylcapaurine inhibited the expression of all the analysed genes. In particular, the expression of BcatrB gene, encoding a membrane drug transporter involved in the resistance to a wide range of xenobiotic compounds, was strongly inhibited (91%).

  7. Novel macrocyclic molecules based on 12a-N substituted 16-membered azalides and azalactams as potential antifungal agents.

    PubMed

    Wang, Xiaolei; Zhang, Shun; Pang, Yanlong; Yuan, Huihui; Liang, Xiaomei; Zhang, Jianjun; Wang, Daoquan; Wang, Mingan; Dong, Yanhong

    2014-02-12

    Novel macrocyclic molecules comprising sulfonyl and acyl moiety at the position N-12a of 16-membered azalides (6a-n) and azalactams (10a-r) scaffold were synthesized from cyclododecanone 1 as starting material via 5 steps and 4 steps, respectively. The antifungal activity of these compounds against Sclerotinia sclerotiorum, Pyricularia oryzae, Botrytis cinerea, Rhizoctonia solani and Phytophthora capsici were evaluated and found that compounds possessing α-exomethylene (6c, 6d, 6e and 6g) showed antifungal activity comparable to commercial fungicide Chlorothalonil against P. oryzae and compounds possessing p-chlorobenzoyl exhibited enhanced antifungal activity than those with other substituents against S. sclerotiorum, P. oryzae, and B. cinerea. These findings suggested that the α-exomethylene and p-chlorobenzoyl may be two potential pharmacological active groups with antifungal activities.

  8. Overexpression of a Chitinase Gene from Trichoderma asperellum Increases Disease Resistance in Transgenic Soybean.

    PubMed

    Zhang, Fuli; Ruan, Xianle; Wang, Xian; Liu, Zhihua; Hu, Lizong; Li, Chengwei

    2016-12-01

    In the present study, a chi gene from Trichoderma asperellum, designated Tachi, was cloned and functionally characterized in soybean. Firstly, the effects of sodium thiosulfate on soybean Agrobacterium-mediated genetic transformation with embryonic tip regeneration system were investigated. The transformation frequency was improved by adding sodium thiosulfate in co-culture medium for three soybean genotypes. Transgenic soybean plants with constitutive expression of Tachi showed increased resistance to Sclerotinia sclerotiorum compared to WT plants. Meanwhile, overexpression of Tachi in soybean exhibited increased reactive oxygen species (ROS) level as well as peroxidase (POD) and catalase (SOD) activities, decreased malondialdehyde (MDA) content, along with diminished electrolytic leakage rate after S. sclerotiorum inoculation. These results suggest that Tachi can improve disease resistance in plants by enhancing ROS accumulation and activities of ROS scavenging enzymes and then diminishing cell death. Therefore, Tachi represents a candidate gene with potential application for increasing disease resistance in plants.

  9. Field tolerance to fungal pathogens of Brassica napus constitutively expressing a chimeric chitinase gene

    SciTech Connect

    Grison, R.; Grezes-Besset, B.; Lucante, N.

    1996-05-01

    Constitutive overexpression of a protein involved in plant defense mechanisms to disease is one of the strategies proposed to increase plant tolerance to fungal pathogens. A hybrid endochitinase gene under a constitutive promoter was introduced by Agrobacterium-mediated transformation into a winter-type oilseed rape (Brassica napus var. oleifera) inbred line. Progeny from transformed plants was challenged using three different fungal pathogens (Cylindrosporium concentricum, Phoma lingam, Sclerotinia sclerotiorum) in field trials at two different geographical locations. These plants exhibited an increased tolerance to disease as compared with the nontransgenic parental plants. 31 refs., 1 fig., 2 tabs.

  10. Biological Control of Lettuce Drop and Host Plant Colonization by Rhizospheric and Endophytic Streptomycetes

    PubMed Central

    Chen, Xiaoyulong; Pizzatti, Cristina; Bonaldi, Maria; Saracchi, Marco; Erlacher, Armin; Kunova, Andrea; Berg, Gabriele; Cortesi, Paolo

    2016-01-01

    Lettuce drop, caused by the soil borne pathogen Sclerotinia sclerotiorum, is one of the most common and serious diseases of lettuce worldwide. Increased concerns about the side effects of chemical pesticides have resulted in greater interest in developing biocontrol strategies against S. sclerotiorum. However, relatively little is known about the mechanisms of Streptomyces spp. as biological control agents against S. sclerotiorum on lettuce. Two Streptomyces isolates, S. exfoliatus FT05W and S. cyaneus ZEA17I, inhibit mycelial growth of Sclerotinia sclerotiorum by more than 75% in vitro. We evaluated their biocontrol activity against S. sclerotiorum in vivo, and compared them to Streptomyces lydicus WYEC 108, isolated from Actinovate®. When Streptomyces spp. (106 CFU/mL) were applied to S. sclerotiorum inoculated substrate in a growth chamber 1 week prior lettuce sowing, they significantly reduced the risk of lettuce drop disease, compared to the inoculated control. Interestingly, under field conditions, S. exfoliatus FT05W and S. cyaneus ZEA17I protected lettuce from drop by 40 and 10% respectively, whereas S. lydicus WYEC 108 did not show any protection. We further labeled S. exfoliatus FT05W and S. cyaneus ZEA17I with the enhanced GFP (EGFP) marker to investigate their rhizosphere competence and ability to colonize lettuce roots using confocal laser scanning microscopy (CLSM). The abundant colonization of young lettuce seedlings by both strains demonstrated Streptomyces' capability to interact with the host from early stages of seed germination and root development. Moreover, the two strains were detected also on 2-week-old roots, indicating their potential of long-term interactions with lettuce. Additionally, scanning electron microscopy (SEM) observations showed EGFP-S. exfoliatus FT05W endophytic colonization of lettuce root cortex tissues. Finally, we determined its viability and persistence in the rhizosphere and endorhiza up to 3 weeks by quantifying its

  11. Endophytic Fungi Isolated from Oil-Seed Crop Jatropha curcas Produces Oil and Exhibit Antifungal Activity

    PubMed Central

    Kumar, Susheel; Kaushik, Nutan

    2013-01-01

    Jatropha curcas L., a perennial plant grown in tropics and subtropics is popularly known for its potential as biofuel. The plant is reported to survive under varying environmental conditions having tolerance to stress and an ability to manage pest and diseases. The plant was explored for its endophytic fungi for use in crop protection. Endophytic fungi were isolated from leaf of Jatropha curcas, collected from New Delhi, India. Four isolates were identified as Colletotrichum truncatum, and other isolates were identified as Nigrospora oryzae, Fusarium proliferatum, Guignardia cammillae, Alternaria destruens, and Chaetomium sp. Dual plate culture bioassays and bioactivity assays of solvent extracts of fungal mycelia showed that isolates of Colletotrichum truncatum were effective against plant pathogenic fungi Fusarium oxysporum and Sclerotinia sclerotiorum. Isolate EF13 had highest activity against S. sclerotiorum. Extracts of active endophytic fungi were prepared and tested against S. sclerotiorum. Ethyl acetate and methanol extract of C. truncatum EF10 showed 71.7% and 70% growth inhibition, respectively. Hexane extracts of C. truncatum isolates EF9, EF10, and EF13 yielded oil and the oil from EF10 was similar to oil of the host plant, i.e., J. curcas. PMID:23409154

  12. Endophytic fungi isolated from oil-seed crop Jatropha curcas produces oil and exhibit antifungal activity.

    PubMed

    Kumar, Susheel; Kaushik, Nutan

    2013-01-01

    Jatropha curcas L., a perennial plant grown in tropics and subtropics is popularly known for its potential as biofuel. The plant is reported to survive under varying environmental conditions having tolerance to stress and an ability to manage pest and diseases. The plant was explored for its endophytic fungi for use in crop protection. Endophytic fungi were isolated from leaf of Jatropha curcas, collected from New Delhi, India. Four isolates were identified as Colletotrichum truncatum, and other isolates were identified as Nigrospora oryzae, Fusarium proliferatum, Guignardia cammillae, Alternaria destruens, and Chaetomium sp. Dual plate culture bioassays and bioactivity assays of solvent extracts of fungal mycelia showed that isolates of Colletotrichum truncatum were effective against plant pathogenic fungi Fusarium oxysporum and Sclerotinia sclerotiorum. Isolate EF13 had highest activity against S. sclerotiorum. Extracts of active endophytic fungi were prepared and tested against S. sclerotiorum. Ethyl acetate and methanol extract of C. truncatum EF10 showed 71.7% and 70% growth inhibition, respectively. Hexane extracts of C. truncatum isolates EF9, EF10, and EF13 yielded oil and the oil from EF10 was similar to oil of the host plant, i.e., J. curcas.

  13. Survival of plant pathogens in static piles of ground green waste.

    PubMed

    Downer, A J; Crohn, D; Faber, B; Daugovish, O; Becker, J O; Menge, J A; Mochizuki, M J

    2008-05-01

    Ground green waste is used as mulch in ornamental landscapes and for tree crops such as avocados. Survival of Armillaria mellea, Phytophthora cinnamomi, Sclerotinia sclerotiorum, and Tylenchulus semipenetrans was assessed for 8 weeks within unturned piles of either recently ground or partially composted green waste. S. sclerotiorum survived at the pile surface and at 10, 30, and 100 cm within the pile for the entire 8 weeks in both fresh green waste (FGW) and aged green waste (AGW). A. mellea and T. semipenetrans did not survive more than 2 days in FGW, while P. cinnamomi persisted for over 21 days in FGW. AGW was less effective in reducing pathogen viability than FGW, most likely because temperatures in AGW peaked at 45 degrees C compared with 70 degrees C in FGW. Survival modeling curves based on pile temperatures indicate the time to inactivate 10 propagules of pathogens was 11, 30, 363, and 50 days for A. mellea, P. cinnamomi, S. sclerotiorum, and T. semipenetrans, respectively. Sclerotia-forming pathogens pose the greatest risk for escape; to ensure eradication of persistent fungi, green waste stockpiles should be turned intermittently to mix pile contents and move pathogen propagules to a location within the pile where they are more likely to be killed by heat, microbial attack, or chemical degradation.

  14. Assessment of inheritance pattern and agronomic performance of transgenic rapeseed having harpin Xooc-encoding hrf2 gene.

    PubMed

    Huo, Rong; Wang, Yu; Ma, Ling-Li; Qiao, Jun-Qing; Shao, Min; Gao, Xue-Wen

    2010-10-01

    hrf2 gene is a member of the harpin-encoding gene family of rice-pathogenic bacterium Xanthomonas oryzae pv. oryzicola. In our previous studies, we observed that harpin(Xooc) could elicit hypersensitive cell death in non-host plants, induce disease and insect resistance in plants, and enhance plant growth. In this study, the rapeseed cultivar, Yangyou 4, was genetically engineered via Agrobacterium-mediated transformation to express the hrf2 gene. Polymerase chain reaction (PCR) and southern blot analyses of T(1) generation of transgenic rapeseed revealed stable integration and expression of the inserted gene hrf2. In addition, the resistance to Sclerotinia sclerotiorum was greatly enhanced. A comparison between agronomic characters of transgenic and control lines displayed significant differences in terms of plant height, stem width, number of pods per plant, number of seeds per pod, 1,000-seed weight, and seed yield per plant. Among lines with resistance to S. sclerotiorum, T(1)1 had improved agronomic traits compared with controls with a 22.7% seed yield increase. These results suggest that the introduction of the hrf2 gene into rapeseed can be an effective strategy for enhancing resistance to S. sclerotiorum.

  15. Histopathological studies of sclerotia of phytopathogenic fungi parasitized by a GFP transformed Trichoderma virens antagonistic strain.

    PubMed

    Sarrocco, Sabrina; Mikkelsen, Lisbeth; Vergara, Mariarosaria; Jensen, Dan Funck; Lübeck, Mette; Vannacci, Giovanni

    2006-02-01

    The gfp gene from the jellyfish Aequorea victoria, coding for the Green Fluorescent Protein (GFP), was used as a reporter gene to transform a Trichoderma virens strain I10, characterized as having a promising biocontrol activity against a large number of phytopathogenic fungi. On the basis of molecular and biological results, a stable GFP transformant was selected for further experiments. In order to evaluate the effects of GFP transformation on mycoparasitic ability of T. virens I10, sclerotia of Sclerotium rolfsii, Sclerotinia sclerotiorum and S. minor were inoculated with the T. virens strain I10 GFP transformant or the wild type strain. Statistical analysis of percentages of decayed sclerotia showed that the transformation of the antagonistic isolate with the GFP reporter gene did not modify mycoparasitic activity against sclerotia. Sclerotium colonization was followed by fluorescent microscopy revealing intracellular growth of the antagonist in the cortex (S. rolfsii) and inter-cellular growth in the medulla (S. rolfsii, and S. sclerotiorum). The uniformly distributed mycelium of T. virens just beneath the rind of sclerotia of both S. rolfsii and S. sclerotiorum suggests that the sclerotia became infected at numerous randomly distributed locations without any preferential point of entry.

  16. Benzofurazan derivatives as antifungal agents against phytopathogenic fungi.

    PubMed

    Wang, Lili; Zhang, Ying-Ying; Wang, Lei; Liu, Feng-you; Cao, Ling-Ling; Yang, Jing; Qiao, Chunhua; Ye, Yonghao

    2014-06-10

    A series of benzofurazan derivatives were prepared and evaluated for their biological activities against four important phytopathogenic fungi, namely, Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum and Phytophthora capsici, using the mycelium growth inhibition method. The structures of these compounds were characterized by (1)H NMR, (13)C NMR, and HRMS. N-(3-chloro-4-fluorophenyl)-7-nitrobenzo[c][1,2,5]oxadiazol-4-amine (A3) displayed the maximum antifungal activity against R. solani (IC50 = 1.91 μg/mL), which is close to that of the positive control Carbendazim (IC50 = 1.42 μg/mL). For other benzofurazan derivatives with nitro group at R(4) position (A series), 9 out of 30 compounds exhibited high antifungal effect against strain R. solani, with IC50 values less than 5 μg/mL. Most of the derivatives with substituents at R(2) and R(3) positions (B series) displayed moderate growth inhibition against S. sclerotiorum (IC50 < 25 μg/mL). Also, several benzofuran derivatives with nitro group at R(4) position and another conjugated aromatic ring at the R(1) position of the phenyl ring displayed high antifungal capability against strain R. solani. Compounds with substituents at R(2) and R(3) position had moderate efficacy against strain S. sclerotiorum.

  17. Optimization for rapid synthesis of silver nanoparticles and its effect on phytopathogenic fungi

    NASA Astrophysics Data System (ADS)

    Krishnaraj, C.; Ramachandran, R.; Mohan, K.; Kalaichelvan, P. T.

    In this present study, silver nanoparticles were synthesized by green chemistry approach using Acalypha indica leaf extract as reducing agents. The reaction medium employed in the synthesis process was optimized to attain better yield, controlled size and stability. Further, the biosynthesized silver nanoparticles were conformed through UV-vis spectrum, XRD and HR-TEM analyses. Different concentration of silver nanoparticles were tested to know the inhibitory effect of fungal plant pathogens namely Alternaria alternata, Sclerotinia sclerotiorum, Macrophomina phaseolina, Rhizoctonia solani, Botrytis cinerea and Curvularia lunata. Interestingly, 15 mg concentration of silver nanoparticles showed excellent inhibitory activity against all the tested pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

  18. Mycoparasitism studies of Trichoderma species against three phytopathogenic fungi: evaluation of antagonism and hydrolytic enzyme production.

    PubMed

    Qualhato, Thiago Fernandes; Lopes, Fabyano Alvares Cardoso; Steindorff, Andrei Stecca; Brandão, Renata Silva; Jesuino, Rosália Santos Amorim; Ulhoa, Cirano José

    2013-09-01

    Trichoderma spp. are used for biocontrol of several plant pathogens. However, their efficient interaction with the host needs to be accompanied by production of secondary metabolites and cell wall-degrading enzymes. Three parameters were evaluated after interaction between four Trichoderma species and plant-pathogenic fungi: Fusarium solani, Rhizoctonia solani and Sclerotinia sclerotiorum. Trichoderma harzianum and T. asperellum were the most effective antagonists against the pathogens. Most of the Trichoderma species produced toxic volatile metabolites, having significant effects on growth and development of the plant pathogens. When these species were grown in liquid cultures with cell walls from these plant pathogens, they produced and secreted β-1,3-glucanase, NAGAse, chitinase, acid phosphatase, acid proteases and alginate lyase.

  19. Biodegradable and bioactive CGP/PVA film for fungal growth inhibition.

    PubMed

    Silva, Bárbara Dumas S; Ulhoa, Cirano J; Batista, Karla A; Di Medeiros, Maria Carolina; Da Silva Filho, Rômulo Roosevelt; Yamashita, Fabio; Fernandes, Kátia F

    2012-07-01

    In this study, chitinolytic enzymes produced by Trichoderma asperellum were immobilized on a biodegradable film manufactured with a blend of cashew gum polysaccharide (CGP) and polyvinyl alcohol (PVA), and tested as a fungal growth inhibitor. The film was produced by casting a blend of CGP and PVA solution on glass molds. The CGP/PVA film showed 68% water solubility, tensile strength of 23.7 MPa, 187.2% elongation and 52% of mass loss after 90 days in soil. The presence of T-CWD enzymes immobilized by adsorption or covalent attachment resulted in effective inhibition of fungal growth. Sclerotinia sclerotiorum was the most sensitive organism, followed by Aspergillus niger and Penicillium sp. SEM micrograph showed that the presence of immobilized T-CWD enzymes on CGP/PVA film produced morphological modifications on vegetative and germinative structures of the microorganisms, particularly hyphae disruption and changes of spores shape.

  20. Phylogenetic Diversity and Antifungal Activity of Endophytic Fungi Associated with Tephrosia purpurea

    PubMed Central

    Luo, Ze-Ping; Lin, Hai-Yan; Ding, Wen-Bing; He, Hua-Liang

    2015-01-01

    Sixty-one endophytic fungus strains with different colony morphologies were isolated from the leaves, stems and roots of Tephrosia purpurea with colonization rates of 66.95%, 37.50%, and 26.92%, respectively. Based on internal transcribed spacer sequence analysis, 61 isolates were classified into 16 genera belonging to 3 classes under the phylum Ascomycota. Of the 61 isolates, 6 (9.84%) exhibited antifungal activity against one or more indicator plant pathogenic fungi according to the dual culture test. Isolate TPL25 had the broadest antifungal spectrum of activity, and isolate TPL35 was active against 5 plant pathogenic fungi. Furthermore, culture filtrates of TPL25 and TPL35 exhibited greater than 80% growth inhibition against Sclerotinia sclerotiorum. We conclude that the endophytic fungal strains TPL25 and TPL35 are promising sources of bioactive compounds. PMID:26839503

  1. Phylogenetic Diversity and Antifungal Activity of Endophytic Fungi Associated with Tephrosia purpurea.

    PubMed

    Luo, Ze-Ping; Lin, Hai-Yan; Ding, Wen-Bing; He, Hua-Liang; Li, You-Zhi

    2015-12-01

    Sixty-one endophytic fungus strains with different colony morphologies were isolated from the leaves, stems and roots of Tephrosia purpurea with colonization rates of 66.95%, 37.50%, and 26.92%, respectively. Based on internal transcribed spacer sequence analysis, 61 isolates were classified into 16 genera belonging to 3 classes under the phylum Ascomycota. Of the 61 isolates, 6 (9.84%) exhibited antifungal activity against one or more indicator plant pathogenic fungi according to the dual culture test. Isolate TPL25 had the broadest antifungal spectrum of activity, and isolate TPL35 was active against 5 plant pathogenic fungi. Furthermore, culture filtrates of TPL25 and TPL35 exhibited greater than 80% growth inhibition against Sclerotinia sclerotiorum. We conclude that the endophytic fungal strains TPL25 and TPL35 are promising sources of bioactive compounds.

  2. The Cerato-Platanin protein Epl-1 from Trichoderma harzianum is involved in mycoparasitism, plant resistance induction and self cell wall protection.

    PubMed

    Gomes, Eriston Vieira; Costa, Mariana do Nascimento; de Paula, Renato Graciano; de Azevedo, Rafael Ricci; da Silva, Francilene Lopes; Noronha, Eliane F; Ulhoa, Cirano José; Monteiro, Valdirene Neves; Cardoza, Rosa Elena; Gutiérrez, Santiago; Silva, Roberto Nascimento

    2015-12-09

    Trichoderma harzianum species are well known as biocontrol agents against important fungal phytopathogens. Mycoparasitism is one of the strategies used by this fungus in the biocontrol process. In this work, we analyzed the effect of Epl-1 protein, previously described as plant resistance elicitor, in expression modulation of T. harzianum genes involved in mycoparasitism process against phytopathogenic fungi; self cell wall protection and recognition; host hyphae coiling and triggering expression of defense-related genes in beans plants. The results indicated that the absence of Epl-1 protein affects the expression of all mycoparasitism genes analyzed in direct confrontation assays against phytopathogen Sclerotinia sclerotiorum as well as T. harzianum itself; the host mycoparasitic coiling process and expression modulation of plant defense genes showing different pattern compared with wild type strain. These data indicated the involvement T. harzianum Epl-1 in self and host interaction and also recognition of T. harzianum as a symbiotic fungus by the bean plants.

  3. Fungal DNA virus infects a mycophagous insect and utilizes it as a transmission vector

    PubMed Central

    Liu, Si; Xie, Jiatao; Cheng, Jiasen; Li, Bo; Chen, Tao; Fu, Yanping; Li, Guoqing; Wang, Manqun; Jin, Huanan; Wan, Hu; Jiang, Daohong

    2016-01-01

    Mycoviruses are usually transmitted horizontally via hyphal anastomosis and vertically via sexual/asexual spores. Previously, we reported that a gemycircularvirus, Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), could infect its fungal host extracellularly. Here, we discovered that SsHADV-1 could infect a mycophagous insect, Lycoriella ingenua, and use it as a transmission vector. Virus acquired by larvae feeding on colonies of a virus-infected strain of S. sclerotiorum was replicated and retained in larvae, pupae, adults, and eggs. Virus could be transmitted to insect offspring when larvae were injected with virus particles and allowed to feed on a nonhost fungus. Virus replication in insect cells was further confirmed by inoculating Spodoptera frugiperda cells with virus particles and analyzing with RT-PCR, Northern blot, immunofluorescence, and flow cytometry assays. Larvae could transmit virus once they acquired virus by feeding on virus-infected fungal colony. Offspring larvae hatched from viruliferous eggs were virus carriers and could also successfully transmit virus. Virus transmission between insect and fungus also occurred on rapeseed plants. Virus-infected isolates produced less repellent volatile substances to attract adults of L. ingenua. Furthermore, L. ingenua was easily observed on Sclerotinia lesions in rapeseed fields, and viruliferous adults were captured from fields either sprayed with a virus-infected fungal strain or nonsprayed. Our findings may facilitate the exploration of mycoviruses for control of fungal diseases and enhance our understanding of the ecology of SsHADV-1 and other newly emerging SsHADV-1–like viruses, which were recently found to be widespread in various niches including human HIV-infected blood, human and animal feces, insects, plants, and even sewage. PMID:27791095

  4. Virus-mediated suppression of host non-self recognition facilitates horizontal transmission of heterologous viruses

    PubMed Central

    Wu, Songsong; Cheng, Jiasen; Fu, Yanping; Chen, Tao; Jiang, Daohong; Ghabrial, Said A.

    2017-01-01

    Non-self recognition is a common phenomenon among organisms; it often leads to innate immunity to prevent the invasion of parasites and maintain the genetic polymorphism of organisms. Fungal vegetative incompatibility is a type of non-self recognition which often induces programmed cell death (PCD) and restricts the spread of molecular parasites. It is not clearly known whether virus infection could attenuate non-self recognition among host individuals to facilitate its spread. Here, we report that a hypovirulence-associated mycoreovirus, named Sclerotinia sclerotiorum mycoreovirus 4 (SsMYRV4), could suppress host non-self recognition and facilitate horizontal transmission of heterologous viruses. We found that cell death in intermingled colony regions between SsMYRV4-infected Sclerotinia sclerotiorum strain and other tested vegetatively incompatible strains was markedly reduced and inhibition barrage lines were not clearly observed. Vegetative incompatibility, which involves Heterotrimeric guanine nucleotide-binding proteins (G proteins) signaling pathway, is controlled by specific loci termed het (heterokaryon incompatibility) loci. Reactive oxygen species (ROS) plays a key role in vegetative incompatibility-mediated PCD. The expression of G protein subunit genes, het genes, and ROS-related genes were significantly down-regulated, and cellular production of ROS was suppressed in the presence of SsMYRV4. Furthermore, SsMYRV4-infected strain could easily accept other viruses through hyphal contact and these viruses could be efficiently transmitted from SsMYRV4-infected strain to other vegetatively incompatible individuals. Thus, we concluded that SsMYRV4 is capable of suppressing host non-self recognition and facilitating heterologous viruses transmission among host individuals. These findings may enhance our understanding of virus ecology, and provide a potential strategy to utilize hypovirulence-associated mycoviruses to control fungal diseases. PMID:28334041

  5. [Suppression of three soil-borne diseases of cucumber by a rhizosphere fungal strain].

    PubMed

    Lyu, Heng; Niu, Yong-chun; Deng, Hui; Lin, Xiao-min; Jin, Chun-li

    2015-12-01

    To understand the effect of rhizosphere fungi on soil-borne diseases of cucumber, 16 fungal, strains from rhizosphere soil were investigated for the antagonistic activity to three soilborne pathogenic fungi with dual culture method and for suppression of cucumber diseases caused by the pathogens in pot experiments. Four strains showed antagonism to one or more pathogenic fungi tested. The strain JCL143, identified as Aspergillus terreus, showed strong antagonistic activity to the three pathogenic fungi Fusarium oxysporum f. sp. cucumerinum, Rhizoctonia solani and Sclerotinia sclerotiorum. In greenhouse pot experiments, inoculation with strain JCL143 provided 74% or more of relative control effect to all the three diseases of cucumber seedling caused by the above three pathogenic fungi, and provided 85% or more of relative control effect to Rhizoctonia root rot and Sclerotinia root and stem rot in pot experiment with non-sterilized substrate. In pot experiment with natural soil as substrate, inoculation with strain JCL143 provided average 84.1% of relative control effect to Fusarium wilt of cucumber at vine elongation stage. The fermentation broth of strain JCL143 showed inhibitory effect in different degrees on the colonial growth of the three pathogenic fungi tested, and reached 63.3% of inhibitory rate of colonial growth to S. sclerotiorum. The inhibitory activity of the fermentation broth decreased with increasing treatment temperature, was liable to decrease to alkaline pH than acid pH, and stable to protease treatment. The results indicated that A. terreus is an important factor in suppression of plant soil-borne diseases, and strain JCL143 with stable disease suppression is potential in biocontrol application.

  6. Transgenic Brassica juncea plants expressing MsrA1, a synthetic cationic antimicrobial peptide, exhibit resistance to fungal phytopathogens.

    PubMed

    Rustagi, Anjana; Kumar, Deepak; Shekhar, Shashi; Yusuf, Mohd Aslam; Misra, Santosh; Sarin, Neera Bhalla

    2014-06-01

    Cationic antimicrobial peptides (CAPs) have shown potential against broad spectrum of phytopathogens. Synthetic versions with desirable properties have been modeled on these natural peptides. MsrA1 is a synthetic chimera of cecropin A and melittin CAPs with antimicrobial properties. We generated transgenic Brassica juncea plants expressing the msrA1 gene aimed at conferring fungal resistance. Five independent transgenic lines were evaluated for resistance to Alternaria brassicae and Sclerotinia sclerotiorum, two of the most devastating pathogens of B. juncea crops. In vitro assays showed inhibition by MsrA1 of Alternaria hyphae growth by 44-62 %. As assessed by the number and size of lesions and time taken for complete leaf necrosis, the Alternaria infection was delayed and restricted in the transgenic plants with the protection varying from 69 to 85 % in different transgenic lines. In case of S. sclerotiorum infection, the lesions were more severe and spread profusely in untransformed control compared with transgenic plants. The sclerotia formed in the stem of untransformed control plants were significantly more in number and larger in size than those present in the transgenic plants where disease protection of 56-71.5 % was obtained. We discuss the potential of engineering broad spectrum biotic stress tolerance by transgenic expression of CAPs in crop plants.

  7. A "footprint" of plant carbon fixation cycle functions during the development of a heterotrophic fungus.

    PubMed

    Lyu, Xueliang; Shen, Cuicui; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Hu, Zijin; Tang, Lihua; Tang, Liguang; Ding, Feng; Li, Kunfei; Wu, Song; Hu, Yanping; Luo, Lilian; Li, Yuanhao; Wang, Qihua; Li, Guoqing; Cheng, Jiasen

    2015-08-11

    Carbon fixation pathway of plants (CFPP) in photosynthesis converts solar energy to biomass, bio-products and biofuel. Intriguingly, a large number of heterotrophic fungi also possess enzymes functionally associated with CFPP, raising the questions about their roles in fungal development and in evolution. Here, we report on the presence of 17 CFPP associated enzymes (ten in Calvin-Benson-Basham reductive pentose phosphate pathway and seven in C4-dicarboxylic acid cycle) in the genome of Sclerotinia sclerotiorum, a heterotrophic phytopathogenic fungus, and only two unique enzymes: ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) and phosphoribulokinase (PRK) were absent. This data suggested an incomplete CFPP-like pathway (CLP) in fungi. Functional profile analysis demonstrated that the activity of the incomplete CLP was dramatically regulated during different developmental stages of S. sclerotiorum. Subsequent experiments confirmed that many of them were essential to the virulence and/or sclerotial formation. Most of the CLP associated genes are conserved in fungi. Phylogenetic analysis showed that many of them have undergone gene duplication, gene acquisition or loss and functional diversification in evolutionary history. These findings showed an evolutionary links in the carbon fixation processes of autotrophs and heterotrophs and implicated the functions of related genes were in course of continuous change in different organisms in evolution.

