Genetic diversity of native soybean bradyrhizobia from different topographical regions along the southern slopes of the Himalayan Mountains in Nepal
Genetic diversity of native soybean bradyrhizobia from different topographical regions along the southern slopes of the Himalayan Mountains in Nepal
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DOI：
10.1016/j.syapm.2010.06.008
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发表时间：
2010-11-01
影响因子：
3.4
通讯作者：
Sekimoto, Hitoshi
中科院分区：
文献类型：
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作者：
Risal, Chandra Prasad;Yokoyama, Tadashi;Sekimoto, Hitoshi
大豆结瘤慢生根瘤菌具有遗传多样性，可归为不同种类。本研究对尼泊尔喜马拉雅山脉南坡不同地形地区分离的大豆慢生根瘤菌的遗传多样性进行了研究。土壤样本来自气候不同的三个不同地形地区。以当地大豆品种Cobb为诱捕植物，分离出慢生根瘤菌。根据菌落形态选择的24个菌株进行了遗传特征分析。对每个分离株进行了16S rRNA基因及其ITS区的全序列测定，以及nifD和nod1基因的部分序列测定。在保守的基因系统发育中有两个谱系：一个代表慢生根瘤菌(71%)，另一个代表慢生根瘤菌(21%)和云南慢生根瘤菌(8%)。系统发育分析揭示了慢生根瘤菌分支中的三个新谱系，表明尼泊尔慢生根瘤菌分离株具有较高的遗传多样性。日本血吸虫和袁明氏血吸虫菌株分布在海拔2420~2660m的温带山区。Elkanii分支分布于海拔1512-1935米的丘陵区和海拔2420-2660米的山区。共检测到10个多位基因座，其中7个为Elkanii菌株，2个为日本B.jonicum菌株，1个为B.yanmingense相关菌株。结果表明，尼泊尔喜马拉雅山脉南坡温带地区的慢生根瘤菌物种多样性高于亚热带地区。(C)2010年爱思唯尔股份有限公司。版权所有。
Soybean-nodulating bradyrhizobia are genetically diverse and are classified into different species. In this study, the genetic diversity of native soybean bradyrhizobia isolated from different topographical regions along the southern slopes of the Himalayan Mountains in Nepal was explored. Soil samples were collected from three different topographical regions with contrasting climates. A local soybean cultivar, Cobb, was used as a trap plant to isolate bradyrhizobia. A total of 24 isolates selected on the basis of their colony morphology were genetically characterized. For each isolate, the full nucleotide sequence of the 16S rRNA gene and ITS region, and partial sequences of the nifD and nodD1 genes were determined. Two lineages were evident in the conserved gene phylogeny; one representing Bradyrhizobium elkanii (71% of isolates), and the other representing Bradyrhizobium japonicum (21%) and Bradyrhizobium yuanmingense (8%). Phylogenetic analyses revealed three novel lineages in the Bradyrhizobium elkanii clade, indicating high levels of genetic diversity among Bradyrhizobium isolates in Nepal. B. japonicum and B. yuanmingense strains were distributed in areas from 2420 to 2660 m above sea level (asl), which were mountain regions with a temperate climate. The B. elkanii clade was distributed in two regions; hill regions ranging from 1512 to 1935 m asl, and mountain regions ranging from 2420 to 2660 m asl. Ten multi-locus genotypes were detected; seven among B. elkanii, two among B. japonicum, and one among B. yuanmingense-related isolates. The results indicated that there was higher species-level diversity of Bradyrhizobium in the temperate region than in the sub-tropical region along the southern slopes of the Himalayan Mountains in Nepal. (C) 2010 Elsevier GmbH. All rights reserved.