柱花草根际土著根瘤菌的丰度及其遗传多样性

为研究我国柱花草根际土著根瘤菌在不同生态环境土壤中的丰度及其遗传多样性,分别在海南、广西、广东、云南、四川等柱花草的主要分布区域采集土样及根瘤,通过MPN法测定得到各种土壤中土著根瘤菌的丰度,并从采集的根瘤中分离获得的55份根瘤菌菌株进行16SrDNA全序列分析,与相关参比菌株的16SrDNA序列进行比对及聚类。结果表明,我国柱花草主要种植区域土著根瘤菌含量差异较大,每克干土中含量为0.7×102～7.5×106个,海南儋州区域的含量最高,广东湛江南亚所区域的含量最低;所分离出的菌株都属慢生根瘤菌属(Bradyrhizobium sp.),在系统发育树上聚合为8大类群,初步确定55株柱花草根瘤菌的亲缘关系及分类地位。

Abundance Ratio and Genetic Diversity of Rhizosphere Indigenous Bacteria of Stylosanthes guianensis(Aublet)Swartz

To investigate the genetic diversity and abundance ratio of the indigenous rhizobia in Stylosanthes guianensis(Aublet)Swartz soils in different habitats across China, the soil samples and nodules isolated from stylo planting areas were collected. The abundance of indigenous was calculated with MPN (most probable number)theory. Fifty five strains isolated from the nodules were tested by full length 16S rDNA sequences analysis, and clustered with sequence alignment. The results indicated that there was obvious difference among the rhizobia ranged from 0.7×102 to 7.5×106 in amounts. The number of rhizobia from Danzhou, Hainan was the largest, while that from Zhanjiang, Guangdong was the least. All the strains belong to Bradyrhizobium, and could be classified into 8 sub-groups in the phylogenetic tree. The genetic relationship and taxonomy of the strains were clarified tentatively.