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Wei Qian - One of the best experts on this subject based on the ideXlab platform.
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identification of genomic regions involved in resistance against Sclerotinia sclerotiorum from wild brassica oleracea
Theoretical and Applied Genetics, 2013Co-Authors: Yijuan Ding, Kun Lu, Joseph Onwusemu Disi, Jiana Li, John K Mckay, Wei QianAbstract: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.
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identification of genomic regions involved in resistance against Sclerotinia sclerotiorum from wild brassica oleracea
Theoretical and Applied Genetics, 2013Co-Authors: Jiaqin Mei, Yijuan Ding, Joseph Onwusemu Disi, John K Mckay, Dayong Wei, Yao Liu, Liezhao Liu, Shengyi Liu, Wei QianAbstract: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.
Da Xing - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Manipulation of the Xanthophyll Cycle Increases Plant Susceptibility to Sclerotinia
2016Co-Authors: Jun Zhou, Lizhang Zeng, Jian Liu, Da XingAbstract:The xanthophyll cycle is involved in dissipating excess light energy to protect the photosyn-thetic 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. Incuba-tion of Sclerotinia led to a localized increase in NPQ even at low light intensity. Further stud-ies showed that this abnormal change in NPQwas 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. Further-more, suppression (with dithiothreitol) or a defect (in the npq1-2mutant) 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. Immunoas-says revealed that the decrease in these xanthophyll precursors reduced de novo abscisic acid (ABA) biosynthesis and apparently weakened tissue defense responses, includin
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manipulation of the xanthophyll cycle increases plant susceptibility to Sclerotinia sclerotiorum
PLOS Pathogens, 2015Co-Authors: Jun Zhou, Lizhang Zeng, Da XingAbstract: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.
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Pigment composition of Sclerotinia-infected plants.
2015Co-Authors: Jun Zhou, Lizhang Zeng, Jian Liu, Da XingAbstract:Four-week-old Arabidopsis leaves were inoculated with Sclerotinia for 3 h and kept under a light intensity of 130 μmol m-2 s-1. Xanthophylls were subjected to HPLC analysis after extraction with pre-cooled acetone. Pigment content was normalized to 100 Chl a+b molecules, except for Chl a/b. Abbreviations: Vio, violaxanthin; Ant, antheraxanthin; Zea, zeaxanthin; Neo, neoxanthin; Lut, lutein; ND, not detectable. Data shown are means ± SE (n = 3).Pigment composition of Sclerotinia-infected plants.
Berlin D. Nelson - One of the best experts on this subject based on the ideXlab platform.
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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
Journal of virology, 2015Co-Authors: Shin-yi Lee Marzano, Glen L Hartman, Houston A. Hobbs, Berlin D. Nelson, Darin M. Eastburn, Nancy K. Mccoppin, Leslie L. DomierAbstract: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 Koch9s 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 hypovirus infections and hypovirulence in S. sclerotiorum were lacking. By establishing a cause-and-effect relationship between Sclerotinia sclerotiorum hypovirus Lactuca (SsHV2L) infection and the reduction in host virulence, we showed direct evidence that hypoviruses have the potential to reduce the severity of white mold disease. In addition to intraspecific recombination, this study showed that recent interspecific recombination is an important factor shaping viral genomes. The construction of an infectious clone of SsHV2L allows future exploration of the interactions between SsHV2L and S. sclerotiorum, a widespread fungal pathogen of plants.
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Sclerotinia sclerotiorum lib de bary biology and molecular traits of a cosmopolitan pathogen
Molecular Plant Pathology, 2006Co-Authors: Melvin D Bolton, Bart P H J Thomma, Berlin D. NelsonAbstract:Sclerotinia sclerotiorum (Lib.) de Bary is a necrotrophic fungal pathogen causing disease in a wide range of plants. This review summarizes current knowledge of mechanisms employed by the fungus to parasitize its host with emphasis on biology, physiology and molecular aspects of pathogenicity. In addition, current tools for research and strategies to combat S. sclerotiorum are discussed. Taxonomy: Sclerotinia sclerotiorum (Lib.) de Bary: kingdom Fungi, phylum Ascomycota, class Discomycetes, order Helotiales, family Sclerotiniaceae, genus Sclerotinia. Identification: Hyphae are hyaline, septate, branched and multinucleate. Mycelium may appear white to tan in culture and in planta. No asexual conidia are produced. Long-term survival is mediated through the sclerotium; a pigmented, multi-hyphal structure that can remain viable over long periods of time under unfavourable conditions for growth. Sclerotia can germinate to produce mycelia or apothecia depending on environmental conditions. Apothecia produce ascospores, which are the primary means of infection in most host plants. Host range: S. sclerotiorum is capable of colonizing over 400 plant species found worldwide. The majority of these species are dicotyledonous, although a number of agriculturally significant monocotyledonous plants are also hosts. Disease symptoms: Leaves usually have water-soaked lesions that expand rapidly and move down the petiole into the stem. Infected stems of some species will first develop dark lesions whereas the initial indication in other hosts is the appearance of water-soaked stem lesions. Lesions usually develop into necrotic tissues that subsequently develop patches of fluffy white mycelium, often with sclerotia, which is the most obvious sign of plants infected with S. sclerotiorum.
