青贮玉米近壳多胞叶斑病菌的分离鉴定及其致病性分析

Identification and Pathogenicity Analysis of Parastagonospora Leaf Spot Pathogens from Silage Maize

为分析青贮玉米来源近壳多胞菌属种类及其致病性,本研究采集疑似病叶,对病原菌进行分离纯化,结合病原菌菌落和子囊孢子形态特征以及核糖体转录间隔区(Internal transcribed spacer,ITS)、核糖体小亚基(Ribosomal small subunit,SSU)和翻译延伸因子(Translation elongation factor,TEF-1α)序列联合分析,鉴定分离自青贮玉米叶斑病样本的近壳多胞菌属种类,明确其有性生殖类型,通过划伤接种和喷雾接种对其致病性进行分析。结果表明,分离得到的40株病原菌为颖枯近壳多胞菌(Parastagonospora nodorum),并只扩增出1种交配型基因片段,为MAT1交配型;颖枯近壳多胞菌可通过室内诱导产生有性后代,有性生殖类型为同宗配合;致病性测定结果表明40株菌株能侵染7个品种的青贮玉米引起叶斑病。本研究初步明确青海省青贮玉米来源近壳多胞菌属真菌种类及其致病性,为后续青贮玉米病害准确识别及综合防治提供理论依据。

In this study,in order to analyze the species and pathogenicity of Parastagonospora pathogens from silage corn,samples were collected and the pathogens were isolated.Morphology of colony and ascospores was observed,and phylogenetic analysis of internal transcribed spacer(rDNA-ITS),ribosomal small subunit(SSU)and translation elongation factor(TEF-1α)gene sequences of the pathogen were analyzed.To identify the species of Parastagonospora isolated from leaf spot disease samples of silage maize and clarify the type of sexual reproduction of this species,the pathogenicity was analyzed by scratching and spraying.The results showed that 40 isolates were Parastagonospora nodorum,and only one mating type gene of P.nodorum fragment was amplified,which was MAT1 mating type.P.nodorum was induced to produce sexual progeny,and the sexual reproduction type was homothallism.Pathogenicity test results showed that all the 40 isolates could infect 7 cultivars of silage maize,and caused leaf spot disease.In this study,we preliminarily clarify the species and pathogenicity of Parastagonospora pathogens from silage maize in Qinghai Province,which provides a theoretical basis for the accurate identification and comprehensive prevention of silage maize diseases.