Stemphylium leaf spot, caused by Stemphylium botryosum f. sp. spinacia, is an important fungal disease of spinach (Spinacia oleracea L.). The aim of this study was to conduct association analysis to identify single nu...Stemphylium leaf spot, caused by Stemphylium botryosum f. sp. spinacia, is an important fungal disease of spinach (Spinacia oleracea L.). The aim of this study was to conduct association analysis to identify single nucleotide polymorphism (SNP) markers associated with Stemphylium leaf spot resistance in spinach. A total of 273 spinach genotypes, including 265 accessions from the USDA spinach germplasm collection and eight commercial cultivars, were used in this study. Phenotyping for Stemphylium leaf spot resistance was evaluated in greenhouse;genotyping was conducted using genotyping by sequencing (GBS) with 787 SNPs;and single marker regression, general linear model, and mixed linear model were used for association analysis of Stemphylium leaf spot. Spinach genotypes showed a skewed distribution for Stemphylium leaf spot resistance, with a range from 0.2% to 23.5% disease severity, suggesting that Stemphylium leaf spot resistance in spinach is a complex, quantitative trait. Association analysis indicated that eight SNP markers, AYZV02052595_115, AYZV02052595_122, AYZV02057770_10404, AYZV02129827_205, AYZV0-2152692_182, AYZV02180153_337, AYZV02225889_197, and AYZV02258563_213 were strongly associated with Stemphylium leaf spot resistance, with a Log of the Odds (LOD) of 2.5 or above. The SNP markers may provide a tool to select for Stemphylium leaf spot resistance in spinach breeding programs through marker-assisted selection (MAS).展开更多
A suspected fungal disease was observed on onion leaves during survey in onion fields of the central rift valley of Ethiopia in the offseason in 2019. The disease symptoms were round to oval small spots on onion leave...A suspected fungal disease was observed on onion leaves during survey in onion fields of the central rift valley of Ethiopia in the offseason in 2019. The disease symptoms were round to oval small spots on onion leaves which coalesce to form blighted leaves that change to brown lesion and black sporulation with time. The disease was of high incidence (up to 95.2%) and severity (up to 4.67) where in some fields it has been causing early plant senescence and reduced bulb size during harvest with massive yield loss, named to be “Yeshinkurt Ebola” to mean “Ebola of onion” by farmers. Dirty white to light grey front colony color and light brown to deep brown reverse colony color with alternative white and brown band fungal growth were isolated from infected onion leaf samples. The conidia were olive brown, oval to ovoid, oblong and ovoid to oblong are born on conidiophores. Pathogenicity of the pathogen was confirmed on 45-days-old onion (cv. Nafis) plant, and it was identified as Stemphylium vesicarium based on cultural, morphological and pathogenic results. This is the first report of S. vesicarium, the causative agent of onion stemphylium leaf blight.展开更多
Most fungi display a mixed mating system with both asexual and sexual reproduction.The timing of the two modes of reproduction must be carefully coordinated through signal perception and coordination in the cell along...Most fungi display a mixed mating system with both asexual and sexual reproduction.The timing of the two modes of reproduction must be carefully coordinated through signal perception and coordination in the cell along with chromatin modification.Here,we investigated coordination of reproductive output by investigating the function of the histone chaper-one anti-silencing factor 1(ASF1)in a fungal species amenable to characterization of both asexual and sexual reproduction.We used knockout approach to show that SeASF1 influenced asexual and sexual reproduction in Stemphylium eturmiunum.SeASF1-deleted strains failed to produce pseudothecia,but produce abnormal conidia and showed an irregular distribution of nuclei in mycelium.Transcriptome sequencing was then used to identify genes with altered expression in the SeASF1-deleted strains.The transcriptional expression of the identified SeDJ-1 was strongly regulated by SeASF1.The interaction of SeDJ-1 and SeASF1 was confirmed using Y2H,Co-IP,and pull-down.Due to some components of phosphatidylinositol 3-kinase/protein kinase B(PI3K/AKT)signaling pathway were known to interact with DJ-1 in mammals,we verified SePI3K,an element of PI3K/AKT signaling pathway in S.eturmiunum,was directly linked to SeDJ-1 and then these two proteins were defined as a coordinator of reproduction.However,knockout of SeDJ-1 or SePI3K altered the asexual and sexual repro-duction,but SePI3K recovered the asexual and sexual development of∆Sedj-1.The SeDJ-1-M6 segment of SeDJ-1 was essential for its interaction with SePI3K and played a critical role in restoring sexual reproduction in the∆Sepi3k,providing a deep understanding of the regulatory mechanism of SeDJ-1 in S.eturmiunum development.Summarily,SeASF1 is able to trigger SeDJ-1 and SeDJ-1can also activate SePI3K,which is orchestrally involved in asexual and sexual reproduction in S.eturmiunum.All these results reveal that SeASF1 manipulates asexual and sexual reproduction in S.eturmiunum by SeDJ-1 perception of PI3K/AKT signaling pathway.These data highlight the deep similarities in coordinating asexual and sexual processes in both fungi and eukaryotes in general.展开更多
