中国东北地区玉米纹枯病菌的融合群鉴定

The anastomosis groups of the corn sheath blight pathogen Rhizoctonia spp. in northeastern China

自东北三省采集玉米纹枯病标本300余份,分离获得286个丝核菌菌株。融合群测定及5.8Sr DNA-ITS区序列分析结果表明,这些菌株分别属于多核丝核菌的AG1-IA、AG1-IB、AG1-IC、AG4-HG-I、AG4-HG-III、AG-5、WAG-Z群及双核丝核菌的AG-Ba群。其中AG1-IA是优势致病群,占分离菌株总数的38.46%,其次是WAG-Z和AG-5群,分别占26.92%及24.83%。AG4-HG-III群菌株是国内首次从罹病玉米植株上分离得到。自各融合群中选取代表性的菌株进行5.8SrDNA-ITS区序列分析,结果表明,隶属不同融合群或亚群的菌株其5.8SrDNA-ITS区序列存在较大的差异,而相同融合群(亚群)不同菌株之间其序列的一致性较高,说明此基因序列可对丝核菌不同融合群或亚群的菌株进行有效区分和鉴定。

Two hundred and eighty-six isolates were obtained from corn sheath blight samples in northeastern China （including Heilongjiang,Jilin and Liaoning provinces）.Anastomosis group identification and 5.8S rDNA-internal transcribed spacer （ITS） sequence analysis showed that the isolates belonged to multinucleate Rhizoctonia AG1-IA,AG1-IB,AG1-IC,AG4-HG-I,AG4-HG-III,AG-5,WAG-Z and binucleate Rhizoctonia AG-Ba.Of these,AG-1-IA was the major anastomosis group （AG） （38.46% of total isolates）,followed by WAG-Z （26.92%） and AG-5 （24.83%）.AG4-HG-III was isolated for the first time from maize in China.5.8S rDNA-ITS sequence analysis showed that the isolates could be distinctly separated based on their AG types.The isolates belonging to the same AG （or sub-AG） showed high sequence identity.