香蕉植株内生细菌群落的PCR-DGGE分析

以健康香蕉植株和感染香蕉枯萎病菌Fusarium oxysporum f.sp.cubense(FOC)后的香蕉植株的根茎叶组织为材料,提取样品中的总DNA,扩增细菌的16S rDNA的V3可变区,对扩增产物进行DGGE电泳分析,并对其中18条优势条带进行切胶回收、克隆测序和系统发育分析。结果表明,香蕉健株与病株各组织中所含内生细菌的种群丰富度为根部>假茎>叶片;感病植株组织内生细菌种类比健康植株丰富;BLAST结果为大部分克隆序列与已知细菌16SrDNA基因序列的同源性较高(94%~100%),分别归属于蓝细菌门(Cyanobacteria)、绿弯菌门(Chloroflexi)、放线菌门(Actinobacteria)、变形杆菌门(Proteobacterium)、拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和绿菌门(Chlorobi)7大类群;其中一个序列同源性较低(91%),可能代表新的分类单元。

Analysis of entophytic bacteria community structure in banana by PCR-DGGE technique

The total genomic DNA was extracted from various tissues of both the healthy bananas and the ones which were infected with Fusarium oxysporum f.sp.cubense(FOC).Then the 16Sr DNA V3 fragment polymerase chain reaction products amplified from the total genomic DNA were analyzed by denaturing gradient gel electrophoresis(DGGE).The results of sequence analysis of the 18 DGGE dominant bands showed that the population abundance of endophytic bacteria contained in the healthy banana plants and the infected plants was different.The most abundant population was found in roots,the middle in the bulb tissue and the least in leaves;The abundance of endophytic bacteria increased after infection with FOC;And most of the sequences were phylogenetically close to Cyanobacteria,Chloroflexi,Actinobacteria,Proteobacterium,Bacteroidetes,Firmicutes and Chlorobi;But the homology for one of the sequences was only 91%.It may represent a new taxon.