引起烟苗软腐的病原鉴定及致病性分析

Identification and pathogenicity analysis of soft rot in tobacco seedlings

为明确导致温室大棚烟苗软腐的病原种类,以温室大棚中的典型病苗为供试样品,采用组织分离法获得纯化菌株,根据菌株生理生化特性及16S r DNA序列分析进行病原菌鉴定,并测定了病原菌对K326、中烟100、大白筋599、革新3号等不同烟草品种的致病性。结果表明,纯化菌株YCS-1为一种细菌性病害,可引起不同烟草品种发病,该菌株生理生化特征与拉乌尔菌属(Raoultella)细菌一致。BLAST比对及系统进化树分析结果显示,菌株YCS-1与解鸟氨酸拉乌尔菌(Raoultella ornithinolytica)位于同一分枝,同源性高达99%。因此,将菌株YCS-1鉴定为解鸟氨酸拉乌尔菌(R.ornithinolytica)。

To identify pathogen species causing soft rot of tobacco seedlings in greenhouses, tobacco seedlings with typical soft rot were sampled to isolate pathogens by organization separation method. The species of pathogens were identified by physiological and biochemical characteristics and 16S rDNA sequence analysis, and the pathogenicity of isolated pathogens to four tobacco cultivars （K326, Zhongyan 100, Dabaijin 599 and Gexin 3） was detected. The results showed that the purified strain YCS-1 was a bacterial disease which could infect different tobacco cultivars. The physiological and biochemical characteristics of YCS-1 were consistent with those of Raoultella. BLAST alignment and phylogenetic tree analysis suggested that YCS-1 and R.ornithinolytica were located in the same branch, and their sequence homology reached 99%. Therefore, YCS-1 was identified as R.ornithinolytica.