  8. Evaluation of Nostoc strain ATCC 53789 as a potential source of natural pesticides.

    PubMed

    Biondi, Natascia; Piccardi, Raffaella; Margheri, M Cristina; Rodolfi, Liliana; Smith, Geoffrey D; Tredici, Mario R

    2004-06-01

    The cyanobacterium Nostoc strain ATCC 53789, a known cryptophycin producer, was tested for its potential as a source of natural pesticides. The antibacterial, antifungal, insecticidal, nematocidal, and cytotoxic activities of methanolic extracts of the cyanobacterium were evaluated. Among the target organisms, nine fungi (Armillaria sp., Fusarium oxysporum f. sp. melonis, Penicillium expansum, Phytophthora cambivora, P. cinnamomi, Rhizoctonia solani, Rosellinia, sp., Sclerotinia sclerotiorum, and Verticillium albo-atrum) were growth inhibited and one insect (Helicoverpa armigera) was killed by the extract, as well as the two model organisms for nematocidal (Caenorhabditis elegans) and cytotoxic (Artemia salina) activity. No antibacterial activity was detected. The antifungal activity against S. sclerotiorum was further studied with both extracts and biomass of the cyanobacterium in a system involving tomato as a host plant. Finally, the herbicidal activity of Nostoc strain ATCC 53789 was evaluated against a grass mixture. To fully exploit the potential of this cyanobacterium in agriculture as a source of pesticides, suitable application methods to overcome its toxicity toward plants and nontarget organisms must be developed.

  9. A “footprint” of plant carbon fixation cycle functions during the development of a heterotrophic fungus

    PubMed Central

    Lyu, Xueliang; Shen, Cuicui; Xie, Jiatao; Fu, Yanping; Jiang, Daohong; Hu, Zijin; Tang, Lihua; Tang, Liguang; Ding, Feng; Li, Kunfei; Wu, Song; Hu, Yanping; Luo, Lilian; Li, Yuanhao; Wang, Qihua; Li, Guoqing; Cheng, Jiasen

    2015-01-01

    Carbon fixation pathway of plants (CFPP) in photosynthesis converts solar energy to biomass, bio-products and biofuel. Intriguingly, a large number of heterotrophic fungi also possess enzymes functionally associated with CFPP, raising the questions about their roles in fungal development and in evolution. Here, we report on the presence of 17 CFPP associated enzymes (ten in Calvin-Benson-Basham reductive pentose phosphate pathway and seven in C4-dicarboxylic acid cycle) in the genome of Sclerotinia sclerotiorum, a heterotrophic phytopathogenic fungus, and only two unique enzymes: ribulose-1, 5-bisphosphate carboxylase-oxygenase (Rubisco) and phosphoribulokinase (PRK) were absent. This data suggested an incomplete CFPP-like pathway (CLP) in fungi. Functional profile analysis demonstrated that the activity of the incomplete CLP was dramatically regulated during different developmental stages of S. sclerotiorum. Subsequent experiments confirmed that many of them were essential to the virulence and/or sclerotial formation. Most of the CLP associated genes are conserved in fungi. Phylogenetic analysis showed that many of them have undergone gene duplication, gene acquisition or loss and functional diversification in evolutionary history. These findings showed an evolutionary links in the carbon fixation processes of autotrophs and heterotrophs and implicated the functions of related genes were in course of continuous change in different organisms in evolution. PMID:26263551

  10. Biocontrol and plant growth-promoting activity of rhizobacteria from Chinese fields with contaminated soils

    PubMed Central

    Wang, Xuefei; Mavrodi, Dmitri V; Ke, Linfeng; Mavrodi, Olga V; Yang, Mingming; Thomashow, Linda S; Zheng, Na; Weller, David M; Zhang, Jibin

    2015-01-01

    The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with heavy metals, recalcitrant organics, petroleum sewage or salinity in China. We screened 1223 isolates for antifungal activity and about 24% inhibited Rhizoctonia solani or Sclerotinia sclerotiorum. Twenty-four strains inhibitory to R. solani, Gaeumannomyces graminis var. tritici and/or S. sclerotiorum and representing the dominant morphotypes were assayed for PGPR activity. Seven strains contained phlD, prnD, pltC or phzF genes and produced the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin, pyoluteorin and phenazines respectively. Six strains contained acdS, which encodes 1-aminocyclopropane-1-carboxylic acid deaminase. Phylogenetic analysis of 16S rDNA and phlD, phzF and acdS genes demonstrated that some strains identified as Pseudomonas were similar to model PGPR strains Pseudomonas protegens Pf-5, Pseudomonas chlororaphis subsp. aureofaciens 30–84 and P. brassicacearum Q8r1-96. Pseudomonas protegens- and P. chlororaphis-like strains had the greatest biocontrol activity against Rhizoctonia root rot and take-all of wheat. Pseudomonas protegens and P. brassicacearum-like strains showed the greatest promotion of canola growth. Our results indicate that strains from contaminated soils are similar to well-described PGPR found in agricultural soils worldwide. Growth-promoting rhizobacteria in polluted soils PMID:25219642

  11. Antifungal efficacy of hydrogen peroxide in dental unit waterline disinfection.

    PubMed

    Szymańska, Jolanta

    2006-01-01

    The concentration and composition of fungal flora in dental unit waterlines (DUWL) were evaluated. For this purpose, water samples from unit reservoirs and high-speed handpieces, and biofilm samples from the waterline walls from units were collected. Subsequently, analogous samples from DUWL were taken before and after disinfection using agent containing hydrogen peroxide. In the examined samples, the yeast-like fungi Candida albicans and Candida curvata were found. The following species of mould were also identified: Aspergillus amstelodami, Aspergillus fumigatus, Aspergillus glaucus group, Aspergillus (=Eurotium herbariorum) repens, Citromyces spp., Geotrichum candidum, Penicillium (glabrum) frequentans, Penicillium pusillum, Penicillium turolense and Sclerotium sclerotiorum (Sclerotinia sclerotiorum). Before disinfection, Candida curvata and Candida albicans constituted the greatest proportion of the total fungi in the reservoirs water; in the water of handpieces--Candida albicans and Aspergillus glaucus group; and in the biofilm samples--Aspergillus glaucus group and Candida albicans. After disinfection, in all 3 kinds of samples, Candida albicans prevailed, constituting from 31.2-85.7 % of the total fungi. The application of agent containing hydrogen peroxide caused a significant decrease both in the number of total fungi and individual fungal species, which confirms the product effectiveness in fungal decontamination of DUWL.

  12. Plant-derived antifungal agent poacic acid targets β-1,3-glucan

    DOE PAGES

    Piotrowski, Jeff S.; Okada, Hiroki; Lu, Fachuang; ...

    2015-03-09

    A rise in resistance to current antifungals necessitates strategies to identify alternative sources of effective fungicides. We report the discovery of poacic acid, a potent antifungal compound found in lignocellulosic hydrolysates of grasses. Chemical genomics using Saccharomyces cerevisiae showed that loss of cell wall synthesis and maintenance genes conferred increased sensitivity to poacic acid. Morphological analysis revealed that cells treated with poacic acid behaved similarly to cells treated with other cell wall-targeting drugs and mutants with deletions in genes involved in processes related to cell wall biogenesis. Poacic acid causes rapid cell lysis and is synergistic with caspofungin and fluconazole.more » The cellular target was identified; poacic acid localized to the cell wall and inhibited β-1,3-glucan synthesis in vivo and in vitro, apparently by directly binding β-1,3-glucan. Through its activity on the glucan layer, poacic acid inhibits growth of the fungi Sclerotinia sclerotiorum and Alternaria solani as well as the oomycete Phytophthora sojae. A single application of poacic acid to leaves infected with the broad-range fungal pathogen S. sclerotiorum substantially reduced lesion development. In conclusion, the discovery of poacic acid as a natural antifungal agent targeting β-1,3-glucan highlights the potential side use of products generated in the processing of renewable biomass toward biofuels as a source of valuable bioactive compounds and further clarifies the nature and mechanism of fermentation inhibitors found in lignocellulosic hydrolysates.« less

  13. Combined effects of Brassica napus seed meal and Trichoderma harzianum on two soilborne plant pathogens.

    PubMed

    Dandurand, L M; Mosher, R D; Knudsen, G R

    2000-11-01

    The effects of soil amendment with rapeseed meal from Brassica napus cv. 'Dwarf Essex' (high glucosinolate concentrations) and 'Stonewall' (low glucosinolate concentrations) on the biological control activity of Trichoderma harzianum towards Sclerotinia sclerotiorum and Aphanomyces euteiches were evaluated. Trichoderma harzianum added to soil reduced myceliogenic germination of S. sclerotiorum by 94%, but did not affect carpogenic germination. In contrast, 100% reduction in carpogenic germination was observed in soil amended with Dwarf Essex meal, along with a 33% reduction in myceliogenic germination. With Stonewall meal as soil amendment, carpogenic germination was reduced by 44% and myceliogenic germination was not affected. Both Dwarf Essex and Stonewall meals inhibited colonization of sclerotia in soil by T. harzianum, from 100% to 0% and 8%, respectively, so that biocontrol activity of T. harzianum was reduced in the presence of either meal. Aphanomyces euteiches root rot of pea was significantly reduced by T. harzianum alone (100%), by amendment with Dwarf Essex meal alone (77%), and by T. harzianum in combination with Dwarf Essex meal (100%). Amendment with Stonewall meal alone did not control root rot, and combination of Stonewall meal with T. harzianum reduced the biocontrol efficacy of T. harzianum.

  14. Plant-derived antifungal agent poacic acid targets β-1,3-glucan

    SciTech Connect

    Piotrowski, Jeff S.; Okada, Hiroki; Lu, Fachuang; Li, Sheena C.; Hinchman, Li; Ranjan, Ashish; Smith, Damon L.; Higbee, Alan J.; Ulbrich, Arne; Coon, Joshua J.; Deshpande, Raamesh; Bukhman, Yury V.; McIlwain, Sean; Ong, Irene M.; Myers, Chad L.; Boone, Charles; Landick, Robert; Ralph, John; Kabbage, Mehdi; Ohya, Yoshikazu

    2015-03-09

    A rise in resistance to current antifungals necessitates strategies to identify alternative sources of effective fungicides. We report the discovery of poacic acid, a potent antifungal compound found in lignocellulosic hydrolysates of grasses. Chemical genomics using Saccharomyces cerevisiae showed that loss of cell wall synthesis and maintenance genes conferred increased sensitivity to poacic acid. Morphological analysis revealed that cells treated with poacic acid behaved similarly to cells treated with other cell wall-targeting drugs and mutants with deletions in genes involved in processes related to cell wall biogenesis. Poacic acid causes rapid cell lysis and is synergistic with caspofungin and fluconazole. The cellular target was identified; poacic acid localized to the cell wall and inhibited β-1,3-glucan synthesis in vivo and in vitro, apparently by directly binding β-1,3-glucan. Through its activity on the glucan layer, poacic acid inhibits growth of the fungi Sclerotinia sclerotiorum and Alternaria solani as well as the oomycete Phytophthora sojae. A single application of poacic acid to leaves infected with the broad-range fungal pathogen S. sclerotiorum substantially reduced lesion development. In conclusion, the discovery of poacic acid as a natural antifungal agent targeting β-1,3-glucan highlights the potential side use of products generated in the processing of renewable biomass toward biofuels as a source of valuable bioactive compounds and further clarifies the nature and mechanism of fermentation inhibitors found in lignocellulosic hydrolysates.

  15. Dispersal of fungal spores on a cooperatively generated wind

    PubMed Central

    Roper, Marcus; Seminara, Agnese; Bandi, M. M.; Cobb, Ann; Dillard, Helene R.; Pringle, Anne

    2010-01-01

    Because of their microscopic size, the forcibly ejected spores of ascomycete fungi are quickly brought to rest by drag. Nonetheless some apothecial species, including the pathogen Sclerotinia sclerotiorum, disperse with astonishing rapidity between ephemeral habitats. Here we show that by synchronizing the ejection of thousands of spores, these fungi create a flow of air that carries spores through the nearly still air surrounding the apothecium, around intervening obstacles, and to atmospheric currents and new infection sites. High-speed imaging shows that synchronization is self-organized and likely triggered by mechanical stresses. Although many spores are sacrificed to produce the favorable airflow, creating the potential for conflict among spores, the geometry of the spore jet physically targets benefits of the airflow to spores that cooperate maximally in its production. The ability to manipulate a local fluid environment to enhance spore dispersal is a previously overlooked feature of the biology of fungal pathogens, and almost certainly shapes the virulence of species including S. sclerotiorum. Synchronous spore ejection may also provide a model for the evolution of stable, self-organized behaviors. PMID:20880834

  16. Colonization of lettuce rhizosphere and roots by tagged Streptomyces

    PubMed Central

    Bonaldi, Maria; Chen, Xiaoyulong; Kunova, Andrea; Pizzatti, Cristina; Saracchi, Marco; Cortesi, Paolo

    2015-01-01

    Beneficial microorganisms are increasingly used in agriculture, but their efficacy often fails due to limited knowledge of their interactions with plants and other microorganisms present in rhizosphere. We studied spatio-temporal colonization dynamics of lettuce roots and rhizosphere by genetically modified Streptomyces spp. Five Streptomyces strains, strongly inhibiting in vitro the major soil-borne pathogen of horticultural crops, Sclerotinia sclerotiorum, were transformed with pIJ8641 plasmid harboring an enhanced green fluorescent protein marker and resistance to apramycin. The fitness of transformants was compared to the wild-type strains and all of them grew and sporulated at similar rates and retained the production of enzymes and selected secondary metabolites as well as in vitro inhibition of S. sclerotiorum. The tagged ZEA17I strain was selected to study the dynamics of lettuce roots and rhizosphere colonization in non-sterile growth substrate. The transformed strain was able to colonize soil, developing roots, and rhizosphere. When the strain was inoculated directly on the growth substrate, significantly more t-ZEA17I was re-isolated both from the rhizosphere and the roots when compared to the amount obtained after seed coating. The re-isolation from the rhizosphere and the inner tissues of surface-sterilized lettuce roots demonstrated that t-ZEA17I is both rhizospheric and endophytic. PMID:25705206

  17. Biocontrol and plant growth-promoting activity of rhizobacteria from Chinese fields with contaminated soils.

    PubMed

    Wang, Xuefei; Mavrodi, Dmitri V; Ke, Linfeng; Mavrodi, Olga V; Yang, Mingming; Thomashow, Linda S; Zheng, Na; Weller, David M; Zhang, Jibin

    2015-05-01

    The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with heavy metals, recalcitrant organics, petroleum sewage or salinity in China. We screened 1223 isolates for antifungal activity and about 24% inhibited Rhizoctonia solani or Sclerotinia sclerotiorum. Twenty-four strains inhibitory to R. solani, Gaeumannomyces graminis var. tritici and/or S. sclerotiorum and representing the dominant morphotypes were assayed for PGPR activity. Seven strains contained phlD, prnD, pltC or phzF genes and produced the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin, pyoluteorin and phenazines respectively. Six strains contained acdS, which encodes 1-aminocyclopropane-1-carboxylic acid deaminase. Phylogenetic analysis of 16S rDNA and phlD, phzF and acdS genes demonstrated that some strains identified as Pseudomonas were similar to model PGPR strains Pseudomonas protegens Pf-5, Pseudomonas chlororaphis subsp. aureofaciens 30-84 and P. brassicacearum Q8r1-96. Pseudomonas protegens- and P. chlororaphis-like strains had the greatest biocontrol activity against Rhizoctonia root rot and take-all of wheat. Pseudomonas protegens and P. brassicacearum-like strains showed the greatest promotion of canola growth. Our results indicate that strains from contaminated soils are similar to well-described PGPR found in agricultural soils worldwide.

  18. Screening of different Trichoderma species against agriculturally important foliar plant pathogens.

    PubMed

    Prabhakaran, Narayanasamy; Prameeladevi, Thokala; Sathiyabama, Muthukrishnan; Kamil, Deeba

    2015-01-01

    Different isolates of Trichoderma were isolated from soil samples which were collected from different part of India. These isolates were grouped into four Trichoderma species viz., Trichoderma asperellum (Ta), T. harzianum (Th), T. pseudokoningii (Tp) and T. longibrachiatum (Tl) based on their morphological characters. Identification of the above isolates was also confirmed through ITS region analysis. These Trichoderma isolates were tested for in vitro biological control of Alternaria solani, Bipolaris oryzae, Pyricularia oryzae and Sclerotinia scierotiorum which cause serious diseases like early blight (target spot) of tomato and potato, brown leaf spot disease in rice, rice blast disease, and white mold disease in different plants. Under in vitro conditions, all the four species of Trichoderma (10 isolates) proved 100% potential inhibition against rice blast pathogen Pyracularia oryzae. T. harzianum (Th-01) and T. asperellum (Ta-10) were effective with 86.6% and 97.7%, growth inhibition of B. oryzae, respectively. Among others, T. pseudokoningii (Tp-08) and T. Iongibrachiatum (Tl-09) species were particularly efficient in inhibiting growth of S. sclerotiorum by 97.8% and 93.3%. T. Iongibrachiatum (TI-06 and TI-07) inhibited maximum mycelial growth of A. solani by 87.6% and 84.75. However, all the T. harzianum isolates showed significantly higher inhibition against S. sclerotiorum (CD value 9.430), causing white mold disease. This study led to the selection of potential Trichoderma isolates against rice blast, early blight, brown leaf spot in rice and white mold disease in different crops.

  19. The fungicidal terpenoids and essential oil from Litsea cubeba in Tibet.

    PubMed

    Yang, Yu; Jiang, Jiazheng; Qimei, Luobu; Yan, Xiaojing; Zhao, Junxia; Yuan, Huizhu; Qin, Zhaohai; Wang, Mingan

    2010-10-13

    A new C₉ monoterpenoid acid (litseacubebic acid, 1) and a known monoterpene lactone (6R)-3,7-dimethyl-7-hydroxy-2-octen-6-olide (2), along with three known compounds--vanillic acid (3), trans-3,4,5-trimethoxylcinnamyl alcohol (4), and oxonantenine (5)--were isolated with bioassay-guided purification from the fruit extract of Litsea cubeba collected in Tibet. The structure of 1 was elucidated by MS, ¹H-NMR, ¹³C-NMR, COSY, HSQC, HMBC, NOE spectral data as 2,6-dimethyl-6-hydroxy-2E,4E-hepta-2,4-diene acid. Additionally 33 compounds were identified from the essential oil of L. cubeba. The preliminary bioassay results showed that 1 and 2 have good fungicidal activities against Sclerotinia sclerotiorum, Thanatephorus cucumeris, Pseudocer-cospora musae and Colletotrichum gloeosporioides at the concentration of 588 and 272 μM, and the essential oil has good fungicidal activities against T. cucumeris and S. sclerotiorum, with IC₅₀ values of 115.58 and 151.25 μg/mL, repectively.

  20. Effects of experimental warming on fungal disease progress in oilseed rape.

    PubMed

    Siebold, Magdalena; von Tiedemann, Andreas

    2013-06-01

    Global warming will influence the growth and development of both crops and pathogens. The aims of this study were to investigate potential effects of future warming on oilseed rape growth and the epidemiology of the three economically important pathogens Verticillium longisporum, Sclerotinia sclerotiorum, and Leptosphaeria maculans (anamorph: Phoma lingam). We utilized climate chambers and a soil warming facility, where treatments represented regional warming scenarios for Lower Saxony, Germany, by 2050 and 2100, and compared results of both approaches on a thermal time scale by calculating degree-days (dd) from day of sowing, December 1st and March 1st until sampling, the latter correlating best with disease progress. Regression analysis showed that plant growth and growth stages in spring responded almost linearly to increasing thermal time until 1000-1500 dd. Colonization of plant tissue by V. longisporum showed an exponential increase when exceeding 1300-1500 dd and reaching plant growth stage BBCH 74/75 (pod development). V. longisporum colonization of plants may be advanced, potentially leading to higher inoculum densities after harvest and increased economic importance of this pathogen under future warming. Sclerotia germination of S. sclerotiorum reached its maximum at 600-900 dd. Advance of these critical degree-days may lead to earlier apothecia production, potentially advancing the infection window, whereas the future importance of S. sclerotiorum may remain constant. Severity of phoma crown canker increased linearly with increasing thermal time, but showed also large variation in response to the warming scenarios, suggesting that factors such as canopy microclimate in fall or leaf shedding over winter may play a bigger role for L. maculans infection and disease severity than higher soil temperatures. Thermal time was a suitable tool to combine and integrate data on biological responses to soil and air temperature increases from climate chamber and field

  1. Fungal Endophyte Diversity and Bioactivity in the Indian Medicinal Plant Ocimum sanctum Linn.

    PubMed

    Chowdhary, Kanika; Kaushik, Nutan

    2015-01-01

    Endophytic mycopopulation isolated from India's Queen of herbs Tulsi (Ocimum sanctum) were explored and investigated for their diversity and antiphytopathogenic activity against widespread plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. 90 fungal isolates, representing 17 genera were recovered from 313 disease-free and surface sterilised plant segments (leaf and stem tissues) from three different geographic locations (Delhi, Hyderabad and Mukteshwar) during distinct sampling times in consequent years 2010 and 2011 in India. Fungal endophytes were subjected to molecular identification based on rDNA ITS sequence analysis. Plant pathogens such as F. verticillioides, B. maydis, C. coarctatum, R. bataticola, Hypoxylon sp., Diaporthe phaseolorum, Alternaria tenuissima and A. alternata have occurred as endophyte only during second sampling (second sampling in 2011) in the present study. Bi-plot generated by principal component analysis suggested tissue specificity of certain fungal endophytes. Dendrogram revealed species abundance as a function of mean temperature of the location at the time of sampling. Shannon diversity in the first collection is highest in Hyderabad leaf tissues (H' = 1.907) whereas in second collection it was highest from leaf tissues of Delhi (H' = 1.846). Mukteshwar (altitude: 7500 feet) reported least isolation rate in second collection. Nearly 23% of the total fungal isolates were considered as potent biocontrol agent. Hexane extract of M. phaseolina recovered from Hyderabad in first collection demonstrated highest activity against S. sclerotiorum with IC50 value of 0.38 mg/ml. Additionally, its components 2H-pyran-2-one, 5,6-dihydro-6-pentyl and palmitic acid, methyl ester as reported by GC-MS Chromatogram upon evaluation for their antiphytopathogenic activity exhibited IC50 value of 1.002 and 0.662 against respectively S. sclerotiorum indicating their significant role in antiphytopathogenic

  2. First report of dollar spot disease, caused by Sclerotinia homoeocarpa, of Agrostis stolonifera in Sweden

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dollar spot is a destructive and widespread disease affecting most grass species grown as turf, but until recently it has been absent from the Scandinavian countries of northern Europe. In the fall of 2014, disease symptoms consistent with dollar spot were observed on a golf course fairway in Sweden...

  3. First report of sunflower white mold caused by Sclerotinia minor Jagger in Inner Mongolia region, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the 2014 growing season, sunflower plants with symptoms of basal stem rot and whole plant wilt were observed in sunflower fields in Inner Mongolia, China. The average disease incidence was between 10-15%. Tiny (0.30 to 2.68 mm) black sclerotia were usually observed on the stem of infected pla...

  4. Transferring Sclerotinia stalk rot resistance genes from wild Helianthus species into cultivated sunflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Replicated field tests of 313 progeny families screened for stalk rot resistance at Carrington, ND in 2009 showed good introgression of resistance genes. These materials were planted again in 2010 for a second year of field evaluation, as well as the new families with seed increased in 2009. In 2010...

  5. Meta-QTL for resistance to white mold in common bean

    PubMed Central

    Vasconcellos, Renato C. C.; Oraguzie, O. Blessing; Soler, Alvaro; Arkwazee, Haidar; Myers, James R.; Ferreira, Juan J.; Song, Qijian; McClean, Phil; Miklas, Phillip N.

    2017-01-01

    White mold, caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease that limits common bean production and quality worldwide. The host-pathogen interaction is complex, with partial resistance in the host inherited as a quantitative trait with low to moderate heritability. Our objective was to identify meta-QTL conditioning partial resistance to white mold from individual QTL identified across multiple populations and environments. The physical positions for 37 individual QTL were identified across 14 recombinant inbred bi-parental populations (six new, three re-genotyped, and five from the literature). A meta-QTL analysis of the 37 QTL was conducted using the genetic linkage map of Stampede x Red Hawk population as the reference. The 37 QTL condensed into 17 named loci (12 previously named and five new) of which nine were defined as meta-QTL WM1.1, WM2.2, WM3.1, WM5.4, WM6.2, WM7.1, WM7.4, WM7.5, and WM8.3. The nine meta-QTL had confidence intervals ranging from 0.65 to 9.41 Mb. Candidate genes shown to express under S. sclerotiorum infection in other studies, including cell wall receptor kinase, COI1, ethylene responsive transcription factor, peroxidase, and MYB transcription factor, were found within the confidence interval for five of the meta-QTL. The nine meta-QTL are recommended as potential targets for MAS for partial resistance to white mold in common bean. PMID:28199342

  6. Broad-spectrum disease resistance to necrotrophic and biotrophic pathogens in transgenic carrots (Daucus carota L.) expressing an Arabidopsis NPR1 gene.

    PubMed

    Wally, Owen; Jayaraj, Jayaraman; Punja, Zamir K

    2009-12-01

    The development of transgenic plants highly resistant to a range of pathogens using traditional signal gene expression strategies has been largely ineffective. Modification of systemic acquired resistance (SAR) through the overexpression of a controlling gene such as NPR1 (non-expressor of PR genes) offers an attractive alternative for augmenting the plants innate defense system. The Arabidopsis (At) NPR1 gene was successfully introduced into 'Nantes Coreless' carrot under control of a CaMV 35S promoter and two independent transgenic lines (NPR1-I and NPR1-XI) were identified by Southern and Northern blot hybridization. Both lines were phenotypically normal compared with non-transformed carrots. Northern analysis did not indicate constitutive or spontaneous induction in carrot cultures of SAR-related genes (DcPR-1, 2, 4, 5 or DcPAL). The duration and intensity of expression of DcPR-1, 2 and 5 genes were greatly increased compared with controls when the lines were treated with purified cell wall fragments of Sclerotinia sclerotiorum as well as with 2,6-dichloroisonicotinic acid. The two lines were challenged with the necrotrophic pathogens Botrytis cinerea, Alternaria radicina and S. sclerotiorum on the foliage and A. radicina on the taproots. Both lines exhibited 35-50% reduction in disease symptoms on the foliage and roots when compared with non-transgenic controls. Leaves challenged with the biotrophic pathogen Erysiphe heraclei or the bacterial pathogen Xanthomonas hortorum exhibited 90 and 80% reduction in disease development on the transgenic lines, respectively. The overexpression of the SAR controlling master switch in carrot tissues offers the ability to control a wide range of different pathogens, for which there is currently little genetic resistance available.

  7. Cyclic nucleotide gated channel gene family in tomato: genome-wide identification and functional analyses in disease resistance

    PubMed Central

    Saand, Mumtaz A.; Xu, You-Ping; Li, Wen; Wang, Ji-Peng; Cai, Xin-Zhong

    2015-01-01

    The cyclic nucleotide gated channel (CNGC) is suggested to be one of the important calcium conducting channels. Nevertheless, genome-wide identification and systemic functional analysis of CNGC gene family in crop plant species have not yet been conducted. In this study, we performed genome-wide identification of CNGC gene family in the economically important crop tomato (Solanum lycopersicum L.) and analyzed function of the group IVb SlCNGC genes in disease resistance. Eighteen CNGC genes were identified in tomato genome, and four CNGC loci that were misannotated at database were corrected by cloning and sequencing. Detailed bioinformatics analyses on gene structure, domain composition and phylogenetic relationship of the SlCNGC gene family were conducted and the group-specific feature was revealed. Comprehensive expression analyses demonstrated that SlCNGC genes were highly, widely but differently responsive to diverse stimuli. Pharmacological assays showed that the putative CNGC activators cGMP and cAMP enhanced resistance against Sclerotinia sclerotiorum. Silencing of group IVb SlCNGC genes significantly enhanced resistance to fungal pathogens Pythium aphanidermatum and S. sclerotiorum, strongly reduced resistance to viral pathogen Tobacco rattle virus, while attenuated PAMP- and DAMP-triggered immunity as shown by obvious decrease of the flg22- and AtPep1-elicited hydrogen peroxide accumulation in SlCNGC-silenced plants. Additionally, silencing of these SlCNGC genes significantly altered expression of a set of Ca2+ signaling genes including SlCaMs, SlCDPKs, and SlCAMTA3. Collectively, our results reveal that group IV SlCNGC genes regulate a wide range of resistance in tomato probably by affecting Ca2+ signaling. PMID:25999969

  8. PtrA Is Functionally Intertwined with GacS in Regulating the Biocontrol Activity of Pseudomonas chlororaphis PA23

    PubMed Central

    Shah, Nidhi; Klaponski, Natasha; Selin, Carrie; Rudney, Rachel; Fernando, W. G. Dilantha; Belmonte, Mark F.; de Kievit, Teresa R.

