慢生根瘤菌16S—23S rDNA IGS的RFLP分析

本文对慢生根瘤菌属（Bracyrhizobium）3个已知种及从10种豆科植物中分离的32株慢生根瘤菌进行了16S—23SrDNAIGS的RFLP分析。IGS的PCR产物电泳只出现一条rDNA片段，但表现在长度上菌株间有一定差异，大小在930～1050bp之间，可大致划分为IGSa、IGSb和IGSc3种。用4种四碱基识别序列的限制性内切酶AluI、HaeIII、HinfI和MspI酶解IGSrDNA，综合得到26种IGS－RFLP类型．每一种酶可产生6—12种不同的酶切图谱．结果表明这一方法能很好区分、鉴别慢生根瘤菌，也支持该技术是一种快速、简单、准确及重复性好的微生物鉴定手段．

GENOTYPIC CHARACTERIZATION OF BREDYRIZOBIUM STRAINS BY PCR-RFLP ANALYSIS OF 16S-23S rDNA INTERGENIC SPACERS (IGS)

Characterization of 32 bradyrhizobial sabins was performed by 16S-23S rDNA intersenic spacer (IGS) RFLPs. These stains were isolated from nodules of 10 species of leguminous plants and several stains of fore known Bradyrizobium species were included. The IGS regions of all strains were amplified with primers FGPS1490 and FGPL132' and yielded single bands (IGS rDNA) ranging from 930 to 1050 bp as estimated by comparison with marker. The majority sizes of IGS rDNA were between 930 bp and 970bp. Four 4-base-cutting restriction endonucleases, Alul, MaeIII, HinfI and MspI, were used to digest the IGS rDNA. Six to 12 distinctrestrichon patterns, with one to five restricted fragments per patteds were detected with each enzyme. Twenty-six different combinations of restrichon patterns, representing 26 rDNA IGS types or genotypes, were recorded among 32 bradyrhizobial strains. The results supported that this technique is a powerful tool for the genotypic identification of Bradyrhizobium stains.