With the development of tourism at home and abroad,Rapeseed(Brassica napus)has become an important ornamental plant.However,its ornamental value at the inflorescence stage is greatly reduced by Sclerotinia sclerotioru...With the development of tourism at home and abroad,Rapeseed(Brassica napus)has become an important ornamental plant.However,its ornamental value at the inflorescence stage is greatly reduced by Sclerotinia sclerotiorum.Identification of important genes in the defense responses is critical for molecular breeding,which is an important strategy for controlling the disease.In this study,we isolated a B.napus WRKY transcription factor gene,BnaWRKY75.BnaWRKY75 was found to encode a nucleus-localized protein and exhibited relatively high expression in the stems.Arabidopsis thaliana transgenic plants expressing BnaWRKY75 showed enhanced resistance to S.sclerotiorum,and both ProBnaWRKY75:GUS and gene expression analyses showed that BnaWRKY75 was highly responsive to S.sclerotiorum infection,indicating the involvement of BnaWRKY75 in response to this infection.Furthermore,overexpression(OE)of BnaWRKY75 in B.napus significantly enhanced the resistance to S.sclerotiorum,whereas the resistance was reduced in RNAi transgenic B.napus plants.Moreover,the BnaWRKY75-OE B.napus plants exhibited constitutive activation of salicylic acid-,jasmonic acid-,and ethylene-mediated defense responses and the inhibition of both H_(2)O_(2)and O_(2)·^(-)accumulation in response to this pathogen.By contrast,BnaWRKY75-RNAi plants showed a reverse pattern,suggesting that BnaWRKY75 is involved in hormonal signaling pathways and in the control of reactive oxygen species accumulation.In conclusion,these data indicate that BnaWRKY75,a regulator of multiple defense responses,positively regulates resistance against S.sclerotiorum,which may guide the improvement of resistance in rapeseed.展开更多
The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. scleroti...The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. sclerotiorum degrades cellulose remain elusive. Here, we unveil a novel secretory cellobiohydrolase, SsdchA, characterized by a signal peptide and a Glyco_hydro_7(GH7) domain. SsdchA exhibits a robust expression of during early infection stages. Interestingly, colony morphology and growth rates remain unaffected across the wild-type, SsdchA deletion strains and SsdchA overexpression strains on potato dextrose agar(PDA) medium. Nevertheless, the pathogenicity and cellobiohydrolase activity decreased in the SsdchA deletion strains, but enhanced in the SsdchA overexpression strains. Moreover,the heterologous expression of SsdchA in Arabidopsis thaliana leads to reduced cellulose content and heightened susceptibility to S. sclerotiorum. Collectively, our data underscore the pivotal role of the novel cellobiohydrolase SsdchA in the pathogenicity of S. sclerotiorum.展开更多
White mold of pea caused by Sclerotinia sclerotiorum is a common disease in China.However,we discovered that the diverse Sclerotinia species could cause white mold on pea plants in Chongqing and Sichuan of China durin...White mold of pea caused by Sclerotinia sclerotiorum is a common disease in China.However,we discovered that the diverse Sclerotinia species could cause white mold on pea plants in Chongqing and Sichuan of China during recent disease surveys.Thus,the objective of this study was to confirm the causal agents from diseased pea plants.The obtained isolates of white mold from Chongqing and Sichuan were identified by morphological characters and molecular characterization to determine the pathogen species,and their pathogenicity was confirmed on pea through completing Koch’s postulates.Fungal isolates of Sclerotinia-like were obtained from diseased plants or sclerotia.Based on morphological characteristics and molecular characterization,30 isolates were identified to three species,six isolates as S.minor,seven as S.sclerotiorum,and 17 as S.trifoliorum.In pathogenicity tests on pea cultivars Zhongwan 4 and Longwan 1,all 30 isolates caused typical symptoms of white mold on the inoculated plants,and the inoculated pathogens were re-isolated from the diseased plants.This study confirmed that white mold of pea was caused by three Sclerotinia species,S.sclerotiorum,S.minor and S.trifoliorum in Chongqing and Sichuan.It is the first report that S.minor and S.trifoliorum cause white mold of pea in Southwest China.展开更多
