小麦茎基褐腐病病原菌组成及其致病力研究

Pathogenic Fungi of Wheat Brown Foot Rot and Their Pathogenicity in China

为明确小麦茎基褐腐病(brown foot rot)病原菌的组成,于2008-2009年春从江苏、安徽、河南、湖北、河北和四川6省48个县市的65个地点采集了具有茎基褐腐症状的病株,并分离到110株病原真菌。根据其培养性状、形态学特征以及分子生物学鉴定,可将这些病原菌分为4类,分别为小麦根腐离蠕孢(Bipo-laris sorokiniana,41株)、镰孢菌(Fusariumspp.,33株)、雪霉叶枯病菌(Microdochium nivale,24株)和黑附球菌(Epicoccum nigrum,12株)。对这些菌株在小麦苗期的致病力及重新分离得率的测定结果表明,4类病原菌之间的致病力存在明显差异,其中以小麦根腐离蠕孢(B.sorokiniana)发病率和致病力最强,其次是镰孢菌(Fusariumspp.),雪霉叶枯病菌(M.nivale)和黑附球菌(E.nigrum)则相对较弱;病菌的重新分离得率与其致病力呈正相关。

Brown foot rot,caused by soil-borne fungi is a complex of cereal stem-base diseases.With global climate warming,the wheat brown foot rot in China becomes serious,and the early symptoms of this disease were difficult to distinguish from wheat sharp eyespot.From 2008 to 2009,we collected a large number of wheat plants with brown foot rot symptoms from different areas of Jiangsu,Anhui,Henan,Hubei,Hebei and Sichuan province,and isolated 110 strains.According to the cultural characteristics,morphology of the conidia and analysis on the rDNA ITS sequences,4 groups of pathogen were identified： Bipolaris sorokiniana（41 isolates）,Fusarium spp.（33 isolates）,Microdochium nivale（24 isolates）,and Epicoccum nigrum（12 isolates）.On wheat cultivar Yumai 49,the pathogenicity of these pathogens was evaluated with artificial inoculation method in greenhouse.The results indicated that the pathogenicity of these pathogens was different,the pathogenicity of B.sorokiniana isolates were higher than that of other 3 pathogens,next were Fusarium spp.,the isolates of M.nivale and E.nigrum were weaker.At the same time,we isolated the pathogens from the inoculated plants with typical brown foot rot symptom,and the re-isolation percentage of the 4 groups pathogen fungi were positive related to their pathogenicity.