三个根瘤菌新亚群的 16SrDNA-RFLP 分析

16S rDNA RFLP Analysis of Three New Rhizobia Subgroups

在对新疆、内蒙干旱地区采集的４８株苜蓿、草木樨、锦鸡儿根瘤菌进行数值分类和ＳＤＳ－ＰＡＧＥ全细胞蛋白分析的基础上，对数值分类确立的三个亚群进行了１６ＳｒＤＮＡ－ＲＦＬＰ分析，在８７％的相似性水平上，三个新亚群的菌株相应聚类成群。其中第２亚群属于Ｓｉｎｏｒｈｉｚｏｂｉｕｍ分枝，与Ｓ．ｍｅｌｉｌｏｔｉ，Ｓ．ｆｒｅｄｉ．Ｓ．ｔｅｒａｎｇａ，Ｓ．Ｓａｈｅｌｉ在９２％的相似水平上聚在一起。第３亚群则与Ｒｈｉｚｏｂｉｕｍ处于同一分枝且与属内各已知种相互区分开，可能为一独立的种。第１亚群有可能为一独立的属，值得进一步研究。此结果进一步证实来自干旱地区的根瘤菌具有很大特异性。

Based on the results of the numerical taxonomy for 48 strains isolated from arid region in Xinjiang and Inner Mongolia, 16S rDNA RFLP is applied to make sure the phylogenetic position of three new subgroups in numerical taxonomy. Above the similarity level of 87%, three new subgroups are clustered into the different subgroups respectively. Subgroup 2 is clustered into Sinorhizobium branch with S.meliloti S.fredii. S. teranga. S.saheli above the similarity level of 92%; Subgroup 3 is located in Rhizobium branch, and separated from the known species in Rhizobium; Subgroup 1 is different from the known genera. These results show particularities of Rhizobia isolated from arid regions in Xinjiang and Inner Mongolia in advance.