韭菜白腐病病原菌的分离与鉴定OA

To identify the pathogen species causing sclerotinia disease in greenhouse chives in Lintao county,Dingxi city,Gansu province,and to provide an etiological basis for local disease control,this study collected typical diseased Chinese chive samples from the local area.A strain designated 25-4-GSJC was isolated and purified.Pathogenicity was confirmed through in vitro leaf inoculation,in vivo potted soil inoculation,and artificial re-inoculation.The pathogen was identified using morphological observation,ITS sequence PCR amplification and sequencing,and phylogenetic analysis.The results showed that both wound inoculation and potted soil inoculation induced typical field disease symptoms on Chinese chives.The re-isolated strain from inoculated plants exhibited the same colony morphology as the original strain,satisfying Koch's postulates.On PDA medium,the mycelium was white,no conidia were produced,and small,dense black sclerotia were formed.An 814 bp ITS gene fragment was amplified by PCR.Sequence homology and phylogenetic tree analysis indicated that the tested strain clustered with the type strain of Stromatinia cepivora in the same evolutionary clade with 96％bootstrap support.In conclusion,the pathogen causing sclerotinia disease in greenhouse Chinese chives in this region is firstly identified as Stromatinia cepivora.