玉米内生菌L10的分离、鉴定及拮抗活性

为获得对玉米茎腐病主要病原菌禾谷镰孢Fusarium graminearum有明显拮抗作用的玉米内生菌，采用平板对峙法从成熟健康玉米茎秆中筛选禾谷镰孢拮抗菌株，并分析其抗菌谱；通过形态特征、生理生化特性及16S rDNA序列分析进行菌种鉴定；利用盆栽生防试验检测其对玉米茎腐病的防治效果。结果表明，共分离获得了164株玉米内生细菌菌株，其中L10菌株对禾谷镰孢具有较好的抑制效果，抑菌圈半径达1.68 cm；该菌对玉米大斑病菌Setosphaeria turcica、层出镰孢F. proliferatum、禾谷镰孢F. graminearum、拟轮枝镰孢F. verticilliodes、玉米弯孢叶斑病菌Curvularia lunata、玉米小斑病菌Bipolaris maydis、立枯丝核菌Rhizoctonia solani、茄链格孢Alternaria solani共8种植物病原菌均有拮抗作用，尤其对禾谷镰孢抑制效果最佳；结合形态特征、生理生化性质及16S rDNA序列分析，将L10菌株鉴定为多粘类芽胞杆菌Paenibacillus polymyxa。L10菌株脂肽类物质对禾谷镰孢菌具有较好的抑制活性，且盆栽生防试验结果显示该菌株对玉米茎腐病具有一定的防治效果。表明菌株L10对玉米镰孢茎腐病的防治具有一定潜力。

Isolation, identification and antagonistic activity of maize endophyte L10

In order to obtain the endophytic bacteria highly antagonistic against Fusarium graminearum, the primary causal agent of corn stalk rot, antagonistic bacterial strains were screened from mature and healthy corn stalks using the plate confrontation method. The results showed that among the 164 strains of endophytic bacteria isolated, strain L10 exhibited a good antagonistic effect against F. graminearum, with the radius of inhibition circle at 1.68 cm on the plate. The antimicrobial spectrum tests showed that strain L10 had antagonistic effects against eight plant pathogens, including Etosphaeria turcica, F. proliferatum, F. graminearum, F. verticilliades, Curvularia lunata, Bipolaris maydis, Rhizoctonia solani and Alternaria solani, especially had the strongest antagonistic effect on F. graminearum. Based on its morphological, physiological and biochemical characteristics, and 16S rDNA gene sequence analysis, L10 was identified as Paenibacillus polymyxa. Lipopeptides extracted from L10 had a strong inhibitory activity on F. graminearum, and the strain had a certain control efficacy on corn stalk rot in pot experiments. The results demonstrated that strain L10 had certain potential in controlling Fusarium stalk rot of maize.