福建青枯雷尔氏菌的遗传多样性及其生防放线菌的筛选

Genetic Diversity of Ralstonia solancearum in Fujian Province and Screening Its Biocontrol Actinomycete

为了明确福建青枯雷尔氏菌(简称青枯菌)的遗传多样性,综合菌株的演化型、生化型及基于内源葡聚糖酶基因egl的序列变种鉴定,对福建省8个地区的番茄、辣椒和茄子寄主分离的56株青枯菌进行分析。结果表明:供试的56株青枯菌均属于演化型Ⅰ;53株为生化型Ⅲ(占94.64%),1株为生化型Ⅱ,2株为非标准生化型;从序列变种来看,4株来自茄子的青枯菌均属序列变种15,24株来自辣椒的青枯菌中,23株属于序列变种14,1株为序列变种16,28株番茄青枯菌鉴定出7个序列变种。进一步,选择上述鉴定的生化型Ⅲ和生化型Ⅱ的代表菌株为靶标菌进行生防菌筛选。结果表明,供试14株放线菌中,筛选到1株对生化Ⅲ青枯菌有拮抗作用的放线菌FJAT-31535。基于菌落形态特征和16S rRNA基因序列相似性分析,菌株FJAT-31535属于链霉菌属(Streptomyces sp.)。

The aim of this study is to illuminate genetic diversity of Ralstonia solanacearum.The combined classification methods,including identification of phylotype,biovar,and egl sequevar,were used to analysis genetic diversity of 56 R.solanacearum strains isolated from different hosts and areas in Fujian province.The results showed that all the tested 56 strains belonged to the phylotypeⅠ.Fifty-three strains were identified as biovar Ⅲ(accounting for 94.64%),one as biovarⅡ,and the remaining two strains as atypical biovar.As for the egl sequevar,all the tested 4 R.solanacearum strains isolated from eggplant hosts belonged to sequevar 15,23 out of 24 strains isolated from pepper hosts belonged to sequevar 14,and 28 strains isolated from tomato hosts could be differed into 7 different sequevars.Subsequently,two representative strains of R.solanacearum biovar Ⅱand Ⅲ were used as the targets to screen biocontrol actinomycete strains.Among the tested 14 actinomycete strains,the strain FJAT-31535 exhibited antibacterial activity against R.solanacearum FJAT-91(biovar Ⅲ).Based on colony morphology and 16S rRNA gene sequence analysis,the strain FJAT-31535 was identified as Streptomyces sp..