[Objective] The study was to investigate roles of Brassica napus EINB in （ BnEIN3 ） resistance to Sclerotinia sclerotiorum. [ Methods] Genomic PCR and RT-PCR were carded out to isolate genomic DNA and cDNA sequences...[Objective] The study was to investigate roles of Brassica napus EINB in （ BnEIN3 ） resistance to Sclerotinia sclerotiorum. [ Methods] Genomic PCR and RT-PCR were carded out to isolate genomic DNA and cDNA sequences of BnEIN3 from oilseed rape, based on the highly conserved region of EIN3 gene from Arabidopsis thaliana and the homologous sequences of oilseed rape ESTs. Expression levels of BnEIN3 were detected in three varieties of oilseed rape inoculated with S. sclerotiorum by real-time quantitative PCR.[Results] A 1 947 bp DNA fragment was obtained from oilseed rape. The fragment shared 82% identity to A. thaliana EIIV3, encoded 614 amino acids containing an EIN3 domain, and was named as BnEIN3. Real-time PCR results showed that expression patterns of BnEIN3 were drastically different in different varieties. In highly resistant oilseed rape variety D083, BnEIN3 expression level was significantly increased 72 h after S. sclerotiorum inoculation whereas in middle resistant and susceptible varieties Zhongshuang 9 and 84039, BnEIN3 expression was suppressed. [ Conclusion ] BnEIIV3 may play an important role in oilseed rape resistance to S. sclerotiorum.展开更多
[ Objective] The paper was to study ISSR molecular makers of resistant gene against Sclerotinia trifoliorum in Medicago sativa L. [ Method] Using mi- crosatellite markers （ISSR） molecular maker technology, combined ...[ Objective] The paper was to study ISSR molecular makers of resistant gene against Sclerotinia trifoliorum in Medicago sativa L. [ Method] Using mi- crosatellite markers （ISSR） molecular maker technology, combined with bulked-segregant analysis （BSA） method, the molecular makers for gene linkage with re- sistance against S. trifoliorum were screened from five resistant plants and seven susceptible plants. Leaf in vitro inoculation method was used to carry out resistant verification on 94 hybrid plants in Ft generation of high resistant No. 83 ~ high susceptible No. 4. [ Result] Among 93 ISSR primers, 35 primers could produce clear and stable amplification bands, and six of them could produce 9 specific bands between resistant and susceptible DNA pools. Resistance verification result showed that 825 - 1400, 831 - 1480, 850 - 1800, 858 - 1600, 866 - 1900, 888 - 1400 could be used as ISSR molecular makers of the resistant gene against S. trifoliorum in M. sativa. [Conclusion] The results provided basis for the further research on mapping,, cloning and genetically modified of resistant gene against S. trifoliorum in M. sativa.展开更多
Zhongshuang9, a new semi-winter Brassica napus variety with high resistance to Sclerotinia sclerotiorum and lodging, high-yield, double-low quality and extensive adaptability, was bred by multiple crossing and microsp...Zhongshuang9, a new semi-winter Brassica napus variety with high resistance to Sclerotinia sclerotiorum and lodging, high-yield, double-low quality and extensive adaptability, was bred by multiple crossing and microspore culture technique. It was registered and released in China in 2002. In regional trial of Hubei Province in China, Zhongshuang9 yielded 2 482. 2 kg ha-1 averagely in 2000 - 2002, 15. 33% higher than the control variety Zhongyou821. Erucic acid, glucosinolates and oil contents of Zhongshuang9 were 0.23%, 22.69 μmol g-1(in meal)and 42%, respectively. In field assessment of resistance to S. Sclerotiorum , the disease incidence and disease index of Zhongshuang9 averaged 13.31 % and 6.47, respectively, which were lower than those of Zhongyou821 by 28% and 36%, respectively. After inoculation of detached leaves with mycelia, the lesion size of Zhongshuang9 was 4. 709 cm2, which was significantly smaller than that of the mid-resistant variety Zhongyou821(5. 933 cm2). The stem lesion length of Zhongshuang9 after match-stick inoculation was 1.275 cm, which was significantly lower than that of Zhongyou821(1.943 cm). The possible mechanism of resistance to S. sclerotiorum was studied through comparing the activities of phenylalanine ammonia lyase(PAL), exo-chitinase, β-1, 3-glucanase, peroxidase(POD)and polyphenoloxidase(PPO)in Zhongshuang9 with those in other resistant, mid-resistant and susceptible cultivars.展开更多