    2016-01-01

    In vitro inhibition of the fungal pathogen Sclerotinia sclerotiorum by Pseudomonas chlororaphis PA23 is reliant upon a LysR-type transcriptional regulator (LTTR) called PtrA. In the current study, we show that Sclerotinia stem rot and leaf infection are significantly increased in canola plants inoculated with the ptrA-mutant compared to the wild type, establishing PtrA as an essential regulator of PA23 biocontrol. LTTRs typically regulate targets that are upstream of and divergently transcribed from the LTTR locus. We identified a short chain dehydrogenase (scd) gene immediately upstream of ptrA. Characterization of a scd mutant revealed that it is phenotypically identical to the wild type. Moreover, scd transcript abundance was unchanged in the ptrA mutant. These findings indicate that PtrA regulation does not involve scd, rather this LTTR controls genes located elsewhere on the chromosome. Employing a combination of complementation and transcriptional analysis we investigated whether connections exist between PtrA and other regulators of biocontrol. Besides ptrA, gacS was the only gene able to partially rescue the wild-type phenotype, establishing a connection between PtrA and the sensor kinase GacS. Transcriptomic analysis revealed decreased expression of biosynthetic (phzA, prnA) and regulatory genes (phzI, phzR, rpoS, gacA, rsmX, rsmZ, retS) in the ptrA mutant; conversely, rsmE, and rsmY were markedly upregulated. The transcript abundance of ptrA was nine-fold higher in the mutant background indicating that this LTTR negatively autoregulates itself. In summary, PtrA is an essential regulator of genes required for PA23 biocontrol that is functionally intertwined with GacS. PMID:27713742

  9. Identification of a Novel Proline-Rich Antimicrobial Peptide from Brassica napus.

    PubMed

    Cao, Huihui; Ke, Tao; Liu, Renhu; Yu, Jingyin; Dong, Caihua; Cheng, Mingxing; Huang, Junyan; Liu, Shengyi

    2015-01-01

    Proline-rich antimicrobial peptides (PR-AMPs) are a group of cationic host defense peptides that are characterized by a high content of proline residues. Up to now, they have been reported in some insects, vertebrate and invertebrate animals, but are not found in plants. In this study, we performed an in silico screening of antimicrobial peptides, which led to discovery of a Brassica napus gene encoding a novel PR-AMP. This gene encodes a 35-amino acid peptide with 13 proline residues, designated BnPRP1. BnPRP1 has 40.5% identity with a known proline-rich antimicrobial peptide SP-B from the pig. BnPRP1 was artificially synthetized and cloned into the prokaryotic expression vector pET30a/His-EDDIE-GFP. Recombinant BnPRP1 was produced in Escherichia coli and has a predicted molecular mass of 3.8 kDa. Analysis of its activity demonstrated that BnPRP1 exhibited strong antimicrobial activity against Gram-positive bacterium, Gram-negative bacterium, yeast and also had strong antifungal activity against several pathogenic fungi, such as Sclerotinia sclerotiorum, Mucor sp., Magnaporthe oryzae and Botrytis cinerea. Circular dichroism (CD) revealed the main secondary structure of BnPRP1 was the random coil. BnPRP1 gene expression detected by qRT-PCR is responsive to pathogen inoculation. At 48 hours after S. sclerotiorum inoculation, the expression of BnPRP1 increased significantly in the susceptible lines while slight decrease occurred in resistant lines. These suggested that BnPRP1 might play a role in the plant defense response against S. sclerotiorum. BnPRP1 isolated from B. napus was the first PR-AMP member that was characterized in plants, and its homology sequences were found in some other Brassicaceae plants by the genome sequences analysis. Compared with the known PR-AMPs, BnPRP1 has the different primary sequences and antimicrobial activity. Above all, this study gives a chance to cast a new light on further understanding about the AMPs' mechanism and application.

  10. Fungal Endophyte Diversity and Bioactivity in the Indian Medicinal Plant Ocimum sanctum Linn

    PubMed Central

    Chowdhary, Kanika; Kaushik, Nutan

    2015-01-01

    Endophytic mycopopulation isolated from India’s Queen of herbs Tulsi (Ocimum sanctum) were explored and investigated for their diversity and antiphytopathogenic activity against widespread plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. 90 fungal isolates, representing 17 genera were recovered from 313 disease-free and surface sterilised plant segments (leaf and stem tissues) from three different geographic locations (Delhi, Hyderabad and Mukteshwar) during distinct sampling times in consequent years 2010 and 2011 in India. Fungal endophytes were subjected to molecular identification based on rDNA ITS sequence analysis. Plant pathogens such as F. verticillioides, B. maydis, C. coarctatum, R. bataticola, Hypoxylon sp., Diaporthe phaseolorum, Alternaria tenuissima and A. alternata have occurred as endophyte only during second sampling (second sampling in 2011) in the present study. Bi-plot generated by principal component analysis suggested tissue specificity of certain fungal endophytes. Dendrogram revealed species abundance as a function of mean temperature of the location at the time of sampling. Shannon diversity in the first collection is highest in Hyderabad leaf tissues (H' = 1.907) whereas in second collection it was highest from leaf tissues of Delhi (H' = 1.846). Mukteshwar (altitude: 7500 feet) reported least isolation rate in second collection. Nearly 23% of the total fungal isolates were considered as potent biocontrol agent. Hexane extract of M. phaseolina recovered from Hyderabad in first collection demonstrated highest activity against S. sclerotiorum with IC50 value of 0.38 mg/ml. Additionally, its components 2H-pyran-2-one, 5,6-dihydro-6-pentyl and palmitic acid, methyl ester as reported by GC-MS Chromatogram upon evaluation for their antiphytopathogenic activity exhibited IC50 value of 1.002 and 0.662 against respectively S. sclerotiorum indicating their significant role in

  11. Pyramiding Sclerotinia head rot and stalk rot resistances into elite sunflower breeding lines with the aid of DNA markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Work was conducted in 2008 to determine the stalk rot resistance of RILs from the RHA 280 x RHA 801 population, as well as to begin introgression of previously identified QTL for head rot resistance into elite sunflower germplasm lines. The stalk rot RILs and their testcrosses with cms HA 89 were t...

  12. Proteomic profile of the Bradysia odoriphaga in response to the microbial secondary metabolite benzothiazole.

    PubMed

    Zhao, Yunhe; Cui, Kaidi; Xu, Chunmei; Wang, Qiuhong; Wang, Yao; Zhang, Zhengqun; Liu, Feng; Mu, Wei

    2016-11-24

    Benzothiazole, a microbial secondary metabolite, has been demonstrated to possess fumigant activity against Sclerotinia sclerotiorum, Ditylenchus destructor and Bradysia odoriphaga. However, to facilitate the development of novel microbial pesticides, the mode of action of benzothiazole needs to be elucidated. Here, we employed iTRAQ-based quantitative proteomics analysis to investigate the effects of benzothiazole on the proteomic expression of B. odoriphaga. In response to benzothiazole, 92 of 863 identified proteins in B. odoriphaga exhibited altered levels of expression, among which 14 proteins were related to the action mechanism of benzothiazole, 11 proteins were involved in stress responses, and 67 proteins were associated with the adaptation of B. odoriphaga to benzothiazole. Further bioinformatics analysis indicated that the reduction in energy metabolism, inhibition of the detoxification process and interference with DNA and RNA synthesis were potentially associated with the mode of action of benzothiazole. The myosin heavy chain, succinyl-CoA synthetase and Ca(+)-transporting ATPase proteins may be related to the stress response. Increased expression of proteins involved in carbohydrate metabolism, energy production and conversion pathways was responsible for the adaptive response of B. odoriphaga. The results of this study provide novel insight into the molecular mechanisms of benzothiazole at a large-scale translation level and will facilitate the elucidation of the mechanism of action of benzothiazole.

  13. Proteomic profile of the Bradysia odoriphaga in response to the microbial secondary metabolite benzothiazole

    PubMed Central

    Zhao, Yunhe; Cui, Kaidi; Xu, Chunmei; Wang, Qiuhong; Wang, Yao; Zhang, Zhengqun; Liu, Feng; Mu, Wei

    2016-01-01

    Benzothiazole, a microbial secondary metabolite, has been demonstrated to possess fumigant activity against Sclerotinia sclerotiorum, Ditylenchus destructor and Bradysia odoriphaga. However, to facilitate the development of novel microbial pesticides, the mode of action of benzothiazole needs to be elucidated. Here, we employed iTRAQ-based quantitative proteomics analysis to investigate the effects of benzothiazole on the proteomic expression of B. odoriphaga. In response to benzothiazole, 92 of 863 identified proteins in B. odoriphaga exhibited altered levels of expression, among which 14 proteins were related to the action mechanism of benzothiazole, 11 proteins were involved in stress responses, and 67 proteins were associated with the adaptation of B. odoriphaga to benzothiazole. Further bioinformatics analysis indicated that the reduction in energy metabolism, inhibition of the detoxification process and interference with DNA and RNA synthesis were potentially associated with the mode of action of benzothiazole. The myosin heavy chain, succinyl-CoA synthetase and Ca+-transporting ATPase proteins may be related to the stress response. Increased expression of proteins involved in carbohydrate metabolism, energy production and conversion pathways was responsible for the adaptive response of B. odoriphaga. The results of this study provide novel insight into the molecular mechanisms of benzothiazole at a large-scale translation level and will facilitate the elucidation of the mechanism of action of benzothiazole. PMID:27883048

  14. Saprotrophic competitiveness and biocontrol fitness of a genetically modified strain of the plant-growth-promoting fungus Trichoderma hamatum GD12.

    PubMed

    Ryder, Lauren S; Harris, Beverley D; Soanes, Darren M; Kershaw, Michael J; Talbot, Nicholas J; Thornton, Christopher R

    2012-01-01

    Trichoderma species are ubiquitous soil fungi that hold enormous potential for the development of credible alternatives to agrochemicals and synthetic fertilizers in sustainable crop production. In this paper, we show that substantial improvements in plant productivity can be met by genetic modification of a plant-growth-promoting and biocontrol strain of Trichoderma hamatum, but that these improvements are obtained in the absence of disease pressure only. Using a quantitative monoclonal antibody-based ELISA, we show that an N-acetyl-β-d-glucosaminidase-deficient mutant of T. hamatum, generated by insertional mutagenesis of the corresponding gene, has impaired saprotrophic competitiveness during antagonistic interactions with Rhizoctonia solani in soil. Furthermore, its fitness as a biocontrol agent of the pre-emergence damping-off pathogen Sclerotinia sclerotiorum is significantly reduced, and its ability to promote plant growth is constrained by the presence of both pathogens. This work shows that while gains in T. hamatum-mediated plant-growth-promotion can be met through genetic manipulation of a single beneficial trait, such a modification has negative impacts on other aspects of its biology and ecology that contribute to its success as a saprotrophic competitor and antagonist of soil-borne pathogens. The work has important implications for fungal morphogenesis, demonstrating a clear link between hyphal architecture and secretory potential. Furthermore, it highlights the need for a holistic approach to the development of genetically modified Trichoderma strains for use as crop stimulants and biocontrol agents in plant agriculture.

  15. Functionalized para-substituted benzenes as 1,8-cineole production modulators in an endophytic Nodulisporium species.

    PubMed

    Nigg, Jared; Strobel, Gary; Knighton, W Berk; Hilmer, Jonathan; Geary, Brad; Riyaz-Ul-Hassan, Syed; Harper, James K; Valenti, Domenic; Wang, Yuemin

    2014-08-01

    A Nodulisporium species (designated Ti-13) was isolated as an endophyte from Cassia fistula. The fungus produces a spectrum of volatile organic compounds (VOCs) that includes ethanol, acetaldehyde and 1,8-cineole as major components. Initial observations of the fungal isolate suggested that reversible attenuation of the organism via removal from the host and successive transfers in pure culture resulted in a 50 % decrease in cineole production unrelated to an overall alteration in fungal growth. A compound (CPM1) was obtained from Betula pendula (silver birch) that increases the production of 1,8-cineole by an attenuated Ti-13 strain to its original level, as measured by a novel bioassay method employing a 1,8-cineole-sensitive fungus (Sclerotinia sclerotiorum). The host plant produces similar compounds possessing this activity. Bioactivity assays with structurally similar compounds such as ferulic acid and gallic acid suggested that the CPM1 does not act as a simple precursor to the biosynthesis of 1,8-cineole. NMR spectroscopy and HPLC-ES-MS indicated that the CPM1 is a para-substituted benzene with alkyl and carboxyl substituents. The VOCs of Ti-13, especially 1,8-cineole, have potential applications in the industrial, fuel and medical fields.

  16. Identification of diverse circular single-stranded DNA viruses in adult dragonflies and damselflies (Insecta: Odonata) of Arizona and Oklahoma, USA.

    PubMed

    Dayaram, Anisha; Potter, Kristen A; Pailes, Roberta; Marinov, Milen; Rosenstein, Dana D; Varsani, Arvind

    2015-03-01

    Next generation sequencing and metagenomic approaches are commonly used for the identification of circular replication associated protein (Rep)-encoding single stranded (CRESS) DNA viruses circulating in various environments. These approaches have enabled the discovery of some CRESS DNA viruses associated with insects. In this study we identified and recovered 31 viral genomes which represent 24 distinct CRESS DNA viruses from seven dragonfly species (Rhionaeschna multicolor, Erythemis simplicicollis, Erythrodiplax fusca, Libellula quadrimaculata, Libellula saturata, Pachydiplax longipennis, and Pantala hymenaea) and two damselfly species (Ischnura posita, Ischnura ramburii) sampled in various locations in the states of Arizona and Oklahoma of the United States of America (USA). We also identified Sclerotinia sclerotiorum hypovirulence-associated DNA virus-1 (SsHADV-1) in P. hymenaea, E. simplicicollis and I. ramburii sampled in Oklahoma, which is the first report of SsHADV-1 in the New World. The genome architectures of the CRESS DNA viruses recovered vary, but they all have at least two major open reading frames (ORFs) that have either a bidirectional or unidirectional arrangement. Four of the viral genomes recovered, in addition to the three isolates of SsHADV-1, show similarities to viruses of the proposed gemycircularvirus group. Analysis of the Rep encoded by the remaining 24 viral genomes reveals that these are highly diverse and allude to the fact that they represent novel CRESS DNA viruses.

  17. Comparative Genome Analyses of Serratia marcescens FS14 Reveals Its High Antagonistic Potential

    PubMed Central

    Li, Pengpeng; Kwok, Amy H. Y.; Jiang, Jingwei; Ran, Tingting; Xu, Dongqing; Wang, Weiwu; Leung, Frederick C.

    2015-01-01

    S. marcescens FS14 was isolated from an Atractylodes macrocephala Koidz plant that was infected by Fusarium oxysporum and showed symptoms of root rot. With the completion of the genome sequence of FS14, the first comprehensive comparative-genomic analysis of the Serratia genus was performed. Pan-genome and COG analyses showed that the majority of the conserved core genes are involved in basic cellular functions, while genomic factors such as prophages contribute considerably to genome diversity. Additionally, a Type I restriction-modification system, a Type III secretion system and tellurium resistance genes are found in only some Serratia species. Comparative analysis further identified that S. marcescens FS14 possesses multiple mechanisms for antagonism against other microorganisms, including the production of prodigiosin, bacteriocins, and multi-antibiotic resistant determinants as well as chitinases. The presence of two evolutionarily distinct Type VI secretion systems (T6SSs) in FS14 may provide further competitive advantages for FS14 against other microbes. To our knowledge, this is the first report of comparative analysis on T6SSs in the genus, which identifies four types of T6SSs in Serratia spp.. Competition bioassays of FS14 against the vital plant pathogenic bacterium Ralstonia solanacearum and fungi Fusarium oxysporum and Sclerotinia sclerotiorum were performed to support our genomic analyses, in which FS14 demonstrated high antagonistic activities against both bacterial and fungal phytopathogens. PMID:25856195

  18. Investigating the beneficial traits of Trichoderma hamatum GD12 for sustainable agriculture-insights from genomics.

    PubMed

    Studholme, David J; Harris, Beverley; Le Cocq, Kate; Winsbury, Rebecca; Perera, Venura; Ryder, Lauren; Ward, Jane L; Beale, Michael H; Thornton, Chris R; Grant, Murray

    2013-01-01

    Trichoderma hamatum strain GD12 is unique in that it can promote plant growth, activate biocontrol against pre- and post-emergence soil pathogens and can induce systemic resistance to foliar pathogens. This study extends previous work in lettuce to demonstrate that GD12 can confer beneficial agronomic traits to other plants, providing examples of plant growth promotion in the model dicot, Arabidopsis thaliana and induced foliar resistance to Magnaporthe oryzae in the model monocot rice. We further characterize the lettuce-T. hamatum interaction to show that bran extracts from GD12 and an N-acetyl-β-D-glucosamindase-deficient mutant differentially promote growth in a concentration dependent manner, and these differences correlate with differences in the small molecule secretome. We show that GD12 mycoparasitises a range of isolates of the pre-emergence soil pathogen Sclerotinia sclerotiorum and that this interaction induces a further increase in plant growth promotion above that conferred by GD12. To understand the genetic potential encoded by T. hamatum GD12 and to facilitate its use as a model beneficial organism to study plant growth promotion, induced systemic resistance and mycoparasitism we present de novo genome sequence data. We compare GD12 with other published Trichoderma genomes and show that T. hamatum GD12 contains unique genomic regions with the potential to encode novel bioactive metabolites that may contribute to GD12's agrochemically important traits.

  19. Investigating the beneficial traits of Trichoderma hamatum GD12 for sustainable agriculture—insights from genomics

    PubMed Central

    Studholme, David J.; Harris, Beverley; Le Cocq, Kate; Winsbury, Rebecca; Perera, Venura; Ryder, Lauren; Ward, Jane L.; Beale, Michael H.; Thornton, Chris R.; Grant, Murray

    2013-01-01

    Trichoderma hamatum strain GD12 is unique in that it can promote plant growth, activate biocontrol against pre- and post-emergence soil pathogens and can induce systemic resistance to foliar pathogens. This study extends previous work in lettuce to demonstrate that GD12 can confer beneficial agronomic traits to other plants, providing examples of plant growth promotion in the model dicot, Arabidopsis thaliana and induced foliar resistance to Magnaporthe oryzae in the model monocot rice. We further characterize the lettuce-T. hamatum interaction to show that bran extracts from GD12 and an N-acetyl-β-D-glucosamindase-deficient mutant differentially promote growth in a concentration dependent manner, and these differences correlate with differences in the small molecule secretome. We show that GD12 mycoparasitises a range of isolates of the pre-emergence soil pathogen Sclerotinia sclerotiorum and that this interaction induces a further increase in plant growth promotion above that conferred by GD12. To understand the genetic potential encoded by T. hamatum GD12 and to facilitate its use as a model beneficial organism to study plant growth promotion, induced systemic resistance and mycoparasitism we present de novo genome sequence data. We compare GD12 with other published Trichoderma genomes and show that T. hamatum GD12 contains unique genomic regions with the potential to encode novel bioactive metabolites that may contribute to GD12's agrochemically important traits. PMID:23908658

  20. Biofortification of oilseed Brassica juncea with the anti-cancer compound glucoraphanin by suppressing GSL-ALK gene family

    PubMed Central

    Augustine, Rehna; Bisht, Naveen C.

    2015-01-01

    Glucosinolates are amino acids derived secondary metabolites, invariably present in Brassicales, which have huge health and agricultural benefits. Sulphoraphane, the breakdown product of glucosinolate glucoraphanin is known to posses anti-cancer properties. AOP (2-oxoglutarate-dependent dioxygenases) or GSL-ALK enzyme catalyzes the conversion of desirable glucoraphanin to deleterious gluconapin and progoitrin, which are present in very high amounts in most of the cultivable Brassica species including Brassica juncea. In this study we showed that B. juncea encodes four functional homologs of GSL-ALK gene and constitutive silencing of GSL-ALK homologs resulted in accumulation of glucoraphanin up to 43.11 μmoles g−1 DW in the seeds with a concomitant reduction in the anti-nutritional glucosinolates. Glucoraphanin content was found remarkably high in leaves as well as sprouts of the transgenic lines. Transcript quantification of high glucoraphanin lines confirmed significant down-regulation of GSL-ALK homologs. Growth and other seed quality parameters of the transgenic lines did not show drastic difference, compared to the untransformed control. High glucoraphanin lines also showed higher resistance towards stem rot pathogen Sclerotinia sclerotiorum. Our results suggest that metabolic engineering of GSL-ALK has huge potential for enriching glucoraphanin content, and improve the oil quality and vegetable value of Brassica crops. PMID:26657321

  1. The Shewanella algae strain YM8 produces volatiles with strong inhibition activity against Aspergillus pathogens and aflatoxins

    PubMed Central

    Gong, An-Dong; Li, He-Ping; Shen, Lu; Zhang, Jing-Bo; Wu, Ai-Bo; He, Wei-Jie; Yuan, Qing-Song; He, Jing-De; Liao, Yu-Cai

    2015-01-01

    Aflatoxigenic Aspergillus fungi and associated aflatoxins are ubiquitous in the production and storage of food/feed commodities. Controlling these microbes is a challenge. In this study, the Shewanella algae strain YM8 was found to produce volatiles that have strong antifungal activity against Aspergillus pathogens. Gas chromatography-mass spectrometry profiling revealed 15 volatile organic compounds (VOCs) emitted from YM8, of which dimethyl trisulfide was the most abundant. We obtained authentic reference standards for six of the VOCs; these all significantly reduced mycelial growth and conidial germination in Aspergillus; dimethyl trisulfide and 2,4-bis(1,1-dimethylethyl)-phenol showed the strongest inhibitory activity. YM8 completely inhibited Aspergillus growth and aflatoxin biosynthesis in maize and peanut samples stored at different water activity levels, and scanning electron microscopy revealed severely damaged conidia and a complete lack of mycelium development and conidiogenesis. YM8 also completely inhibited the growth of eight other agronomically important species of phytopathogenic fungi: A. parasiticus, A. niger, Alternaria alternate, Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum, Monilinia fructicola, and Sclerotinia sclerotiorum. This study demonstrates the susceptibility of Aspergillus and other fungi to VOCs from marine bacteria and indicates a new strategy for effectively controlling these pathogens and the associated mycotoxin production during storage and possibly in the field. PMID:26500631

  2. A test of taxonomic predictivity: resistance to early blight in wild relatives of cultivated potato.

    PubMed

    Jansky, S H; Simon, R; Spooner, D M

    2008-06-01

    Host plant resistance offers an attractive method of control for early blight (caused by the foliar fungus Alternaria solani), a widespread disease that appears annually in potato crops worldwide. We tested the assumed ability of taxonomy to predict the presence of early blight resistance genes in wild Solanum species for which resistance was observed in related species. We also tested associations to ploidy, crossing group, breeding system, and geography. As in a prior study of Sclerotinia sclerotiorum (white mold) resistance, tremendous variation for resistance to early blight was found to occur within and among species. There was no discernable relationship between the distribution of resistant phenotypes and taxonomic series (based on an intuitive interpretation of morphological data), clade (based on a cladistic analysis of plastid DNA data), ploidy, breeding system, geographic distance, or climate parameters. Species and individual accessions with high proportions of early blight resistant plants were identified, but high levels of inter- and intra-accession variability were observed. Consequently, the designation of species or accessions as resistant or susceptible must take this variation into account. This study calls into question the assumption that taxonomic or geographic data can be used to predict sources of early blight resistance in wild Solanum species.

  3. Functional characterization of NAC55 transcription factor from oilseed rape (Brassica napus L.) as a novel transcriptional activator modulating reactive oxygen species accumulation and cell death.

    PubMed

    Niu, Fangfang; Wang, Chen; Yan, Jingli; Guo, Xiaohua; Wu, Feifei; Yang, Bo; Deyholos, Michael K; Jiang, Yuan-Qing

    2016-09-01

    NAC transcription factors (TFs) are plant-specific and play important roles in development, responses to biotic and abiotic cues and hormone signaling. So far, only a few NAC genes have been reported to regulate cell death. In this study, we identified and characterized a NAC55 gene isolated from oilseed rape (Brassica napus L.). BnaNAC55 responds to multiple stresses, including cold, heat, abscisic acid (ABA), jasmonic acid (JA) and a necrotrophic fungal pathogen Sclerotinia sclerotiorum. BnaNAC55 has transactivation activity and is located in the nucleus. BnaNAC55 is able to form homodimers in planta. Unlike ANAC055, full-length BnaNAC55, but not either the N-terminal NAC domain or C-terminal regulatory domain, induces ROS accumulation and hypersensitive response (HR)-like cell death when expressed both in oilseed rape protoplasts and Nicotiana benthamiana. Furthermore, BnaNAC55 expression causes obvious nuclear DNA fragmentation. Moreover, quantitative reverse transcription PCR (qRT-PCR) analysis identified that the expression levels of multiple genes regulating ROS production and scavenging, defense response as well as senescence are significantly induced. Using a dual luciferase reporter assay, we further confirm that BnaNAC55 could activate the expression of a few ROS and defense-related gene expression. Taken together, our work has identified a novel NAC TF from oilseed rape that modulates ROS accumulation and cell death.

  4. Canola (Brassica napus L.) NAC103 transcription factor gene is a novel player inducing reactive oxygen species accumulation and cell death in plants.

    PubMed

    Niu, Fangfang; Wang, Boya; Wu, Feifei; Yan, Jingli; Li, Liang; Wang, Chen; Wang, Yiqiao; Yang, Bo; Jiang, Yuan-Qing

    2014-11-07

    NAC transcription factors are plant-specific and play important roles in many processes including plant development, response to biotic and abiotic stresses and hormone signaling. So far, only a few NAC genes have been identified to mediate cell death. In this study, we identified a novel NAC gene from canola (Brassica napus L.), BnaNAC103 which induces reactive oxygen species (ROS) accumulation and cell death in Nicotianabenthamiana leaves. We found that BnaNAC103 responded to multiple signalings, including cold, salicylic acid (SA) and a fungal pathogen Sclerotinia sclerotiorum. BnaNAC103 is located in the nucleus. Expression of full-length BnaNAC103, but not either the N-terminal NAC domain or C-terminal regulatory domain, was identified to induce hypersensitive response (HR)-like cell death when expressed in N. benthamiana. The cell death triggered by BnaNAC103 is preceded by accumulation of ROS, with diaminobenzidine (DAB) staining supporting this. Moreover, quantification of ion leakage and malondialdehyde (MDA) of leaf discs indicates significant cell membrane breakage and lipid peroxidation induced by BnaNAC103 expression. Taken together, our work has identified a novel NAC transcription factor gene modulating ROS level and cell death in plants.

  5. Diverse circular ssDNA viruses discovered in dragonflies (Odonata: Epiprocta).

    PubMed

    Rosario, Karyna; Dayaram, Anisha; Marinov, Milen; Ware, Jessica; Kraberger, Simona; Stainton, Daisy; Breitbart, Mya; Varsani, Arvind

    2012-12-01

    Viruses with circular ssDNA genomes that encode a replication initiator protein (Rep) are among the smallest viruses known to infect both eukaryotic and prokaryotic organisms. In the past few years an overwhelming diversity of novel circular Rep-encoding ssDNA (CRESS-DNA) viruses has been unearthed from various hosts and environmental sources. Since there is limited information regarding CRESS-DNA viruses in invertebrates, this study explored the diversity of CRESS-DNA viruses circulating among insect populations by targeting dragonflies (Epiprocta), top insect predators that accumulate viruses from their insect prey over space and time. Using degenerate PCR and rolling circle amplification coupled with restriction digestion, 17 CRESS-DNA viral genomes were recovered from eight different dragonfly species collected in tropical and temperate regions. Nine of the genomes are similar to cycloviruses and represent five species within this genus, suggesting that cycloviruses are commonly associated with insects. Three of the CRESS-DNA viruses share conserved genomic features with recently described viruses similar to the mycovirus Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1, leading to the proposal of the genus Gemycircularvirus. The remaining viruses are divergent species representing four novel CRESS-DNA viral genera, including a gokushovirus-like prokaryotic virus (microphage) and three eukaryotic viruses with Reps similar to circoviruses. The novelty of CRESS-DNA viruses identified in dragonflies using simple molecular techniques indicates that there is an unprecedented diversity of ssDNA viruses among insect populations.

  6. Sulfur fertilization and fungal infections affect the exchange of H(2)S and COS from agricultural crops.

    PubMed

    Bloem, Elke; Haneklaus, Silvia; Kesselmeier, Jürgen; Schnug, Ewald

    2012-08-08

    The emission of gaseous sulfur (S) compounds by plants is related to several factors, such as the plant S status or fungal infection. Hydrogen sulfide (H(2)S) is either released or taken up by the plant depending on the ambient air concentration and the plant demand for S. On the contrary, carbonyl sulfide (COS) is normally taken up by plants. In a greenhouse experiment, the dependence of H(2)S and COS exchange with ambient air on the S status of oilseed rape (Brassica napus L.) and on fungal infection with Sclerotinia sclerotiorum was investigated. Thiol contents were determined to understand their influence on the exchange of gaseous S compounds. The experiment revealed that H(2)S emissions were closely related to pathogen infections as well as to S nutrition. S fertilization caused a change from H(2)S consumption by S-deficient oilseed rape plants to a H(2)S release of 41 pg g(-1) (dw) min(-1) after the addition of 250 mg of S per pot. Fungal infection caused an even stronger increase of H(2)S emissions with a maximum of 1842 pg g(-1) (dw) min(-1) 2 days after infection. Healthy oilseed rape plants acted as a sink for COS. Fungal infection caused a shift from COS uptake to COS releases. The release of S-containing gases thus seems to be part of the response to fungal infection. The roles the S-containing gases may play in this response are discussed.

  7. Transfer Assessment of Carbendazim Residues from Rape Flowers to Apicultural Products

    PubMed Central

    Li, Ying-Hong; Zhou, Bei-Lei; Qian, Ming-Rong; Wang, Qiang

    2017-01-01

    Carbendazim is usually used to control the Sclerotinia sclerotiorum of rapes during the flowering period. This paper presents a study on transfer assessment of carbendazim residues from rape flowers to apicultural products. In the field trials, the rapes were sprayed with carbendazim on standard dosage. Bees produced apicultural products (bee pollen, honey, and royal jelly) from sprayed rapes. Apicultural products were collected on a regular basis. Carbendazim residues were extracted from bee pollen, honey, and royal jelly, respectively. HPLC/ESI-MS/MS method was developed and partially validated to identify and quantify carbendazim residues. The limits of quantification in pollen, honey, and royal jelly were 0.01 mg/kg. Mathematical curve fitting was carried out on the basis of transfer assessment of carbendazim residues from rape flowers to apicultural products. The respective carbendazim residues were 1.10 ± 0.03 mg/kg in pollen on 18th day, 0.032 ± 0.001 mg/kg in honey on 24th day, and 0.077 ± 0.002 mg/kg in royal jelly on 22nd day. Transfer assessment and mathematical curve fitting of carbendazim residues from rape flowers to apicultural products show carbendazim diminished over spraying time. The gap of carbendazim residues between pollen and honey is decreased with time. The carbendazim residues in pollen are 10 times higher than that of honey and jelly. PMID:28246574

  8. Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.)

