两株生防芽孢杆菌的分子鉴定及拮抗活性测定

对两株分离自青海年宝玉泽及玛多高寒草甸根围土壤的拮抗菌株GL18和MD1进行鉴定分析。生理生化试验鉴定为枯草芽孢杆菌(Bacillus subtilis)菌群;16SrDNA分子鉴定表明,菌株GL18、MD1与Ba-cillus methylotrophicus及Bacillus amyloliquefaciens的序列相同(或一致)性均为99%;gyrB分子鉴定表明,菌株GL18、MD1与B.methylotrophicus具有最高序列相同(或一致)性;以两株菌株的16SrDNA及gyrB基因序列与模式菌株序列构建系统发育树,结果表明,两株菌株均与B.methylotrophicus具有更近亲缘关系;综合几种鉴定结果最终将菌株GL18、MD1鉴定为B.methylotrophicus。平板对峙试验表明,菌株GL18和MD1对油菜菌核菌具有显著拮抗活性;油菜离体叶片接种试验表明,菌株对油菜菌核病菌的侵染具有较好的防效。

Molecular Identification of Two Bio control Bacillus Strains and Its Antagonistic Activity Analysis

Strains GL18 and MD1, isolated from altiplaino meadow rhizosphere soil of Nianbaoyuze and Maduo region in Qinghai province, were identified by means of bio chemistry experiments and molecular taxonomy methods including 16S rDNA and gyrB partial sequence analysis. Physiological and bio chemical identification results showed that two strains belong to Bacillus subtilis group; 16S rDNA sequence analysis results showed that two strains both presented 99% closet match with Bacillus methylotrophicus and Bacillus amyloliquefaciens; gyrB gene sequence analysis results showed that strains GL18 and MD1 presented closet match with B. methylotrophicus . Moreover, phylogenetic tree of Bacillus strains based on 16S rDNA and gyrB gene sequences with model strains showed two strains presented closer homology with B. methylotrophicus . Colligating identification results, strains GL18 and MD1 were identified as B. methylotrophicus.Both strains presented distinct antagonistic activity and bio control efficacy to Sclerotinia sclerotiorum according to antagonistic activity detection and leaf blight on the detached leaves methods, respectively. The research provided Bacillus strains for further development and application of bio fertilizer and bio control to S. sclerotiorum diaease adapting in Qing Tibet altiplano special environment.