辣椒根际链霉菌WKFF34的分离鉴定及拮抗作用

摘要

Actinomycete is an important resource of antibiotic and antagonistic microbe.In this study,in order to find valuable actinomycete strain and evaluate its antagonistic activity,the strain WKFF34 was isolated from the rhizosphere soil collected from the chilli(Capsicum annuum)plantation by the serial dilution method.Its biological activities against several phytopathogens and cyanobacteria were assessed using spread plate,plate confrontation,mycelium growth rate and double-plate methods.The antibiotic sensitivity of the strain WKFF34 was tested by Kirby Bauer disc diffusion method.The strain WKFF34 was identified based on its morphological, cultural,physiological and biochemical characteristics and 16S rRNA sequence analysis.The isolate was found to possess a remarkable inhibitory activity against indicatory microorganisms.The antimicrobial spectrum test and inhibition re-screening found that the fermentation broth of the strain WKFF34 displayed broad antimicro-bial spectrum,and strongly inhibited the growth of Sclerotinia sclerotiorum,with an inhibition rate of 80.43%. The results of antibiotic sensitivity test showed that the strain WKFF34 was susceptible to twelve antibiotics (compound sulfamethoxazole,vancomycin,chloramphenicol,minocyline,kanamycin,medemycin,doxytetracy-cline,polymyxin,neomycin,gentamycin,amikacin and ampicillin).Based on the characteristics of morphologi-cal,cultural,physiological and biochemical tests and 16S rRNA sequence phylogenetic analysis,the strain WKFF34 was identified as a strain of valid specie Streptomyces cyaneofuscatus,and named after Streptomyces cy-aneofuscatus WKFF34.It has potential application prospects for plant protection and environmental protection due to its strong inhibition on crop pathogens and algicidal effect.%放线菌是产抗生素和生防菌的重要来源,为发现有价值的拮抗放线菌并评估其拮抗活性,采用连续稀释法,从辣椒根际土壤样品中分离筛选到一株放线菌WKFF34.使用平板对峙法、抑制菌丝生长速率法及双层平板法分别对该菌株的抑菌活性以及溶藻活性进行了生物活性评估,通过纸片法测定了该菌株对不同抗生素的药物敏感性,基于形态学特征、培养性状、生理生化特征和16S rRNA基因序列的系统发育分析,对其进行分类鉴定.研究发现,菌株WKFF34对多种供试植物病原细菌、真菌和铜绿微囊藻具有较好的拮抗作用.抗菌谱及抑菌活性复筛发现该菌株的发酵液有广谱的抑菌活性,其中对油菜菌核病原菌的抑制效果最好,抑制率达80.43%.药敏试验结果表明WKFF34对12种抗生素如四环素、复方新诺明、万古霉素、氯霉素、米诺环素、麦迪霉素、强力霉素、多粘菌素、新霉素、庆大霉素、阿米卡星和氨苄西林敏感.研究发现,菌株WKFF34属于链霉菌属中有效发表种蓝微褐链霉菌(Streptomyces cyaneofuscatus)的一个菌株,鉴定为 Streptomyces cyaneofuscatus WKFF34,因其具有较强的抑菌活性和溶藻活性,在作物保护和环境保护中具有潜在的应用前景.