Sclerotinia stem rot(SSR) caused by Sclerotinia sclerotiorum(Lib.) de Bary is one of the most devastating diseases of Brassica napus worldwide. Both SSR resistance and flowering time(FT) adaptation are major breeding ...Sclerotinia stem rot(SSR) caused by Sclerotinia sclerotiorum(Lib.) de Bary is one of the most devastating diseases of Brassica napus worldwide. Both SSR resistance and flowering time(FT) adaptation are major breeding goals in B. napus. However, early maturing rapeseed varieties, which are important for rice-rapeseed rotation in China, are often highly susceptible to SSR. Here, we found that SSR resistance was significantly negatively correlated with FT in a natural population containing 521 rapeseed inbred lines and a double haploid(DH) population with 150 individual lines, both of which had great variation in FT. Four chromosomal regions on A2, A6, C2, and C8 affecting both SSR resistance and FT were identified using quantitative trait loci(QTL) mapping after constructing a high-density genetic map based on single nucleotide polymorphism markers in the DH population.Furthermore, we aligned QTL for the two traits identified in the present and previous studies to the B. napus reference genome, and identified four colocalized QTL hotspots of SSR resistance and FT on A2(0–7.7 Mb), A3(0.8–7.5 Mb), C2(0–15.2 Mb), and C6(20.2–36.6 Mb). Our results revealed a genetic link between SSR resistance and FT in B.napus, which should facilitate the development of effective strategies in both early maturing and SSR resistance breeding and in map-based cloning of SSR resistance QTL.展开更多
A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experimen...A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions. The optimal dry flowable formulation of C. rosea included 30% C. rosea （ratio of conidia powder and its fermentation broth is 1：3）, 3% Morwet EFW, 4% K12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid （NNO）, 5% croscarmellose sodium, 5% （NH4）2SO4, 0.5% carboxymethyl cellulose sodium （CMC-Na）, 1% oxalic acid and palygorskite （carrier） up to 100%. The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life. Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%. This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.展开更多
Sclerotinia sclerotiorum is one of the most devastating necrotrophic phytopathogens. Virulence of the hyphae of this fungus at different ages varies significantly. Molecular mechanisms underlying this functional disti...Sclerotinia sclerotiorum is one of the most devastating necrotrophic phytopathogens. Virulence of the hyphae of this fungus at different ages varies significantly. Molecular mechanisms underlying this functional distinction are largely unknown. In this study, we confirmed the effect of mycelial culture time/age on virulence in two host plants and elucidated its molecular and morphological basis. The virulence of the S. sclerotiorum mycelia in plants dramatically decreases along with the increase of the mycelial age. Three-day-old mycelia lost the virulence in plants. Comparative proteomics analyses revealed that metabolism pathways were comprehensively reprogrammed to suppress the oxalic acid（OA） accumulation in old mycelia. The oxaloacetate acetylhydrolase（OAH）, which catalyzes OA biosynthesis, was identified in the S. sclerotiorum genome. Both gene expression and protein accumulation of OAH in old mycelia were strongly repressed. Moreover, in planta OA accumulation was strikingly reduced in old mycelia-inoculated plants compared with young vegetative mycelia-inoculated plants. Furthermore, supply with 10 mmol L^（-1） OA enabled the old mycelia infect the host plants, demonstrating that loss of virulence of old mycelia is mainly caused by being unable to accumulate OA. Additionally, aerial mycelia started to develop from 0.5-day-old vegetative mycelia and dominated over 1-day-old mycelia grown on potato dextrose agar plates. They were much smaller in hypha diameter and grew significantly slower than young vegetative mycelia when subcultured, which did not maintain to progenies. Collectively, our results reveal that S. sclerotiorum aerial hyphae-dominant old mycelia fail to accumulate OA and thereby lose the virulence in host plants.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31771836)the National Key Research and Development Program of China(Grant No.2018YFD0201003).
