贵州省赫章县半夏软腐病病原鉴定

Identification of Pathogens of Pinellia ternatea Soft Rot in Hezhang County of Guizhou Province

目的:明确贵州省赫章县半夏软腐病病原类型。方法:采用平板划线分离法分离病原菌,通过病原菌形态特征观察、致病性测定、16S rDNA和icdA基因序列系统分析对病原菌进行鉴定。结果:从采集的带病样品中分离到8株菌株,致病性测定表明,菌株Bxrf1-2、Hbxrf2-4、Hbxrf3-1、Hbxrf4-6和Hbxrf4-7可经人工接种导致半夏、胡萝卜、马铃薯、黄瓜和大白菜腐软;5株病原菌株在NB固体培养基上菌落圆形、表面光滑、半透明、乳白色且边缘整齐,革兰氏染色呈红色,为革兰氏阴性菌;基于16S rDNA和icdA基因序列系统发育关系分析均表明,5株病原菌与已报道的Pectobacterium aroidearum菌株聚集在同一分支上。结论:综合形态学特征和分子特征,将贵州省赫章县半夏软腐病病原鉴定为Pectobacterium aroidearum。

Objective:To identify the pathogen types of Pinellia ternata soft rot in Hezhang county,Guizhou province.Methods:Pathogens were isolated by streak plate method and identified by morphological characteristics observation,pathogenicity determination and phylogenetic analysis using 16 S rDNA and icdA gene sequences.Results:Eight strains were isolated from the infected samples,pathogenicity tests results showed that strains Bxrf1-2,Hbxrf2-4,Hbxrf3-1,Hbxrf4-6 and Hbxrf4-7 could cause soft rot of Pinellia ternata,carrot,potato,cucumber and Chinese cabbage by artificial inoculation.On NB solid medium,the bacterial colonies of the five pathogenic strains were round,smooth,translucent,milky white with neat edges,and the gram staining was red,indicating gram-negative bacteria.Phylogenetic relationship analysis based on 16 S rDNA and icdA gene sequences showed that the five pathogenic strains clustered in the same branch with Pectobacterium aroidearum,which had been reported.Conclusion:Based on morphological characteristics and molecular characteristics,the pathogen of Pinellia ternata soft rot disease in Guizhou is identified as Pectobacterium aroidearum.