文摘Stemphylium leaf spot, caused by Stemphylium botryosum f. sp. spinacia, is an important fungal disease of spinach (Spinacia oleracea L.). The aim of this study was to conduct association analysis to identify single nucleotide polymorphism (SNP) markers associated with Stemphylium leaf spot resistance in spinach. A total of 273 spinach genotypes, including 265 accessions from the USDA spinach germplasm collection and eight commercial cultivars, were used in this study. Phenotyping for Stemphylium leaf spot resistance was evaluated in greenhouse;genotyping was conducted using genotyping by sequencing (GBS) with 787 SNPs;and single marker regression, general linear model, and mixed linear model were used for association analysis of Stemphylium leaf spot. Spinach genotypes showed a skewed distribution for Stemphylium leaf spot resistance, with a range from 0.2% to 23.5% disease severity, suggesting that Stemphylium leaf spot resistance in spinach is a complex, quantitative trait. Association analysis indicated that eight SNP markers, AYZV02052595_115, AYZV02052595_122, AYZV02057770_10404, AYZV02129827_205, AYZV0-2152692_182, AYZV02180153_337, AYZV02225889_197, and AYZV02258563_213 were strongly associated with Stemphylium leaf spot resistance, with a Log of the Odds (LOD) of 2.5 or above. The SNP markers may provide a tool to select for Stemphylium leaf spot resistance in spinach breeding programs through marker-assisted selection (MAS).
文摘A suspected fungal disease was observed on onion leaves during survey in onion fields of the central rift valley of Ethiopia in the offseason in 2019. The disease symptoms were round to oval small spots on onion leaves which coalesce to form blighted leaves that change to brown lesion and black sporulation with time. The disease was of high incidence (up to 95.2%) and severity (up to 4.67) where in some fields it has been causing early plant senescence and reduced bulb size during harvest with massive yield loss, named to be “Yeshinkurt Ebola” to mean “Ebola of onion” by farmers. Dirty white to light grey front colony color and light brown to deep brown reverse colony color with alternative white and brown band fungal growth were isolated from infected onion leaf samples. The conidia were olive brown, oval to ovoid, oblong and ovoid to oblong are born on conidiophores. Pathogenicity of the pathogen was confirmed on 45-days-old onion (cv. Nafis) plant, and it was identified as Stemphylium vesicarium based on cultural, morphological and pathogenic results. This is the first report of S. vesicarium, the causative agent of onion stemphylium leaf blight.
基金Funding was provided by National Natural Science Foundation of China(Grant nos.31230001,U200220015).
文摘Most fungi display a mixed mating system with both asexual and sexual reproduction.The timing of the two modes of reproduction must be carefully coordinated through signal perception and coordination in the cell along with chromatin modification.Here,we investigated coordination of reproductive output by investigating the function of the histone chaper-one anti-silencing factor 1(ASF1)in a fungal species amenable to characterization of both asexual and sexual reproduction.We used knockout approach to show that SeASF1 influenced asexual and sexual reproduction in Stemphylium eturmiunum.SeASF1-deleted strains failed to produce pseudothecia,but produce abnormal conidia and showed an irregular distribution of nuclei in mycelium.Transcriptome sequencing was then used to identify genes with altered expression in the SeASF1-deleted strains.The transcriptional expression of the identified SeDJ-1 was strongly regulated by SeASF1.The interaction of SeDJ-1 and SeASF1 was confirmed using Y2H,Co-IP,and pull-down.Due to some components of phosphatidylinositol 3-kinase/protein kinase B(PI3K/AKT)signaling pathway were known to interact with DJ-1 in mammals,we verified SePI3K,an element of PI3K/AKT signaling pathway in S.eturmiunum,was directly linked to SeDJ-1 and then these two proteins were defined as a coordinator of reproduction.However,knockout of SeDJ-1 or SePI3K altered the asexual and sexual repro-duction,but SePI3K recovered the asexual and sexual development of∆Sedj-1.The SeDJ-1-M6 segment of SeDJ-1 was essential for its interaction with SePI3K and played a critical role in restoring sexual reproduction in the∆Sepi3k,providing a deep understanding of the regulatory mechanism of SeDJ-1 in S.eturmiunum development.Summarily,SeASF1 is able to trigger SeDJ-1 and SeDJ-1can also activate SePI3K,which is orchestrally involved in asexual and sexual reproduction in S.eturmiunum.All these results reveal that SeASF1 manipulates asexual and sexual reproduction in S.eturmiunum by SeDJ-1 perception of PI3K/AKT signaling pathway.These data highlight the deep similarities in coordinating asexual and sexual processes in both fungi and eukaryotes in general.
