甘肃窖藏马铃薯干腐病病原菌分离鉴定及致病性分析

Isolation, identification and pathogenicity of pathogens causing dry rot of stored potato tubers in Gansu Province

中文关键词:  马铃薯  干腐病  镰刀菌  分离  致病性

英文关键词:potato  dry rot  Fusarium spp.  isolation  pathogenicity

中文摘要:

      目的 明确引起甘肃马铃薯主产区窖藏块茎干腐病致病菌的种类, 确定强致病性的优势种群。方法 通过组织分离法从甘肃省通风贮藏库窖藏的典型马铃薯干腐病发病块茎组织中分离纯化获得病原菌, 采用形态学结合真菌ITS序列进行菌种鉴定, 用MEGA软件比较亲缘关系, 根据柯赫氏法则测定分离菌株对‘大西洋’和‘陇薯7号’马铃薯微型薯的致病性。结果 从采集的马铃薯罹病组织中分离纯化得到15株真菌, 分别鉴定为三线镰刀菌(Fusarium tricinctum)、茄病镰刀菌(F. solani)、锐顶镰刀菌(F. acuminatum)、木贼镰刀菌(F. equiseti)、尖孢镰刀菌(F. oxysporum)和环孢镰刀菌(F. annulatum), 分离频率在6.67%~26.67%之间。6种镰刀菌均可导致马铃薯块茎发病, 其中锐顶镰刀菌、三线镰刀菌和茄病镰刀菌引起的病斑显著大于其他3种镰刀菌引起的病斑。结论 引起甘肃窖藏马铃薯干腐病的病原菌主要有三线镰刀菌、茄病镰刀菌、锐顶镰刀菌、木贼镰刀菌、尖孢镰刀菌和环孢镰刀菌, 致病力强的优势种群为锐顶镰刀菌、三线镰刀菌和茄病镰刀菌。环孢镰刀菌作为马铃薯干腐病的致病菌属首次在我国被报道。

英文摘要:

      Objective To clarify the pathogen species and pathogenicity, and identify the dominant pathogens during storage period causing dry rot of potato tubers in Gansu Province. Methods Using tissue separation method, pathogens were isolated and purified from potato tubers with typical symptoms of dry rot in ventilation storage of Gansu province. The species were identified by morphological characters and molecular sequence analysis of ITS. The phylogeny tree was constructed with MEGA software to compare the genetic relationship, and the pathogenicity was determined in potato mini tubers (cv. Atlantic and cv. Longshu No.7) according to Koch’s rules. Results A total of fifteen strains were isolated from the infected tuber tissue, and six Fusarium species were identified as F. tricinctum, F. solani, F. acuminatum, F. equiseti, F. oxysporum and F. annulatum, respectively. The isolation rate was between 6.67% and 26.67%. The 6 kinds of Fusarium species could cause typical symptoms of potato dry rot, among which F. acuminatum, F. tricinctum and F. solani caused significantly larger disease lesions than the other 3 kinds of Fusarium strains. Conclusions The 6 kinds of Fusarium species are identified from the typical symptoms of potato dry rot tubers, which are F. tricinctum, F. solani, F. acuminatum, F. equiseti, F. oxysporum and F. annulatum. The pathogenicity results show that the dominant pathogens causing dry rot of potato tubers in Gansu Province are F. acuminatum, F. tricinctum, and F. solani. F. annulatum is a new recorded strain on dry rot of potato tubers in China.