刺梨白粉病拮抗菌生长条件优化及其发酵液抑菌稳定性探究

为找到防治刺梨白粉病的拮抗菌培养液,经过刺梨叶片离体防治试验表明拮抗菌浓度与白粉病防治效果成正相关,采用三因素三水平响应面法优化拮抗菌JK-6的生长条件。同时探究温度、pH、紫外光、蛋白酶以及不同贮藏时间对JK-6发酵液抑制白粉病稳定性的影响。结果表明:JK-6的最佳培养条件组合为葡萄糖2 g/mL、蛋白胨1 g/mL、NaCl浓度0.8%、温度33.6℃、pH 7.6、装液量40 mL、摇床转速160 r/min,在该条件下拮抗菌JK-6的发酵液OD600为1.418;发酵液温度高于40℃、pH为酸性和碱性时,JK-6发酵液对白粉病孢子萌发的抑制效果均降低,发酵液对紫外光和蛋白酶的耐受能力较高,在常温下保藏1个月仍然具有较高的抑菌活性。JK-6对刺梨白粉病具有一定的防治效果。

Growth Conditions Optimization of Antagonistic Bacteria Against Powdery Mildew of Rosa roxburghii Tratt and Its Fermentation Broth Antibacterial Stability

In order to research the optimal culture solution of antagonistic bacteria against the Rosa roxburghii powdery mildew, this study carried out in vitro control experiment on leaves of R. roxburghii. The results showed that the concentration of antagonistic bacteria was positively correlated with the control effect of powdery mildew. The growth conditions of antagonistic bacteria JK-6 were optimized by 3-factor and 3-level response surface methodology. Meanwhile, the effects of temperature, pH, ultraviolet light, protease and different storage period on the stability of JK-6 fermentation broth for inhibiting powdery mildew were investigated. The results showed that the optimal medium formula of JK-6 was glucose 2 g/mL, peptone 1 g/mL, and NaCl concentration 0.8%; the best culture conditions was temperature 33.6 ℃, pH 7.6, liquid volume 40 mL, shaker speed 160 r/min. Under these conditions, the OD600 of the antagonistic bacteria JK-6 fermentation broth was 1.418. When the fermentation temperature was over 40 ℃, and the pH was acidity and alkalinity, the inhibitory effect of JK-6 fermentation broth on germination of powdery mildew spores decreased. The tolerance of fermentation broth to ultraviolet light and protease were higher, and under room temperature for one month, the fermentation broth still had high antibacterial activity. The present research suggested that JK-6 could significantly inhibit R. roxburghii powdery mildew and had certain guiding significance for the prevention and control of R. roxburghii powdery mildew.