湖北省烟草靶斑病病原鉴定及其菌丝融合群遗传分化研究

2020—2021年湖北烟区爆发新型烟草叶部病害，本研究对病原菌进行分离培养、形态观察、镜检菌丝和科赫法则验证，并提取30个菌株的DNA使用通用引物ITS1/ITS4进行rDNA-ITS序列的PCR扩增，及MEGA-X软件进行基因序列比对及系统发育树构建，同时以Rs1F2/Rs2R1为引物，进行30个菌株的rDNA-ITS基因的PCR专化性鉴定。结果表明，该病害病原菌为立枯丝核菌（Rhizoctonia solani Kühn），30个菌株序列都隶属于R. solani AG-3融合群且均具有AG-3融合群所特有的504 bp片段。因此，确定该病害为烟草靶斑病。这是首次从湖北省烟草产区分离鉴定到该病菌。

Identification and Anastomosis Group Study of the Tobacco Target Spot Pathogen in Hubei Province

In 2020 and 2021, a new type of tobacco leaf disease broke out in the main tobacco producing areas of Hubei Province. The pathogen was analyzed through isolation and morphological observation, microscopic examination of hyphae and verification of Koch's postulates, extraction of the DNA of 30 strains and amplification of the rDNA- ITS sequence by PCR with universal primers ITS1/ITS4. The MEGA-X software was used for gene sequence alignment and phylogenetic tree construction, and the PCR specificity of rDNA-ITS genes of 30 strains was identified with Rs1F2/Rs2R1 as primers. The results showed that the pathogen was identified as Rhizoctonia solani Kühn, all 30 strains belonged to the R. solani AG-3 anastomosis group and with a 504 bp fragment unique to AG-3 anastomosis group. Therefore, the disease was identified as tobacco target spot. This is the first time that the pathogen was isolated from tobacco producing areas in Hubei Province.