    PubMed Central

    Elhag, Osama; Zhou, Dingzhong; Song, Qi; Soomro, Abdul Aziz; Cai, Minmin; Zheng, Longyu; Yu, Ziniu; Zhang, Jibin

    2017-01-01

    Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens. PMID:28056070

  9. Volatile antimicrobials from Muscodor crispans, a novel endophytic fungus.

    PubMed

    Mitchell, Angela M; Strobel, Gary A; Moore, Emily; Robison, Richard; Sears, Joe

    2010-01-01

    Muscodor crispans is a recently described novel endophytic fungus of Ananas ananassoides (wild pineapple) growing in the Bolivian Amazon Basin. The fungus produces a mixture of volatile organic compounds (VOCs); some of the major components of this mixture, as determined by GC/MS, are propanoic acid, 2-methyl-, methyl ester; propanoic acid, 2-methyl-; 1-butanol, 3-methyl-;1-butanol, 3-methyl-, acetate; propanoic acid, 2-methyl-, 2-methylbutyl ester; and ethanol. The fungus does not, however, produce naphthalene or azulene derivatives as has been observed with many other members of the genus Muscodor. The mixture of VOCs produced by M. crispans cultures possesses antibiotic properties, as does an artificial mixture of a majority of the components. The VOCs of the fungus are effective against a wide range of plant pathogens, including the fungi Pythium ultimum, Phytophthora cinnamomi, Sclerotinia sclerotiorum and Mycosphaerella fijiensis (the black sigatoka pathogen of bananas), and the serious bacterial pathogen of citrus, Xanthomonas axonopodis pv. citri. In addition, the VOCs of M. crispans killed several human pathogens, including Yersinia pestis, Mycobacterium tuberculosis and Staphylococcus aureus. Artificial mixtures of the fungal VOCs were both inhibitory and lethal to a number of human and plant pathogens, including three drug-resistant strains of Mycobacterium tuberculosis. The gaseous products of Muscodor crispans potentially could prove to be beneficial in the fields of medicine, agriculture, and industry.

  10. Different drying technologies and alternation of mycobiots in the raw material of Hyssopus officinalis L.

    PubMed

    Raila, Algirdas; Lugauskas, Albinas; Kemzūraite, Aurelija; Zvicevicius, Egidijus; Ragazinskiene, Ona; Railiene, Marija

    2009-01-01

    Contamination of medicinal plant mass with mycobiots is one of the negative factors deteriorating the quality of raw material. In order to evaluate the impact of the yield processing technologies upon the changes of mycobiots in raw material, the mycobiotic conditions of herb hyssop (Hyssopus officinalis L.) raw material were evaluated under various regimes of active ventilation and optimization of the drying parameters. The impact of ventilation intensity and temperature of drying agent upon the changes and abundance of mycobiota species in medicinal raw material was determined. Irrespective of the temperature of the airflow, the strongest suppressive effect upon the mycobiotic contamination in Hyssopi herba was produced by the 5,000 m3 x (t x h)(-1) airflow. Analysis of the isolated fungi revealed the prevalence of Penicillium, Aspergillus, Alternaria, Cladosporium, Mucor, Rhizopus species in the raw material. In separate samples Botrytis cinerea, Sclerotinia sclerotiorum, Aureobasidium pullulans, Chrysosporium merdarium, Cladorrhinum foecundissimum, Ulocladium consortiale, Trichoderma hamatum, T. harzianum, Gilmaniella humicola, Talaromyces flavus, Rhizomucor pusillus, Hansfordia ovalispora, Verticicladium trifi dum, Trichosporiella cerebriformis micromycetes were also rather abundant. Detection of the above-mentioned micromycetes in herb hyssop samples differed, and partially depended upon the medium used for their isolation.

  11. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat

    PubMed Central

    Foley, Rhonda C.; Kidd, Brendan N.; Hane, James K.; Anderson, Jonathan P.; Singh, Karam B.

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction. PMID:27031952

  12. Biofortification of oilseed Brassica juncea with the anti-cancer compound glucoraphanin by suppressing GSL-ALK gene family.

    PubMed

    Augustine, Rehna; Bisht, Naveen C

    2015-12-10

    Glucosinolates are amino acids derived secondary metabolites, invariably present in Brassicales, which have huge health and agricultural benefits. Sulphoraphane, the breakdown product of glucosinolate glucoraphanin is known to posses anti-cancer properties. AOP (2-oxoglutarate-dependent dioxygenases) or GSL-ALK enzyme catalyzes the conversion of desirable glucoraphanin to deleterious gluconapin and progoitrin, which are present in very high amounts in most of the cultivable Brassica species including Brassica juncea. In this study we showed that B. juncea encodes four functional homologs of GSL-ALK gene and constitutive silencing of GSL-ALK homologs resulted in accumulation of glucoraphanin up to 43.11 μmoles g(-1) DW in the seeds with a concomitant reduction in the anti-nutritional glucosinolates. Glucoraphanin content was found remarkably high in leaves as well as sprouts of the transgenic lines. Transcript quantification of high glucoraphanin lines confirmed significant down-regulation of GSL-ALK homologs. Growth and other seed quality parameters of the transgenic lines did not show drastic difference, compared to the untransformed control. High glucoraphanin lines also showed higher resistance towards stem rot pathogen Sclerotinia sclerotiorum. Our results suggest that metabolic engineering of GSL-ALK has huge potential for enriching glucoraphanin content, and improve the oil quality and vegetable value of Brassica crops.

  13. Detection of Fungus Infection on Petals of Rapeseed (Brassica napus L.) Using NIR Hyperspectral Imaging

    PubMed Central

    Zhao, Yan-Ru; Yu, Ke-Qiang; Li, Xiaoli; He, Yong

    2016-01-01

    Infected petals are often regarded as the source for the spread of fungi Sclerotinia sclerotiorum in all growing process of rapeseed (Brassica napus L.) plants. This research aimed to detect fungal infection of rapeseed petals by applying hyperspectral imaging in the spectral region of 874–1734 nm coupled with chemometrics. Reflectance was extracted from regions of interest (ROIs) in the hyperspectral image of each sample. Firstly, principal component analysis (PCA) was applied to conduct a cluster analysis with the first several principal components (PCs). Then, two methods including X-loadings of PCA and random frog (RF) algorithm were used and compared for optimizing wavebands selection. Least squares-support vector machine (LS-SVM) methodology was employed to establish discriminative models based on the optimal and full wavebands. Finally, area under the receiver operating characteristics curve (AUC) was utilized to evaluate classification performance of these LS-SVM models. It was found that LS-SVM based on the combination of all optimal wavebands had the best performance with AUC of 0.929. These results were promising and demonstrated the potential of applying hyperspectral imaging in fungus infection detection on rapeseed petals. PMID:27958386

  14. Occurence of fungal diseases on lemon balm (Mellisa officinalis L.) and peppermint (Mentha x piperita L.) in the region of Malopolska.

    PubMed

    Szczeponek, A; Mazur, S

    2006-01-01

    This paper presents the results of the researches carried out on the subject of the diseases on herbs such as lemon balm and peppermint focusing on the health status of the plants grown in the region of Malopolska. The field and laboratory research proved that perpetrators of the diseases on the examined plants were fungi species with the numerical majority. On lemon balm septoria leaf spot (Septoria melissae) was most often observed. Moreover, fungal genera of different taxonomic groups were detected. Alternaria, Epicoccum, Fusarium, and Sclerotinia sclerotiorum occurred most often on the medicinal plant samples. The disease mint rust Puccinia menthae, has caused major problems for the peppermint growers. In the populations of fungi found on the diseased leaves the dominating were Alternaria, Epicoccum and Sphaceloma menthae. It has been stated that among all fungi isolated from lemon balm, the species Fusarium avenaceum had the highest pathogenicity to seedlings (80% of diseased seedlings). For peppermint plants the highest pathogenicity had species Epicoccum purpurascens, and caused 82% of diseased seedlings. Conducted evaluation of health status of plants showed that the lemon balm mean disease index was yearly differentiated and was the highest in 2003 (44.39). For peppermint, the highest disease index was in third year of cultivation (62.75) and was statistically higher than in previous years.

  15. Detection of Fungus Infection on Petals of Rapeseed (Brassica napus L.) Using NIR Hyperspectral Imaging

    NASA Astrophysics Data System (ADS)

    Zhao, Yan-Ru; Yu, Ke-Qiang; Li, Xiaoli; He, Yong

    2016-12-01

    Infected petals are often regarded as the source for the spread of fungi Sclerotinia sclerotiorum in all growing process of rapeseed (Brassica napus L.) plants. This research aimed to detect fungal infection of rapeseed petals by applying hyperspectral imaging in the spectral region of 874–1734 nm coupled with chemometrics. Reflectance was extracted from regions of interest (ROIs) in the hyperspectral image of each sample. Firstly, principal component analysis (PCA) was applied to conduct a cluster analysis with the first several principal components (PCs). Then, two methods including X-loadings of PCA and random frog (RF) algorithm were used and compared for optimizing wavebands selection. Least squares-support vector machine (LS-SVM) methodology was employed to establish discriminative models based on the optimal and full wavebands. Finally, area under the receiver operating characteristics curve (AUC) was utilized to evaluate classification performance of these LS-SVM models. It was found that LS-SVM based on the combination of all optimal wavebands had the best performance with AUC of 0.929. These results were promising and demonstrated the potential of applying hyperspectral imaging in fungus infection detection on rapeseed petals.

  16. Expression of a fungal sterol desaturase improves tomato drought tolerance, pathogen resistance and nutritional quality

    PubMed Central

    Kamthan, Ayushi; Kamthan, Mohan; Azam, Mohammad; Chakraborty, Niranjan; Chakraborty, Subhra; Datta, Asis

    2012-01-01

    Crop genetic engineering mostly aims at improving environmental stress (biotic and abiotic) tolerance as well as nutritional quality. Empowering a single crop with multiple traits is highly demanding and requires manipulation of more than one gene. However, we report improved drought tolerance and fungal resistance along with the increased iron and polyunsaturated fatty acid content in tomato by expressing a single gene encoding C-5 sterol desaturase (FvC5SD) from an edible fungus Flammulina velutipes. FvC5SD is an iron binding protein involved in ergosterol biosynthesis. Morphological and biochemical analyses indicated ≈23% more epicuticular wax deposition in leaves of transgenic plants that provides an effective waterproof barrier resulting in improved protection from drought and infection by phytopathogenic fungus Sclerotinia sclerotiorum. Furthermore, the transgenic fruits have improved nutritional value attributed to enhanced level of beneficial PUFA and 2-3 fold increase in total iron content. This strategy can be extended to other economically important crops. PMID:23230516

  17. Biocontrol Activity of Bacillus amyloliquefaciens CNU114001 against Fungal Plant Diseases

    PubMed Central

    Ji, Seung Hyun; Paul, Narayan Chandra; Deng, Jian Xin; Kim, Young Sook; Yun, Bong-Sik

    2013-01-01

    A total of 62 bacterial isolates were obtained from Gomsohang mud flat, Mohang mud flat, and Jeju Island, Republic of Korea. Among them, the isolate CNU114001 showed significant antagonistic activity against pathogenic fungi by dual culture method. The isolate CNU114001 was identified as Bacillus amyloliquefaciens by morphological observation and molecular data analysis, including 16SrDNA and gyraseA (gyrA) gene sequences. Antifungal substances of the isolate were extracted and purified by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. The heat and UV ray stable compound was identified as iturin, a lipopeptide (LP). The isolate CNU114001 showed broad spectrum activity against 12 phytopathogenic fungi by dual culture method. The semi purified compound significantly inhibits the mycelial growth of pathogenic fungi (Alternaria panax, Botrytis cinera, Colletotrichum orbiculare, Penicillium digitatum, Pyricularia grisea and Sclerotinia sclerotiorum) at 200 ppm concentration. Spore germ tube elongation of Botrytis cinerea was inhibited by culture filtrate of the isolate. Crude antifungal substance showed antagonistic activity against cucumber scleotiorum rot in laboratory, and showed antagonistic activity against tomato gray mold, cucumber, and pumpkin powdery mildew in greenhouse condition. PMID:24493945

  18. Reactive Oxygen Species Play a Role in the Infection of the Necrotrophic Fungi, Rhizoctonia solani in Wheat.

    PubMed

    Foley, Rhonda C; Kidd, Brendan N; Hane, James K; Anderson, Jonathan P; Singh, Karam B

    2016-01-01

    Rhizoctonia solani is a nectrotrophic fungal pathogen that causes billions of dollars of damage to agriculture worldwide and infects a broad host range including wheat, rice, potato and legumes. In this study we identify wheat genes that are differentially expressed in response to the R. solani isolate, AG8, using microarray technology. A significant number of wheat genes identified in this screen were involved in reactive oxygen species (ROS) production and redox regulation. Levels of ROS species were increased in wheat root tissue following R. solani infection as determined by Nitro Blue Tetrazolium (NBT), 3,3'-diaminobenzidine (DAB) and titanium sulphate measurements. Pathogen/ROS related genes from R. solani were also tested for expression patterns upon wheat infection. TmpL, a R. solani gene homologous to a gene associated with ROS regulation in Alternaria brassicicola, and OAH, a R. solani gene homologous to oxaloacetate acetylhydrolase which has been shown to produce oxalic acid in Sclerotinia sclerotiorum, were highly induced in R. solani when infecting wheat. We speculate that the interplay between the wheat and R. solani ROS generating proteins may be important for determining the outcome of the wheat/R. solani interaction.

  19. Purification and characterization of a novel antifungal protein from Bacillus subtilis strain B29*

    PubMed Central

    Li, Jing; Yang, Qian; Zhao, Li-hua; Zhang, Shu-mei; Wang, Yu-xia; Zhao, Xiao-yu

    2009-01-01

    An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel® P-100. The protein was absorbed on DEAE-cellulose and Bio-Gel® P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pI value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited inhibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia sclerotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B29I also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germinated spores. PMID:19353744

  20. Screening, Expression, Purification and Functional Characterization of Novel Antimicrobial Peptide Genes from Hermetia illucens (L.).

    PubMed

    Elhag, Osama; Zhou, Dingzhong; Song, Qi; Soomro, Abdul Aziz; Cai, Minmin; Zheng, Longyu; Yu, Ziniu; Zhang, Jibin

    2017-01-01

    Antimicrobial peptides from a wide spectrum of insects possess potent microbicidal properties against microbial-related diseases. In this study, seven new gene fragments of three types of antimicrobial peptides were obtained from Hermetia illucens (L), and were named cecropinZ1, sarcotoxin1, sarcotoxin (2a), sarcotoxin (2b), sarcotoxin3, stomoxynZH1, and stomoxynZH1(a). Among these genes, a 189-basepair gene (stomoxynZH1) was cloned into the pET32a expression vector and expressed in the Escherichia coli as a fusion protein with thioredoxin. Results show that Trx-stomoxynZH1 exhibits diverse inhibitory activity on various pathogens, including Gram-positive bacterium Staphylococcus aureus, Gram-negative bacterium Escherichia coli, fungus Rhizoctonia solani Khün (rice)-10, and fungus Sclerotinia sclerotiorum (Lib.) de Bary-14. The minimum inhibitory concentration of Trx-stomoxynZH1 is higher against Gram-positive bacteria than against Gram-negative bacteria but similar between the fungal strains. These results indicate that H. illucens (L.) could provide a rich source for the discovery of novel antimicrobial peptides. Importantly, stomoxynZH1 displays a potential benefit in controlling antibiotic-resistant pathogens.

  1. Trichoderma species mediated differential tolerance against biotic stress of phytopathogens in Cicer arietinum L.

    PubMed

    Saxena, Amrita; Raghuwanshi, Richa; Singh, Harikesh Bahadur

    2015-02-01

    Trichoderma spp. have been reported to aid in imparting biotic as well as abiotic tolerance to plants. However, there are only few reports unfolding the differential ability of separate species of Trichoderma genera generally exploited for their biocontrol potential in this framework. A study was undertaken to evaluate the biocontrol potential of different Trichoderma species namely T. harzianum, T. asperellum, T. koningiopsis, T. longibrachiatum, and T. aureoviride as identified in the group of indigenous isolates from the agricultural soils of Eastern Uttar Pradesh, India. Their biocontrol potential against three major soilborne phytopathogens, i.e., Sclerotium rolfsii, Sclerotinia sclerotiorum, and Colletotrichum capsici was confirmed by dual culture plate technique. Efficient mycoparasitic ability was further assessed in all the isolates in relation to chitinase, β-1,3 glucanase, pectinase, lipase, amylase, and cellulase production while equally consistent results were obtained for their probable phosphate solubilization and indole acetic acid (IAA) production abilities. The selected isolates were further subjected to test their ability to promote plant growth, to reduce disease incidence and to tolerate biotic stress in terms of lignification pattern against S. rolfsii in chickpea plants. Among the identified Trichoderma species, excellent results were observed for T. harzianum and T. koningiopsis indicating better biocontrol potential of these species in the group and thus exhibiting perspective for their commercial exploitation.

  2. A promising strain of Streptomyces sp. with agricultural traits for growth promotion and disease management.

    PubMed

    Alam, Mansoor; Dharni, Seema; Abdul-Khaliq; Srivastava, Santosh Kumar; Samad, Abdul; Gupta, Mahesh Kumar

    2012-08-01

    A bacterial strain, Streptomyces sp. CIMAP- A1 was isolated from Geranium rhizosphere and identified by morphological, physiological, biochemical and molecular characters (16S rDNA gene sequence). Phylogenetically, it was found most closely related to S. vinacendrappus, strain NRRL-2363 with 99% sequence similarity. The strain had potential antagonistic activity (in vitro) against wide range of phytopathogenic fungi like Stemphylium sp., Botrytis cinerea, Sclerotinia sclerotiorum, Colletotrichum spp., Curvularia spp., Corynespora cassicola and Thielavia basicola. The extracellular secondary metabolites produced by the strain in the culture filtrates significantly inhibited the spore germination, growth of germ tube of the germinated spores and radial growth of Alternaria alternata, Colletotrichum acutatum, Curvularia andropogonis and Fusarium moniliforme. The extraction of culture filtrate with solvents and purification by following VLC and PTLC methods always yielded a 10th fraction antifungal compound showing activity against wide range of phytopathogenic fungi. The strain was able to produce siderophores and indole-3-acetic acid. The strain was found to enhance the growth and biomass production of Geranium. It increased 11.3% fresh shoot biomass of Geranium and 21.7% essential oil yield.

  3. Overexpression of the brassinosteroid biosynthetic gene DWF4 in Brassica napus simultaneously increases seed yield and stress tolerance

    PubMed Central

    Sahni, Sangita; Prasad, Bishun D.; Liu, Qing; Grbic, Vojislava; Sharpe, Andrew; Singh, Surinder P.; Krishna, Priti

    2016-01-01

    As a resource allocation strategy, plant growth and defense responses are generally mutually antagonistic. Brassinosteroid (BR) regulates many aspects of plant development and stress responses, however, genetic evidence of its integrated effects on plant growth and stress tolerance is lacking. We overexpressed the Arabidopsis BR biosynthetic gene AtDWF4 in the oilseed plant Brassica napus and scored growth and stress response phenotypes. The transgenic B. napus plants, in comparison to wild type, displayed increased seed yield leading to increased overall oil content per plant, higher root biomass and root length, significantly better tolerance to dehydration and heat stress, and enhanced resistance to necrotrophic fungal pathogens Leptosphaeria maculans and Sclerotinia sclerotiorum. Transcriptome analysis supported the integrated effects of BR on growth and stress responses; in addition to BR responses associated with growth, a predominant plant defense signature, likely mediated by BES1/BZR1, was evident in the transgenic plants. These results establish that BR can interactively and simultaneously enhance abiotic and biotic stress tolerance and plant productivity. The ability to confer pleiotropic beneficial effects that are associated with different agronomic traits suggests that BR–related genes may be important targets for simultaneously increasing plant productivity and performance under stress conditions. PMID:27324083

  4. Hypovirulence of Sclerotium rolfsii Caused by Associated RNA Mycovirus

    PubMed Central

    Chen, Dan; Zhu, Hong J.; Gao, Bi D.; Zhou, Qian

    2016-01-01

    Mycoviruses associated with hypovirulence are potential biological control agents and could be useful to study the pathogenesis of fungal host pathogens. Sclerotium rolfsii, a pathogenic fungus, causes southern blight in a wide variety of crops. In this study, we isolated a series of dsRNAs from a debilitated S. rolfsii strain, BLH-1, which had pronounced phenotypic aberrations including reduced pathogenicity, mycelial growth and deficient sclerotia production. Virus-curing and horizontal transmission experiments that eliminated or transmitted, respectively, all dsRNA elements showed that the dsRNAs were involved in the hypovirulent traits of BLH-1. Ultrastructure examination also showed hyphae fracture and cytoplasm or organelle degeneration in BLH-1 hyphal cells compared to the virus-free strain. Three assembled cDNA contigs generated from the cDNA library cloned from the purified dsRNA indicated that strain BLH-1 was infected by at least three novel mycoviruses. One has similarity to the hypovirulence-associated Sclerotinia sclerotiorum hypovirus 2 (SsHV2) in the family Hypoviridae, and the other two are related to two different unclassified dsRNA mycovirus families. To our knowledge, this is the first report of S. rolfsii hypovirulence that was correlated with its associated dsRNA. PMID:27891121

  5. Complete genome sequences of the Serratia plymuthica strains 3Rp8 and 3Re4-18, two rhizosphere bacteria with antagonistic activity towards fungal phytopathogens and plant growth promoting abilities.

    PubMed

    Adam, Eveline; Müller, Henry; Erlacher, Armin; Berg, Gabriele

    2016-01-01

    The Serratia plymuthica strains 3Rp8 and 3Re4-18 are motile, Gram-negative, non-sporulating bacteria. Strain 3Rp8 was isolated from the rhizosphere of Brassica napus L. and strain 3Re4-18 from the endorhiza of Solanum tuberosum L. Studies have shown in vitro activity against the soil-borne fungi Verticillium dahliae Kleb., Rhizoctonia solani Kühn, and Sclerotinia sclerotiorum. Here, we announce and describe the complete genome sequence of S. plymuthica 3Rp8 consisting of a single circular chromosome of 5.5 Mb that encodes 4954 protein-coding and 108 RNA-only encoding genes and of S. plymuthica 3Re4-18 consisting of a single circular chromosome of 5.4 Mb that encodes 4845 protein-coding and 109 RNA-only encoding genes. The whole genome sequences and annotations are available in NCBI under the locus numbers CP012096 and CP012097, respectively. The genome analyses revealed genes putatively responsible for the promising plant growth promoting and biocontrol properties including predicting factors such as secretion systems, iron scavenging siderophores, chitinases, secreted proteases, glucanases and non-ribosomal peptide synthetases, as well as unique genomic islands.

  6. Deep Sequencing Analysis Reveals the Mycoviral Diversity of the Virome of an Avirulent Isolate of Rhizoctonia solani AG-2-2 IV

    PubMed Central

    Bartholomäus, Anika; Wibberg, Daniel; Winkler, Anika; Pühler, Alfred; Schlüter, Andreas; Varrelmann, Mark

    2016-01-01

    Rhizoctonia solani represents an important plant pathogenic Basidiomycota species complex and the host of many different mycoviruses, as indicated by frequent detection of dsRNA elements in natural populations of the fungus. To date, eight different mycoviruses have been characterized in Rhizoctonia and some of them have been reported to modulate its virulence. DsRNA extracts of the avirulent R. solani isolate DC17 (AG2-2-IV) displayed a diverse pattern, indicating multiple infections with mycoviruses. Deep sequencing analysis of the dsRNA extract, converted to cDNA, revealed that this isolate harbors at least 17 different mycovirus species. Based on the alignment of the conserved RNA-dependent RNA-polymerase (RdRp) domain, this viral community included putative members of the families Narnaviridae, Endornaviridae, Partitiviridae and Megabirnaviridae as well as of the order Tymovirales. Furthermore, viruses, which could not be assigned to any existing family or order, but showed similarities to so far unassigned species like Sclerotinia sclerotiorum RNA virus L, Rhizoctonia solani dsRNA virus 1, Aspergillus foetidus slow virus 2 or Rhizoctonia fumigata virus 1, were identified. This is the first report of a fungal isolate infected by 17 different viral species and a valuable study case to explore the diversity of mycoviruses infecting R. solani. PMID:27814394

  7. Preservation of viral genomes in 700-y-old caribou feces from a subarctic ice patch.

    PubMed

    Ng, Terry Fei Fan; Chen, Li-Fang; Zhou, Yanchen; Shapiro, Beth; Stiller, Mathias; Heintzman, Peter D; Varsani, Arvind; Kondov, Nikola O; Wong, Walt; Deng, Xutao; Andrews, Thomas D; Moorman, Brian J; Meulendyk, Thomas; MacKay, Glen; Gilbertson, Robert L; Delwart, Eric

    2014-11-25

    Viruses preserved in ancient materials provide snapshots of past viral diversity and a means to trace viral evolution through time. Here, we use a metagenomics approach to identify filterable and nuclease-resistant nucleic acids preserved in 700-y-old caribou feces frozen in a permanent ice patch. We were able to recover and characterize two viruses in replicated experiments performed in two different laboratories: a small circular DNA viral genome (ancient caribou feces associated virus, or aCFV) and a partial RNA viral genome (Ancient Northwest Territories cripavirus, or aNCV). Phylogenetic analysis identifies aCFV as distantly related to the plant-infecting geminiviruses and the fungi-infecting Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 and aNCV as within the insect-infecting Cripavirus genus. We hypothesize that these viruses originate from plant material ingested by caribou or from flying insects and that their preservation can be attributed to protection within viral capsids maintained at cold temperatures. To investigate the tropism of aCFV, we used the geminiviral reverse genetic system and introduced a multimeric clone into the laboratory model plant Nicotiana benthamiana. Evidence for infectivity came from the detection of viral DNA in newly emerged leaves and the precise excision of the viral genome from the multimeric clones in inoculated leaves. Our findings indicate that viral genomes may in some circumstances be protected from degradation for centuries.

  8. Effects of volatile organic compounds from Streptomyces albulus NJZJSA2 on growth of two fungal pathogens.

    PubMed

    Wu, Yuncheng; Yuan, Jun; E, Yaoyao; Raza, Waseem; Shen, Qirong; Huang, Qiwei

    2015-09-01

    A Streptomyces albulus strain NJZJSA2 was isolated from the forest soil sample of Tzu-chin Mountain (Nanjing China) and identified based on its morphological and physiological properties and 16S rDNA gene sequence analysis. The strain S. albulus NJZJSA2 was evaluated for the production of antifungal volatile organic compounds (VOCs) against two fungal pathogens. Results showed that the VOCs generated by S. albulus NJZJSA2 inhibited mycelial growth of Sclerotinia sclerotiorum (SS) and Fusarium oxysporum (FO) by 100 and 56.3%, respectively. The germination of SS sclerotia and FO conidia was completely inhibited in the presence of VOCs produced by S. albulus NJZJSA2 in vitro. In soil, the VOCs delayed the germination of SS sclerotia and inhibited the germination of FO conidia for 45 days. The strain S. albulus NJZJSA2 was able to produce 13 VOCs based on GC/MS analyses. Among those, six compounds were purchased and used for the antifungal activity assay. Three relatively abundant VOCs, 4-methoxystyrene, 2-pentylfuran, and anisole were proved to have antifungal activity. Microscopy analysis showed that the pathogen hyphae were shriveled and damaged after treatment with 4-methoxystyrene. These results suggest that the S. albulus strain NJZJSA2 produce VOCs that not only reduce the growth of SS and FO, but also significantly inhibit the SS sclerotia and FO conidia. The results are useful for the better understanding of biocontrol mechanisms by S. albulus strains and will help to improve the biological control efficiency of lethal plant diseases.

  9. Genome-Wide Analysis and Expression Profiling of the SUC and SWEET Gene Families of Sucrose Transporters in Oilseed Rape (Brassica napus L.)

