大豆疫霉拮抗菌株的筛选与鉴定

Screening and Identification of Antagonistic Strain against Phytophthora sojae

[目的]筛选具有生防潜力的大豆疫霉拮抗菌,为寻找病害防控措施、设计新的疫病控制策略提供基础。[方法]从黑龙江省3个不同地区采集大豆根围土壤样本并分离各类土壤微生物,采用对峙培养法筛选出对大豆疫霉有拮抗作用的微生物,并在此基础上测定拮抗力较强微生物对大豆疫霉菌的生长抑制率及其对大豆疫病的控制作用。[结果]从土壤中分离得到1株拮抗效果相对较好的细菌,命名为B048菌株。对峙试验结果显示,拮抗细菌B048菌株对大豆疫霉的生长抑制率达97.5%;拮抗持久力测定显示,在与大豆疫霉对峙培养21d时抑菌带宽度仍达20.0mm;在盆栽试验中,B048对大豆疫病的防治效果为100%。经形态学和16SrDNA序列分析,初步鉴定该拮抗细菌为短小芽孢杆菌(Bacillus pumilus)。[结论]拮抗细菌B048菌株具有较好的开发成大豆疫病生物防治菌的前景。

[Objective]The paper was to screen the antagonistic strain against Phytophthora sojae with biocontrol potential,and provide basis for searching control measures and designing new control strategies against P.sojae.[Method]The rhizosphere soil of soybean was collected from three different places in Heilongjiang Province,and various soil microorganisms were isolated.Dual culture method was used to screen the microorganism with antagonistic effect against P.sojae.On this basis,the growth inhibition rate of the microorganism with stronger antagonistic effect against P.sojae was determined,and its control effect against P.sojae was also measured.[Result]A strain of bacterium with relatively good antagonistic effect was isolated from soil,and named as strain B048.Dual test showed that the growth inhibition rate of antagonistic bacterium B048 against P.sojae reached 97.5%.Antagonistic endurance tests showed that the width of inhibition zone was still 20.0 mm after dual culture with P.sojae for 21 d.In potting experiment,the control effect of B048 against P.sojae was 100%.The antagonistic bacterium was primarily identified to be Bacillus pumilus through morphology and 16S rDNA sequence analysis.[Conclusion]The antagonistic bacterium B048 had good prospect to be developed as the biocontrol bacterium against P.sojae.