基于分离培养方法的香蒲根内生细菌多样性

Diversity of Endophytic Bacteria in Roots of Typha orientalis Estimated by Culture Method

为了探究湿地植物香蒲(Typha orientalis)根内生细菌在不同培养基环境下组成多样性与生态学意义,以北京市密云段白河人工湿地香蒲根为研究对象,采用LB培养基、R2A培养基、YG培养基联合的分离培养方法,研究香蒲根内生可培养细菌群落及其在不同培养基环境下群落结构及功能特征差异。研究结果显示,从不同培养基细菌群落丰富度看,LB培养基(152株有效菌株,12个菌属,29个菌种)分离的香蒲根内生细菌效果相对较好,R2A培养基(68株菌株,9个菌属,23个菌种)和YG培养基(85株菌株,10个菌属,19个菌属)分离的内生细菌效果相差不大。从不同培养基优势类群组成结构看,从3种培养基中分离的内生细菌都属于g-变形菌纲(Gammaproteobacteria)类群,并且在LB培养基、R2A培养基和YG培养基中最优势属分别为假单胞菌属(Pseudomonas)(47株)、拉恩氏菌属(Rahnella)(17株)和拉恩氏菌属(34株)。从不同培养基分离的菌株功能特征,在LB培养基中,参与除碳(3.95%)、重金属(15.13%)和有机污染物(8.55%)的菌株所占比例最高;在R2A培养基中,参与除磷(10.29%)的菌株所占比例最高;在YG培养基中,参与除氮(76.47%)的菌株所占比例最高;同时,分别在YG培养基(10.59%)和R2A培养基(13.24%)中分离到较多的抑制病原菌的菌株和致病菌。

To investigate difference of the diversity of the cultural endophytic bacteria community in Typha orientalis roots and adhere ecological functions of these bacteria, the roots of Typha orientalis in Baihe artificial wetland in Miyun, Beijing were sampled as a case study. We used isolation and cultivation methods based on three different culture medium （LB, R2A, YG） to analyze the structure of the endophytic bacteria community in the roots of Typha orientalis and their functional characteristics in each culture medium. The results showed that the richness of bacterial community cultured by LB medium was higher than those by R2A and YG medium, while there was no significant variation of richness of communities cultured by R2A and YG medium. All endophytic bacteria isolated from these three types of medium belong to Gammaproteobacteria group. The most dominant genera of the LB, R2A, YG medium cultivation is Pseudoraonas sp., Rahnella sp., Rahnella sp., respectively. Most of strains that involved in the removal of carbon, heavy metals and organic pollutants were found through the LB cultivation, and most strains that involved in the removal of phosphorus were found by the R2A cultivation, while strains involved in the removal of nitrogen were most likely isolated by YG cultivation. In addition, strains having inhibiting effects on pathogens and pathogens were mainly isolated in the YG and R2A cultivation respectively.