Genome rearrangements of indigenous soybean bradyrhizobia and their ecological significance

本土大豆慢生根瘤菌基因组重排及其生态意义

• 批准号: 10460028
• 负责人: MINAMISAWA Kiwamu
• 金额: $ 7.74万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10460028/
• 关键词: Bradyrhizobium japonicum; genetic ecology; insertion sequence; nodulation; soil bacteria; soybean; stress resistance; 増殖; ストレス; 土壌; ダイズ根粒菌; 遺伝的多様性; 窒素固定; Bradyrhizobium

In order to understand the generation and ecological roles of Bradyrhizobium japonicum HRS strains possessing high copy numbers of insertion sequences (IS), we have investigated (1) geographical and phylogenetic distributions of HRS strains, (2) their excellent features in field ecosystem, (3) their genome rearrangements, and (4) horizontal transfer of nodulation (nod) gene from HRS strains. We found a correlation among the IS copy number, phylogenetic position, serogroup and growth rate of HRS strains, which are derived from USA, China and Japan. Nodule occupancy of HRS strains increased in a water-logged soil condition. Moreover, HRS strains showed stress resistance. The nif gene cluster of HRS strain were subjected to DNA rearrangement probably by IS elements. We have observed horizontal transfer of nod genes from B. japonicum HRS strain to B. elkanii USDA94 mutant lacking common nod genes as a recipient. In this project, we could show the ecological and genetic features of B. japonicum HRS strains.

为了了解具有高插入序列拷贝数（IS）的缓生根瘤菌HRS菌株的产生及其生态作用，我们对HRS菌株的地理和系统发育分布、野外生态系统的优良特性、基因组重排和结瘤基因的水平转移进行了研究。结果表明，来自美国、中国和日本的HRS菌株的IS拷贝数、系统发育位置、血清群和生长速率存在相关性。浸水土壤条件下，HRS菌株的结核占用率增加。HRS菌株表现出抗逆性。HRS菌株的nif基因簇可能受到IS元件的DNA重排。我们观察到日本血吸虫HRS菌株的nod基因水平转移到缺乏共同nod基因的elkanii B. USDA94突变体作为受体。本项目旨在揭示日本芽孢杆菌HRS菌株的生态和遗传特征。

项目成果

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Minamisawa, K.: "Chapter 8: Genetic ecology of soybean bradyrhizobia. In Soil Biochemistry Volume 10"Marcel Dekker, New York. 519(348-377) (2000)

Minamisawa, K.：“第 8 章：大豆缓生根瘤菌的遗传生态学。土壤生物化学第 10 卷”Marcel Dekker，纽约。

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