抗水稻细菌性条斑病芽孢杆菌菌株的选育

摘要

[Objective] The aim was to screen a Bacillus strain with antagonistic ability to bacterial leaf streak and identify,and optimize the fermentation condition to enhance the spore production.[Method] We used Oxford cup method to determine the antagonistic ability;16S rDNA sequence analysis was used to identify the strain;single factor and response surface tests to optimize sporulation conditions.[Result] The JF48 strain belonged to Bacillus amyloliquefaciens,and the diameter of the inhibition zone reached (37 ± 3) mm;the optimal spore culture conditions of Bacillus amyloliquefaciens JF48 were as followsed:corn flour 14.69 g/L,soybean meal 9.54 g/L,CaCl22.O0 g/L,NaCl 5.00 g/L,MgSO4 1.00 g/L,liquid volume 50 mL/250 mL,rotation 200 r/min,initial pH 7.5,temperature 38 ℃,inoculation 1.0％.Under this fermentation condition,the spore production of JF48 strain reached 3.6 × 109 cfu/mL,which was 105 times that of optimizing before.[Conclusion] The strain JF48 has a strong antagonistic ability to bacterial leaf streak and response surface method effectively improves its spore production.%[目的]分离筛选得到抗水稻细菌性条斑病芽孢杆菌菌株,并进行鉴定,最后优化其产芽孢发酵条件.[方法]采用牛津杯法测定菌株拮抗能力,通过单因素试验对培养基成分和培养条件进行优化,利用Plackett-Burman试验筛选出3个显著影响因子,最后利用响应面法确定显著因子的最佳组合浓度.[结果]菌株JF48对细菌性条斑病菌的抑菌圈直径达(37±3)mm,经鉴定为解淀粉芽孢杆菌,其最佳产芽孢发酵条件为玉米粉14.69 g/L,豆粕粉9.54 g/L,CaCl22.00 g/L,NaCl 5.00 g/L,MgSO41.00 g/L,装液量50/250 mL,转速为200 r/min,初始pH 7.5,温度38℃,接种量1.0％,最高芽孢产量为3.6×109 cfu/mL,与优化前相比提高了105倍.[结论]菌株JF48对细菌性条斑病具有很强抗性,响应面法有效提高了其芽孢产量.