特基拉芽胞杆菌JN-369抗菌粗蛋白的理化性质和抑菌效果

特基拉芽胞杆菌Bacillus tequilensis JN-369是1株对稻瘟病菌Magnaporthe oryzae有较好拮抗作用的植物内生细菌，其发酵液经硫酸铵沉淀后得到抗菌粗蛋白。为明确菌株JN-369抗菌粗蛋白的抑菌机理，首先确定了该抗菌粗蛋白抑菌谱、热稳定性、酸碱稳定性、紫外稳定性以及酶稳定性，并观察研究了抗菌粗蛋白对稻瘟病菌菌丝和分生孢子的抑制作用。并采用针刺离体接种法测定了40%稻瘟灵EC、25%三环唑WP及不同浓度JN-369抗菌粗蛋白对水稻稻瘟病的拮抗效果。结果表明：菌株JN-369抗菌粗蛋白抑菌谱广，对葡萄灰霉病菌、草莓灰霉病菌和水稻稻瘟病菌等13种植物病原真菌及卵菌表现出抑制作用，而对油菜菌核病菌没有抑制作用；该粗蛋白理化性质相对稳定，具有应用于粮食作物生物防治的潜力；对稻瘟病菌的菌丝生长和分生孢子萌发有双重抑制作用，能使病原菌菌丝细胞膨大，并可抑制病菌分生孢子的萌发；离体防效试验显示，供试杀菌剂对水稻稻瘟病均有显著的拮抗效果，菌株JN-369抗菌粗蛋白在浓度为50～100 μg/mL时对稻瘟病的拮抗效果最好，该菌株有望开发为防治稻瘟病的生防菌株。

Physical and Chemical Properties and Inhibitory Effect of Crude Antifungal Protein Produced by Bacillus tequilensis JN-369

Bacillus tequilensis strain JN-369 is a biocontrol strain with antagonism on Magnaporthe oryzae. The antifungal protein crude extraction was precipitated by ammonium sulphate after fermentation. To determine the antifungal mechanism of the crude protein the inhibition spectrum, thermostability, acid-base stability, UV stability and enzyme stability were investigated, the inhibition effect to M. oryzae hyphae and spores was observed, and the antagonistic effects of 40% Isoprothiolane EC, 25% Tricyclazole WP and the crude antifungal protein against M. oryzae in rice were detected by tissue inoculation in vitro. Results indicated that the crude antifungal protein of the strain JN-369 had a broad inhibition spectrum, with inhibition activity on 13 plant pathogenic fungi and oomycetes, such as B. cinerea, M. oryzae, but no inhibition on S. sclerotiorum. The crude proteinstill had antifungal activity after heat treatment, pH treatment, UV treatment and enzyme treatment, indicating it has potential application value in biocontrol of food crops. After treatment with crude protein, M. oryzae hyphae became enlargement and could inhibit conidiospores germination. The in vitro efficacy experiments showed that all treatments had significant antagonistic effects on rice blast, and the crude antifungal protein at 50 ug/mL to 100 ug/mL had the best antagonistic effect on rice blast.The strain JN-369 was expected to be developed as a Biocontrol Strain for the control of rice blast.