    PubMed Central

    Jian, Hongju; Lu, Kun; Yang, Bo; Wang, Tengyue; Zhang, Li; Zhang, Aoxiang; Wang, Jia; Liu, Liezhao; Qu, Cunmin; Li, Jiana

    2016-01-01

    Sucrose is the principal transported product of photosynthesis from source leaves to sink organs. SUTs/SUCs (sucrose transporters or sucrose carriers) and SWEETs (Sugars Will Eventually be Exported Transporters) play significant central roles in phloem loading and unloading. SUTs/SUCs and SWEETs are key players in sucrose translocation and are associated with crop yields. The SUT/SUC and SWEET genes have been characterized in several plant species, but a comprehensive analysis of these two gene families in oilseed rape has not yet been reported. In our study, 22 and 68 members of the SUT/SUCs and SWEET gene families, respectively, were identified in the oilseed rape (Brassica napus) genome through homology searches. An analysis of the chromosomal distribution, phylogenetic relationships, gene structures, motifs and the cis-acting regulatory elements in the promoters of BnSUC and BnSWEET genes were analyzed. Furthermore, we examined the expression of the 18 BnSUC and 16 BnSWEET genes in different tissues of “ZS11” and the expression of 9 BnSUC and 7 BnSWEET genes in “ZS11” under various conditions, including biotic stress (Sclerotinia sclerotiorum), abiotic stresses (drought, salt and heat), and hormone treatments (abscisic acid, auxin, cytokinin, brassinolide, gibberellin, and salicylic acid). In conclusion, our study provides the first comprehensive analysis of the oilseed rape SUC and SWEET gene families. Information regarding the phylogenetic relationships, gene structure and expression profiles of the SUC and SWEET genes in the different tissues of oilseed rape helps to identify candidates with potential roles in specific developmental processes. Our study advances our understanding of the important roles of sucrose transport in oilseed rape. PMID:27733861

  10. The global regulator ANR is essential for Pseudomonas chlororaphis strain PA23 biocontrol.

    PubMed

    Nandi, Munmun; Selin, Carrie; Brawerman, Gabriel; Fernando, W G Dilantha; de Kievit, Teresa R

    2016-12-01

    Pseudomonas chlororaphis PA23 is a biocontrol agent capable of protecting canola from stem rot disease caused by the fungus Sclerotinia sclerotiorum. The focus of the current study was to elucidate the role of the transcriptional regulator ANR in the biocontrol capabilities of this bacterium. An anr mutant was created, PA23anr, that was devoid antifungal activity. In other pseudomonads, ANR is essential for regulating HCN production. Characterization of PA23anr revealed that, in addition to HCN, ANR controls phenazine (PHZ), pyrrolnitrin (PRN), protease and autoinducer (AHL) signal molecule production. In gene expression studies, hcnA, phzA, prnA and phzI were found to be downregulated, consistent with our endproduct analysis. Because the phenotype of PA23anr closely resembles that of quorum sensing (QS)-deficient strains, we explored whether there is a connection between ANR and the PhzRI QS system. Both phzI and phzR are positively regulated by ANR, whereas PhzR represses anr transcription. Complementation of PA23anr with pUCP-phzR, C6-HSL or both yielded no change in phenotype. Conversely, PA23phzR harbouring pUCP23-anr exhibited partial-to-full restoration of antifungal activity, HCN, PRN and AHL production together with hcnA, prnA, phzI and rpoS expression. PHZ and protease production remained unchanged indicating that ANR can complement the QS-deficient phenotype with respect to some but not all traits. Our experiments were conducted at atmospheric O2 levels underscoring the fact that ANR has a profound effect on PA23 physiology under aerobic conditions.

  11. Molecular characterization of a novel hypovirus from the plant pathogenic fungus Fusarium graminearum.

    PubMed

    Li, Pengfei; Zhang, Hailong; Chen, Xiaoguang; Qiu, Dewen; Guo, Lihua

    2015-07-01

    A novel mycovirus, termed Fusarium graminearum Hypovirus 2 (FgHV2/JS16), isolated from a plant pathogenic fungus, Fusarium graminearum strain JS16, was molecularly and biologically characterized. The genome of FgHV2/JS16 is 12,800 nucleotides (nts) long, excluding the poly (A) tail. This genome has only one large putative open reading frame, which encodes a polyprotein containing three normal functional domains, papain-like protease, RNA-dependent RNA polymerase, RNA helicase, and a novel domain with homologous bacterial SMC (structural maintenance of chromosomes) chromosome segregation proteins. A defective RNA segment that is 4553-nts long, excluding the poly (A) tail, was also detected in strain JS16. The polyprotein shared significant aa identities with Cryphonectria hypovirus 1 (CHV1) (16.8%) and CHV2 (16.2%). Phylogenetic analyses based on multiple alignments of the polyprotein clearly divided the members of Hypoviridae into two major groups, suggesting that FgHV2/JS16 was a novel hypovirus of a newly proposed genus-Alphahypovirus-composed of the members of Group 1, including CHV1, CHV2, FgHV1 and Sclerotinia sclerotiorum hypovirus 2. FgHV2/JS16 was shown to be associated with hypovirulence phenotypes according to comparisons of the biological properties shared between FgHV2/JS16-infected and FgHV2/JS16-free isogenic strains. Furthermore, we demonstrated that FgHV2/JS16 infection activated the RNA interference pathway in Fusarium graminearum by relative quantitative real time RT-PCR.

  12. Identification of high-quality single-nucleotide polymorphisms in Glycine latifolia using a heterologous reference genome sequence.

    PubMed

    Chang, Sungyul; Hartman, Glen L; Singh, Ram J; Lambert, Kris N; Hobbs, Houston A; Domier, Leslie L

    2013-06-01

    Like many widely cultivated crops, soybean [Glycine max (L.) Merr.] has a relatively narrow genetic base, while its perennial distant relatives in the subgenus Glycine Willd. are more genetically diverse and display desirable traits not present in cultivated soybean. To identify single-nucleotide polymorphisms (SNPs) between a pair of G. latifolia accessions that were resistant or susceptible to Sclerotinia sclerotiorum (Lib.) de Bary, reduced-representations of DNAs from each accession were sequenced. Approximately 30 % of the 36 million 100-nt reads produced from each of the two G. latifolia accessions aligned primarily to gene-rich euchromatic regions on the distal arms of G. max chromosomes. Because a genome sequence was not available for G. latifolia, the G. max genome sequence was used as a reference to identify 9,303 G. latifolia SNPs that aligned to unique positions in the G. max genome with at least 98 % identity and no insertions and deletions. To validate a subset of the SNPs, nine TaqMan and 384 GoldenGate allele-specific G. latifolia SNP assays were designed and analyzed in F2 G. latifolia populations derived from G. latifolia plant introductions (PI) 559298 and 559300. All nine TaqMan markers and 91 % of the 291 polymorphic GoldenGate markers segregated in a 1:2:1 ratio. Genetic linkage maps were assembled for G. latifolia, nine of which were uninterrupted and nearly collinear with the homoeologous G. max chromosomes. These results made use of a heterologous reference genome sequence to identify more than 9,000 informative high-quality SNPs for G. latifolia, a subset of which was used to generate the first genetic maps for any perennial Glycine species.

  13. The Kinome of Edible and Medicinal Fungus Wolfiporia cocos

    PubMed Central

    Wei, Wei; Shu, Shaohua; Zhu, Wenjun; Xiong, Ying; Peng, Fang

    2016-01-01

    Wolfiporia cocos is an edible and medicinal fungus that grows in association with pine trees, and its dried sclerotium, known as Fuling in China, has been used as a traditional medicine in East Asian countries for centuries. Nearly 10% of the traditional Chinese medicinal preparations contain W. cocos. Currently, the commercial production of Fuling is limited because of the lack of pine-based substrate and paucity of knowledge about the sclerotial development of the fungus. Since protein kinase (PKs) play significant roles in the regulation of growth, development, reproduction, and environmental responses in filamentous fungi, the kinome of W. cocos was analyzed by identifying the PKs genes, studying transcript profiles and assigning PKs to orthologous groups. Of the 10 putative PKs, 11 encode atypical PKs, and 13, 10, 2, 22, and 11 could encoded PKs from the AGC, CAMK, CK, CMGC, STE, and TLK Groups, respectively. The level of transcripts from PK genes associated with sclerotia formation in the mycelium and sclerotium stages were analyzed by qRT-PCR. Based on the functions of the orthologs in Sclerotinia sclerotiorum (a sclerotia-formation fungus) and Saccharomyces cerevisiae, the potential roles of these W. cocos PKs were assigned. To the best of our knowledge, our study is the first identification and functional discussion of the kinome in the edible and medicinal fungus W. cocos. Our study systematically suggests potential roles of W. cocos PKs and provide comprehensive and novel insights into W. cocos sclerotial development and other economically important traits. Additionally, based on our result, genetic engineering can be employed for over expression or interference of some significant PKs genes to promote sclerotial growth and the accumulation of active compounds. PMID:27708635

  14. Enhanced disease resistance in transgenic carrot (Daucus carota L.) plants over-expressing a rice cationic peroxidase.

    PubMed

    Wally, O; Punja, Z K

    2010-10-01

    Plant class III peroxidases are involved in numerous responses related to pathogen resistance including controlling hydrogen peroxide (H(2)O(2)) levels and lignin formation. Peroxidases catalyze the oxidation of organic compounds using H(2)O(2) as an oxidant. We examined the mechanisms of disease resistance in a transgenic carrot line (P23) which constitutively over-expresses the rice cationic peroxidase OsPrx114 (previously known as PO-C1) and which exhibits enhanced resistance to necrotrophic foliar pathogens. OsPrx114 over-expression led to a slight enhancement of constitutive transcript levels of pathogenesis-related (PR) genes. These transcript levels were dramatically increased in line P23 compared to controls [GUS construct under the control of 35S promoter (35S::GUS)] when tissues were treated with cell wall fragments of the fungal pathogen Sclerotinia sclerotiorum (SS-walls), and to a lesser extent with 2,6-dichloroisonicotinic acid. There was no basal increase in basal H(2)O(2) levels in tissues of the line P23. However, during an oxidative burst response elicited by SS-walls, H(2)O(2) accumulation was reduced in line P23 despite, typical media alkalinization associated with oxidative burst responses was observed, suggesting that OsPrx114 was involved in rapid H(2)O(2) consumption during the oxidative burst response. Tap roots of line P23 had increased lignin formation in the outer periderm tissues, which was further increased during challenge inoculation with Alternaria radicina. Plant susceptibility to a biotrophic pathogen, Erysiphe heraclei, was not affected. Disease resistance to necrotrophic pathogens in carrot as a result of OsPrx114 over-expression is manifested through increased PR transcript accumulation, rapid removal of H(2)O(2) during oxidative burst response and enhanced lignin formation.

  15. Phylogeny of Plant Calcium and Calmodulin-Dependent Protein Kinases (CCaMKs) and Functional Analyses of Tomato CCaMK in Disease Resistance

    PubMed Central

    Wang, Ji-Peng; Munyampundu, Jean-Pierre; Xu, You-Ping; Cai, Xin-Zhong

    2015-01-01

    Calcium and calmodulin-dependent protein kinase (CCaMK) is a member of calcium/calmodulin-dependent protein kinase superfamily and is essential to microbe- plant symbiosis. To date, the distribution of CCaMK gene in plants has not yet been completely understood, and its function in plant disease resistance remains unclear. In this study, we systemically identified the CCaMK genes in genomes of 44 plant species in Phytozome and analyzed the function of tomato CCaMK (SlCCaMK) in resistance to various pathogens. CCaMKs in 18 additional plant species were identified, yet the absence of CCaMK gene in green algae and cruciferous species was confirmed. Sequence analysis of full-length CCaMK proteins from 44 plant species demonstrated that plant CCaMKs are highly conserved across all domains. Most of the important regulatory amino acids are conserved throughout all sequences, with the only notable exception being observed in N-terminal autophosphorylation site corresponding to Ser 9 in the Medicago truncatula CCaMK. CCaMK gene structures are similar, mostly containing six introns with a phase profile of 200200 and the exception was only noticed at the first exons. Phylogenetic analysis demonstrated that CCaMK lineage is likely to have diverged early from a calcium-dependent protein kinase (CDPK) gene in the ancestor of all nonvascular plant species. The SlCCaMK gene was widely and differently responsive to diverse pathogenic stimuli. Furthermore, knock-down of SlCCaMK reduced tomato resistance to Sclerotinia sclerotiorum and Pseudomonas syringae pv. tomato (Pst) DC3000 and decreased H2O2 accumulation in response to Pst DC3000 inoculation. Our results reveal that SlCCaMK positively regulates disease resistance in tomato via promoting H2O2 accumulation. SlCCaMK is the first CCaMK gene proved to function in plant disease resistance. PMID:26697034

  16. High abundance of Serine/Threonine-rich regions predicted to be hyper-O-glycosylated in the secretory proteins coded by eight fungal genomes

    PubMed Central

    2012-01-01

    Background O-glycosylation of secretory proteins has been found to be an important factor in fungal biology and virulence. It consists in the addition of short glycosidic chains to Ser or Thr residues in the protein backbone via O-glycosidic bonds. Secretory proteins in fungi frequently display Ser/Thr rich regions that could be sites of extensive O-glycosylation. We have analyzed in silico the complete sets of putatively secretory proteins coded by eight fungal genomes (Botrytis cinerea, Magnaporthe grisea, Sclerotinia sclerotiorum, Ustilago maydis, Aspergillus nidulans, Neurospora crassa, Trichoderma reesei, and Saccharomyces cerevisiae) in search of Ser/Thr-rich regions as well as regions predicted to be highly O-glycosylated by NetOGlyc (http://www.cbs.dtu.dk). Results By comparison with experimental data, NetOGlyc was found to overestimate the number of O-glycosylation sites in fungi by a factor of 1.5, but to be quite reliable in the prediction of highly O-glycosylated regions. About half of secretory proteins have at least one Ser/Thr-rich region, with a Ser/Thr content of at least 40% over an average length of 40 amino acids. Most secretory proteins in filamentous fungi were predicted to be O-glycosylated, sometimes in dozens or even hundreds of sites. Residues predicted to be O-glycosylated have a tendency to be grouped together forming hyper-O-glycosylated regions of varying length. Conclusions About one fourth of secretory fungal proteins were predicted to have at least one hyper-O-glycosylated region, which consists of 45 amino acids on average and displays at least one O-glycosylated Ser or Thr every four residues. These putative highly O-glycosylated regions can be found anywhere along the proteins but have a slight tendency to be at either one of the two ends. PMID:22994653

  17. Muscodor albus E-6, an endophyte of Guazuma ulmifolia making volatile antibiotics: isolation, characterization and experimental establishment in the host plant.

    PubMed

    Strobel, Gary A; Kluck, Katreena; Hess, Wilford M; Sears, Joe; Ezra, David; Vargas, Percy N

    2007-08-01

    Muscodor albus is an endophytic fungus, represented by a number of isolates from tropical tree and vine species in several of the world's rainforests, that produces volatile organic compounds (VOCs) with antibiotic activity. A new isolate, E-6, of this organism, with unusual biochemical and biological properties, has been obtained from the branches of a mature Guazuma ulmifolia (Sterculiaceae) tree growing in a dry tropical forest in SW Ecuador. This unique organism produces many VOCs not previously observed in other M. albus isolates, including butanoic acid, 2-methyl-; butanoic acid, 3-methyl-; 2-butenal, 2-methyl-; butanoic acid, 3-methylbutyl ester; 3-buten-1-ol, 3-methyl; guaiol; 1-octene, 3-ethyl-; formamide, N-(1-methylpropyl); and certain azulene and naphthalene derivatives. Some compounds usually seen in other M. albus isolates also appeared in the VOCs of isolate E-6, including caryophyllene; phenylethyl alcohol; acetic acid, 2-phenylethyl ester; bulnesene; and various propanoic acid, 2-methyl- derivatives. The biological activity of the VOCs of E-6 appears different from the original isolate of this fungus, CZ-620, since a Gram-positive bacterium was killed, and Sclerotinia sclerotiorum and Rhizoctonia solani were not. Scanning electron micrographs of the mycelium of isolate E-6 showed substantial intertwining of the hyphal strands. These strands seemed to be held together by an extracellular matrix accounting for the strong mat-like nature of the mycelium, which easily lifts off the agar surface upon transfer, unlike any other isolate of this fungus. The ITS-5.8S rDNA partial sequence data showed 99 % similarity to the original M. albus strain CZ-620. For the first time, successful establishment of M. albus into its natural host, followed by recovery of the fungus, was accomplished in seedlings of G. ulmifolia. Overall, isolates of M. albus, including E-6, have chemical, biological and structural characteristics that make them potentially useful in

  18. Comparative mapping of the wild perennial Glycine latifolia and soybean (G. max) reveals extensive chromosome rearrangements in the genus Glycine.

    PubMed

    Chang, Sungyul; Thurber, Carrie S; Brown, Patrick J; Hartman, Glen L; Lambert, Kris N; Domier, Leslie L

    2014-01-01

    Soybean (Glycine max L. Mer.), like many cultivated crops, has a relatively narrow genetic base and lacks diversity for some economically important traits. Glycine latifolia (Benth.) Newell & Hymowitz, one of the 26 perennial wild Glycine species related to soybean in the subgenus Glycine Willd., shows high levels of resistance to multiple soybean pathogens and pests including Alfalfa mosaic virus, Heterodera glycines Ichinohe and Sclerotinia sclerotiorum (Lib.) de Bary. However, limited information is available on the genomes of these perennial Glycine species. To generate molecular resources for gene mapping and identification, high-density linkage maps were constructed for G. latifolia using single nucleotide polymorphism (SNP) markers generated by genotyping by sequencing and evaluated in an F2 population and confirmed in an F5 population. In each population, greater than 2,300 SNP markers were selected for analysis and segregated to form 20 large linkage groups. Marker orders were similar in the F2 and F5 populations. The relationships between G. latifolia linkage groups and G. max and common bean (Phaseolus vulgaris L.) chromosomes were examined by aligning SNP-containing sequences from G. latifolia to the genome sequences of G. max and P. vulgaris. Twelve of the 20 G. latifolia linkage groups were nearly collinear with G. max chromosomes. The remaining eight G. latifolia linkage groups appeared to be products of multiple interchromosomal translocations relative to G. max. Large syntenic blocks also were observed between G. latifolia and P. vulgaris. These experiments are the first to compare genome organizations among annual and perennial Glycine species and common bean. The development of molecular resources for species closely related to G. max provides information into the evolution of genomes within the genus Glycine and tools to identify genes within perennial wild relatives of cultivated soybean that could be beneficial to soybean production.

  19. IGS Minisatellites Useful for Race Differentiation in Colletotrichum lentis and a Likely Site of Small RNA Synthesis Affecting Pathogenicity.

    PubMed

    Durkin, Jonathan; Bissett, John; Pahlavani, Mohammadhadi; Mooney, Brent; Buchwaldt, Lone

    2015-01-01

    Colletotrichum lentis is a fungal pathogen of lentil in Canada but rarely reported elsewhere. Two races, Ct0 and Ct1, have been identified using differential lines. Our objective was to develop a PCR-probe differentiating these races. Sequences of the translation elongation factor 1α (tef1α), RNA polymerase II subunit B2 (rpb2), ATP citrate lyase subunit A (acla), and internal transcribed spacer (ITS) regions were monomorphic, while the intergenic spacer (IGS) region showed length polymorphisms at two minisatellites of 23 and 39 nucleotides (nt). A PCR-probe (39F/R) amplifying the 39 nt minisatellite was developed which subsequently revealed 1-5 minisatellites with 1-12 repeats in C. lentis. The probe differentiated race Ct1 isolates having 7, 9 or 7+9 repeats from race Ct0 having primarily 2 or 4 repeats, occasionally 5, 6, or 8, but never 7 or 9 repeats. These isolates were collected between 1991 and 1999. In a 2012 survey isolates with 2 and 4 repeats increased from 34% to 67%, while isolated with 7 or 9 repeats decreased from 40 to 4%, likely because Ct1 resistant lentil varieties had been grown. The 39 nt repeat was identified in C. gloeosporioides, C. trifolii, Ascochyta lentis, Sclerotinia sclerotiorum and Botrytis cinerea. Thus, the 39F/R PCR probe is not species specific, but can differentiate isolates based on repeat number. The 23 nt minisatellite in C. lentis exists as three length variants with ten sequence variations differentiating race Ct0 having 14 or 19 repeats from race Ct1 having 17 repeats, except for one isolate. RNA-translation of 23 nt repeats forms hairpins and has the appropriate length to suggest that IGS could be a site of small RNA synthesis, a hypothesis that warrants further investigation. Small RNA from fungal plant pathogens able to silence genes either in the host or pathogen thereby aiding infection have been reported.

  20. Calcium-dependent protein kinase (CDPK) and CDPK-related kinase (CRK) gene families in tomato: genome-wide identification and functional analyses in disease resistance.

    PubMed

    Wang, Ji-Peng; Xu, You-Ping; Munyampundu, Jean-Pierre; Liu, Tian-Yu; Cai, Xin-Zhong

    2016-04-01

    Calcium-dependent protein kinases (CDPKs) and CDPK-related kinases (CRKs) play multiple roles in plant. Nevertheless, genome-wide identification of these two families is limited to several plant species, and role of CRKs in disease resistance remains unclear. In this study, we identified the CDPK and CRK gene families in genome of the economically important crop tomato (Solanum lycopersicum L.) and analyzed their function in resistance to various pathogens. Twenty-nine CDPK and six CRK genes were identified in tomato genome. Both SlCDPK and SlCRK proteins harbored an STKc_CAMK type protein kinase domain, while only SlCDPKs contained EF-hand type Ca(2+) binding domain(s). Phylogenetic analysis revealed that plant CRK family diverged early from CDPKs, and shared a common ancestor gene with subgroup IV CDPKs. Subgroup IV SlCDPK proteins were basic and their genes contained 11 introns, which were distinguished from other subgroups but similar to CRKs. Subgroup I SlCDPKs generally did not carry an N-terminal myristoylation motif while those of the remaining subgroups and SlCRKs universally did. SlCDPK and SlCRK genes were differently responsive to pathogenic stimuli. Furthermore, silencing analyses demonstrated that SlCDPK18 and SlCDPK10 positively regulated nonhost resistance to Xanthomonas oryzae pv. oryzae and host resistance to Pseudomonas syringae pv. tomato (Pst) DC3000, respectively, while SlCRK6 positively regulated resistance to both Pst DC3000 and Sclerotinia sclerotiorum in tomato. In conclusion, CRKs apparently evolved from CDPK lineage, SlCDPK and SlCRK genes regulate a wide range of resistance and SlCRK6 is the first CRK gene proved to function in plant disease resistance.

  1. Novel Hypovirulence-Associated RNA Mycovirus in the Plant-Pathogenic Fungus Botrytis cinerea: Molecular and Biological Characterization

    PubMed Central

    Yu, Lin; Sang, Wen; Wu, Ming-De; Zhang, Jing; Yang, Long; Zhou, Ying-Jun; Chen, Wei-Dong

    2015-01-01

    Botrytis cinerea is a pathogenic fungus causing gray mold on numerous economically important crops and ornamental plants. This study was conducted to characterize the biological and molecular features of a novel RNA mycovirus, Botrytis cinerea RNA virus 1 (BcRV1), in the hypovirulent strain BerBc-1 of B. cinerea. The genome of BcRV1 is 8,952 bp long with two putative overlapped open reading frames (ORFs), ORF1 and ORF2, coding for a hypothetical polypeptide (P1) and RNA-dependent RNA polymerase (RdRp), respectively. A −1 frameshifting region (designated the KNOT element) containing a shifty heptamer, a heptanucleotide spacer, and an H-type pseudoknot was predicted in the junction region of ORF1 and ORF2. The −1 frameshifting role of the KNOT element was experimentally confirmed through determination of the production of the fusion protein red fluorescent protein (RFP)-green fluorescent protein (GFP) by the plasmid containing the construct dsRed-KNOT-eGFP in Escherichia coli. BcRV1 belongs to a taxonomically unassigned double-stranded RNA (dsRNA) mycovirus group. It is closely related to grapevine-associated totivirus 2 and Sclerotinia sclerotiorum nonsegmented virus L. BcRV1 in strain BerBc-1 was found capable of being transmitted vertically through macroconidia and horizontally to other B. cinerea strains through hyphal contact. The presence of BcRV1 was found to be positively correlated with hypovirulence in B. cinerea, with the attenuation effects of BcRV1 on mycelial growth and pathogenicity being greatly affected by the accumulation level of BcRV1. PMID:25595766

  2. Selection of reference genes for quantitative reverse-transcription polymerase chain reaction normalization in Brassica napus under various stress conditions.

    PubMed

    Wang, Zheng; Chen, Yu; Fang, Hedi; Shi, Haifeng; Chen, Keping; Zhang, Zhiyan; Tan, Xiaoli

    2014-10-01

    Data normalization is essential for reliable output of quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR) assays, as the unsuitable choice of reference gene(s), whose expression might be influenced by exogenous treatments in plant tissues, could cause misinterpretation of results. To date, no systematic studies on reference genes have been performed in stressed Brassica napus. In this study, we investigated the expression variations of nine candidate reference genes in 40 samples of B. napus leaves subjected to various exogenous treatments. Parallel analyses by geNorm and NormFinder revealed that optimal reference genes differed across the different sets of samples. The best-ranked reference genes were PP2A and TIP41 for salt stress, TIP41 and ACT7 for heavy metal (Cr(6+)) stress, PP2A and UBC21 for drought stress, F-box and SAND for cold stress, F-box and ZNF for salicylic acid stress, TIP41, ACT7, and PP2A for methyl jasmonate stress, TIP41 and ACT7 for abscisic acid stress, and TIP41, UBC21, and PP2A for Sclerotinia sclerotiorum stress. Two newly employed reference genes, TIP41 and PP2A, showed better performances, suggesting their suitability in multiple conditions. To further validate the suitability of the reference genes, the expression patterns of BnWRKY40 and BnMKS1 were studied in parallel. This study is the first systematic analysis of reference gene selection for qRT-PCR normalization in B. napus, an agriculturally important crop, under different stress conditions. The results will contribute toward more accurate and widespread use of qRT-PCR in gene analysis of the genus Brassica.

  3. A Previously Unknown Oxalyl-CoA Synthetase Is Important for Oxalate Catabolism in Arabidopsis[W

    PubMed Central

    Foster, Justin; Kim, Hyun Uk; Nakata, Paul A.; Browse, John

    2012-01-01

    Oxalate is produced by several catabolic pathways in plants. The best characterized pathway for subsequent oxalate degradation is via oxalate oxidase, but some species, such as Arabidopsis thaliana, have no oxalate oxidase activity. Previously, an alternative pathway was proposed in which oxalyl-CoA synthetase (EC 6.2.1.8) catalyzes the first step, but no gene encoding this function has been found. Here, we identify ACYL-ACTIVATING ENZYME3 (AAE3; At3g48990) from Arabidopsis as a gene encoding oxalyl-CoA synthetase. Recombinant AAE3 protein has high activity against oxalate, with Km = 149.0 ± 12.7 μM and Vmax = 11.4 ± 1.0 μmol/min/mg protein, but no detectable activity against other organic acids tested. Allelic aae3 mutants lacked oxalyl-CoA synthetase activity and were unable to degrade oxalate into CO2. Seeds of mutants accumulated oxalate to levels threefold higher than the wild type, resulting in the formation of oxalate crystals. Crystal formation was associated with seed coat defects and substantially reduced germination of mutant seeds. Leaves of mutants were damaged by exogenous oxalate and more susceptible than the wild type to infection by the fungus Sclerotinia sclerotiorum, which produces oxalate as a phytotoxin to aid infection. Our results demonstrate that, in Arabidopsis, oxalyl-CoA synthetase encoded by AAE3 is required for oxalate degradation, for normal seed development, and for defense against an oxalate-producing fungal pathogen. PMID:22447686

  4. The requirement for the LysR-type regulator PtrA for Pseudomonas chlororaphis PA23 biocontrol revealed through proteomic and phenotypic analysis

    PubMed Central

    2014-01-01

    Background Pseudomonas chlororaphis strain PA23 is a biocontrol agent capable of suppressing the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces the antibiotics phenazine and pyrrolnitrin together with other metabolites believed to contribute to biocontrol. A mutant no longer capable of inhibiting fungal growth was identified harboring a transposon insertion in a gene encoding a LysR-type transcriptional regulator (LTTR), designated ptrA (Pseudomonas transcriptional regulator). Isobaric tag for relative and absolute quantitation (iTRAQ) based protein analysis was used to reveal changes in protein expression patterns in the ptrA mutant compared to the PA23 wild type. Results Relative abundance profiles showed 59 differentially-expressed proteins in the ptrA mutant, which could be classified into 16 clusters of orthologous groups (COGs) based on their predicted functions. The largest COG category was the unknown function group, suggesting that many yet-to-be identified proteins are involved in the loss of fungal activity. In the secondary metabolite biosynthesis, transport and catabolism COG, seven proteins associated with phenazine biosynthesis and chitinase production were downregulated in the mutant. Phenotypic assays confirmed the loss of phenazines and chitinase activity. Upregulated proteins included a lipoprotein involved in iron transport, a flagellin and hook-associated protein and four proteins categorized into the translation, ribosome structure and biogenesis COG. Phenotypic analysis revealed that the mutant exhibited increased siderophore production and flagellar motility and an altered growth profile, supporting the proteomic findings. Conclusion PtrA is a novel LTTR that is essential for PA23 fungal antagonism. Differential protein expression was observed across 16 COG categories suggesting PtrA is functioning as a global transcriptional regulator. Changes in protein expression were confirmed by phenotypic assays that showed reduced

  5. Characterization and Phylogenetic Analysis of the Mitochondrial Genome of Glarea lozoyensis Indicates High Diversity within the Order Helotiales

    PubMed Central

    Youssar, Loubna; Grüning, Björn Andreas; Günther, Stefan; Hüttel, Wolfgang

    2013-01-01

    Background Glarea lozoyensis is a filamentous fungus used for the industrial production of non-ribosomal peptide pneumocandin B0. In the scope of a whole genome sequencing the complete mitochondrial genome of the fungus has been assembled and annotated. It is the first one of the large polyphyletic Helotiaceae family. A phylogenetic analysis was performed based on conserved proteins of the oxidative phosphorylation system in mitochondrial genomes. Results The total size of the mitochondrial genome is 45,038 bp. It contains the expected 14 genes coding for proteins related to oxidative phosphorylation,two rRNA genes, six hypothetical proteins, three intronic genes of which two are homing endonucleases and a ribosomal protein rps3. Additionally there is a set of 33 tRNA genes. All genes are located on the same strand. Phylogenetic analyses based on concatenated mitochondrial protein sequences confirmed that G. lozoyensis belongs to the order of Helotiales and that it is most closely related to Phialocephala subalpina. However, a comparison with the three other mitochondrial genomes known from Helotialean species revealed remarkable differences in size, gene content and sequence. Moreover, it was found that the gene order found in P. subalpina and Sclerotinia sclerotiorum is not conserved in G. lozoyensis. Conclusion The arrangement of genes and other differences found between the mitochondrial genome of G. lozoyensis and those of other Helotiales indicates a broad genetic diversity within this large order. Further mitochondrial genomes are required in order to determine whether there is a continuous transition between the different forms of mitochondrial genomes or G. lozoyensis belongs to a distinct subgroup within Helotiales. PMID:24086376

  6. Biochemical and molecular characterization of high population density bacteria isolated from sunflower.

    PubMed

    Guerra Pinheiro de Goes, Kelly Campos; de Castro Fisher, Maria Luisa; Cattelan, Alexandre José; Nogueira, Marco Antonio; Portela de Carvalho, Claudio Guilherme; Martinez de Oliveira, Andre Luiz

    2012-04-01

    Natural and beneficial associations between plants and bacteria have demonstrated potential commercial application for several agricultural crops. The sunflower has acquired increasing importance in Brazilian agribusiness owing to its agronomic characteristics such as the tolerance to edaphoclimatic variations, resistance to pests and diseases, and adaptation to the implements commonly used for maize and soybean, as well as the versatility of the products and by-products obtained from its cultivation. A study of the cultivable bacteria associated with two sunflower cultivars, using classical microbiological methods, successfully obtained isolates from different plant tissues (roots, stems, florets, and rhizosphere). Out of 57 plantgrowth- promoting isolates obtained, 45 were identified at the genus level and phylogenetically positioned based on 16S rRNA gene sequencing: 42 Bacillus (B. subtilis, B. cereus, B. thuringiensis, B. pumilus, B. megaterium, and Bacillus sp.) and 3 Methylobacterium komagatae. Random amplified polymorphic DNA (RAPD) analysis showed a broad diversity among the Bacillus isolates, which clustered into 2 groups with 75% similarity and 13 subgroups with 85% similarity, suggesting that the genetic distance correlated with the source of isolation. The isolates were also analyzed for certain growth-promoting activities. Auxin synthesis was widely distributed among the isolates, with values ranging from 93.34 to 1653.37 microM auxin per microng of protein. The phosphate solubilization index ranged from 1.25 to 3.89, and siderophore index varied from 1.15 to 5.25. From a total of 57 isolates, 3 showed an ability to biologically fix atmospheric nitrogen, and 7 showed antagonism against the pathogen Sclerotinia sclerotiorum. The results of biochemical characterization allowed identification of potential candidates for the development of biofertilizers targeted to the sunflower crop.

