关键词: 拮抗菌, 生长条件, 发酵液, 抑菌, 稳定性

Abstract: 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.

Key words: antagonistic bacteria, growth conditions, fermentation broth, antibacterial, stability