西藏油菜种子内生菌分离及具有多种促生特性的拮抗菌筛选

Isolation of endophytes from rapeseeds in Tibet and screening of antagonistic bacteria with multiple plant growth promoting traits

为保障油料作物安全和绿色农业发展,从西藏自治区4个市收集5种甘蓝型油菜种子样品,通过平板分离获得种子可培养内生菌,对获得的菌株进行溶磷、解钾、固氮和产吲哚乙酸(indoleacetic acid,IAA)促生特性测定,筛选具有多种促生特性的菌株,测定其对禾谷镰孢菌Fusarium graminearum、油菜菌核病菌Sclerotinia sclerotiorum和燕麦镰刀菌F.avenaceum三种病原菌的拮抗性能及对油菜幼苗的促生效果,并对其进行分子生物学鉴定。结果显示,西藏油菜种子可培养内生菌丰富,优势菌为芽胞杆菌,共分离到110株内生菌,其中具有多种促生特性的菌株为12株,有4株菌株对禾谷镰孢菌、油菜菌核病菌和燕麦镰刀菌中2种以上菌有抑制作用,抑制率在49.50%~66.83%之间,分别为DJ-T-6、NM-8-10、DJ-L-4和BL-T-15菌株,经16S rDNA基因序列鉴定其分别为贝莱斯芽胞杆菌Bacillus velezensis、萎缩芽胞杆菌Ba.atrophaeus和缺陷短波单胞菌Brevundimonas diminuta,且均对油菜幼苗有显著的促生作用。表明所筛选的4株拮抗菌株具有促生和生防潜力。

For ensuring oilseed crop security and promoting the development of green agriculture,endophytic bacterial strains were isolated from five types of rapeseeds collected from four cities in Tibet with plate isolation,and tested for phosphate-dissolving,potassium solubilisation,nitrogen fixation,and indoleacetic acid production.In addition to antagonistic activities against Fusarium graminearum,Sclerotinia sclerotiorum,and F.avenaceum,the strains were tested for growth-promoting effects on rape seedlings,as well as molecularly identified via 16S rDNA gene sequence comparison.The results showed that Tibetan rapeseeds were rich in culturable endophytic bacteria.Total 110 endophytic bacterial strains were isolated,and the dominant species were Bacillus spp.,including 12 strains with multiple plant growth-promoting characteristics.Of them,four strains,DJ-T-6,NM-8-10,DJ-L-4 and BL-T-15,which were identified by 16S rDNA gene sequences as Ba.velezensis,Ba.atrophaeus and Brevundimonas diminuta,respectively,had inhibition rates ranging from 49.50%to 66.83%against more than two species of F.graminearum,S.sclerotiorum and F.avenaceum,and all had significant growth-promoting effects on rape seedlings.The four antagonistic strains screened were shown to have growth-promoting and biocontrol potential.