  7. In vitro antagonistic activity, plant growth promoting traits and phylogenetic affiliation of rhizobacteria associated with wild plants grown in arid soil.

    PubMed

    El-Sayed, Wael S; Akhkha, Abdellah; El-Naggar, Moustafa Y; Elbadry, Medhat

    2014-01-01

    The role of plant growth-promoting rhizobacteria (PGPR) in adaptation of plants in extreme environments is not yet completely understood. For this study native bacteria were isolated from rhizospeheric arid soils and evaluated for both growth-promoting abilities and antagonistic potential against phytopathogenic fungi and nematodes. The phylogentic affiliation of these representative isolates was also characterized. Rhizobacteria associated with 11 wild plant species from the arid soil of Almadinah Almunawarah, Kingdom of Saudi Arabia (KSA) were investigated. From a total of 531 isolates, only 66 bacterial isolates were selected based on their ability to inhibit Fusarium oxysporum, and Sclerotinia sclerotiorum. The selected isolates were screened in vitro for activities related to plant nutrition and plant growth regulation as well as for antifungal and nematicidal traits. Isolated bacteria were found to exhibit capabilities in fix atmospheric nitrogen, produce ammonia, indoleacetic acid (IAA), siderophores, solubilize phosphate and zinc, and showed an antagonistic potential against some phytopathogenic fungi and one nematode species (Meloidogyne incognita) to various extent. Isolates were ranked by their potential ability to function as PGPR. The 66 isolates were genotyped using amplified rDNA restriction analysis (ARDRA) and 16S rRNA gene sequence analysis. The taxonomic composition of the representative genotypes from both rhizosphere and rhizoplane comprised Bacillus, Enterobacter and Pseudomonas. Out of the 10 genotypes, three strains designated as PHP03, CCP05, and TAP02 might be regarded as novel strains based on their low similarity percentages and high bootstrap values. The present study clearly identified specific traits in the isolated rhizobacteria, which make them good candidates as PGPR and might contribute to plant adaption to arid environments. Application of such results in agricultural fields may improve and enhance plant growth in arid soils.

  8. The characterization of the soybean polygalacturonase-inhibiting proteins (Pgip) gene family reveals that a single member is responsible for the activity detected in soybean tissues.

    PubMed

    D'Ovidio, R; Roberti, S; Di Giovanni, M; Capodicasa, C; Melaragni, M; Sella, L; Tosi, P; Favaron, F

    2006-08-01

    Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) proteins that inhibit fungal endopolygalacturonases (PGs). They are encoded by multigene families whose members show functional redundancy and subfunctionalization for recognition of fungal PGs. In order to expand the information on the structure and functional features of legume PGIP, we have isolated and characterized four members of the soybean Pgip gene family and determined the properties of the encoded protein products. Sequence analysis showed that these genes form two clusters: one cluster of about 5 kbp containing Gmpgip1 and Gmpgip2, and the other containing Gmpgip3 and Gmpgip4 within a 60 kb fragment of a separate BAC clone. Sequence diversification of the four members resides mainly in the xxLxLxx region that includes residues forming the beta-sheet B1. When compared with other legume Pgip genes, Gmpgip3 groups with the bean genes Pvpgip1 and Pvpgip2, suggesting that these genes are closer to the ancestral gene. At the protein level, only GmPGIP3 shows the capability to inhibit fungal PGs. The spectrum of inhibition of GmPGIP3 against eight different fungal PGs mirrors that of the PGIP purified from soybean tissues and is similar to that of the bean PvPGIP2, one of the most efficient inhibitors so far characterized. We also report that the four Gmpgip genes are differentially regulated after wounding or during infection with the fungal pathogen Sclerotinia sclerotiorum. Following fungal infection Gmpgip3 is up regulated promptly, while Gmpgip2 is delayed.

  9. The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution

    PubMed Central

    2014-01-01

    Background Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. Results BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. Conclusions The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type. PMID:25034494

  10. An Oxalyl-CoA Dependent Pathway of Oxalate Catabolism Plays a Role in Regulating Calcium Oxalate Crystal Accumulation and Defending against Oxalate-Secreting Phytopathogens in Medicago truncatula

    PubMed Central

    Foster, Justin; Luo, Bin; Nakata, Paul A.

    2016-01-01

    Considering the widespread occurrence of oxalate in nature and its broad impact on a host of organisms, it is surprising that so little is known about the turnover of this important acid. In plants, oxalate oxidase is the most well studied enzyme capable of degrading oxalate, but not all plants possess this activity. Recently, an Acyl Activating Enzyme 3 (AAE3), encoding an oxalyl-CoA synthetase, was identified in Arabidopsis. AAE3 has been proposed to catalyze the first step in an alternative pathway of oxalate degradation. Whether this enzyme and proposed pathway is important to other plants is unknown. Here, we identify the Medicago truncatula AAE3 (MtAAE3) and show that it encodes an oxalyl-CoA synthetase activity exhibiting high activity against oxalate with a Km = 81 ± 9 μM and Vmax = 19 ± 0.9 μmoles min-1mg protein-1. GFP-MtAAE3 localization suggested that this enzyme functions within the cytosol of the cell. Mtaae3 knock-down line showed a reduction in its ability to degrade oxalate into CO2. This reduction in the capacity to degrade oxalate resulted in the accumulation of druse crystals of calcium oxalate in the Mtaae3 knock-down line and an increased susceptibility to oxalate-secreting phytopathogens such as Sclerotinia sclerotiorum. Taken together, these results suggest that AAE3 dependent turnover of oxalate is important to different plants and functions in the regulation of tissue calcium oxalate crystal accumulation and in defense against oxalate-secreting phytopathogens. PMID:26900946

  11. Alpha-momorcharin, a RIP produced by bitter melon, enhances defense response in tobacco plants against diverse plant viruses and shows antifungal activity in vitro.

    PubMed

    Zhu, Feng; Zhang, Ping; Meng, Yan-Fa; Xu, Fei; Zhang, Da-Wei; Cheng, Jian; Lin, Hong-Hui; Xi, De-Hui

    2013-01-01

    Alpha-momorcharin (α-MMC) is type-1 ribosome inactivating proteins (RIPs) with molecular weight of 29 kDa and has lots of biological activity. Our recent study indicated that the α-MMC purified from seeds of Momordica charantia exhibited distinct antiviral and antifungal activity. Tobacco plants pre-treated with 0.5 mg/mL α-MMC 3 days before inoculation with various viruses showed less-severe symptom and less reactive oxygen species (ROS) accumulation compared to that inoculated with viruses only. Quantitative real-time PCR analysis revealed that the replication levels of viruses were lower in the plants treated with the α-MMC than control plants at 15 days post inoculation. Moreover, the coat protein expression of viruses was almost completely inhibited in plants which were treated with the α-MMC compared with control plants. Furthermore, the SA-responsive defense-related genes including non-expressor of pathogenesis-related genes 1 (NPR1), PR1, PR2 were up-regulated and activities of some antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) were increased after the α-MMC treatment. In addition, the α-MMC (500 μg/mL) revealed remarkable antifungal effect against phytopathogenic fungi, in the growth inhibition range 50.35-67.21 %, along with their MIC values ranging from 100 to 500 μg/mL. The α-MMC had also a strong detrimental effect on spore germination of all the tested plant pathogens along with concentration as well as time-dependent kinetic inhibition of Sclerotinia sclerotiorum. The α-MMC showed a remarkable antiviral and antifungal effect and hence could possibly be exploited in crop protection for controlling certain important plant diseases.

  12. Harzianolide, a novel plant growth regulator and systemic resistance elicitor from Trichoderma harzianum.

    PubMed

    Cai, Feng; Yu, Guanghui; Wang, Ping; Wei, Zhong; Fu, Lin; Shen, Qirong; Chen, Wei

    2013-12-01

    A detailed understanding of the effect of natural products on plant growth and protection will underpin new product development for plant production. The isolation and characterization of a known secondary metabolite named harzianolide from Trichoderma harzianum strain SQR-T037 were described, and the bioactivity of the purified compound as well as the crude metabolite extract in plant growth promotion and systemic resistance induction was investigated in this study. The results showed that harzianolide significantly promoted tomato seedling growth by up to 2.5-fold (dry weight) at a concentration of 0.1 ppm compared with the control. The result of root scan suggested that Trichoderma secondary metabolites may influence the early stages of plant growth through better root development for the enhancement of root length and tips. Both of the purified harzianolide and crude metabolite extract increased the activity of some defense-related enzymes to response to oxidative stress. Examination of six defense-related gene expression by real-time reverse transcription-PCR analysis revealed that harzianolide induces the expression of genes involved in the salicylic acid (PR1 and GLU) and jasmonate/ethylene (JERF3) signaling pathways while crude metabolite extract inhibited some gene expression (CHI-II and PGIP) related to basal defense in tomato plants. Further experiment showed that a subsequent challenge of harzianolide-pretreated plants with the pathogen Sclerotinia sclerotiorum resulted in higher systemic resistance by the reduction of lesion size. These results indicate that secondary metabolites of Trichoderma spp., like harzianolide, may play a novel role in both plant growth regulation and plant defense responses.

  13. In vitro antagonistic activity, plant growth promoting traits and phylogenetic affiliation of rhizobacteria associated with wild plants grown in arid soil

    PubMed Central

    El-Sayed, Wael S.; Akhkha, Abdellah; El-Naggar, Moustafa Y.; Elbadry, Medhat

    2014-01-01

    The role of plant growth-promoting rhizobacteria (PGPR) in adaptation of plants in extreme environments is not yet completely understood. For this study native bacteria were isolated from rhizospeheric arid soils and evaluated for both growth-promoting abilities and antagonistic potential against phytopathogenic fungi and nematodes. The phylogentic affiliation of these representative isolates was also characterized. Rhizobacteria associated with 11 wild plant species from the arid soil of Almadinah Almunawarah, Kingdom of Saudi Arabia (KSA) were investigated. From a total of 531 isolates, only 66 bacterial isolates were selected based on their ability to inhibit Fusarium oxysporum, and Sclerotinia sclerotiorum. The selected isolates were screened in vitro for activities related to plant nutrition and plant growth regulation as well as for antifungal and nematicidal traits. Isolated bacteria were found to exhibit capabilities in fix atmospheric nitrogen, produce ammonia, indoleacetic acid (IAA), siderophores, solubilize phosphate and zinc, and showed an antagonistic potential against some phytopathogenic fungi and one nematode species (Meloidogyne incognita) to various extent. Isolates were ranked by their potential ability to function as PGPR. The 66 isolates were genotyped using amplified rDNA restriction analysis (ARDRA) and 16S rRNA gene sequence analysis. The taxonomic composition of the representative genotypes from both rhizosphere and rhizoplane comprised Bacillus, Enterobacter and Pseudomonas. Out of the 10 genotypes, three strains designated as PHP03, CCP05, and TAP02 might be regarded as novel strains based on their low similarity percentages and high bootstrap values. The present study clearly identified specific traits in the isolated rhizobacteria, which make them good candidates as PGPR and might contribute to plant adaption to arid environments. Application of such results in agricultural fields may improve and enhance plant growth in arid soils

  14. White mold of Jerusalem artichoke

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jerusalem artichoke (Helianthus tuberosus) is a Native American food plant closely related to the common sunflower (Helianthus annuus). Tubers of Jerusalem artichoke are increasingly available in retail grocery outlets. White mold (Sclerotinia stem rot), caused by the fungus, Sclerotinia sclerotioru...

  15. Registration of high-oleic peanut germplasm line ARSOK-S1 (TX996784) with enhanced resistance to Sclerotinia blight and pod rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The high oleic Spanish peanut (Arachis hypogaea L. subsp. fastigiata var. vulgaris) germplasm line ARSOK-S1 was developed cooperatively between the USDA Agricultural Research Service, Texas AgriLife Research, and Oklahoma State University, and was released in 2013. ARSOK-S1 (tested early as TX99678...

  16. Identification of Diverse Mycoviruses through Metatranscriptomics Characterization of the Viromes of Five Major Fungal Plant Pathogens

    PubMed Central

    Nelson, Berlin D.; Ajayi-Oyetunde, Olutoyosi; Bradley, Carl A.; Hughes, Teresa J.; Hartman, Glen L.; Eastburn, Darin M.

    2016-01-01

    ABSTRACT Mycoviruses can have a marked effect on natural fungal communities and influence plant health and productivity. However, a comprehensive picture of mycoviral diversity is still lacking. To characterize the viromes of five widely dispersed plant-pathogenic fungi, Colletotrichum truncatum, Macrophomina phaseolina, Diaporthe longicolla, Rhizoctonia solani, and Sclerotinia sclerotiorum, a high-throughput sequencing-based metatranscriptomic approach was used to detect viral sequences. Total RNA and double-stranded RNA (dsRNA) from mycelia and RNA from samples enriched for virus particles were sequenced. Sequence data were assembled de novo, and contigs with predicted amino acid sequence similarities to viruses in the nonredundant protein database were selected. The analysis identified 72 partial or complete genome segments representing 66 previously undescribed mycoviruses. Using primers specific for each viral contig, at least one fungal isolate was identified that contained each virus. The novel mycoviruses showed affinity with 15 distinct lineages: Barnaviridae, Benyviridae, Chrysoviridae, Endornaviridae, Fusariviridae, Hypoviridae, Mononegavirales, Narnaviridae, Ophioviridae, Ourmiavirus, Partitiviridae, Tombusviridae, Totiviridae, Tymoviridae, and Virgaviridae. More than half of the viral sequences were predicted to be members of the Mitovirus genus in the family Narnaviridae, which replicate within mitochondria. Five viral sequences showed strong affinity with three families (Benyviridae, Ophioviridae, and Virgaviridae) that previously contained no mycovirus species. The genomic information provides insight into the diversity and taxonomy of mycoviruses and coevolution of mycoviruses and their fungal hosts. IMPORTANCE Plant-pathogenic fungi reduce crop yields, which affects food security worldwide. Plant host resistance is considered a sustainable disease management option but may often be incomplete or lacking for some crops to certain fungal pathogens

  17. Pyrrolnitrin and Hydrogen Cyanide Production by Pseudomonas chlororaphis Strain PA23 Exhibits Nematicidal and Repellent Activity against Caenorhabditis elegans

    PubMed Central

    Nandi, Munmun; Selin, Carrie; Brassinga, Ann Karen C.; Belmonte, Mark F.; Fernando, W. G. Dilantha; Loewen, Peter C.; de Kievit, Teresa R.

    2015-01-01

    Pseudomonas chlororaphis strain PA23 is a biocontrol agent able to suppress growth of the fungal pathogen Sclerotinia sclerotiorum. This bacterium produces an arsenal of exometabolites including pyrrolnitrin (PRN), phenazine (PHZ), hydrogen cyanide (HCN), and degradative enzymes. Production of these compounds is controlled at both the transcriptional and posttranscriptional levels by the Gac-Rsm system, RpoS, PsrA, and the Phz quorum-sensing system. Beyond pathogen-suppression, the success of a biocontrol agent is dependent upon its ability to establish itself in the environment where predation by bacterivorous organisms, including nematodes, may threaten persistence. The focus of this study was to investigate whether PA23 is able to resist grazing by Caenorhabditis elegans and to define the role played by exoproducts in the bacterial-nematode interaction. We discovered that both PRN and HCN contribute to fast- and slow-killing of C. elegans. HCN is well-established as having lethal effects on C. elegans; however, PRN has not been reported to be nematicidal. Exposure of L4 stage nematodes to purified PRN reduced nematode viability in a dose-dependent fashion and led to reduced hatching of eggs laid by gravid adults. Because bacterial metabolites can act as chemoattractants or repellents, we analyzed whether PA23 exhibited attractant or repulsive properties towards C. elegans. Both PRN and HCN were found to be potent repellents. Next we investigated whether the presence of C. elegans would elicit changes in PA23 gene activity. Co-culturing the two organisms increased expression of a number of genes associated with biocontrol, including phzA, hcnA, phzR, phzI, rpoS and gacS. Exoproduct analysis showed that PHZ and autoinducer signals were upregulated, consistent with the gene expression profiles. Collectively, these findings indicate that PA23 is able to sense the presence of C. elegans and it is able to both repel and kill the nematodes, which should facilitate

  18. Identification and expression analysis of WRKY transcription factor genes in canola (Brassica napus L.) in response to fungal pathogens and hormone treatments

    PubMed Central

    Yang, Bo; Jiang, Yuanqing; Rahman, Muhammad H; Deyholos, Michael K; Kav, Nat NV

    2009-01-01

    Background Members of plant WRKY transcription factor families are widely implicated in defense responses and various other physiological processes. For canola (Brassica napus L.), no WRKY genes have been described in detail. Because of the economic importance of this crop, and its evolutionary relationship to Arabidopsis thaliana, we sought to characterize a subset of canola WRKY genes in the context of pathogen and hormone responses. Results In this study, we identified 46 WRKY genes from canola by mining the expressed sequence tag (EST) database and cloned cDNA sequences of 38 BnWRKYs. A phylogenetic tree was constructed using the conserved WRKY domain amino acid sequences, which demonstrated that BnWRKYs can be divided into three major groups. We further compared BnWRKYs to the 72 WRKY genes from Arabidopsis and 91 WRKY from rice, and we identified 46 presumptive orthologs of AtWRKY genes. We examined the subcellular localization of four BnWRKY proteins using green fluorescent protein (GFP) and we observed the fluorescent green signals in the nucleus only. The responses of 16 selected BnWRKY genes to two fungal pathogens, Sclerotinia sclerotiorum and Alternaria brassicae, were analyzed by quantitative real time-PCR (qRT-PCR). Transcript abundance of 13 BnWRKY genes changed significantly following pathogen challenge: transcripts of 10 WRKYs increased in abundance, two WRKY transcripts decreased after infection, and one decreased at 12 h post-infection but increased later on (72 h). We also observed that transcript abundance of 13/16 BnWRKY genes was responsive to one or more hormones, including abscisic acid (ABA), and cytokinin (6-benzylaminopurine, BAP) and the defense signaling molecules jasmonic acid (JA), salicylic acid (SA), and ethylene (ET). We compared these transcript expression patterns to those previously described for presumptive orthologs of these genes in Arabidopsis and rice, and observed both similarities and differences in expression patterns

  19. Electrophoretic and Immunological Comparisons of Developmentally Regulated Proteins in Members of the Sclerotiniaceae and Other Sclerotial Fungi

    PubMed Central

    Novak, Lily Ann; Kohn, Linda M.

    1991-01-01

    The fungal stroma is a distinct developmental stage, a compact mass of hyphal cells enveloped by a melanized layer of rind cells which is produced from vegetative mycelium. Two types of stromata that are characteristic of members of the Sclerotiniaceae but are also produced in a wide range of other fungi, i.e., the determinate tuberlike sclerotium and the indeterminate platelike substratal stroma, were compared in these studies. Developmental proteins found in determinate sclerotial and indeterminate substratal stromata, but not in mycelia, were characterized and compared in 52 isolates of fungi, both ascomycetes (including 18 species in the Sclerotiniaceae and 5 species of Aspergillus) and the basidiomycete Sclerotium rolfsii. One-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of mycelial, stromatal initial, and stromatal extracts demonstrated that all members of the Sclerotiniaceae produced proteins unique to stromatal extracts within a molecular weight range of 31,000 to 39,500 which composed 13 to 58% of the total protein in stromata. Proteins unique to the sclerotial stage were also produced in Sclerotium rolfsii and the Aspergillus species but within a generally lower-molecular-weight range of 11,000 to 30,000. The proteins were then characterized by two-dimensional electrophoresis to determine the number and isoelectric point of polypeptides composing each protein. Polyclonal antibodies were raised to the major 36-kDa sclerotial protein of Sclerotinia sclerotiorum (Ssp). Immunoblots demonstrated that all sclerotial proteins from species in the Sclerotiniaceae cross-reacted with anti-Ssp antibodies, while no cross-reaction was observed with proteins from substratal stromatal species in the Sclerotiniaceae, sclerotial species of Aspergillus, or Sclerotium rolfsii. Results of discriminant analysis of the data from competitive inhibition enzyme-linked immunosorbent assays were consistent with the results of immunoblotting. Three groupings

  20. 7 CFR 810.302 - Definitions of other terms.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Conspicuous Admixture. All matter other than canola, including but not limited to ergot, sclerotinia, and... crushed, exhibit a distinctly green color. (d) Dockage. All matter other than canola that can be removed.... (h) Sclerotia (Sclerotium, sing.). Dark colored or black resting bodies of the fungi Sclerotinia...

  1. 7 CFR 810.302 - Definitions of other terms.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Conspicuous Admixture. All matter other than canola, including but not limited to ergot, sclerotinia, and... crushed, exhibit a distinctly green color. (d) Dockage. All matter other than canola that can be removed.... (h) Sclerotia (Sclerotium, sing.). Dark colored or black resting bodies of the fungi Sclerotinia...

  2. 7 CFR 810.302 - Definitions of other terms.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Conspicuous Admixture. All matter other than canola, including but not limited to ergot, sclerotinia, and... crushed, exhibit a distinctly green color. (d) Dockage. All matter other than canola that can be removed.... (h) Sclerotia (Sclerotium, sing.). Dark colored or black resting bodies of the fungi Sclerotinia...

  3. 7 CFR 810.302 - Definitions of other terms.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Conspicuous Admixture. All matter other than canola, including but not limited to ergot, sclerotinia, and... crushed, exhibit a distinctly green color. (d) Dockage. All matter other than canola that can be removed.... (h) Sclerotia (Sclerotium, sing.). Dark colored or black resting bodies of the fungi Sclerotinia...

  4. 7 CFR 810.302 - Definitions of other terms.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Conspicuous Admixture. All matter other than canola, including but not limited to ergot, sclerotinia, and... crushed, exhibit a distinctly green color. (d) Dockage. All matter other than canola that can be removed.... (h) Sclerotia (Sclerotium, sing.). Dark colored or black resting bodies of the fungi Sclerotinia...

  5. Registration of 'VENUS' peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    VENUS is a large-seeded high-oleic Virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) that has enhanced Sclerotinia blight and pod rot resistance when compared to the cultivar Jupiter. VENUS is the first high-oleic Virginia peanut developed for optimal performance in the South...

  6. Disease evaluations and agronomic traits of advanced peanut breeding lines in 2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 38 peanut cultivars and high-oleic advanced breeding lines were evaluated in small field plots in 2012 for yield, seed grade and size, and resistance to Sclerotinia minor and Sclerotium rolfsii. Among the 14 Spanish entries, the cultivar Tamnut 06 (3258 lbs/acre) and breeding line 140-1O...

  7. Release of OLe peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OLe is a high oleic Spanish-type peanut that has excellent yield and enhanced Sclerotinia blight and pod rot resistance when compared to other high oleic Spanish cultivars. The purpose for releasing OLe is to provide peanut producers with a true Spanish peanut that is high oleic and has enhanced yi...

  8. Release of Lariat Peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lariat is a high-oleic runner-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) that has enhanced Sclerotinia blight and pod rot tolerance when compared to the cultivar Red River Runner. Lariat (experimental designation ARSOK-R35) is the result of a cross between cultivar Red River Ru...

  9. Disease evaluations and agronomic traits of advanced peanut breeding lines in 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 20 commercially available peanut cultivars and high-oleic advanced breeding lines were evaluated in small field plots in 2015 for agronomic traits (crop value, yield, seed grade, and characteristics). Environmental conditions in 2015 were not favorable for Sclerotinia blight, southern bl...

  10. Disease evaluations and agronomic traits of advanced peanut breeding lines in 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 21 peanut cultivars and high-oleic advanced breeding lines were evaluated in small field plots in 2013 for agronomic traits (crop value, yield, seed grade, and characteristics) and resistance to diseases (Sclerotinia blight, southern blight, and Pythium and Rhizoctonia pod rot). Among th...

  11. Documentation for release of a high oleic runner peanut cultivar (tested as TX 994313)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the peanut acreage diminished in 2008 to 18,000 acres, the peanut crop remains a viable agricultural commodity in western and southwestern Oklahoma with an annual estimated value of $14 million. Production of peanut is adversely affected by soilborne pathogens, especially Sclerotinia minor...

  12. High-oleic Virginia peanuts in the Southwestern US: A summary of data supporting the release of 'VENUS'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'VENUS' is a large-seeded high-oleic Virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) that has enhanced Sclerotinia blight and pod rot tolerance when compared to the cultivar Jupiter. 'VENUS' is the first high-oleic Virginia peanut developed for and proposed for release in t...

  13. The rising star of high-oleic Virginia peanuts: A summary of data supporting the release of 'VENUS'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'VENUS' is a large-seeded high-oleic Virginia-type peanut that has enhanced Sclerotinia blight and pod rot tolerance when compared to the cultivar Jupiter. 'VENUS' is the first high-oleic Virginia peanut developed for and proposed for release in the Southwestern US. 'VENUS' (experimental designati...

  14. Evaluation of seashore paspalum germplasm for resistance to dollar spot disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of seashore paspalum (Paspalum vaginatum Swartz) cultivars that exhibit resistance to dollar spot disease, caused by Sclerotinia homoeocarpa F.T. Bennett, are needed. Seashore paspalum is a warm-season turfgrass often utilized on golf courses and athletic fields in the southeastern Unite...

  15. Effects of genotype and isolate on expression of dollar spot in seashore paspalum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seashore paspalum (Paspalum vaginatum Swartz) is a warm-season turfgrass species primarily utilized on golf courses and athletic fields and is often impacted by dollar spot disease. Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, is a major fungal disease and the most common turfgrass p...

  16. Identification of high-quality single-nucleotide polymorphisms in Glycine latifolia using a heterologous reference genome sequence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Like most widely cultivated crops, soybean (Glycine max) has a relatively narrow genetic base, while its wild perennial relatives are more genetically diverse and can display desirable traits not present in cultivated soybean. For example, no sources of complete resistance to Sclerotinia...

  17. Stereoselective Bioreduction of α-Azido Ketones by Whole Cells of Marine-Derived Fungi.

    PubMed

    Rocha, Lenilson C; Seleghim, Mirna H R; Comasseto, João V; Sette, Lara D; Porto, André L M

    2015-12-01

    Seven strains of marine-derived fungi (Aspergillus sclerotiorum CBMAI 849, Cladosporium cladosporioides CBMAI 857, Penicillium raistrickii CBMAI 931, Penicillium citrinum CBMA 1186, Mucor racemosus CBMAI 847, Beauveria felina CBMAI 738, and Penicillium oxalicum CBMAI 1185) and terrestrial fungus Penicillium chrysogenum CBMA1199 were screened as catalysts for the asymmetric reduction of α-keto azides 5-8 to their corresponding β-azidophenylethanols 9-12. The marine fungi showed Prelog and anti-Prelog selectivities to the reduction α-keto azides 5-8. The fungi A. sclerotiorum CBMAI 849, C. cladosporioides CBMAI 857, P. raistrickii CBMAI 931, and P. citrinum CBMA 1186 catalyzed the reduction of azido ketone 6 to the corresponding (R)-2-azido-1-(4-methoxyphenyl)ethanol (10) with good conversions (68-100 %) and excellent enantiomeric excesses (>99 % ee) according to Prelog rule.

  18. Allelochemical effects of volatile compounds from Muscodor yucatanensis, an endophytic fungus from Bursera simaruba

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Muscodor yucatanensis, a recently described endophytic fungus, was isolated from the leaves of Bursera simaruba. In the present study we tested in vitro the mixture of volatile organic compounds (VOCs) produced by M. yucatanensis for the allelochemical effects against phytopathogenic fungi and fungo...

  19. Fungi Associated with Softening of Bisulfite-Brined Cherries.

    PubMed

    Lewis, J C; Pierson, C F; Powers, M J

    1963-03-01

    Softening of sound, calcium bisulfite-brined cherries was induced fairly quickly by brining them with cherries rotted by Aspergillus niger, Cytospora leucostoma, and Penicillium expansum, but not with cherries rotted by a variety of other microorganisms, including Alternaria sp., Aspergillus oryzae, Aureobasidium pullulans, Botrytis cinerea, Cladosporium sp., Mucor racemosus, Rhizopus stolonifer, and Sclerotinia fructicola. Rapid softening was correlated with the presence of a bisulfite-stable polygalacturonase, as demonstrated by a cup-plate test. A survey of naturally rotted cherries suggests the involvement of a bark-canker fungus, C. leucostoma, in softening of commercially brined cherries in the Pacific Northwest.

