番茄枯萎病菌和青枯病菌拮抗细菌的评价
Evaluation of antagonistic bacteria against Fusarium oxysporum f. sp. lycopersici and Ralstonia solanacearum

为筛选出对番茄枯萎病和青枯病有较好防效的生防菌,采用平板对峙法,以番茄枯萎病菌Fusarium oxysporum和番茄青枯病菌Ralstonia solanacearum为靶标菌,从江苏沭阳、宿迁、溧水及内蒙古海拉尔分离到的2 062株细菌菌株中筛选拮抗菌株,并采用平板对峙法、拮抗菌液灌根法、分子生物学方法进行拮抗物质检测、盆栽试验及种属鉴定.结果表明:从2 062株细菌中共筛选到21株对番茄枯萎病和青枯病具有很强拮抗作用的菌株,均能分泌蛋白酶,具有解磷作用;不能分泌几丁质酶和纤维素酶,仅4株细菌能分泌嗜铁素.拮抗细菌SY290对番茄枯萎病和番茄青枯病防效最高,分别达到74.2%和75.0%,SQ728和LS536次之,但防效均大于60%.结合各菌株形态特征、16S rDNA与gyr-B序列分析结果,菌株SY177、SY290和SQ728鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens,菌株LS536为枯草芽胞杆菌B. subtilis.
To obtain antagonistic bacteria for biocontrol of Fusarium wilt and bacterial wilt of tomato, the control efficiencies of antagonistic bacteria against Fusarium oxysporum and Ralstonia solanacearum were screened and evaluated in vitro. A total of 2 062 strains were isolated and purified from rhizosphere soils of tomato in Shuyang, Suqian, Lishui in Jiangsu Province and Hailaer in Inner Mongolia. The plate confrontation, root irrigation and molecular methods were used to detect antibacterial substances, and pot experiments and species identification were conducted. Total 21 strains which were screened and evaluated from 2 062 strains could produce protease and had phosphate-solubilizing effect, but could not produce chitinase and cellulase. Four strains could produce siderophore. The strain SY290 could control Fusarium wilt and bacterial wilt effectively, with control efficiency of 74.2% and 75.0%, respectively, and the control efficiencies of strains SQ728, LS536 were all above 60%. Based on morphological characteristics, 16s rDNA and gyr-B sequence analysis, SY177, SY290, and SQ728 were identified as Bacillus amyloliquefaciens, and LS536 was identified as B. subtilis.