马铃薯早疫病生防细菌WB-1的筛选及鉴定

Screening and Identification of Potato Early Blight Biocontrol Bacteria WB-1

为有效防控马铃薯早疫病,从马铃薯早疫病病株根际土壤分离、筛选出有明显拮抗作用的细菌为供试菌株,筛选出一株对靶标病原菌平板抑菌率达到76%的拮抗菌株WB-1,菌落形态呈淡黄色,边缘规则,近圆形,微凸,表面湿润且光滑,不透明,菌体杆状,两端钝圆。经16S rDNA及gyrB基因序列分析,其与Bacillus velezensis(LC506620.1)及B.velezensis(MN365038.1)的同源性分别为71%、95%。经鉴定,菌株WB-1为贝莱斯芽孢杆菌(B.velezensis)。具有解无机磷、产吲哚乙酸(Indoleaceticacid,IAA)及铁载体的能力。盆栽试验结果表明,菌株WB-1可显著降低马铃薯早疫病的病情指数,相对防效为69.26%。因此,本试验获得的生防菌株WB-1对马铃薯早疫病菌具有较好的抑制效果,可以作为防治马铃薯早疫病害的候选菌株。

Screening and development of bacterial strains with biocontrol effects against early blight of potato,to provide strain resources and basis for effective prevention and control of this disease.Bacteria with obvious antagonistic effects were isolated and screened from the rhizosphere soil of potato early blight diseased plants as the tested strains.As a result,an antagonistic strain WB-1 with an inhibition rate of 76% against the target pathogen was screened out.The colony shape was light yellow,with regular edges,nearly round,slightly convex,moist and smooth,opaque,and rod-shaped.The ends are blunt and rounded.After 16S rDNA and gyrB gene sequence analysis,the homology with Bacillus velezensis(LC506620.1) and B.velezensis(MN365038.1) was 71% and 95%,respectively.After identification,the strain WB-1 is B.velezensis.It has the ability to dissolve inorganic phosphorus,produce indoleaceticacid(IAA) and siderophores.The pot experiment results showed that the strain WB-1 can significantly reduce the disease index of potato early blight,with a relative control effect of 69.26%.Therefore,the biocontrol strain WB-1 obtained in this experiment has a good inhibitory effect on potato early blight and can be used as a candidate strain for preventing and controlling potato early blight.