为开发安全、高效的微生物农药提供生防菌株资源，对玉米叶片内分离得到1株具有优良生防潜能的内生枯草芽孢杆菌(Bacillus subtilis)拮抗菌株YM3-3进行鉴定及发酵条件优化，为生防菌剂防治玉米病害提供技术参数和理论依据。试验采用平板对峙法，测定了其对玉米穗腐病病原菌(拟轮枝镰孢Fusarium verticillioides)、玉米大斑病菌(Exserohilum turcicum)、西瓜蔓枯病菌(Mycosphaerella melonis)、苹果腐烂病菌(Valsa mali)、苹果轮纹病菌(Physalospora piricola)、茄子菌核病菌(Sclerotinia sclerotiorum)、马铃薯立枯丝核病菌(Rhizoctonia solani)、番瓜绵腐病菌(Pythiun aphanidermatum)、辣椒疫霉病菌(Phytophthora capsici)和棉花枯萎病菌(Fusarium oxysporum f .sp.vesinfectum)等10种病原真菌的抑制效果。结果显示，菌株YM3-3对这些病原真菌均具有良好的抑制效果，抑制率为(53.19±3.78)%~(81.94±1.54)%，表明其具有显著的生防潜能。通过形态学及16SrDNA和gyrB序列分析相结合的方法，将其鉴定为枯草芽孢杆菌。为进一步优化其发酵条件，进行了培养条件优化试验，确定最佳培养时间为3 d，最佳培养温度为27 ℃，最佳转速为150 r/min，最佳pH为7，最佳装液量为90 mL；发酵培养基的最优组合为15.0 g/L甘露醇、2.5 g/L蛋白胨、7.5 g/L硝酸钾、5.0 g/L碳酸钙。

To provide biocontrol strain resources for high-efficiency and safe microbial pesticides, the endophytic Bacillus subtilis YM3-3, a strain with ideal biocontrol potential, isolated from maize leaves was identified, and the fermentation conditions were optimized. This study provided technical parameters and a theoretical basis on control maize diseases as biocontrol agents. The inhibition effect of strain YM3-3 against 10 pathogenic fungi(including Fusarium verticillioides, Exserohilum turcicum, Mycosphaerella melonis, Valsa mali, Physalospora piricola, Sclerotinia sclerotiorum, Rhizoctonia solani, Pythiunaphanidermatum, Phytophthora capsici and Fusarium oxysporum f. sp. vesinfectum.) was measured by the dural culture method. The results showed that it had good antagonistic effect, and the inhibition rate against 10 pathogenic fungi was (53.19±3.78)% to (81.94±1.54)%, showing good biocontrol potential. According to morphological, 16SrDNA, and gyrB sequence analysis, it was identified as Bacillus subtilis. In order to further optimize the fermentation conditions, the optimization experiment of culture conditions was carried out. The results showed that the optimal culture time, temperature, rotational speed, pH, and liquid volume were 3 d, 27 ℃, 150 r/min, 7 and 90 mL, respectively. The optimal combination of fermentation medium was 15 g/L mannitol, 2.5 g/L peptone, 7.5 g/L potassium nitrate, and 5.0 g/L calcium carbonate.

Q939.9；S513

甘肃省科技计划-自然科学基金项目(24JRRA729)；甘肃省科技计划-科技特派员(团)专项(24CXNA048)。