稻瘟菌拮抗细菌的筛选与鉴定

从不同水稻根际土壤样品中分离纯化了486株细菌。采用平板测定法和微培养离体测定试验获得12株对稻瘟菌有不同程度抑制作用的拮抗细菌。结果表明:B4,B8,B18,B31,B34,B73和B74等菌株对稻瘟菌菌丝生长抑制率均在80%以上,其培养液100%抑制稻瘟菌孢子萌发;同时对水稻纹枯病菌、油菜菌核病菌、小麦赤霉病菌、草莓炭疽病菌和黄瓜枯萎病菌等多种病原真菌有较好抑制作用,经鉴定该组拮抗细菌为枯草芽孢杆菌。B1,B43和B44菌株对稻瘟菌菌丝生长和孢子萌发有较好抑制作用,对水稻纹枯病菌具有一定的抑制作用,经鉴定为短小芽孢杆菌。B48和B59为链霉菌,对稻瘟菌的抑菌带明显,但对稻瘟菌孢子萌发和附着胞的形成抑制作用不明显。

Screening and identification of antagonistic bacteria to Magnaporthe grisea

A total of 486 bacterial isolates were obtained from different rice rhizosphere soil samples.Twelve out of them showed antagonistic activities against Magnaporthe grisea using both in vitro dual culture method and micro-culture method.In particular,strains B4,B8,B18,B31,B34,B73 and B74 showed more than 80% inhibition in the hyphal growth of M.oryzae,while spores germination of M.grisea were completely inhibited by the supernatants of these antagonistic bacteria.Furthermore,these antagonistic bacteria were able to inhibit the hyphal growth of Rhizoctonia solani,Sclerotinia sclerotiorum,Fusarium graminearum,Colletotrichum gloeosporioides and Fusarium oxysporum f.sp.cucumerinum and were identified as Bacillus subtilis.In addition,strains B1,B43 and B44 of Bacillus pumilus showed a moderate inhibition in the hyphal growth and spores germination of M.grisea and a slight inhibition in the hyphal growth of R.solani,while strains B48 and B59 of Streptomyces showed strong inhibition in the hyphal growth and slight inhibition in spore germination and appressorium formation of M.grisea.