文摘With the development of tourism at home and abroad,Rapeseed(Brassica napus)has become an important ornamental plant.However,its ornamental value at the inflorescence stage is greatly reduced by Sclerotinia sclerotiorum.Identification of important genes in the defense responses is critical for molecular breeding,which is an important strategy for controlling the disease.In this study,we isolated a B.napus WRKY transcription factor gene,BnaWRKY75.BnaWRKY75 was found to encode a nucleus-localized protein and exhibited relatively high expression in the stems.Arabidopsis thaliana transgenic plants expressing BnaWRKY75 showed enhanced resistance to S.sclerotiorum,and both ProBnaWRKY75:GUS and gene expression analyses showed that BnaWRKY75 was highly responsive to S.sclerotiorum infection,indicating the involvement of BnaWRKY75 in response to this infection.Furthermore,overexpression(OE)of BnaWRKY75 in B.napus significantly enhanced the resistance to S.sclerotiorum,whereas the resistance was reduced in RNAi transgenic B.napus plants.Moreover,the BnaWRKY75-OE B.napus plants exhibited constitutive activation of salicylic acid-,jasmonic acid-,and ethylene-mediated defense responses and the inhibition of both H_(2)O_(2)and O_(2)·^(-)accumulation in response to this pathogen.By contrast,BnaWRKY75-RNAi plants showed a reverse pattern,suggesting that BnaWRKY75 is involved in hormonal signaling pathways and in the control of reactive oxygen species accumulation.In conclusion,these data indicate that BnaWRKY75,a regulator of multiple defense responses,positively regulates resistance against S.sclerotiorum,which may guide the improvement of resistance in rapeseed.
基金financially supported by the National Nature Science Foundation of China (32372077)the Project of Chongqing Science and Technology Commission (CSTB2023NSCQ-MSX0355)the Fundamental Research Funds for the Central Universities (SWU120075)。
文摘The necrotrophic fungus, Sclerotinia sclerotiorum, employs an array of cell wall-degrading enzymes(CWDEs), including cellulase, to dismantle host cell walls. However, the molecular mechanisms through which S. sclerotiorum degrades cellulose remain elusive. Here, we unveil a novel secretory cellobiohydrolase, SsdchA, characterized by a signal peptide and a Glyco_hydro_7(GH7) domain. SsdchA exhibits a robust expression of during early infection stages. Interestingly, colony morphology and growth rates remain unaffected across the wild-type, SsdchA deletion strains and SsdchA overexpression strains on potato dextrose agar(PDA) medium. Nevertheless, the pathogenicity and cellobiohydrolase activity decreased in the SsdchA deletion strains, but enhanced in the SsdchA overexpression strains. Moreover,the heterologous expression of SsdchA in Arabidopsis thaliana leads to reduced cellulose content and heightened susceptibility to S. sclerotiorum. Collectively, our data underscore the pivotal role of the novel cellobiohydrolase SsdchA in the pathogenicity of S. sclerotiorum.
基金supported by the China Agriculture Research System of MOF and MARA(CARS-08)the National Crop Germplasm Resources Center of China(NCGRC-2020-09)the Scientific Innovation Program of the Chinese Academy of Agricultural Sciences。
文摘White mold of pea caused by Sclerotinia sclerotiorum is a common disease in China.However,we discovered that the diverse Sclerotinia species could cause white mold on pea plants in Chongqing and Sichuan of China during recent disease surveys.Thus,the objective of this study was to confirm the causal agents from diseased pea plants.The obtained isolates of white mold from Chongqing and Sichuan were identified by morphological characters and molecular characterization to determine the pathogen species,and their pathogenicity was confirmed on pea through completing Koch’s postulates.Fungal isolates of Sclerotinia-like were obtained from diseased plants or sclerotia.Based on morphological characteristics and molecular characterization,30 isolates were identified to three species,six isolates as S.minor,seven as S.sclerotiorum,and 17 as S.trifoliorum.In pathogenicity tests on pea cultivars Zhongwan 4 and Longwan 1,all 30 isolates caused typical symptoms of white mold on the inoculated plants,and the inoculated pathogens were re-isolated from the diseased plants.This study confirmed that white mold of pea was caused by three Sclerotinia species,S.sclerotiorum,S.minor and S.trifoliorum in Chongqing and Sichuan.It is the first report that S.minor and S.trifoliorum cause white mold of pea in Southwest China.
