毛乌素沙地中间锦鸡儿根瘤菌遗传多样性及16S rDNA全序列分析

Genetic Diversity and 16S rDNA Sequence of Rhizobia Isolated from Nodules of Caragana intermedia in Maowusu Sandland

野生豆科植物中间锦鸡儿是毛乌素沙地的优势种。从蛋白质和DNA水平分析与其共生的根瘤菌的遗传多样性。在蛋白质水平上 ,2 4株中间锦鸡儿根瘤菌和 9株参比菌株分为 2组 ,A组包含 95 8%供试中间锦鸡儿根瘤菌 ,参比菌株聚为B组 ,菌株GH72不与其余供试根瘤菌聚类。应用 1 6SrDNAPCR RFLP方法将供试菌株分为 2 2种基因型 ,中间锦鸡儿根瘤菌组成 1 2种 ,其余 1 0种由参比菌株构成 ,表明中间锦鸡儿根瘤菌具高水平遗传多样性。选取代表菌株GH2 0 0 1进行 1 6SrDNA全序列测定 ,与已知相关根瘤菌菌株 1 6SrDNA进行同源性比较 ,构建系统发育树状图。GH2 0 0 1位于Rhizobium分支 ,与且Agrobacteriumradiobacter、Ag .rubi、Rhizobiumgiardinii、R .mongolense、R .yanglingense、R .galegae和R .huautlense的序列同源性分别达到 99%、98 3 %、96 3 %、95 5 %、95 6 %、95 2 %和 95 7%。

Caragana intermedia is a wild dominant shrub in Maowusu sandland. Genetic diversity of symbiotic rhizobia was studies at the level of whole cell soluble protein and DNA. Twenty four Caragana intermedia rhizobia and nine reference strains were clustered into 2 groups. Group A was composed of 95.8% Caragana intermedia rhizobia, group B included all reference strains, while GH72 strain was quite different from other strains. Twenty two genotypes were obtained from 16S rDNA PCR-RFLP. Caragana intermedia rhizobia belonged to 12 genotypes, which showed rich genetic diversity. An unrooted phylogenetic tree was constructed based on the 16S rDNA sequence homology. The representative strain GH2001 belonged to the Rhizobium branch. Similarity of 16S rDNA sequence of GH2001 to other known stains such as R.giardinii、R.mongolense、R.yanglingense、R.galegae and R.huautlense was up to 96.3%、95.5%、95.6%、95.2% and 95.7% respectively, which indicated that CH2001 should belong to Rhizobium.