玉米灰斑病拮抗链霉菌S3-5的筛选及鉴定

Screening and identification of an antagonistic Streptomyces S3-5 against gray leaf spot in maize

为筛选对灰斑病有高效拮抗作用的微生物,采集四川双流、平武以及云南文山州三地玉米种植田土壤,利用平板对峙实验筛选到对灰斑病病原菌玉蜀黍尾孢菌（Cercospora zeae-maydis Tehon＆Daniels）菌丝生长有抑制作用的6株细菌和2株放线菌.放线菌S3-5的抑菌效果最好,其抑菌能力是可稳定遗传的性状;结合菌株形态学、生理生化特征以及16S rDNA序列同源性分析将S3-5鉴定为淡紫灰链霉菌（Streptomyces lavendulae）.S3-5对玉蜀黍平脐蠕孢、立枯丝核菌、茄链格孢、核盘菌、胶孢炭疽菌、链格孢菌等常见植物病原真菌均有较好抑制作用,其生长的NaCl浓度耐受度为5%,最适生长温度为25~30℃,显示S3-5具有应用于田间抑制灰斑病发生的潜能.

In order to screen the efficient antagonism against the pathogenic fungus, soil samples from Shuangliu, Pingwu and Wenshanzhou were collected and a total of 8 strains showed inhibition effects on C. zeae-rnaydis, among which 2 were actinomyces. Actinomyces S3-5 obtained from Gauses synthetic agar had the strongest inhibition effect on C. zeae-rnaydis and this characteristic was genetically stable. S3-5 was defined as Streptornyces lavendulae according to its morphological, physiological and biochemi- cal characteristics, and 16S rDNA gene sequence homology analysis. S. lavendulae 83-5 had suppres- sion ability on several common pathogenic fungi including Bipolaris rnaydis, Rhizoctonia solani, Alternaria solani Sorauer, Sclerotinia sclerotiorum , Colletotrichum gloeosporioides , and Alteraria alternata. S3-5 could survive below 5 % salt concentration and the optimum growth temperature ranged from 25℃ to 30 ℃, indicating that S3-5 had a good environmental adaptability and a potential to be applied in the prevention of gray leaf spot in maize plantation.