黑木相思根瘤菌的系统发育分析及其结瘤效果研究

Phylogenetic analysis of rhizobia nodulating with Acacia melanoxylon R. Br. and their nodulation effect on several woody legume plants

【目的】针对采集自福建、广东的34株黑木相思根瘤菌进行分类研究,进一步确定其分类地位,丰富我国黑木相思根瘤菌种质资源。【方法】对选取的34株菌株测定了16S r RNA基因、持家基因atp D和gln II序列,以14株菌为代表菌株分析其系统发育情况。而且选取了部分菌株进行结瘤实验。【结果】16S r RNA基因以及持家基因atp D和gln II的系统发育分析结果与16S r RNA PCR-RFLP分型结果基本一致,14株代表菌株被分为10个不同的类群,其中有2个群组属于中慢生根瘤菌属(Mesorhizobium),其余群组属于慢生根瘤菌属(Bradyrhizobium)。结瘤试验证明,相关的供试根瘤菌能与黑木相思、银合欢、南洋楹和网脉相思结瘤共生,显示出较广的宿主范围,且对黑木相思和银合欢的促生效果较明显。【结论】研究发现黑木相思根瘤菌具有丰富的遗传多样性和共生多样性。

[Objective] Thirty four strains isolated from the root nodules of Acacia melanoxylon R. Br. in Fujian and Guangdong were studied about the taxonomic position in order to abundant germplasm resources of rhizobia. [Methods] 16 S r RNA genes and housekeeping genes（atp D and gln II） of all 34 strains were sequenced, 14 type strains of which were used to perform phylogenetic analysis. Furthermore, some representative strains were chosen to perform nodule experiment. [Results] The results of phylogenetic analysis of 16 S r RNA genes and housekeeping genes（atp D and gln II） were mostly in agreement with which of 16 S r RNA PCR-RFLP. And 14 type strains were divided into 10 groups, 2 of which belonged to Mesorhizobium and the others were Bradyrhizobium. In addition, nodule experiment suggested that the tested strains have a large rang of hosts because they could nodulate with A. melanoxylon, Leucaena leucocephala, Albizia falcataria and Acacia aneura. Moreover, the growth promoting effect of these stains was significant when inoculated on A. melanoxylon and L. Leucocephala. [Conclusion] This study illustrated genetic and symbiotic diversity of rhizobia isolated from the root of A. melanoxylon.