向日葵核盘菌一种拮抗菌的初步研究

Preliminary Study on An Antagonistic Bacterium of Sclerotinia sclerotiorum of Sunflower

从土壤带菌的菌核上分离出一种向日葵核盘菌的拮抗菌,初步鉴定为革兰氏阴性菌,杆状。该菌室内平板对峙培养表现出良好的拮抗效果,拮抗带宽度可达到10 mm以上,且转代培养后其拮抗活性稳定。拮抗菌培养液对向日葵种子萌发没有明显的抑制作用,对生根有一定的促进作用。温室盆栽试验证明该菌对向日葵幼苗期菌核病有明显防效,成苗率达到75%,而对照只有34%。该拮抗菌可作为向日葵菌核病的生防材料进一步加以研究和利用。

An antagonistic bacterium was isolated from infected sclerotium. The identification result showed that the antagonistic bacterium was bacillus and G^-. The antagonistic assay in plates showed that the antagonistic bacterium exhibited in vitro antagonistic activity to Sclerotinia sclerotiorum by the antifungal band with a width of over 10 mm and the inhibitive efficacy maintained stable. Greenhouse experiments showed that the antagonistic bacterium could not inhibit germination of seed, and germination rate in culture liquid of antagonism was 98.6%, 97.3% in H2O, and 93.3% in PS culture liquid respectively. The test also showed that the antagonistic bacterium could promote growth of root, and average root length treated with antagonistic bacterium was 1.8 cm, obviously higher compared to the check （only 1.5 cm）. In addition, the antagonistic bacterium showed significant biological control ability to Sclerotinia sclerotiorum at seedling stage in greenhouse experiments, and frequency of seedling emergence reached 75 %, significantly higher than that of the check （only 34 % ）. The results indicated that the antifungal bacterium was well worth further study.