铅锌矿区蜈蚣草内生放线菌的多样性及群落结构

Diversity and community structure of endophytic actinomycetes of Pteris vittata in a Pb-Zn mining area

为了认识重金属累积对植物内生菌的影响,采用变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)技术及序列分析对四川汉源铅锌矿区蜈蚣草内生放线菌的多样性进行了研究,并分析了内生放线菌多样性与Pb、Zn、Cu和Cd等主要重金属之间的相互关系.结果表明,蜈蚣草不同部分内生放线菌的群落结构和多样性存在一定的差异,多样性指数在2.79~3.29之间,与其他非重金属污染环境植物内生放线菌的多样性指数相似,说明在重金属污染地区仍然存在较为多样的内生放线菌类群.相关分析表明,蜈蚣草内生放线菌多样性指数与Cu、Cd和Pb的含量之间存在显著负相关.DGGE条带序列系统发育显示,链霉菌(Streptomyces)、假诺卡氏菌(Pseudonocardia)、小单孢菌(Micromonospora)、Xianggella为蜈蚣草内生放线菌优势类群,拟诺卡氏菌(Nocardiopsis)、小双孢菌(Microbispora)、马杜拉放线菌(Actinomadura)、弗兰克氏菌(Frankia)以及一些未培养放线菌也在蜈蚣草中存在.研究表明铅锌矿区蜈蚣草内生放线菌存在丰富的多样性,重金属的累积影响了内生放线菌的分布.

To better understand the impact of heavy metal accumulation on plant endophytes,this study employed both denaturing gradient gel electrophoresis(DGGE) and sequencing techniques to investigate the diversity of endophytic actinomycetes in the Pteris vittata isolated from a zinc-lead mine in Hanyuan of Sichuan Province,China.The relationship between the diversity of endophytic actinomycete community and the major heavy metals like Pb,Zn,Cu and Cd was also examined.The results indicated that the diversity and community structure of endophytic actinomycetes varied among different plant tissue parts.The value of Shannon-Wiener diversity index of endophytic actinomycetes,ranging from 2.79 to 3.29 and similar to those in other unpollution environments,suggested that a high diversity of actinomycete species still occurred inside the P.vittata growing in areas contaminated by heavy metal.Correlation analysis revealed a significant negatively correlation between the diversity index and the concentrations of Cu,Cd and Pb.Phylogeny analysis of the DGGE bands showed that Streptomyces,Pseudonocardia,Micromonospora and Xianggella were the predominant species,and Nocardiopsis,Microbispora,Actinomadura,Frankia and some uncultured actinomycetes could also colonize the P.vittata.Study results suggested that a relatively high diversity of endophytic actinomycetes of the P.vittata in the zinc-lead mining area,and heavy metal accumulation affected the distribution of endophytic actinomycetes.