柑橘溃疡病生防内生细菌的筛选、鉴定及其活性代谢产物的稳定性

Screening,identification of bio-control endophytic bacterium against citrus canker and stability of its bioactive metabolites

通过皿内检测和离体叶片法筛选到一株柑橘溃疡病生防内生细菌GN232,对其进行了分类鉴定,并对其抗细菌活性代谢产物的特性进行了研究。形态特征、培养特性、生理生化特性和16S rDNA序列分析表明,该内生细菌为枯草芽孢杆菌(Bacillus subtilis subsp.subtilis);发酵滤液活性测定结果表明,菌株GN232抗细菌活性代谢产物在中性环境下稳定,对温度不敏感,紫外线照射25 min后发酵滤液抑菌活性降低,胰蛋白酶对发酵滤液活性无明显影响;此外,该菌株发酵上清液和农用链霉素混用后对溃疡病菌的抑制效果较单独发酵滤液、农用链霉素的抑菌效果分别提高26.8%和20.7%。

In this experiment, an endophytic bacterium named GN232 against Xanthomonas axonopodis pv. cirri Xac. was isolated from navel orange and screened in plate and on leaf in vitro. And the identification and charac- terisics of its antibacterial active metabolites were studied. By the analyses of morphological, cultural, physiological, biochemical characteristics and 16S rDNA sequence, GN232 was indentified as Bacillus subtilis subsp, subtilis. The activity detection of its fermentation liquid indicated that the antibacterial substances were not sensitive to the temper- ature less than 100~C, and stable under neutral pH/trypsin, but the activity was decreased under ultraviolet radiation for 25 minutes. In addition, when the fermentation liquid was mixed with agricultural streptomycin, the inhibition effects on Xanthomonas axonopodis pv. citri were increased by 26. 8% and 20. 7% compared with using fermentation liquid or agricultural streptomycin separately.