青贮玉米蠕形菌的分离鉴定及其致病性分析

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

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。

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.