文摘[Objective] The study was to investigate roles of Brassica napus EINB in （ BnEIN3 ） resistance to Sclerotinia sclerotiorum. [ Methods] Genomic PCR and RT-PCR were carded out to isolate genomic DNA and cDNA sequences of BnEIN3 from oilseed rape, based on the highly conserved region of EIN3 gene from Arabidopsis thaliana and the homologous sequences of oilseed rape ESTs. Expression levels of BnEIN3 were detected in three varieties of oilseed rape inoculated with S. sclerotiorum by real-time quantitative PCR.[Results] A 1 947 bp DNA fragment was obtained from oilseed rape. The fragment shared 82% identity to A. thaliana EIIV3, encoded 614 amino acids containing an EIN3 domain, and was named as BnEIN3. Real-time PCR results showed that expression patterns of BnEIN3 were drastically different in different varieties. In highly resistant oilseed rape variety D083, BnEIN3 expression level was significantly increased 72 h after S. sclerotiorum inoculation whereas in middle resistant and susceptible varieties Zhongshuang 9 and 84039, BnEIN3 expression was suppressed. [ Conclusion ] BnEIIV3 may play an important role in oilseed rape resistance to S. sclerotiorum.
基金Support by Research and Demonstration of Seed Breeding Technology of South Alfalfa(2009AB1183)Development of Fine Germplasm Resources of Pasture and New Variety Breeding(2009AA1008)~~
文摘[ Objective] The paper was to study ISSR molecular makers of resistant gene against Sclerotinia trifoliorum in Medicago sativa L. [ Method] Using mi- crosatellite markers （ISSR） molecular maker technology, combined with bulked-segregant analysis （BSA） method, the molecular makers for gene linkage with re- sistance against S. trifoliorum were screened from five resistant plants and seven susceptible plants. Leaf in vitro inoculation method was used to carry out resistant verification on 94 hybrid plants in Ft generation of high resistant No. 83 ~ high susceptible No. 4. [ Result] Among 93 ISSR primers, 35 primers could produce clear and stable amplification bands, and six of them could produce 9 specific bands between resistant and susceptible DNA pools. Resistance verification result showed that 825 - 1400, 831 - 1480, 850 - 1800, 858 - 1600, 866 - 1900, 888 - 1400 could be used as ISSR molecular makers of the resistant gene against S. trifoliorum in M. sativa. [Conclusion] The results provided basis for the further research on mapping,, cloning and genetically modified of resistant gene against S. trifoliorum in M. sativa.
文摘Zhongshuang9, a new semi-winter Brassica napus variety with high resistance to Sclerotinia sclerotiorum and lodging, high-yield, double-low quality and extensive adaptability, was bred by multiple crossing and microspore culture technique. It was registered and released in China in 2002. In regional trial of Hubei Province in China, Zhongshuang9 yielded 2 482. 2 kg ha-1 averagely in 2000 - 2002, 15. 33% higher than the control variety Zhongyou821. Erucic acid, glucosinolates and oil contents of Zhongshuang9 were 0.23%, 22.69 μmol g-1(in meal)and 42%, respectively. In field assessment of resistance to S. Sclerotiorum , the disease incidence and disease index of Zhongshuang9 averaged 13.31 % and 6.47, respectively, which were lower than those of Zhongyou821 by 28% and 36%, respectively. After inoculation of detached leaves with mycelia, the lesion size of Zhongshuang9 was 4. 709 cm2, which was significantly smaller than that of the mid-resistant variety Zhongyou821(5. 933 cm2). The stem lesion length of Zhongshuang9 after match-stick inoculation was 1.275 cm, which was significantly lower than that of Zhongyou821(1.943 cm). The possible mechanism of resistance to S. sclerotiorum was studied through comparing the activities of phenylalanine ammonia lyase(PAL), exo-chitinase, β-1, 3-glucanase, peroxidase(POD)and polyphenoloxidase(PPO)in Zhongshuang9 with those in other resistant, mid-resistant and susceptible cultivars.