Jun Zhou - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH ARTICLE Manipulation of the Xanthophyll Cycle Increases Plant Susceptibility to Sclerotinia
2016Co-Authors: Jun Zhou, Lizhang Zeng, Jian Liu, Da XingAbstract:The xanthophyll cycle is involved in dissipating excess light energy to protect the photosyn-thetic 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. Incuba-tion of Sclerotinia led to a localized increase in NPQ even at low light intensity. Further stud-ies showed that this abnormal change in NPQwas 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. Further-more, suppression (with dithiothreitol) or a defect (in the npq1-2mutant) 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. Immunoas-says revealed that the decrease in these xanthophyll precursors reduced de novo abscisic acid (ABA) biosynthesis and apparently weakened tissue defense responses, includin
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manipulation of the xanthophyll cycle increases plant susceptibility to Sclerotinia sclerotiorum
PLOS Pathogens, 2015Co-Authors: Jun Zhou, Lizhang Zeng, Da XingAbstract: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.
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Pigment composition of Sclerotinia-infected plants.
2015Co-Authors: Jun Zhou, Lizhang Zeng, Jian Liu, Da XingAbstract:Four-week-old Arabidopsis leaves were inoculated with Sclerotinia for 3 h and kept under a light intensity of 130 μmol m-2 s-1. Xanthophylls were subjected to HPLC analysis after extraction with pre-cooled acetone. Pigment content was normalized to 100 Chl a+b molecules, except for Chl a/b. Abbreviations: Vio, violaxanthin; Ant, antheraxanthin; Zea, zeaxanthin; Neo, neoxanthin; Lut, lutein; ND, not detectable. Data shown are means ± SE (n = 3).Pigment composition of Sclerotinia-infected plants.
Damon L Smith - One of the best experts on this subject based on the ideXlab platform.
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An overview of the Sclerotinia sclerotiorum pathosystem in soybean: impact, fungal biology, and current management strategies
Tropical Plant Pathology, 2019Co-Authors: Jaime Willbur, Megan Mccaghey, Mehdi Kabbage, Damon L SmithAbstract:Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum , is one of the most important diseases of soybean. Disease management is complicated by the long-term survival of sclerotia in the soil and the absence of resistance in elite, commercial cultivars. Furthermore, the lifecycle of S. sclerotiorum in soybean fields is highly dependent on weather conditions, leading to a highly sporadic occurrence of the disease over seasons and an aggregated distribution within fields. Management relies on a multi-pronged approach of combining partially resistant cultivars with cultural practices, such as altering row spacing and planting population, along with chemical control. These control measures are constrained by economic trade-offs, incomplete efficacy of chemicals, and a lack of understanding of application timing for fungicides. Newer tools have been developed to improve management, such as disease prediction models that can assist farmers in making decisions about fungicide application. This review aims to introduce the Sclerotinia pathosystem in soybean, while covering the complicated biology of S. sclerotiorum that leads to the need for integrated management by soybean farmers.
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comprehensive Sclerotinia stem rot screening of soybean germplasm requires multiple isolates of Sclerotinia sclerotiorum
Plant Disease, 2017Co-Authors: Jaime Willbur, C R Grau, Mehdi Kabbage, Shunping Ding, Michelle Marks, H Lucas, Carol L Groves, Damon L SmithAbstract:Sclerotinia sclerotiorum population variability directly affects Sclerotinia stem rot (SSR) resistance breeding programs. In the north-central United States, however, soybean germplasm selection has often involved only a single isolate. Forty-four S. sclerotiorum isolates from Illinois, Michigan, Minnesota, Nebraska, Wisconsin, Poland, and across 11 different host species were evaluated for variation in isolate in vitro growth, in vitro oxalate production, and in planta aggressiveness on the susceptible soybean ‘Williams 82’. Significant differences (P < 0.0001) were detected in isolate in planta aggressiveness, in vitro growth, and in vitro oxalate production. Furthermore, diverse isolate characteristics were observed within all hosts and locations of collection. Aggressiveness was not correlated to colony growth and was only weakly correlated (r = 0.26, P < 0.0001) to isolate oxalate production. In addition, the host or location of collection did not explain isolate aggressiveness. Isolate oxalic acid p...
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discriminatory simplex and multiplex pcr for four species of the genus Sclerotinia
Journal of Microbiological Methods, 2013Co-Authors: Ahmed Abdelmagid, Damon L Smith, Patricia Garrido, R M Hunger, Justin L Lyles, Michele A Mansfield, Beth K Gugino, Hassan A Melouk, Carla D GarzonAbstract: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.
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evaluation of application timing and efficacy of the fungicides fluazinam and boscalid for control of Sclerotinia blight of peanut
Crop Protection, 2008Co-Authors: Damon L Smith, T G Isleib, J. E. Hollowell, M C Garrison, B B ShewAbstract:Abstract Sclerotinia blight of peanut ( Arachis hypogaea ) is caused by the soilborne fungus Sclerotinia minor. Management of Sclerotinia blight of peanut requires an integrated approach that includes rotation with non-hosts, resistant cultivars, cultural practices, and fungicides. Greenhouse experiments compared fluazinam and boscalid and investigated pre- and post-inoculation applications of fungicide or no fungicide to control infections by S. minor . Significant reductions in successful infections in the greenhouse occurred when fungicide was applied prior to, or up to 2 d after, inoculation, but not when applied 4 d after inoculation. Field experiments were conducted from 2004 to 2006 to investigate the comparative efficacy of the fungicides fluazinam and boscalid using alternating sequences of those fungicides or no fungicide for each of three sprays per season. In the field, applications of fungicide that preceded the largest incremental increase in disease incidence provided the best control of disease or increased yield. In both the field and greenhouse studies boscalid performed marginally better than fluazinam. Disease advisories or intensive scouting should be used to determine when epidemics initiate so that a fungicide can be applied prior to infection.