  20. Synthesis, Characterization, and Antifungal Studies of Cr(III) Complex of Norfloxacin and Bipiridyl Ligand

    PubMed Central

    Debnath, Anamika; Hussain, Firasat; Masram, Dhanraj T.

    2014-01-01

    A novel slightly distorted octahedral complex of Cr(III) of norfloxacin (Nor) with the formula [CrIII(Nor)(Bipy)Cl2]Cl·2CH3OH has been synthesized hydrothermally in the presence of a N-containing heterocyclic compound 2,2′-bipyridyl (Bipy). The complex was characterized with FT-IR, elemental analysis, UV-visible spectroscopy, and X-ray crystallography. Spectral studies suggest that the Nor acts as a deprotonated bidentate ligand. Thermal studies were also carried out. The synthesised complex was screened against four fungi Pythium aphanidermatum (PA), Sclerotinia rolfsii (SR), Rhizoctonia solani (RS), and Rhizoctonia bataticola (RB). PMID:25276111

  1. A thaumatin-like protein of Ocimum basilicum confers tolerance to fungal pathogen and abiotic stress in transgenic Arabidopsis.

    PubMed

    Misra, Rajesh Chandra; Sandeep; Kamthan, Mohan; Kumar, Santosh; Ghosh, Sumit

    2016-05-06

    Plant often responds to fungal pathogens by expressing a group of proteins known as pathogenesis-related proteins (PRs). The expression of PR is mediated through pathogen-induced signal-transduction pathways that are fine-tuned by phytohormones such as methyl jasmonate (MeJA). Here, we report functional characterization of an Ocimum basilicum PR5 family member (ObTLP1) that was identified from a MeJA-responsive expression sequence tag collection. ObTLP1 encodes a 226 amino acid polypeptide that showed sequence and structural similarities with a sweet-tasting protein thaumatin of Thaumatococcus danielli and also with a stress-responsive protein osmotin of Nicotiana tabacum. The expression of ObTLP1 in O. basilicum was found to be organ-preferential under unstressed condition, and responsive to biotic and abiotic stresses, and multiple phytohormone elicitations. Bacterially-expressed recombinant ObTLP1 inhibited mycelial growth of the phytopathogenic fungi, Scleretonia sclerotiorum and Botrytis cinerea; thereby, suggesting its antifungal activity. Ectopic expression of ObTLP1 in Arabidopsis led to enhanced tolerance to S. sclerotiorum and B. cinerea infections, and also to dehydration and salt stress. Moreover, induced expression of the defense marker genes suggested up-regulation of the defense-response pathways in ObTLP1-expressing Arabidopsis upon fungal challenge. Thus, ObTLP1 might be useful for providing tolerance to the fungal pathogens and abiotic stresses in crops.

  2. A thaumatin-like protein of Ocimum basilicum confers tolerance to fungal pathogen and abiotic stress in transgenic Arabidopsis

    PubMed Central

    Misra, Rajesh Chandra; Sandeep; Kamthan, Mohan; Kumar, Santosh; Ghosh, Sumit

    2016-01-01

    Plant often responds to fungal pathogens by expressing a group of proteins known as pathogenesis-related proteins (PRs). The expression of PR is mediated through pathogen-induced signal-transduction pathways that are fine-tuned by phytohormones such as methyl jasmonate (MeJA). Here, we report functional characterization of an Ocimum basilicum PR5 family member (ObTLP1) that was identified from a MeJA-responsive expression sequence tag collection. ObTLP1 encodes a 226 amino acid polypeptide that showed sequence and structural similarities with a sweet-tasting protein thaumatin of Thaumatococcus danielli and also with a stress-responsive protein osmotin of Nicotiana tabacum. The expression of ObTLP1 in O. basilicum was found to be organ-preferential under unstressed condition, and responsive to biotic and abiotic stresses, and multiple phytohormone elicitations. Bacterially-expressed recombinant ObTLP1 inhibited mycelial growth of the phytopathogenic fungi, Scleretonia sclerotiorum and Botrytis cinerea; thereby, suggesting its antifungal activity. Ectopic expression of ObTLP1 in Arabidopsis led to enhanced tolerance to S. sclerotiorum and B. cinerea infections, and also to dehydration and salt stress. Moreover, induced expression of the defense marker genes suggested up-regulation of the defense-response pathways in ObTLP1-expressing Arabidopsis upon fungal challenge. Thus, ObTLP1 might be useful for providing tolerance to the fungal pathogens and abiotic stresses in crops. PMID:27150014

  3. Entrapment of mycelial fragments in calcium alginate: a general technique for the use of immobilized filamentous fungi in biocatalysis.

    PubMed

    Peart, Patrice C; Chen, Avril R M; Reynolds, William F; Reese, Paul B

    2012-01-01

    Transformation reactions on 3β,17β-dihydroxyandrost-5-ene using free fungal cells were compared with those carried out by macerated mycelia, immobilized in calcium alginate beads. Six fungi were utilized in this study, namely Rhizopus oryzae ATCC 11145, Mucor plumbeus ATCC 4740, Cunninghamella echinulata var. elegans ATCC 8688a, Aspergillus niger ATCC 9142, Phanerochaete chrysosporium ATCC 24725 and Whetzelinia sclerotiorum ATCC 18687. The results show, for the first time, that encapsulated mycelial fragments essentially carry out the same bioconversions as those observed with growing cells. As the immobilized cells were "resting", the products formed were free of contamination by natural products, and this greatly aided the purification of the metabolites. Conditions for bead preparation were optimized. Furthermore, it was noted that the beads could be reused, once they had been subjected to a rejuvenation process.

  4. New 1,3,4-bisthiadiazolines: synthesis, characterization and antimicrobial evaluations.

    PubMed

    Yusuf, Mohamad; Kaur, Manvinder; Jain, Payal; Solanki, Indu

    2012-11-01

    The bisthiadiazolines 4a-4g have been synthesized in good yields from the cyclization reactions of bisthiosemicarbazones 3a-3g with acetic anhydride. The condensation reaction of dibenzaldehydes 2a-2g with thiosemicarbazide in alcoholic medium provided 3a-3g and former were obtained from the O-alkylation of 3-hydroxybenzaldehyde with suitable 1,ω-dibromoalkanes under alkaline conditions in the presence of dry EtOH/DMF. The intermediates 3a-3g and bishetrocyclics 4a-4g were also screened for their in vitro antimicrobial activities against seven bacterial strains (Klubsellia pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Straphylococcus aureus, Bacillius subtilis, Pseudomonas fluorescens and Streptoccus pyrogens) and five fungi strains (Aspergillius janus, Pencillium glabrum, Fusarium oxysporum, Aspergillus sclerotiorum, Aspergillus niger). The compounds 3f, 3g, 4f &4g were found to be significantly active against the tested microorganisms.

  5. New 1,3,4-bisthiadiazolines: Synthesis, characterization and antimicrobial evaluations

    NASA Astrophysics Data System (ADS)

    Yusuf, Mohamad; Kaur, Manvinder; Jain, Payal; Solanki, Indu

    2012-11-01

    The bisthiadiazolines 4a-4g have been synthesized in good yields from the cyclization reactions of bisthiosemicarbazones 3a-3g with acetic anhydride. The condensation reaction of dibenzaldehydes 2a-2g with thiosemicarbazide in alcoholic medium provided 3a-3g and former were obtained from the O-alkylation of 3-hydroxybenzaldehyde with suitable 1,ω-dibromoalkanes under alkaline conditions in the presence of dry EtOH/DMF. The intermediates 3a-3g and bishetrocyclics 4a-4g were also screened for their in vitro antimicrobial activities against seven bacterial strains (Klubsellia pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Straphylococcus aureus, Bacillius subtilis, Pseudomonas fluorescens and Streptoccus pyrogens) and five fungi strains (Aspergillius janus, Pencillium glabrum, Fusarium oxysporum, Aspergillus sclerotiorum, Aspergillus niger). The compounds 3f, 3g, 4f &4g were found to be significantly active against the tested microorganisms.

  6. General description and operation of the agro-environmental system: Crop management modeling. [Virginia

    NASA Technical Reports Server (NTRS)

    Gross, E.; Scott, J. H., Jr.

    1981-01-01

    Input for a data management system to provide farmers with information to improve crop management practices in Virginia requires monitoring of control crops at field stations, crop surveys derived from remotely sensed aircraft data, meteorological data from synchronous satellites, and details of local agricultural conditions. Presently models are under development for determining pest problems, water balance in the soil, stages of plant maturity, and optimum planting date. The status of the Cerospora leafspot model for peanut crop management is considered. Other models under development planned relate to Cylindtocladium Blackrot and Sclerotinia blight of peanuts, cyst nematode (Globerdena solanacearum) of tobacco, and red crown rot of soybeans. A software for program for estimating precipitation and solar radiation on a statewise basis is also being developed.

  7. Green fluorescent protein is lighting up fungal biology

    USGS Publications Warehouse

    Lorang, J.M.; Tuori, R.P; Martinez, J.P; Sawyer, T.L.; Redman, R.S.; Rollins, J. A.; Wolpert, T.J.; Johnson, K.B.; Rodriguez, R.J.; Dickman, M. B.; Ciuffetti, L.M.

    2001-01-01

    Expression of gfp in filamentous fungi requires agfp variant that is efficiently translated in fungi, a transformation system, and a fungal promoter that satisfies the requirements of a given experimental objective. Transformation of fungi has recently been reviewed by Gold et al. (26). Robinson and Sharon (44) suggest that GFP can actually be used to optimize transformation protocols. In addition to reporting the construction of a new fungal transformation vector that expressesSGFP under the control of the ToxA gene promoter from Pyrenophora tritici-repentis (12) and demonstrating its use in plant pathogens belonging to eight different genera of filamentous fungi (Fusarium, Botrytis, Pyrenophora, Alternaria, Cochliobolus, Sclerotinia, Colletotrichum, andVerticillium), in this review we also enumerate and describe a comprehensive list of vectors for expressing GFP in fungi.

  8. Use of remote sensing in agriculture

    NASA Technical Reports Server (NTRS)

    Pettry, D. E.; Powell, N. L.

    1975-01-01

    The remote sensing studies of (a) cultivated peanut areas in Southeastern Virginia; (b) studies at the Virginia Truck and Ornamentals Research Station near Painter, Virginia, the Eastern Virginia Research Station near Warsaw, Virginia, the Tidewater Research and Continuing Education Center near Suffolk, Virginia, and the Southern Piedmont Research and Continuing Education Center Blackstone, Virginia; and (c) land use classification studies at Virginia Beach, Virginia are presented. The practical feasibility of using false color infrared imagery to detect and determine the areal extent of peanut disease infestation of Cylindrocladium black rot and Sclerotinia blight is demonstrated. These diseases pose a severe hazard to this major agricultural food commodity. The value of remote sensing technology in terrain analyses and land use classification of diverse land areas is also investigated. Continued refinement of spectral signatures of major agronomic crops and documentation of pertinent environmental variables have provided a data base for the generation of an agricultural-environmental prediction model.

  9. Analysis of Gene Expression Profiles in Leaf Tissues of Cultivated Peanuts and Development of EST-SSR Markers and Gene Discovery

    PubMed Central

    Guo, Baozhu; Chen, Xiaoping; Hong, Yanbin; Liang, Xuanqiang; Dang, Phat; Brenneman, Tim; Holbrook, Corley; Culbreath, Albert

    2009-01-01

    Peanut is vulnerable to a range of foliar diseases such as spotted wilt caused by Tomato spotted wilt virus (TSWV), early (Cercospora arachidicola) and late (Cercosporidium personatum) leaf spots, southern stem rot (Sclerotium rolfsii), and sclerotinia blight (Sclerotinia minor). In this study, we report the generation of 17,376 peanut expressed sequence tags (ESTs) from leaf tissues of a peanut cultivar (Tifrunner, resistant to TSWV and leaf spots) and a breeding line (GT-C20, susceptible to TSWV and leaf spots). After trimming vector and discarding low quality sequences, a total of 14,432 high-quality ESTs were selected for further analysis and deposition to GenBank. Sequence clustering resulted in 6,888 unique ESTs composed of 1,703 tentative consensus (TCs) sequences and 5185 singletons. A large number of ESTs (5717) representing genes of unknown functions were also identified. Among the unique sequences, there were 856 EST-SSRs identified. A total of 290 new EST-based SSR markers were developed and examined for amplification and polymorphism in cultivated peanut and wild species. Resequencing information of selected amplified alleles revealed that allelic diversity could be attributed mainly to differences in repeat type and length in the SSR regions. In addition, a few additional INDEL mutations and substitutions were observed in the regions flanking the microsatellite regions. In addition, some defense-related transcripts were also identified, such as putative oxalate oxidase (EU024476) and NBS-LRR domains. EST data in this study have provided a new source of information for gene discovery and development of SSR markers in cultivated peanut. A total of 16931 ESTs have been deposited to the NCBI GenBank database with accession numbers ES751523 to ES768453. PMID:19584933

  10. Chestnut green waste composting for sustainable forest management: Microbiota dynamics and impact on plant disease control.

    PubMed

    Ventorino, Valeria; Parillo, Rita; Testa, Antonino; Viscardi, Sharon; Espresso, Francesco; Pepe, Olimpia

    2016-01-15

    Making compost from chestnut lignocellulosic waste is a possible sustainable management strategy for forests that employs a high-quality renewable organic resource. Characterization of the microbiota involved in composting is essential to better understand the entire process as well as the properties of the final product. Therefore, this study investigated the microbial communities involved in the composting of chestnut residues obtained from tree cleaning and pruning. The culture-independent approach taken highlighted the fact that the microbiota varied only slightly during the process, with the exception of those of the starting substrate and mature compost. The statistical analysis indicated that most of the bacterial and fungal species in the chestnut compost persisted during composting. The dominant microbial population detected during the process belonged to genera known to degrade recalcitrant lignocellulosic materials. Specifically, we identified fungal genera, such as Penicillium, Fusarium, Cladosporium, Aspergillus and Mucor, and prokaryotic species affiliated with Bacilli, Actinobacteria, Flavobacteria and γ-Proteobacteria. The suppressive properties of compost supplements for the biocontrol of Sclerotinia minor and Rhizoctonia solani were also investigated. Compared to pure substrate, the addition of compost to the peat-based growth substrates resulted in a significant reduction of disease in tomato plants of up to 70 % or 51 % in the presence of Sclerotinia minor or Rhizoctonia solani, respectively. The obtained results were related to the presence of putative bio-control agents and plant growth-promoting rhizobacteria belonging to the genera Azotobacter, Pseudomonas, Stenotrophomonas, Bacillus, Flavobacterium, Streptomyces and Actinomyces in the chestnut compost. The composting of chestnut waste may represent a sustainable agricultural practice for disposing of lignocellulosic waste by transforming it into green waste compost that can be used to

  11. The contribution of moulds and yeasts to the fermentation of 'agbelima' cassava dough.

    PubMed

    Amoa-Awua, W K; Frisvad, J C; Sefa-Dedeh, S; Jakobsen, M

    1997-09-01

    Agbelima, a fermented cassava meal widely consumed in Ghana, Togo and Benin, is produced by fermenting grated cassava with one of several types of traditional cassava dough inoculum. During fermentation a smooth textured sour dough is produced, the toxicity of cassava is reduced and there is a build up of volatile aroma compounds. Four types of inocula were included in the present investigation. In one type moulds were found to form a dominant part of the microbiota, the species present being Penicillium sclerotiorum, P. citrinum, P. nodulum, Geotrichum candidum and a basidiomycete. All these moulds were found to possess cellulase activity which was responsible for the hydrolysis of cassava tuber cellulose during fermentation leading to a breakdown of the coarse texture of cassava dough. The yeasts Candida krusei, C. tropicalis and Zygosaccharomyces spp. were present in high numbers in the four types of inocula including the moudly inoculum. The yeasts C. tropicalis and some strains of Zygosaccharomyces, all of which possessed cellulase activity, were also found to contribute to the modification of cassava texture during fermentation. All yeasts and moulds exhibited linamarase activity and were therefore capable of breaking down the cyanogenic glucosides present in cassava.

  12. Activity in vitro and in vivo against plant pathogenic fungi of grifolin isolated from the basidiomycete Albatrellus dispansus.

    PubMed

    Luo, Du-Qiang; Shao, Hong-Jun; Zhu, Hua-Jie; Liu, Ji-Kai

    2005-01-01

    In the course of screening for novel naturally occurring fungicides from mushrooms in Yunnan province, China, the ethanol extract of the fruiting bodies of Albatrellus dispansus was found to show antifungal activity against plant pathogenic fungi. The active compound was isolated from the fruiting bodies of A. dispansus by bioassay-guided fractionation of the extract and identified as grifolin by IR, 1H and 13C NMR and mass spectral analysis. Its antifungal activities were evaluated in vitro against 9 plant pathogenic fungi and in vivo against the plant disease of Erysiphe graminis. In vitro, Sclerotinina sclerotiorum and Fusarium graminearum were the most sensitive fungi to grifolin, and their mycelial growth inhibition were 86.4 and 80.9% at 304.9 microM, respectively. Spore germination of F. graminearum, Gloeosporium fructigenum and Pyricularia oryzae was almost completely inhibited by 38.1microM grifolin. In vivo, the curative effect of grifolin against E. graminis was 65.5% at 304.9 microM after 8 days.

  13. Influence of physical and chemical characteristics of wine grapes on the incidence of Penicillium and Aspergillus fungi in grapes and ochratoxin A in wines.

    PubMed

    Freire, Luísa; Passamani, Fabiana Reinis Franca; Thomas, Ariela Betsy; Nassur, Rita de Cássia Mirela Resende; Silva, Lais Mesquita; Paschoal, Fabiano Narciso; Pereira, Giuliano Elias; Prado, Guilherme; Batista, Luís Roberto

    2017-01-16

    The incidence of filamentous fungi and toxin levels in grapes and wines varies depending on the variety of grapes, the wine region, agricultural practices, weather conditions, the harvest and the winemaking process. In this sense, the objective of this study was to evaluate the diversity of Aspergillus and Penicillium fungi isolated from wine grapes of the semi-arid tropical region of Brazil, evaluate the presence of ochratoxin A (OTA) in the experimental wine and verify if there is a correlation between occurrence of these fungi and the physicochemical characteristics of the wine grapes grown in the region. For the isolation of fungi we used the direct plating technique. The presence of OTA in the experimental wine was detected by high-performance liquid chromatography. The species found were Aspergillus niger, A. carbonarius, A. aculeatus, A. niger Aggregate, A. flavus, A. sojae, Penicillium sclerotiorum, P. citrinum, P. glabrum, P. decumbens, P. solitum and P. implicatum. All isolates of A. carbonarius were OTA producers and all P. citrinum were citrinin producers. The highest concentration of OTA was found in red wine (0.29μg/L). All species identified in this study, except A. flavus, showed a positive correlation with at least one physicochemical parameter assessed, highlighting the pectin content, total sugar, total acidity and phenolic compounds.

  14. A Perilipin Gene from Clonostachys rosea f. Catenulata HL-1-1 Is Related to Sclerotial Parasitism

    PubMed Central

    Sun, Zhan-Bin; Li, Shi-Dong; Zhong, Zeng-Ming; Sun, Man-Hong

    2015-01-01

    Clonostachys rosea f. catenulata is a promising biocontrol agent against many fungal plant pathogens. To identify mycoparasitism-related genes from C. rosea f. catenulata, a suppression subtractive hybridization (SSH) cDNA library of C. rosea f. catenulata HL-1-1 that parasitizes the sclerotia of S. sclerotiorum was constructed. 502 clones were sequenced randomly, and thereby 472 expressed sequence tags (ESTs) were identified. Forty-three unigenes were annotated and exhibited similarity to a wide diversity of genes. Quantitative real -time PCR showed that a perilipin-like protein encoding gene, Per3, was up-regulated by 6.6-fold over the control at 96 h under the induction of sclerotia. The full-length sequence of Per3 was obtained via 5' and 3' rapid identification of cDNA ends. Overexpression of Per3 in HL-1-1 significantly enhanced the parasitic ability on sclerotia. The results indicated that Per3 might be involved in the mycoparasitism of C. rosea f. catenulata HL-1-1. This is the first report of a perilipin as a potential biocontrol gene in mycoparasites. The study provides usefu l insights into the interaction between C. rosea f. catenulata and fungal plant pathogens. PMID:25761240

  15. Multilocus Phylogeny and Antifungal Susceptibility of Aspergillus Section Circumdati from Clinical Samples and Description of A. pseudosclerotiorum sp. nov.

    PubMed

    Siqueira, J P Z; Sutton, D A; Gené, J; García, D; Wiederhold, N; Peterson, S W; Guarro, J

    2017-03-01

    A multilocus phylogenetic study was carried out to assess species identity of a set of 34 clinical isolates from Aspergillus section Circumdati from the United States and to determine their in vitro antifungal susceptibility against eight antifungal drugs. The genetic markers used were the internal transcribed spacer (ITS) region, and fragments of the beta-tubulin (BenA), calmodulin (CaM), and RNA polymerase II second largest subunit (RPB2) genes. The drugs tested were amphotericin B, itraconazole, posaconazole, voriconazole, anidulafungin, caspofungin, micafungin, and terbinafine. The most common species sampled was A. westerdijkiae (29.4%), followed by a novel species, which was described here as A. pseudosclerotiorum (23.5%). Other species identified were A. sclerotiorum (17.6%), A. ochraceus (8.8%), A. subramanianii (8.8%), and A. insulicola and A. ochraceopetaliformis, with two isolates (5.9%) of each. The drugs that showed the most potent activity were caspofungin, micafungin, and terbinafine, while amphotericin B showed the least activity.

  16. In vitro and in vivo characterization of plant growth promoting Bacillus strains isolated from extreme environments of Eastern Algeria.

    PubMed

    Ait-Kaki, Asma; Kacem-Chaouche, Noreddine; Ongena, Marc; Kara-Ali, Mounira; Dehimat, Laid; Kahlat, Karima; Thonart, Philippe

    2014-02-01

    This report is to our knowledge the first to study plant growth promotion and biocontrol characteristics of Bacillus isolates from extreme environments of Eastern Algeria. Seven isolates of 14 (50 %) were screened for their ability to inhibit growth of some phytopathogenic fungi on PDA and some roots exudates. The bacteria identification based on 16S r-RNA and gyrase-A gene sequence analysis showed that 71 % of the screened isolates belonged to Bacillus amyloliquefaciens and the rest were closely related to B. atrophaeus and B. mojavensis. Most of them had high spore yields (22 × 10(8)-27 × 10(8) spores/ml). They produced protease and cellulase cell wall-degrading enzymes while the chitinase activity was only observed in the B. atrophaeus (6SEL). A wide variety of lipopeptides homologous was detected by liquid chromatography-electrospray ionization-mass spectrometry analysis. Interestingly, some additional peaks with new masses were characterized, which may correspond to new fengycin classes. The isolates produced siderophores and indole-3- acetic acid phytohormone. The greenhouse experiment using a naturally infested soil with Sclerotonia sclerotiorum showed that the B. atrophaeus (6SEL) significantly increased the size of the chickpea plants and reduced the stem rot disease (P < 0.05). These results suggest that these isolates may be used further as bio-inoculants to improve crop systems.

  17. Detection of single copy sequences using BAC-FISH and C-PRINS techniques in sunflower chromosomes.

    PubMed

    Talia, Paola; Greizerstein, Eduardo J; Hopp, H Esteban; Paniego, Norma; Poggio, Lidia; Heinz, Ruth A

    2011-04-01

    Bacterial artificial chromosome-fluorescence in situ hybridization (BAC-FISH) and cycling-primed in situ labeling (C-PRINS) techniques were evaluated for integration of physical and genetic maps of sunflower (Helianthus annuus L.). Single-site SSR markers were selected from three linkage groups of a high-density sunflower genetic map. This selection was based on previously identified QTL associated to S. sclerotiorum. These markers were used to select BACs contaning single copy sequences for BAC-FISH aplication. Blocking of highly dispersed repetitive sunflower sequences reduced unspecific hybridization, and allowed the detection of specific signals for BACs containing SSR markers HA4222 and HA2600, anchored to LG 16 and LG 10, respectively. Single-site FISH signal detection was optimized by adjusting the relative quantity and quality of unlabelled repetitive sequences present in the blocking DNA. The SSR marker ORS1247 anchored to the LG 17 was detected by C-PRINS, which yielded fluorescence signals that were specific and intense. This progress in localizing single-copy sequences using BAC-FISH and indirect C-PRINS strategies in sunflower will facilitate the integration of genetic and physical maps, allowing the identification of chromosomes containing key genes and/or QTL associated to agronomic important traits in sunflower.

  18. Occurrence and characterization of Colletotrichum dematium (Fr.) grove.

    PubMed

    Machowicz-Stefaniak, Zofia

    2010-01-01

    Colletotrichum dematium was isolated from caraway for the first time in Poland in 2005. Isolations of this fungus were repeated in 2006 and 2007. The cultures of fungus were obtained from superficially disinfected leaves, root necks, roots, stems and umbels. The isolates were identified on culture media: PDA and malt agar with addition of pieces of caraway stems and on the base of macro and microscopic structures. Studies on the biotic effect between C. dematium and other species of phyllosphere fungi of caraway showed that the majority of the studied species limited the growth and development of C. dematium, but the size of the limiting effect was different. The species from Trichoderma and Gliocladium genera were the most effective against C. dematium, causing degeneration and lysis of hyphae and precluded the formation of the pathogen's acervuli and conidia. C. dematium in dual culture with E. purpurascens, A. radicina, S. sclerotiorum, B. cinerea and R. solani produced an inhibition zone which indicated its capacity for antibiosis.

  19. Enhancement of Seed Dehiscence by Seed Treatment with Talaromyces flavus GG01 and GG04 in Ginseng (Panax ginseng)

    PubMed Central

    Kim, Min-Jeong; Shim, Chang-Ki; Kim, Yong-Ki; Hong, Sung-Jun; Park, Jong-Ho; Han, Eun-Jung; Kim, Seok-Cheol

    2017-01-01

    Seed dehiscence of ginseng (Panax ginseng C. A. Mayer) is affected by moisture, temperature, storage conditions and microbes. Several microbes were isolated from completely dehisced seed coat of ginseng cultivars, Chunpoong and Younpoong at Gumsan, Korea. We investigated the potential of five Talaromyces flavus isolates from the dehiscence of ginseng seed in four traditional stratification facilities. The isolates showed antagonistic activities against fungal plant pathogens, such as Cylindrocarpon destructans, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia nivalis, Botrytis cinerea, and Phytophthora capsici. The dehiscence ratios of ginseng seed increased more than 33% by treatment of T. flavus GG01, GG02, GG04, GG12, and GG23 in comparison to control (28%). Among the treatments, the reformulating treatment of T. flavus isolates GG01 and GG04 showed the highest of stratification ratio of ginseng seed. After 16 weeks, the reformulating treatment of T. flavus isolates GG01 and GG04 significantly enhanced dehiscence of ginseng seed by about 81% compared to the untreated control. The candidate’s treatment of T. flavus GG01 and GG04 showed the highest decreasing rate of 93% in seed coat hardness for 112 days in dehiscence period. The results suggested that the pre-inoculation of T. flavus GG01 and GG04 found to be very effective applications in improving dehiscence and germination of ginseng seed. PMID:28167883

  20. Mating types and sexual development in filamentous ascomycetes.

    PubMed Central

    Coppin, E; Debuchy, R; Arnaise, S; Picard, M

    1997-01-01

    The progress made in the molecular characterization of the mating types in several filamentous ascomycetes has allowed us to better understand their role in sexual development and has brought to light interesting biological problems. The mating types of Neurospora crassa, Podospora anserina, and Cochliobolus heterostrophus consist of unrelated and unique sequences containing one or several genes with multiple functions, related to sexuality or not, such as vegetative incompatibility in N. crassa. The presence of putative DNA binding domains in the proteins encoded by the mating-type (mat) genes suggests that they may be transcriptional factors. The mat genes play a role in cell-cell recognition at fertilization, probably by activating the genes responsible for the hormonal signal whose occurrence was previously demonstrated by physiological experiments. They also control recognition between nuclei at a later stage, when reproductive nuclei of each mating type which have divided in the common cytoplasm pair within the ascogenous hyphae. How self is distinguished from nonself at the nuclear level is not known. The finding that homothallic species, able to mate in the absence of a partner, contain both mating types in the same haploid genome has raised more issues than it has resolved. The instability of the mating type, in particular in Sclerotinia trifolorium and Botrytinia fuckeliana, is also unexplained. This diversity of mating systems, still more apparent if the yeasts and the basidiomycetes are taken into account, clearly shows that no single species can serve as a universal mating-type model. PMID:9409146

  1. In vitro and in vivo antagonism of pathogenic turfgrass fungi by Streptomyces hygroscopicus strains YCED9 and WYE53.

    PubMed

    Chamberlain, K; Crawford, D L

    1999-07-01

    Disease prevention is a current practice used to minimize fungal diseases of turfgrasses in lawns and golf greens. Prevention is accomplished through fungicide applications, and by periodic thatch removal. During the development of a microbial biodethatch product utilizing the lignocellulose-degrading Streptomyces hygroscopicus strains YCED9 and WYE53, we demonstrated using in vitro plate antagonism bioassays that both strains are antagonists of various turfgrass fungal pathogens. These activities were present when the cultures were growing on thatch, as demonstrated by antifungal antagonism bioassays with culture filtrates. Experiments conducted using a growth chamber demonstrated that a bio-dethatch formulation containing spores of strains YCED9 and WYE53 in a zeolite carrier, provided protection for Kentucky bluegrass seedlings against turfgrass pathogens, including Pythium ultimum, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia homeocarpa, Gaeumannomyces graminis and Microdochium nivale. Results showed that by integrating the use of the S. hygroscopicus YCED9/WYE53 bio-dethatch formulation into routine turf management practices, it should be possible to both minimize thatch build-up while also controlling fungal turfgrass diseases by way of the antifungal biocontrol activity of these strains. This in turn would help control fungal pathogens in turfgrass while minimizing the need for routine chemical fungicide applications.

