烟草马铃薯Y病毒拮抗细菌ZF-10的筛选鉴定及发酵条件优化OA北大核心CSTPCD

In order to obtain antagonistic bacteria with inhibitory effects on tobacco Potato Virus Y(PVY),broad-spectrum antibacterial activities and biological functions of highly effective antagonistic bacteria against PVY from tobacco rhizosphere soil were screened and characterized.The fermentation conditions for the strain were optimized by a single-factor test,and the pot control effect of the strain on tobacco PVY was verified.The results showed that 216 strains of antagonistic bacteria were isolated and purified,of which 4 strains had a significant antagonistic activity against PVY,and ZF-10 had the best antagonistic effect with an antagonistic rate of 90.20％.The strain was identified as Bacillus velezensis by morphological observation,detection of physiological and biochemical characteristics,and molecular biological analysis.ZF-10 showed inhibitory effects on various pathogenic fungi,and had the ability to produce ammonia,cellulase production,protease production,dissolve inorganic phosphorus,and siderophore production,but no ability to release potassium.The optimal fermentation medium for ZF-10 was soluble starch at 15.0 g/L,yeast extract at 25.0 g/L,magnesium sulfate at 7.5 g/L,and the optimal fermentation conditions were culture temperature at 32 ℃,inoculum at 1％,250 mL flask volume 60 mL,initial pH at 7.0,fermentation time at 36 h.The results of the pot experiment showed that the relative control effect of ZF-10 fermentation broth on tobacco PVY disease was 61.85％,indicating a satisfactory biocontrol potential.