烟草黑胫病拮抗芽孢杆菌的筛选及生防效果评价

Selecting of Antagonistic Bacillus against Tobacco Black Shank and Detecting of Control Efficacy

为了防治烟草疫霉对烟草引起的病害,从不同烟田健康烟株根际土壤中筛选分离42株根际细菌,经平板对峙初筛、细菌发酵液115℃处理后复筛得到10株对烟草黑胫病病原菌(Phytophthora parasitica)具有较好抑制效果的芽孢杆菌。经分子生物学鉴定可将其分为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)、枯草芽孢杆菌(B. subtilis)和贝莱斯芽孢杆菌(B. velezensis)3类。选取枯草芽孢杆菌GJ1、解淀粉芽孢杆菌GJ7和贝莱斯芽孢杆菌GJ11对各类芽孢杆菌进行纤维素酶和蛋白酶分泌特性检测、烟草根际土壤、根和茎定殖能力检测以及田间试验,得出这3种芽孢杆菌均可分泌纤维素酶和蛋白酶,均能在烟草根际土壤、根和茎中定殖,在根际土壤中定殖能力为GJ1>GJ7>GJ11,在根和茎中定殖能力均为GJ7>GJ1>GJ11。GJ1、GJ7、GJ11对烟草黑胫病田间相对防治效果分别为33.33%、80.00%、28.60%,初步确定拮抗芽孢杆菌田间防治效果取决于其在烟草内定殖能力。

In order to control the tobacco black shank caused by Phytophthora parasitica var. nicotianae,42 bacterial strains were isolated from different health status tobacco rhizosphere soil,10 of them had an antagonistic effect on P. nicotianae by using the plate confronting method and treatment with fermentation filtrate after heated at 115 ℃. Three groups of Bacillus could be identified under the 16S rDNA sequence analysis：Bacillus amyloliquefaciens, B. subtilis and B. velezensis. The characteristics of cellulase and protease activity,colonization of Bacillus in tobacco rhizosphere soil,root and stem,and field experiments were carried out on B. subtilis GJ1,B. amyloliquefaciens GJ7 and B. velezensis GJ11. The results showed that GJ1,GJ7 and GJ11 strains could secrete cellulase and protease,and colonize in the rhizosphere soil,root and stem of tobacco. The ability of colonization in the rhizosphere soil was GJ1〉GJ7〉GJ11,in root and stem was GJ7〉GJ1〉GJ11. However,the control efficiency against tobacco black shank of GJ1,GJ7 and GJll were 33.33%,80.00% and 28.60%,respectively,suggesting that the control efficacy in field of antagonistic Bacillus may depend on its colonization ability in tobacco.