青贮玉米蠕形菌的分离鉴定及其致病性分析

本研究为初步明确引起青贮玉米(Zea Mays L.)叶斑病的蠕形菌种类，采集疑似病斑叶片样本，对病原菌进行分离纯化，形态特征观察，ITS-rDNA序列和GADPH基因序列系统发育分析及致病性测定。形态学和分子生物学鉴定结果表明分离得到的142株病原菌为3属6种真菌，其中麦根腐平脐蠕孢(Bipolaris sorokiniana)和玉米生平脐蠕孢(B.zeicola)为优势病原菌，分别为77株和48株；其次为大斑病菌(Exserohilum turcicum)9株，疣状弯孢(Curvularia verruculosa)2株，新月弯孢(C.lunata)3株，穗状弯孢(C.spicifera)3株。致病性测定发现麦根腐平脐蠕孢和玉米生平脐蠕孢对青海省8个主栽青贮玉米品种均有致病性，其余4种病原菌的致病性各有差异。本研究初步明确引起青贮玉米叶斑病的蠕形菌种类及其致病性，为后续开展病害诊断及其综合防控奠定了基础。

Isolation,Identification and Pathogenicity Analysis of Helminthosporioid Fungi from Silage Maize

In this study leaf spots of silage maize were suspected to be caused by Helminthosporioid fungi,and samples were collected,pathogens were isolated. We then analyzed the morphological characteristics,phylogeny of ITS-rDNA sequence and GADPH gene sequence of pathogens,and tested the pathogenicity for understanding the species of Helminthosporioid fungi pathogens from silage maize. All the 142 isolates belonged to 3 genera and 6 species.Bipolaris sorokiniana and B. zeicola were the dominant pathogens,with 77 and 48 isolates,respectively. And 9 isolates were Exserohilum turcicum. The number of Curvularia verruculosa,C. lunata and C. spicifera pathogens were 2,3 and 3,respectively. Pathogenicity tests showed that B. sorokiniana and B. zeicola could infect 8 cultivars of silage maize,and the pathogenicity on 8 cultivars of another 4 species was different. Here,we preliminary clarified the species and pathogenicity of Helminthosporioid fungi causing leaf spot disease on silage maize,and lay a foundation for disease diagnosis and comprehensive prevention.