  2. Controlling weeds with fungi, bacteria and viruses: a review.

    PubMed

    Harding, Dylan P; Raizada, Manish N

    2015-01-01

    Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested.

  3. Linkage map construction in allotetraploid creeping bentgrass (Agrostis stolonifera L.).

    PubMed

    Chakraborty, N; Bae, J; Warnke, S; Chang, T; Jung, G

    2005-08-01

    Creeping bentgrass (Agrostis stolonifera L.) is one of the most adapted bentgrass species for use on golf course fairways and putting greens because of its high tolerance to low mowing height. It is a highly outcrossing allotetraploid species (2n=4x=28, A(2) and A(3) subgenomes). The first linkage map in this species is reported herein, and it was constructed based on a population derived from a cross between two heterozygous clones using 169 RAPD, 180 AFLP, and 39 heterologous cereal and 36 homologous bentgrass cDNA RFLP markers. The linkage map consists of 424 mapped loci covering 1,110 cM in 14 linkage groups, of which seven pairs of homoeologous chromosomes were identified based on duplicated loci. The numbering of all seven linkage groups in the bentgrass map was assigned according to common markers mapped on syntenous chromosomes of ryegrass and wheat. The number of markers linked in coupling and repulsion phase was in a 1:1 ratio, indicating disomic inheritance. This supports a strict allotetraploid inheritance in creeping bentgrass, as suggested by previous work based on chromosomal pairing and isozymes. This linkage map will assist in the tagging and eventually in marker-assisted breeding of economically important quantitative traits like disease resistance to dollar spot (Sclerotinia homoeocarpa F.T. Bennett) and brown patch (Rhizoctonia solani Kuhn).

  4. Mapping candidate QTLs related to plant persistency in red clover.

    PubMed

    Klimenko, Irina; Razgulayeva, Nadejda; Gau, Mitsuru; Okumura, Kenji; Nakaya, Akihiro; Tabata, Satoshi; Kozlov, Nicolay N; Isobe, Sachiko

    2010-04-01

    Red clover (Trifolium pratense L.) is a diploid (2n = 14), self-incompatible legume that is widely cultivated as a forage legume in cold geographical regions. Because it is a short-lived perennial species, improvement of plant persistency is the most important objective for red clover breeding. To develop a marker-assisted selection (MAS) approach for red clover, we identified candidate QTLs related to plant persistency. Two full-sib mapping populations, 272 x WF1680 and HR x R130, were used for QTL identification. Resistance to Sclerotinia trifoliorum and Fusarium species, as well as to winter hardiness, was investigated in the laboratory and in field experiments in Moscow region (Russia), and Sapporo (Japan). With the genotype data derived from microsatellite and other DNA markers, candidate QTLs were identified by simple interval mapping (SIM), Kruskal-Wallis analysis (KW analysis) and genotype matrix mapping (GMM). A total of 10 and 23 candidate QTL regions for plant persistency were identified in the 272 x WF1680 and the HR x R130 mapping populations, respectively. The QTLs identified by multiple mapping approaches were mapped on linkage group (LG) 3 and LG6. The significant QTL interactions identified by GMM explained the higher phenotypic variation than single effect QTLs. Identification of haplotypes having positive effect QTLs in each parent were first demonstrated in this study for pseudo-testcross mapping populations in plant species using experimental data.

  5. Genetic diversity and antifungal activity of native Pseudomonas isolated from maize plants grown in a central region of Argentina.

    PubMed

    Cordero, Paula; Cavigliasso, Andrea; Príncipe, Analía; Godino, Agustina; Jofré, Edgardo; Mori, Gladys; Fischer, Sonia

    2012-07-01

    Pseudomonas strains producing antimicrobial secondary metabolites play an important role in the biocontrol of phytopathogenic fungi. In this study, native Pseudomonas spp. isolates were obtained from the rhizosphere, endorhizosphere and bulk soil of maize fields in Córdoba (Argentina) during both the vegetative and reproductive stages of plant growth. However, the diversity based on repetitive-element PCR (rep-PCR) and amplified ribosomal DNA restriction analysis (ARDRA) fingerprinting was not associated with the stage of plant growth. Moreover, the antagonistic activity of the native isolates against phytopathogenic fungi was evaluated in vitro. Several strains inhibited members of the genera Fusarium, Sclerotinia or Sclerotium and this antagonism was related to their ability to produce secondary metabolites. A phylogenetic analysis based on rpoB or 16S rRNA gene sequences confirmed that the isolates DGR22, MGR4 and MGR39 with high biocontrol potential belonged to the genus Pseudomonas. Some native strains of Pseudomonas were also able to synthesise indole acetic acid and to solubilise phosphate, thus possessing potential plant growth-promoting (PGPR) traits, in addition to their antifungal activity. It was possible to establish a relationship between PGPR or biocontrol activity and the phylogeny of the strains. The study allowed the creation of a local collection of indigenous Pseudomonas which could be applied in agriculture to minimise the utilisation of chemical pesticides and fertilisers.

  6. Controlling weeds with fungi, bacteria and viruses: a review

    PubMed Central

    Harding, Dylan P.; Raizada, Manish N.

    2015-01-01

    Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested. PMID:26379687

  7. Genes Required for the Anti-fungal Activity of a Bacterial Endophyte Isolated from a Corn Landrace Grown Continuously by Subsistence Farmers Since 1000 BC

    PubMed Central

    Shehata, Hanan R.; Ettinger, Cassandra L.; Eisen, Jonathan A.; Raizada, Manish N.

    2016-01-01

    Endophytes are microbes that inhabit internal plant tissues without causing disease. Some endophytes are known to combat pathogens. The corn (maize) landrace Chapalote has been grown continuously by subsistence farmers in the Americas since 1000 BC, without the use of fungicides, and the crop remains highly valued by farmers, in part for its natural tolerance to pests. We hypothesized that the pathogen tolerance of Chapalote may, in part, be due to assistance from its endophytes. We previously identified a bacterial endophyte from Chapalote seeds, Burkholderia gladioli strain 3A12, for its ability to combat a diversity of crop pathogens, including Sclerotinia homoeocarpa, the most important fungal disease of creeping bentgrass, a relative of maize used here as a model system. Strain 3A12 represents a unique opportunity to understand the anti-fungal activities of an endophyte associated with a crop variety grown by subsistence farmers since ancient times. Here, microscopy combined with Tn5-mutagenesis demonstrates that the anti-fungal mode of action of 3A12 involves flagella-dependent swarming toward its pathogen target, attachment and biofilm-mediated microcolony formation. The mutant screen revealed that YajQ, a receptor for the secondary messenger c-di-GMP, is a critical signaling system that mediates this endophytic mobility-based defense for its host. Microbes from the traditional seeds of farmers may represent a new frontier in elucidating host–microbe mutualistic interactions. PMID:27757101

  8. Genes Required for the Anti-fungal Activity of a Bacterial Endophyte Isolated from a Corn Landrace Grown Continuously by Subsistence Farmers Since 1000 BC.

    PubMed

    Shehata, Hanan R; Ettinger, Cassandra L; Eisen, Jonathan A; Raizada, Manish N

    2016-01-01

    Endophytes are microbes that inhabit internal plant tissues without causing disease. Some endophytes are known to combat pathogens. The corn (maize) landrace Chapalote has been grown continuously by subsistence farmers in the Americas since 1000 BC, without the use of fungicides, and the crop remains highly valued by farmers, in part for its natural tolerance to pests. We hypothesized that the pathogen tolerance of Chapalote may, in part, be due to assistance from its endophytes. We previously identified a bacterial endophyte from Chapalote seeds, Burkholderia gladioli strain 3A12, for its ability to combat a diversity of crop pathogens, including Sclerotinia homoeocarpa, the most important fungal disease of creeping bentgrass, a relative of maize used here as a model system. Strain 3A12 represents a unique opportunity to understand the anti-fungal activities of an endophyte associated with a crop variety grown by subsistence farmers since ancient times. Here, microscopy combined with Tn5-mutagenesis demonstrates that the anti-fungal mode of action of 3A12 involves flagella-dependent swarming toward its pathogen target, attachment and biofilm-mediated microcolony formation. The mutant screen revealed that YajQ, a receptor for the secondary messenger c-di-GMP, is a critical signaling system that mediates this endophytic mobility-based defense for its host. Microbes from the traditional seeds of farmers may represent a new frontier in elucidating host-microbe mutualistic interactions.

  9. In vitro activity of glucosinolates and their degradation products against brassica-pathogenic bacteria and fungi.

    PubMed

    Sotelo, T; Lema, M; Soengas, P; Cartea, M E; Velasco, P

    2015-01-01

    Glucosinolates (GSLs) are secondary metabolites found in Brassica vegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about their in vitro biocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enriched Brassica crops on suppressing in vitro growth of two bacterial (Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. maculicola) and two fungal (Alternaria brassicae and Sclerotinia scletoriorum) Brassica pathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of different Brassica species, have potential to inhibit pathogen growth and offer new opportunities to study the use of Brassica crops in biofumigation for the control of multiple diseases.

  10. In Vitro Activity of Glucosinolates and Their Degradation Products against Brassica-Pathogenic Bacteria and Fungi

    PubMed Central

    Sotelo, T.; Lema, M.; Soengas, P.; Cartea, M. E.

    2014-01-01

    Glucosinolates (GSLs) are secondary metabolites found in Brassica vegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about their in vitro biocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enriched Brassica crops on suppressing in vitro growth of two bacterial (Xanthomonas campestris pv. campestris and Pseudomonas syringae pv. maculicola) and two fungal (Alternaria brassicae and Sclerotinia scletoriorum) Brassica pathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of different Brassica species, have potential to inhibit pathogen growth and offer new opportunities to study the use of Brassica crops in biofumigation for the control of multiple diseases. PMID:25362058

  11. A permeable cuticle in Arabidopsis leads to a strong resistance to Botrytis cinerea.

    PubMed

    Bessire, Michael; Chassot, Céline; Jacquat, Anne-Claude; Humphry, Matt; Borel, Sandra; Petétot, Jean Macdonald-Comber; Métraux, Jean-Pierre; Nawrath, Christiane

    2007-04-18

    The plant cuticle composed of cutin, a lipid-derived polyester, and cuticular waxes covers the aerial portions of plants and constitutes a hydrophobic extracellular matrix layer that protects plants against environmental stresses. The botrytis-resistant 1 (bre1) mutant of Arabidopsis reveals that a permeable cuticle does not facilitate the entry of fungal pathogens in general, but surprisingly causes an arrest of invasion by Botrytis. BRE1 was identified to be long-chain acyl-CoA synthetase2 (LACS2) that has previously been shown to be involved in cuticle development and was here found to be essential for cutin biosynthesis. bre1/lacs2 has a five-fold reduction in dicarboxylic acids, the typical monomers of Arabidopsis cutin. Comparison of bre1/lacs2 with the mutants lacerata and hothead revealed that an increased permeability of the cuticle facilitates perception of putative elicitors in potato dextrose broth, leading to the presence of antifungal compound(s) at the surface of Arabidopsis plants that confer resistance to Botrytis and Sclerotinia. Arabidopsis plants with a permeable cuticle have thus an altered perception of their environment and change their physiology accordingly.

  12. Assessment of toxigenic fungi on Argentinean medicinal herbs.

    PubMed

    Rizzo, Inés; Vedoya, Gabriela; Maurutto, Silvio; Haidukowski, Miriam; Varsavsky, Edith

    2004-01-01

    This work was performed to determine the incidence of toxigenic fungi and their mycotoxins on 152 dried medicinal and aromatic herbs, belonging to 56 species, which are used as raw material for drugs. International methodologies for fungal enumeration and identification were applied as well as TLC and HPLC techniques for toxins detection. The 52% out of 152 samples were contaminated with species from Aspergillus genus, 27% belonging to the Flavi section and 25% to the Circumdati section. The 16% of the total samples was contaminated with species from Fusarium genus. Aspergillus flavus and A. parasiticus (Flavi section), were the predominant species isolated, 50% out of 40 isolates were toxigenic. Aflatoxin concentrations ranged from 10 to 2000 ng/g. Only 26% of isolates from the Circumdati section (A. alliaceus, A. ochraceus and A. sclerotiorum) produced ochratoxin A in low concentrations between 0.12 and 9 ng/g. From a total of 29 strains of Fusarium spp., 27.5% were Fusarium verticillioides and F. proliferatum, which produced fumonisin Bland fumonisin B2 ranged from 20 to 22000 microg/g and from 5 to 3000 microg/g respectively. The remaining species, F. equiseti, F. oxysporum, F. semitectum, F. compactum, F. sombucinum and F. solani were able to produce neither group A and B trichothecenes nor zearalenone. The incidence of A. ochraceus and Fusarium spp. and their toxigenic capacities on medicinal herbs were studied for the first time in Argentina. It would be important to look for natural contamination to define acceptability Limits which allow the control of sanitary quality of medicinal herbs used as phytotherapic medicines in several countries.

  13. Isolation, identification and toxigenic potential of ochratoxin A-producing Aspergillus species from coffee beans grown in two regions of Thailand.

    PubMed

    Noonim, Paramee; Mahakarnchanakul, Warapa; Nielsen, Kristian F; Frisvad, Jens C; Samson, Robert A

    2008-12-10

    In 2006 and 2007, 32 Thai dried coffee bean samples (Coffea arabica) from two growing sites of Chiang Mai Province, and 32 Thai dried coffee bean samples (Coffea canephora var. robusta) from two growing sites of Chumphon Province, Thailand, were collected and assessed for the distribution of fungi with the potential to produce ochratoxin A (OTA). The overall percentage of fungal contamination in coffee was 98% and reduced to 60% after surface disinfection. There were remarkable ecological differences in the composition of ochratoxigenic species present in these two regions. Arabica coffee bean samples from the North had an average of 78% incidence of colonization with Aspergillus of section Circumdati with Aspergillus westerdijkiae and A. melleus as the predominant species. Aspergillus spp. of section Nigri were found in 75% of the samples whereas A. ochraceus was not detected. Robusta coffee beans from the South were 98-100% contaminated with predominantly A. carbonarius and A. niger. A. westerdijkiae was only found in one sample. The diversity of the fungal population was probably correlated with the geographical origin of the coffee, coffee cultivar, and processing method. Representative isolates of section Circumdati (52) and Nigri (82) were examined for their OTA production using HPLC with fluorescence detection. Aspergillus westerdijkiae (42 isolates out of 42), A. steynii (13/13), and A. carbonarius (35/35) in general produced large amounts of OTA, while one isolate of A. sclerotiorum produced intermediate amounts of OTA. 13% of the A. niger isolates produced OTA in intermediate amounts. OTA levels in coffee bean samples were analyzed using the Ridascreen OTA ELISA kits. Of the 64 coffee bean samples analyzed, 98% were contaminated with OTA in levels of <0.6-5.5 microg/kg (Arabica) and 1-27 microg/kg (Robusta). Presence of OTA in representative coffee samples was also confirmed by LC-MS/MS after ion-exchange purification.

  14. Mapping QTL for dollar spot resistance in creeping bentgrass (Agrostis stolonifera L.).

    PubMed

    Chakraborty, N; Curley, J; Warnke, S; Casler, M D; Jung, G

    2006-11-01

    Dollar spot caused by Sclerotinia homoeocarpa F. T. Bennett is the most economically important turf disease on golf courses in North America. Dollar spot resistance in a creeping bentgrass cultivar would greatly reduce the frequency, costs, and environmental impacts of fungicide application. Little work has been done to understand the genetics of resistance to dollar spot in creeping bentgrass. Therefore, QTL analysis was used to determine the location, number and effects of genomic regions associated with dollar spot resistance in the field. To meet this objective, field inoculations using a single isolate were performed over 2 years and multiple locations using progeny of a full sib mapping population '549 x 372'. Dollar spot resistance seems to be inherited quantitatively and broad sense heritability for resistance was estimated to be 0.88. We have detected one QTL with large effect on linkage group 7.1 with LOD values ranging from 3.4 to 8.6 and explaining 14-36% of the phenotypic variance. Several smaller effect QTL specific to rating dates, locations and years were also detected. The association of the tightly linked markers with the LG 7.1 QTL based on 106 progeny was further examined by single marker analysis on all 697 progeny. The high significance of the QTL on LG 7.1 at a sample size of 697 (P < 0.0001), along with its consistency across locations, years and ratings dates, indicated that it was stable over environments. Markers tightly linked to the QTL can be utilized for marker-assisted selection in future bentgrass breeding programs.

  15. Allelopathic effect of new introduced biofuel crops on the soil biota: A comparative study

    NASA Astrophysics Data System (ADS)

    Heděnec, Petr; Frouz, Jan; Ustak, Sergej; Novotny, David

    2015-04-01

    Biofuel crops as an alternative to fossil fuels are a component of the energy mix in many countries. Many of them are introduced plants, so they pose a serious threat of biological invasions. Production of allelopathic compounds can increase invasion success by limiting co-occurring species in the invaded environment (novel weapons hypothesis). In this study, we focused on plant chemistry and production of allelopathic compounds by biofuel crops (hybrid sorrel Rumex tianschanicus x Rumex patientia and miscanthus Miscanthus sinensis) in comparison with invasive knotweed (Fallopia sachalinensis) and cultural meadow species. First, we tested the impact of leachates isolated from hybrid sorrel, miscanthus, knotweed and cultural meadow species compared to deionized water, used as a control, on seed germination of mustard (Sinapis arvensis) and wheat (Triticum aestivum) cultivated on sand and soil. Secondly, we studied the effect of leachates on the growth of soil fungal pathogens Fusarium culmorum, Rhizoctonia solani, Sclerotinia solani and Cochliobolus sativus. Finally, we tested the effect of litter of hybrid sorrel, miscanthus, knotweed and cultural meadow litter mixed with soil on population growth of Enchytraeus crypticus and Folsomia candida. Miscanthus and knotweed litter had a higher C:N ratio than the control meadow and hybrid sorrel litter. Miscanthus and hybrid sorrel litter had a higher content of phenols than knotweed and cultural meadow litter. Leachates from hybrid sorrel, miscanthus and knotweed biomass significantly decreased seed germination of wheat and mustard in both substrates. Soil fungal pathogens grew less vigorously on agar enriched by leachates from both biofuel crops than on agar enriched by knotweed and leachates. Litter from hybrid sorrel, miscanthus and knotweed significantly altered (both ways) the population growth of the soil mesofauna.

  16. Using RADARSAT-2 and TerraSAR-X satellite data for the identification of canola crop phenology

    NASA Astrophysics Data System (ADS)

    Pacheco, Anna; McNairn, Heather; Li, Yifeng; Lampropoulos, George; Powers, Jarrett

    2016-10-01

    Knowing the exact growth stage of agricultural crops can be valuable information for crop management and monitoring. In Canada, canola fields are particularly vulnerable for crop disease development during their flowering stage, especially when the fields are under persistent wet conditions. Clubroot and sclerotinia are diseases that can occur in canola when these two factors come together. Remote sensing can provide an interesting tool for the monitoring of crop phenological stages over large agriculture landscapes. Reliable and frequent access to data is needed to determine field-specific growth stages. Given their all-weather capability, radar sensors are optimal for monitoring such a dynamic crop parameter. In 2014, Agriculture and Agri-Food Canada collected crop phenology information over multiple canola fields in the area of Carman, Manitoba. Coincidental to ground data collection, fully polarimetric RADARSAT-2 and dual-polarimetric TerraSAR-X satellite data were acquired over the study site. In collaboration with A. U. G. Signals Ltd., a methodology will be developed and validated for the identification of inflorescence emergence and flowering in canola fields. Analysis of the polarimetric datasets from this study determined that several polarimetric parameters were sensitive to the emergence of flower buds and the flowering stage in canola. The alpha angle and entropy in both the C- and X-band were able to identify these growth stages, in addition to any of the reflectivity ratios and differential reflectivity responses that incorporated an HV response. The RADARSAT-2 scatter diversity, degree of purity and depolarization index also demonstrated great potential at identifying canola flower emergence and flowering. These latter polarimetric parameters along with the reflectivity ratios may be advantageous given their ease in implementation within a larger risk assessment satellite-derived methodology for canola crop disease.

  17. Comparison of lettuce diseases and yield under subsurface drip and furrow irrigation.

    PubMed

    Subbarao, K V; Hubbard, J C; Schulbach, K F

    1997-08-01

    ABSTRACT Subsurface drip and furrow irrigation were compared on lettuce (Lactuca sativa) cvs. Salinas and Misty Day for yield and incidence and severity of three important diseases of lettuce in the Salinas Valley, CA. Experiments were conducted between 1993 and 1995 during the spring and fall seasons. The diseases examined included lettuce drop (Sclerotinia minor), downy mildew (Bremia lactucae), and corky root (Rhizomonas suberifaciens). Replicated plots of subsurface drip and furrow irrigation were arranged in a randomized complete-block design. All plants were inoculated with S. minor at the initiation of the experiment during the 1993 spring season. Plots were not inoculated for downy mildew and corky root during any season nor were the plots reinoculated with S. minor. During each season, all plots were sprinkler irrigated until thinning, and subsequently, the irrigation treatments were begun. The furrow plots were irrigated once per week, and the drip plots received water twice per week. The distribution of soil moisture at two soil depths (0 to 5 and 6 to 15 cm) at 5, 10, and 15 cm distance on either side of the bed center in two diagonal directions was significantly lower in drip-irrigated compared with furrow-irrigated plots. Plots were evaluated for lettuce drop incidence and downy mildew incidence and severity at weekly intervals until harvest. Corky root severity and yield components were determined at maturity. Lettuce drop incidence and corky root severity were significantly lower and yields were higher in plots under subsurface drip irrigation compared with furrow irrigation, regardless of the cultivar, except during the 1994 fall season. Incidence and severity of downy mildew were not significantly different between the two irrigation methods throughout the study. The differential microclimates created by the two irrigation treatments did not affect downy mildew infection, presumably because the mesoclimate is usually favorable in the Salinas

  18. Ochratoxin production and taxonomy of the yellow aspergilli (Aspergillus section Circumdati)

    PubMed Central

    Visagie, C.M.; Varga, J.; Houbraken, J.; Meijer, M.; Kocsubé, S.; Yilmaz, N.; Fotedar, R.; Seifert, K.A.; Frisvad, J.C.; Samson, R.A.

    2014-01-01

    Aspergillus section Circumdati or the Aspergillus ochraceus group, includes species with rough walled stipes, biseriate conidial heads, yellow to ochre conidia and sclerotia that do not turn black. Several species are able to produce mycotoxins including ochratoxins, penicillic acids, and xanthomegnins. Some species also produce drug lead candidates such as the notoamides. A polyphasic approach was applied using morphological characters, extrolite data and partial calmodulin, β-tubulin and ITS sequences to examine the evolutionary relationships within this section. Based on this approach the section Circumdati is revised and 27 species are accepted, introducing seven new species: A. occultus, A. pallidofulvus, A. pulvericola, A. salwaensis, A. sesamicola, A. subramanianii and A. westlandensis. In addition we correctly apply the name A. fresenii (≡ A. sulphureus (nom. illeg.)). A guide for the identification of these 27 species is provided. These new species can be distinguished from others based on morphological characters, sequence data and extrolite profiles. The previously described A. onikii and A. petrakii were found to be conspecific with A. ochraceus, whilst A. flocculosus is tentatively synonymised with A. ochraceopetaliformis, despite extrolite differences between the two species. Based on the extrolite data, 13 species of section Circumdati produce large amounts of ochratoxin A: A. affinis, A. cretensis, A. fresenii, A. muricatus, A. occultus, A. ochraceopetaliformis (A. flocculosus), A. ochraceus, A. pseudoelegans, A. pulvericola, A. roseoglobulosus, A. sclerotiorum, A. steynii and A. westerdijkiae. Seven additional species produce ochratoxin A inconsistently and/or in trace amounts: A. melleus, A. ostianus, A. persii, A. salwaensis, A. sesamicola, A. subramanianii and A. westlandensis. The most important species regarding potential ochratoxin A contamination in agricultural products are A. ochraceus, A

  19. A Meta-Analysis of the Impact of Anaerobic Soil Disinfestation on Pest Suppression and Yield of Horticultural Crops

    PubMed Central

    Shrestha, Utsala; Augé, Robert M.; Butler, David M.

    2016-01-01

    Anaerobic soil disinfestation (ASD) is a proven but relatively new strategy to control soil borne pests of horticultural crops through anaerobic decomposition of organic soil amendments. The ASD technique has primarily been used to control soil borne pathogens; however, this technique has also shown potential to control plant parasitic nematodes and weeds. ASD can utilize a broad range of carbon (C) amendments and optimization may improve efficacy across environments. In this context, a meta-analysis using a random-effects model was conducted to determine effect sizes of the ASD effect on soil borne pathogens (533 studies), plant parasitic nematodes (91 studies), and weeds (88 studies) compared with unamended controls. Yield response to ASD was evaluated (123 studies) compared to unamended and fumigated controls. We also examined moderator variables for environmental conditions and amendments to explore the impact of these moderators on ASD effectiveness on pests and yield. Across all pathogen types with the exception of Sclerotinia spp., ASD studies show suppression of bacterial, oomycete and fungal pathogens (59 to 94%). Pathogen suppression was effective under all environmental conditions (50 to 94%) and amendment types (53 to 97%), except when amendments were applied at rates less than 0.3 kg m-2. The ASD effect ranged from 15 to 56% for nematode suppression and 32 to 81% for weed suppression, but these differences were not significant. Significant nematode moderators included study type, soil type, sampling depth, incubation period, and use of mixed amendments. Weed suppression due to ASD showed significant heterogeneity for all environmental conditions, confirming that these studies do not share a common effect size. Total crop yield was not reduced by ASD when compared to a fumigant control and yield was significantly higher (30%) compared to an unamended control, suggesting ASD as a feasible option to maintain yield without chemical soil fumigants. We

  20. A Meta-Analysis of the Impact of Anaerobic Soil Disinfestation on Pest Suppression and Yield of Horticultural Crops.

    PubMed

    Shrestha, Utsala; Augé, Robert M; Butler, David M

    2016-01-01

    Anaerobic soil disinfestation (ASD) is a proven but relatively new strategy to control soil borne pests of horticultural crops through anaerobic decomposition of organic soil amendments. The ASD technique has primarily been used to control soil borne pathogens; however, this technique has also shown potential to control plant parasitic nematodes and weeds. ASD can utilize a broad range of carbon (C) amendments and optimization may improve efficacy across environments. In this context, a meta-analysis using a random-effects model was conducted to determine effect sizes of the ASD effect on soil borne pathogens (533 studies), plant parasitic nematodes (91 studies), and weeds (88 studies) compared with unamended controls. Yield response to ASD was evaluated (123 studies) compared to unamended and fumigated controls. We also examined moderator variables for environmental conditions and amendments to explore the impact of these moderators on ASD effectiveness on pests and yield. Across all pathogen types with the exception of Sclerotinia spp., ASD studies show suppression of bacterial, oomycete and fungal pathogens (59 to 94%). Pathogen suppression was effective under all environmental conditions (50 to 94%) and amendment types (53 to 97%), except when amendments were applied at rates less than 0.3 kg m(-2). The ASD effect ranged from 15 to 56% for nematode suppression and 32 to 81% for weed suppression, but these differences were not significant. Significant nematode moderators included study type, soil type, sampling depth, incubation period, and use of mixed amendments. Weed suppression due to ASD showed significant heterogeneity for all environmental conditions, confirming that these studies do not share a common effect size. Total crop yield was not reduced by ASD when compared to a fumigant control and yield was significantly higher (30%) compared to an unamended control, suggesting ASD as a feasible option to maintain yield without chemical soil fumigants. We

  1. Properties, origin and nomenclature of rodlets of the inertinite maceral group in coals of the central Appalachian basin, U.S.A.

    USGS Publications Warehouse

    Lyons, P.C.; Finkelman, R.B.; Thompson, C.L.; Brown, F.W.; Hatcher, P.G.

    1982-01-01

    cross sections and many are characterized by dense (probably oxidized) rims. The orientation and amounts of void space and mineralization of resin rodlets in coal have resulted in much confusion in their recognition and classification. The resin rodlets are petrographically recognized as sclerotinites of the inertinite maceral group. We here propose that resin rodlets be assigned to the maceral variety of sclerotinites termed "resino-sclerotinite" because of their presumable resinous origin. Other investigators have confused some fusinitized resin rodlets with fungal masses, which have different morphological properties and which probably have different chemical properties. We here propose that such fungal masses be assigned to the maceral variety of sclerotinites termed "fungo-sclerotinite.". The sclerenchyma strands examined in our study are cellular, thick-walled, and crescent-shaped in cross section. They exhibit high reflectance and high relief and belong to semifusinite and fusinite of the inertinite maceral group. Sclerenchyma strands are commonly associated with resin canals in Medullosa and related seed-fern genera, which are common in coal balls of the Illinois basin. We here propose adoption of the maceral varietal terms "sclerenchymo-fusinite" and "sclerenchymo-semifusinite" for these bodies. The woody splinters in the Pomeroy coal bed are cellular and thin-walled and have scattered pits as much as a few microns in diameter. They are dark brown to black in transmitted light and commonly have a lower reflectance than the resino-sclerotinite and sclerenchymo-fusinite of the Pomeroy coal. The woody splinters belong to semifusinite and fusinite of the inertinite maceral group. The maceral varietal terms "xylemo-semifusinite" and "xylemo-fusinite" are here proposed for these bodies. Elemental chemical data for the resin rodlets of the Pomeroy coal bed of the central Appalachian basin indicate that resin rodlets have significantly lower atomic H/C and O/C ratio