生防放线菌CY-14的鉴定及其发酵液对香蕉炭疽病的防治效果

香蕉炭疽病是由香蕉炭疽菌Colletotrichum musae侵染引起的，是香蕉采后贮藏、运输和销售过程中发生的主要病害之一，严重影响中国香蕉的北运和出口。从土壤中分离到1株对香蕉炭疽菌具有拮抗作用的放线菌CY-14，通过形态特征、培养特性、生理生化特性和16S rDNA序列分析对该菌株进行了初步鉴定，并对其发酵液进行了活性评价。结果表明:经初步鉴定，该放线菌为链霉菌属Streptomyces sp.；其发酵液稀释10倍对香蕉炭疽菌的抑制率达92.5%，同时对其他8种植物病原真菌均具有较强的抑菌活性，抗菌谱较广；其发酵液热稳定性较好，经100 ℃处理2 h后，体积分数为10%的发酵液对香蕉炭疽菌的抑制率为55.7%，发酵液稀释1 000倍后仍可完全抑制香蕉炭疽菌的孢子萌发；CY-14纯发酵液对香蕉炭疽病具有一定的防效，与对照药剂1 000 mg/L百菌清的防效相当。菌株CY-14作为香蕉炭疽病的生防放线菌，具有发现新型抗生素或者活性化合物的潜能，可对其进行深入的研究。

Identification of a biocontrol actinomycete strain CY-14 and the effect of its fermentation broth on Colletotrichum musae

Banana anthracnose is caused by Colletotrichum musae. In China, it is one of the main diseases that happens during the post harvest storage, including transportation and sale, which seriously affects the north transportation and export of the banana. A actinomycete strain of CY-14, which had antagonistic effect on C. musae, was isolated from the soil. The strain was preliminarily identified by morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. The bioactivity of its fermentation broth was also evaluated. The results showed that strain CY-14 was preliminarily identified as Streptomyces sp. The inhibition rate of 10 times diluted fermentation broth to C . musae was 92.5%. The fermentation broth also had a broad-spectrum antifungal activity to other 8 kinds of plant pathogenic fungi. In addition, the fermentation broth had good thermal stability. After heated up at 100 ℃ for 2 hours, the inhibition rate of 10% fermentation broth was 55.7%. The 1 000 times diluted fermentation broth could completely inhibited the spore germination of C . musae. While the pure fermentation broth had the same control effect as 1 000 mg/L chlorothalonil. Strain CY-14, as a biocontrol actinomycetes of banana anthracnose, has a potential application in the discovery of new antibiotics or active compounds, and is well worthy of further study.