一株拮抗香蕉枯萎病菌的链霉菌分离和鉴定

摘要

A Streptomyces strain named HW1 against banana wilt caused by Fusarium oxysporum f. sp. cubense race 4(FOC4) was isolated from a hot spring in Hainan Province. The morphological characteristics, cultural characteristics, physiological, biochemical characteristics and 16S rDNA sequences analysis of Streptomyces HW1 were studied. Besides, the co-culture tests in soil between HW1 and FOC4 were studied at different temperature.The results showed that, on PDA medium, the substrate mycelia of HW1 had no partition, and the spores were round and clustered on the aerial mycelia. The clone of HW1 was white when it started growing on PDA medium,after matured, the aerial mycelia of HW1 became gray gradually and finally became brown because of spores.Besides, HW1 could produce yellow ,soluble pigment on PI)A medium. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the related species. HW1 strain was preliminarily classed to Streptomyces costaricanus. The co-culture tests in soil between HW1 and FOC4 indicated that HWI showed better resistance on FOC4 when grown at 45 C than at room temperature.%从海南温泉中分离到1株对香蕉枯萎病病原菌4号小种有强拮抗作用的链霉菌菌株HW1,对该菌株进行了形态特征、培养特征、生理生化特征及16S rDNA序列分析.并对该菌株和香蕉枯萎病病原菌4号小种在土壤中进行了不同温度下的共培养试验.结果表明,其在PDA培养基上,内生菌丝无横隔、不断裂;孢子圆形,簇聚在气生菌丝上.在PDA培养基上,菌落生长开始为白色,培养成熟后,气丝逐渐南白色变灰,最后因为产生孢子变为褐色,并可产黄色可溶色素.以16S rDNA序列为基础构建了菌株HW1的系统发育树,其与模式链霉菌株的16SrDNA序列的同源性为99%.初步将该菌株鉴定为Streptomyces costaricanus.HW1菌株和香蕉枯萎病病原菌4号小种在土壤中的共培养试验表明,HW1菌株在45℃温度的生长环境中,表现出对香蕉枯萎病病原菌较好的抗性.