拮抗马铃薯晚疫病菌的高寒草地牧草内生细菌的鉴定及其生物功能测定

为获得对马铃薯晚疫病菌Phytophthora infestans具有拮抗效果的内生细菌,采用平板对峙法对21株分离自东祁连山高寒草地牧草的内生细菌进行抑菌能力测定,并结合形态学特征和16S r DNA基因序列同源性分析对拮抗菌株进行鉴定。结果表明,分离的21株内生细菌对马铃薯晚疫菌均有一定的抑制作用,其中262AY11、262AY6和264AY2抑菌效果最好,抑菌率分别为78.41%、78.03%和75.38%,根据16S r DNA基因序列分析将其分别鉴定为韦氏芽胞杆菌Bacillus weihenstephanensis、解淀粉芽胞杆菌B.amyloliquefaciens和枯草芽胞杆菌B.subtilis,在Gen Bank中的登陆号分别为KC414703、KC441759和HQ202817。262AY11和262AY6具有固氮能力;262AY6具有分泌IAA能力,在不含和含色氨酸的金氏培养基中产IAA的量分别为9.94 mg/L和14.79mg/L,且对马铃薯坏疽病菌Phoma foveata、马铃薯枯萎病菌Fusarium avenaceum和马铃薯炭疽病菌Colletotrichum coccodes的抑菌率分别为70.25%、62.38%和81.75%;264AY2对3种病原菌的抑菌率分别为67.09%、50.75%和75.99%。表明芽胞杆菌262AY11、262AY6和264AY2能有效抑制马铃薯晚疫病菌的生长,具有固氮和产IAA的生物学功能,且对另外3种马铃薯病原真菌也具有一定的生防潜力,可作为生防菌进行开发和利用。

Identification and determination of biological functions of endophytic bacteria from alpine pasture against Phytophthora infestans

To obtain antagonistic bacteria for control of Phytophthora infestans, the inhibitory effect of 21 bacterial isolates which from the alpine pasture on eastern Qilian mountains were determined by using opposite culture method, and the phylogenetic positions were determined with morphological characteristics and 16S rDNA genes sequence analysis. The results showed that 21 isolates from 138 endophytic bacteria had inhibition effects on P. infestans. 262AY11, 262AY6 and 264AY2 had the highest inhibition effects with the inhibition rates were 78.41%, 78.03% and 75.38%, respectively. The GenBank accession numbers of 262AY11, 262AY6 and 264AY2 were KC414703, KC441759 and HQ202817, respectively, and three of isolates were identified as Bacillus weihenstephanensis, B.amyloliquefaciens and B.subtilis, respectively. 262AY11 and 262AY6 could fix nitrogen; 262AY6 had the ability of secreting IAA, and the concentration of IAA was 14.79 mg/L in the King medium with Trp, and 9.94 mg/L without Trp. The inhibition rates of 262AY6 for Phoma foveata, Fusarium avenaceum, and Colletotrichum coccodes were 70.25%, 62.38% and 81.75%, and the inhibition rates of 264AY2 for P. foveata, F. avenaceum, and C. coccodes were 67.09%, 50.75% and 75.99%. In conclusion, the three bacterial strains had great potential for biocontrol of four fungal pathogens of potato.