基金supported by the National Natural Science Foundation of China(31671725,31601330,31330057)the National Key Basic Research Program of China(2015CB150201)+1 种基金Science&Technology Special Project of Guizhou Academy of Agricultural Sciences([2014] 014,[2017] 08)the China Postdoctoral Science Foundation(2015M581867,2016T90514)
文摘Sclerotinia stem rot(SSR) caused by Sclerotinia sclerotiorum(Lib.) de Bary is one of the most devastating diseases of Brassica napus worldwide. Both SSR resistance and flowering time(FT) adaptation are major breeding goals in B. napus. However, early maturing rapeseed varieties, which are important for rice-rapeseed rotation in China, are often highly susceptible to SSR. Here, we found that SSR resistance was significantly negatively correlated with FT in a natural population containing 521 rapeseed inbred lines and a double haploid(DH) population with 150 individual lines, both of which had great variation in FT. Four chromosomal regions on A2, A6, C2, and C8 affecting both SSR resistance and FT were identified using quantitative trait loci(QTL) mapping after constructing a high-density genetic map based on single nucleotide polymorphism markers in the DH population.Furthermore, we aligned QTL for the two traits identified in the present and previous studies to the B. napus reference genome, and identified four colocalized QTL hotspots of SSR resistance and FT on A2(0–7.7 Mb), A3(0.8–7.5 Mb), C2(0–15.2 Mb), and C6(20.2–36.6 Mb). Our results revealed a genetic link between SSR resistance and FT in B.napus, which should facilitate the development of effective strategies in both early maturing and SSR resistance breeding and in map-based cloning of SSR resistance QTL.
基金supported by grants from the Fundamental Research Funds for the Central Universities, China (2572016DA02)the National Natural Science Foundation of China (31570642)the Science and Technology Innovation and Entrepreneurship Projects of Returned Overseas Personnel in Jilin Province, China (2013-36)
文摘A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions. The optimal dry flowable formulation of C. rosea included 30% C. rosea （ratio of conidia powder and its fermentation broth is 1：3）, 3% Morwet EFW, 4% K12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid （NNO）, 5% croscarmellose sodium, 5% （NH4）2SO4, 0.5% carboxymethyl cellulose sodium （CMC-Na）, 1% oxalic acid and palygorskite （carrier） up to 100%. The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life. Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%. This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.
基金supported by grants from the Special Fund for Agro-Scientific Research in the Public Interest, China (201103016)the Specialized Research Fund for the Doctoral Program of Higher Education, China (SRFDP) (20110101110092)+2 种基金the National Natural Science Foundation of China (31371892)the Program for New Century Excellent Talents in University (NCET-08-0485)the Program for New Century 151 Talents of Zhejiang Province, China
文摘Sclerotinia sclerotiorum is one of the most devastating necrotrophic phytopathogens. Virulence of the hyphae of this fungus at different ages varies significantly. Molecular mechanisms underlying this functional distinction are largely unknown. In this study, we confirmed the effect of mycelial culture time/age on virulence in two host plants and elucidated its molecular and morphological basis. The virulence of the S. sclerotiorum mycelia in plants dramatically decreases along with the increase of the mycelial age. Three-day-old mycelia lost the virulence in plants. Comparative proteomics analyses revealed that metabolism pathways were comprehensively reprogrammed to suppress the oxalic acid（OA） accumulation in old mycelia. The oxaloacetate acetylhydrolase（OAH）, which catalyzes OA biosynthesis, was identified in the S. sclerotiorum genome. Both gene expression and protein accumulation of OAH in old mycelia were strongly repressed. Moreover, in planta OA accumulation was strikingly reduced in old mycelia-inoculated plants compared with young vegetative mycelia-inoculated plants. Furthermore, supply with 10 mmol L^（-1） OA enabled the old mycelia infect the host plants, demonstrating that loss of virulence of old mycelia is mainly caused by being unable to accumulate OA. Additionally, aerial mycelia started to develop from 0.5-day-old vegetative mycelia and dominated over 1-day-old mycelia grown on potato dextrose agar plates. They were much smaller in hypha diameter and grew significantly slower than young vegetative mycelia when subcultured, which did not maintain to progenies. Collectively, our results reveal that S. sclerotiorum aerial hyphae-dominant old mycelia fail to accumulate OA and thereby lose the virulence in host plants.
