一株拮抗链霉菌SM3-7的鉴定及其对玉米茎基腐病的防效

为获得对玉米茎基腐病具有良好防效的拮抗菌株，从玉米根际土壤中分离以玉米茎基腐病拟轮枝镰孢菌Fusarium verticillioides为靶标菌的拮抗放线菌菌株。采用平板对峙法测定不同菌株的抑菌活性，用抑菌圈法筛选效果良好的拮抗菌株并进行种类鉴定、抑菌谱和防效测定。结果表明，从土壤中分离并筛选获得1株对拟轮枝镰孢菌具有明显抑制作用的菌株SM3-7。经形态学、生理生化特征和16S rDNA系统发育分析，将菌株SM3-7鉴定为核粒链霉菌Streptomyces sclerogranulatus。该菌株抑菌谱广，对玉米上的8种植物病原菌有良好的抑制作用，对拟轮枝镰孢菌抑菌圈直径可达（28.03±0.45mm）。盆栽防效结果表明，菌株SM3-7发酵液对抗病品种“良玉99”和感病品种“全玉1233”的玉米茎基腐病14d防效分别达77.28%和76.12%，21d防效达72.20%和71.89%。核粒链霉菌菌株SM3-7发酵液可有效防治玉米茎基腐病，为利用微生物防治玉米茎基腐病拟轮枝镰孢菌提供参考。

Identification and Control Effect of Antagonistic Streptomyces SM 3-7 against Maize Stalk Rot Disease

In order to obtain an antagonistic bacterium with good control effect against maize stalk rot disease, the antagonistic bacteria were isolated from the rhizosphere soil of maize, with Fusarium verticillioides as the target fungi. The antibacterial activity of different strains was determined by the confrontation method, and the strains with the best antibacterial effect were selected by inhibition zone method. The selected strains were identified and its bacteriostatic spectrum and control effect were determined. The results showed that the strain SM3-7 had obvious inhibitory effect on F. verticillioides. Based on morphological, physiological, biochemical characteristics and 16S rDNA phylogenetic analysis, the strain SM3-7 was identified as Streptomyces sclerogranulatus. This strain had a broad antibacterial spectrum and had good inhibitory effect against 8 plant pathogens on corn, and inhibition zone diameter was (28.03±0.45) mm against F. verticillioides. In pot experiment, the control efficacies of strain SM3-7 against maize stalk rot on ‘Liangyu 99’ and ‘Quanyu 1233’ varieties reached 77.28% and 76.12% in 14 days, 77.28% and 76.12% in 21 days, respectively. The results showed that SM3-7 fermentation broth could effectively control maize stalk rot, which could lay a theoretical foundation for the development of biological control products against maize stalk rot.