克隆文库分析红树林土壤中放线菌的多样性

直接提取8个红树林土壤的总DNA,用放线菌门的特异性PCR引物进行扩增,通过构建16S rRNA文库,测序及系统发育分析,获取新颖放线菌菌株.结果发现,有酸微菌亚纲(Acidimicrobidae) (30.2％)、放线菌亚纲(Actinobacteridae) (68.0％)、红蝽菌亚纲(Coriobacteridae)(1.1％)和去腈基菌亚纲(Nitriliruptoridae)( 0.7％)成员,没有红色杆菌亚纲( Rubrobacteridae)成员.仙农指数和Chao1物种多样性指数(Schao1)表明,红树林土壤样品中含有丰富的放线菌多样性.以16S rDNA基因的相似率≥97％作为临界点,45.1％可能代表新候选种(candidate species)(未培养、分离).本研究为进一步获取新颖的红树林放线菌资源提供了基础.

Clone Library Analysis of Actinobacterial Diversity in Mangrove Soils

Cultivation-independent methods could be used to gain an insight into the presence,distribution and taxonomic diversity of Actinobacteria in natural habitats.In this research,total DNA were extracted directly from soil samples collected from eight mangrove areas in the south China,and used as the template for polymerase chain reaction(PCR)amplification,which employed specific primers for phylum Actinobacteria.The 16S rRNA gene libraries were then constructed.Biodiversity was analyzed by DNA sequencing and phylogenetic characters.The results revealed there were four subclasses in Actinobacteria phylum: Acidimicrobidae(30.2%),Actinobacteridae(68.0%),Coriobacteridae(1.1%)and Nitriliruptoridae(0.7%),but without the subclass of Rubrobacteridae.The results of diversity Shannon-Wiener index(H′)and calculated species richness(Schao1)indicated that culture-independent studies showed that mangrove soil had a high diversity of Actinobacterial species that were rarely recovered by cultivation-based methods.Employjng a standard of using 16S rDNA similarity≥97% as the same species,there were at least 45.1% of Actinobacterial species undiscovered.This study provides a good insight into the diversity of Actinobacterial species in mangrove soil and would guide the selective isolation of members for novel actinomycete taxa.