中文摘要：

采用数值分类、BOXAIR—PCR和16SrDNAPCR—RFLP方法，对分离自四川攀西干热河谷区11种豆科植物上的43株根瘤菌的表型和遗传多样性进行了研究．数值分类结果表明，攀西地区根瘤菌具有极大的表型性状多样性，在80％相似性水平上绝大多数供试菌株单独成群，能耐60℃（10min处理）的高温，在低温（10℃）或者低pH（4．0）条件下生长很差．与数值分类结果相比较，BOXAIR—PCR的分群结果更分散，说明供试菌株在遗传性状上也具有多样性．在数值分群基础上，选取15个代表菌株进行16SrDNAPCR—RFLP分析．结果表明，供试的15株代表菌株遗传差异明显，仅CCBAU61224与Rhizobium leguminosarum USDA2370T，CCBAU61303与Agrobacterium tumerfaciense IAMl3129T具有相同的遗传图谱类型．数值分类和16SrDNAPCR—RFLP分析具有较好的一致性，BOXAIR—PCR适合于对根瘤菌种内菌株问的遗传多样性研究．

英文摘要：

Forty-three rhizobia isolated from eleven species of plants of Legnminosae in Panzhihua and Liangshan, southwest Siehuan were studied together with twenty recognized reference rhizobial strains by numerical taxonomy, BOXAIR - PCR fingerprinting and 16S rDNA PCR - RFLP. The result of numerical analysis showed that there was a great phenotypie diversity among the isolates. Compared with the reference strains, more than 70% new isolates had different phenotypie characteristics and fell into single clusters respectively at a similarity level of 80%. All the new strains could grow normally at 60 ℃ and could not grow well at 10 ℃ or pH 〈4.0. The same strains used in numerical taxonomy were analyzed by BOXAIR - PCR fingerprinting. Compared with the result of numerical taxonomy, the tested strains belonging to one phenon in numerical taxonomy always distributed in several BOXAIR- PCR groups, and most reference strains from one recognized rhizobial species were not grouped together. As a result, BOXAIR -PCR fingerprinting was appropriate as a method revealing genetic diversity within a rhizobial species. The result above showed that there was a great genotypic diversity among the isolated rhizobial strains. Based on the results of numerical taxonomy, 16S rDNA PCR - RFLP was applied to study the genotype of the selected fifteen representative isolates and seven type strains. The fifteen isolates tested had their own unique genotypes by four kinds of restriction endonucleases （Haelll ,Msp I ,Dde I and Rsa I ）. Only the central strains CCBAU61224 and Rhizobium leguminosarum USDA2370T, CCBAU61303 and Agrobacterium tumeqCaciense IAM13129T had the same genotype. The results of numerical taxonomy and 16S rDNA PCR - RFLP analysis were in good agreement.