五味子中内生拮抗活性细菌的分离与筛选

Isolation and screening of endophytic bacteria with antagonistic activity from Schisandra chinensis

目的从不同地区采集五味子植株,分离内生细菌,并进行菌群密度、拮抗菌筛选和抑菌活性研究。方法采用平板分离法分离内生细菌并纯化典型菌株;平板对峙法测定体外拮抗活性;生长速率法测定抑菌活性。结果不同种植地、五味子不同器官中内生细菌的菌群密度差异较大,野生的较栽培的大;五味子各器官中,根中的内生细菌最多,其次为茎,叶片中最少。从分得的大量内生细菌中共纯化出302株内生细菌,拮抗菌比率平均为24.19%。从中选出了12株对五味子茎基腐病菌、人参根腐病菌、棉花枯萎病菌、番茄灰霉病菌、人参黑斑病菌具有较好拮抗作用的菌株。12株菌株的发酵产物对供试病原菌菌丝生长均有一定的抑制作用,其中JYg-2对人参根腐病的抑制率最高,达80.02%。结论五味子植株体内存在大量内生细菌,并且含有一定比率的拮抗菌,拮抗活性稳定。因此五味子内生细菌可以成为开发拮抗菌资源的重要途径,并具有较大潜能。

Objective To isolate the endophytic bacteria from the plants in Schisandra chinensis, collected from different regions, and to study the flora density, antagonistic bacteria screening, and antibacterial activity. Methods The endophytic bacteria were isolated by plate isolation method, and to purify their typical strains. Their antagonistic activity in vitro and antibacterial activity were tested by plate confrontation method and growth rate method, respectively. Results The difference in the flora density ofendophytic bacteria in the wild cultivars ofS. chinensis was significantly higher than that in the cultured cultivars. Among the parts ofS. chinensis, the density of endophytic bacteria was the highest in the roots, followed by the stems, and the lowest in the leaves. Endophytic bacteria （302 strains） were obtained from the isolated bacteria by purification, and the ratio of antagonistic bacteria was 24.19%. Twelve strains were selected with antagonistic action against the pathogens of Fusarium oxysporum, Fusarium Solani, Fusarium oxyrForum, Botrytis cirerea, and Alternaria panax, and the fermention of them had inhibitory effect on inhibiting mycelial growth of the tested pathogens. The inhibitory rate of JYg-2 to A. panax was the highest with 80.02%. Conclusion Plenty ofendophytic bacteria are found in healthy plant of S. chinensis and some of them have stable antagonistic activity. Endophytic bacteria of S. chinensis have the great potential on developing biocontrol bacteria.