野生酸枣内生细菌筛选、鉴定及其抑菌活性测定

为广泛开发植物内生菌资源,采用组织分离法从野生酸枣的根、茎、叶和果实中进行生防菌的分离和筛选,通过平板对峙法和发酵液法测定了所得菌株对8种植物病原菌的活性,并利用生物学和分子学方法对所得菌株进行了鉴定。结果显示,从野生酸枣的根、茎、叶和果实中共分离得到76株内生细菌;通过对所有菌株进行初筛和复筛,最终得到8株拮抗作用较强的菌株,菌株SZG-23、SZG-1、SZY-13和SZS-3对梨黑斑病菌Alternaria kikuchiana和黄瓜枯萎病菌Fusarium oxysporum f.sp.cucumerinum的抑制作用较强,抑制率均分别高于82.5%和71.1%,其中菌株SZG-23的抑制率最高,达90.3%和72.4%。菌株SZG-23发酵液对8种植物病原菌生长均有一定的抑制作用,其中对梨黑斑病菌和番茄灰霉病菌Bortytis cinerea的抑制作用最好,抑制率分别达92.2%和90.5%。菌株SZG-23的抗利福平突变菌株能在酸枣幼苗中定殖和移动。结合形态观察、生理生化特征及16S r DNA同源性分析将菌株SZG-23鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens,16S r DNA序列在Gen Bank中登录号为KF483660。

Study on screening, identification and detection of antibiotic activity of endophytic bacteria from wild jujube

In order to exploit the resources of endophyte from plants, bio-bacteria were separated and screened from the roots, stems, leaves and fruits in wild jujube with tissue separation method. The activity of the acquired strains on the eight pathogens was determined with the flat plate confrontation method and fermentation method. The obtained strain was identified with biological and molecular methods. The results showed that 76 endophytic bacterial strains were isolated from roots, stems, leaves and fruits in wild jujube. The inhibition of all strains was tested on pathogens through the primary and secondary screening. Finally, there were eight of strong antagonism endophytic bacteria were obtained. Among them, strains of antagonist SZG-23, SZG-1, SZY-13 and SZS-3 were stronger on Alternaria kikuchiana and Fusarium oxysporum f. sp. cucumerinum, and inhibiting rate exceeded 82.5% and 71.1%, respectively. Strain SZG-23 had the strongest inhibiting rate on two pathogens, up to 90.3% and 72.4%. Its fermentation broth could inhibit eight kinds of pathogens, and inhibiting rate on A. kikuchiana and Bortytis cinerea were the best, up to 92.2% and 90.5%. The mutant strain of strains SZG-23 resisting Rif could colonize and move in jujube seedling. According to morphology, physiological and biochemical characters as well as 16S rDNA sequences, strain SZG-23 was identified as Bacillus amyloliquefaciens (GenBank accession number was KF483660).