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目的:分离对农作物致病菌具有拮抗作用的株内生放线菌,并对其进行系统鉴定。方法:经表面消毒采用研磨法从蓝麻黄中分离内生放线菌;再通过琼脂扩散法筛选具有抗农作物致病菌活性的内生放线菌;利用菌株形态特征、培养特征、生理生化特性和16S rRNA序列分析对拮抗菌进行鉴定;并对代谢产物做了生物碱的检测。结果:从蓝麻黄中分离到菌7株内生放线菌而其中的XJEG-GA-16具有较好拮抗作用,该菌对7种植物病原菌具有较好的拮抗作用,尤其是对玉米大斑病菌的拮抗作用显著抑菌圈大于20mm。经形态学观察,培养特征、生理生化特和分子分类学分析鉴定与Streptomyces albus subsp.albus在同一个分支上,同源性为99%。该菌株代谢产物中含有生物碱。结论:蓝麻黄内生放线菌XJEG-GA-16对农作物致病菌有明显的拮抗作用,最终鉴定为链霉菌Streptomyces albus subsp.Albus。
OBJECTIVE: To isolate endophytic actinomycetes that antagonize pathogenic bacteria in crops and systematically identify them. Methods: The endophytic actinomycetes were isolated from blue-yellow plant by surface-sterilizing method. The endophytic actinomycetes with anti-plant pathogenic fungi were screened by agar diffusion method. The morphological characteristics, culture characteristics, physiological and biochemical characteristics And 16S rRNA sequence analysis of antagonistic bacteria were identified; and metabolites alkaloids were detected. Results: Seven strains of endophytic actinomycetes isolated from blue ephedra, of which XJEG-GA-16 had a good antagonistic effect. The bacterium had good antagonistic effects on seven plant pathogens, especially on large spot of corn The antagonistic effect of bacteria significant inhibition zone greater than 20mm. Morphological observation, culture characteristics, physiological and biochemical characteristics and molecular taxonomic analysis identified on the same branch as Streptomyces albus subsp. Albus with 99% homology. The strain metabolites contain alkaloids. CONCLUSION: The endophytic actinomycetes XJEG-GA-16 from Streptomyces acerifolia has obvious antagonism against pathogenic bacteria in crops and finally identified as Streptomyces albus subsp. Albus.