铁皮石斛内生细菌群落结构分析

采集人工种植2年的铁皮石斛，将根、茎和叶研磨为粉末，采用NA培养基分离纯化其内生细菌，酶切去除冗余，利用16S rRNA基因序列同源性分析，对铁皮石斛根、茎和叶中分离得到的49株内生细菌进行分离鉴定。结果表明，获得的49株内生细菌在根、茎、叶中分别有24株、15株和10株，分别属于芽孢杆菌属的5个种、假单孢杆菌属的1个种和沙雷氏菌属的1个种。分离出的内生细菌表现出一定程度的细菌区系相似性，也表现出细菌区系的器官特异性。铁皮石斛内生细菌在石斛根部分布的属、种数量明显比茎、叶多，土壤可能是铁皮石斛内生细菌的主要来源；铁皮石斛不同部位内生细菌群落结构存在一定差异，群落种数根＞茎＞叶。研究获得荧光假单胞杆菌20株，占总内生细菌数量的40.82％，判断其可能为优势菌株。

Analysis of Community Structure of Endophytic Bacteria from Dendrobium officinale

2-year-old cultivated Dendrobium officinale was collected, and its root, stem and leaf were grinded into powder.The NA medium was used to study the diversity of endophytic bacteria from Dendrobium officinale .After removing of the redundant isolates , 49 strains were founded.49 endophytic bacteria isolates were ascertained , and among these , 24 strains were from roots , 15 strains were from stems , 10 strains were from leaves.Phylogenetic a-nalysis based on 16S rRNA sequences showed that the 49 strains attributed to 5 species of the genera Bacillus , 1 specie of Pseudomonas and 1 specie of Serratia . The isolated endophytic bacteria in roots , stems and leaves showed that there were some similarities in terms of bacterial flora and organ-specific of bacterial flora .Most of the endophytic bacteria were distributed in the root , and the soil might be the major source of endophytic bacteria . Community structure diversity order was root 〉stem〉leave.The acquired 20 Pseudomonas fluorescens accounted for 40.82 % of the total separated endophytic bacteria , and they were judged activity strains .