烟草镰刀菌根腐病的病原鉴定

为了探明烟草镰刀菌根腐病的病原菌分类地位，2015-2017年从福建省三明市主要烟区采集的烟草根腐病病样中分离获得31个镰孢菌属菌株（F1~F31）。对所分离的菌株进行形态学甄别、系统进化分析、种特异分子鉴定及致病性测定，结果表明分离菌株显微形态特征与尖孢镰刀菌（Fusarium oxysporum）和共享镰刀菌（F. commune）相似；采用贝叶斯法（Bayesian Analysis）对4株分离菌F-04、F-18、F-19和F-28的rDNA基因内间隔区（IGS）基因作系统发育分析，结果显示这4个菌株同F. commune聚为一类并与F. oxysporum明确区分；特异性引物扩增鉴定结果表明分离菌株均为F. commune。通过室内与田间接种试验验证了分离菌株F. commune的致病性，明确其为烟草根腐病的主要病原物，这是我国首次报道共享镰刀菌F. commune引起烟草根腐病。 

Identification of tobacco Fusarium root rot pathogen

In order to identify tobacco root rot pathogen, 31 strains of Fusarium spp. were isolated from samples of tobacco Fusarium root rot disease which were collected from the main tobacco areas of Sanming city, Fujian province from 2015 to 2017. The pathogen was identified as Fusarium commune by morphological comparison, pathogenicity determination, species-specific molecular detection and phylogenetic analysis. Micro-morphological characteristics of F. commune were similar to F. oxysporum. All 31 Fusarium spp. isolates were identified as F. commune by using specific primers; strain F-04, F-18, F-19, F-28 was clustered with F. commune and clearly distinguished from F. oxysporum by phylogenetic analysis of the rRNA intergenic spacer region gene (IGS) using Bayesian analysis. Pathogenicity of the isolates was tested by greenhouse pots and field inoculation experiments. It is the first report that F. commune caused tobacco root rot disease in China.