Wide distribution range of rhizobial symbionts associated with pantropical sea-dispersed legumes
Wide distribution range of rhizobial symbionts associated with pantropical sea-dispersed legumes
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DOI：
10.1007/s10482-016-0761-y
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发表时间：
2016-12-01
影响因子：
2.6
通讯作者：
Kajita, Tadashi
中科院分区：
文献类型：
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作者：
Bamba, Masaru;Nakata, Sayuri;Kajita, Tadashi
为了了解与广泛分布的野生豆科植物相关的根瘤菌的地理分布，研究人员对来自 41 个个体的 66 个根瘤进行了研究，其中包括分布在世界热带和亚热带沿海地区的三种海洋传播的豆科植物（Vigna marina、Vigna uteola 和 Canavalia Rosea）。从根瘤中提取的16S rRNA和nodC基因的部分序列表明，只有慢生根瘤菌和中华根瘤菌与泛热带豆科植物相关，并且一些共生菌株广泛分布在太平洋上空。在慢生根瘤菌和中华根瘤菌谱系中观察到结瘤基因的水平基因转移。 GenBank 中的 BLAST 搜索还发现了来自世界各地各种豆类（包括农作物物种）的这些菌株的记录。然而，GenBank 中并未发现其中一种根瘤菌菌株，这意味着该菌株可能已经适应了沿海环境。我们的研究结果表明，一些根瘤菌与广泛分布的海洋豆科植物相关，分布在广泛的地理范围内。通过与广泛分布的根瘤菌建立共生关系，泛热带豆科植物也可能比其他豆科植物物种更广泛地扩展其范围。
To understand the geographic distributions of rhizobia that associated with widely distributed wild legumes, 66 nodules obtained from 41 individuals including three sea-dispersed legumes (Vigna marina, Vigna luteola, and Canavalia rosea) distributed across the tropical and subtropical coastal regions of the world were studied. Partial sequences of 16S rRNA and nodC genes extracted from the nodules showed that only Bradyrhizobium and Sinorhizobium were associated with the pantropical legumes, and some of the symbiont strains were widely distributed over the Pacific. Horizontal gene transfer of nodulation genes were observed within the Bradyrhizobium and Sinorhizobium lineages. BLAST searches in GenBank also identified records of these strains from various legumes across the world, including crop species. However, one of the rhizobial strains was not found in GenBank, which implies the strain may have adapted to the littoral environment. Our results suggested that some rhizobia, which associate with the widespread sea-dispersed legume, distribute across a broad geographic range. By establishing symbiotic relationships with widely distributed rhizobia, the pantropical legumes may also be able to extend their range much further than other legume species.