Abstract: Burkholderia cepacia is regarded as genetically distinct but phenotypically similar bacterial group referring to Burkholderia cepacia complex(Bcc).It’s not only found in clinic but also in rice growing environment.It is very important in microbial safety of rice to understand the genomovar status of Bcc.Genomovar analysis was performed among 87 Bcc isolates by means of Hae Ⅲ-recA RFLP assays and species-specific PCR tests.Three genomovars were found in the rice rhizosphere includingⅠ,ⅢB and Ⅴ,and genomovarⅤwas the predominant.GenomovarsⅠ,ⅢA and ⅢB existed in the clinical samples,and genomovar ⅢA was the most popular.It showed genomovar composition was different between the Bcc strains from the rice rhizosphere and clinical environment.Moreover,the results revealed the genetic diversity of Bcc strains from the rice rhizosphere,and genomovar Ⅲ referred as virulent species in clinic also existed in the rice rhizosphere.

Key words: Burkholderia cepacia complex, rice rhizosphere, clinical bacteria, genomovars, diversity, biological safety

摘要： 洋葱伯克氏菌是一组表型相似但基因型不同的细菌群（Burkholderia cepacia complex, 简称Bcc）,它存在于水稻生境和医院中，了解水稻根围Bcc菌株基因型的地位对水稻微生物安全性具有重要的意义。以recA基因的HaeⅢRFLP技术和基因型特异性PCR扩增为主要方法对来自水稻根围的78株和来自医院的9株Bcc菌株进行了基因型分析。研究表明水稻根围存在Bcc菌株Ⅰ、ⅢB和Ⅴ基因型， 其中Ⅴ型为优势菌；而在医院来源的Bcc菌株中，存在Ⅰ、ⅢA和ⅢB型，以ⅢA型菌株最多。这表明我国水稻根围和医院中的洋葱伯克氏菌基因型构成存在差异。同时研究发现水稻根围的Bcc菌群具有明显的遗传多态性，且存在致病力强的Ⅲ型菌株。

关键词: 洋葱伯克氏菌群, 水稻根围, 医院分离菌株, 基因型, 多样性, 生物安全