GGDEF and EAL proteins play different roles in the control of Sinorhizobium meliloti growth, motility, exopolysaccharide production, and competitive nodulation on host alfalfa.
GGDEF and EAL proteins play different roles in the control of Sinorhizobium meliloti growth, motility, exopolysaccharide production, and competitive nodulation on host alfalfa.
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DOI：
10.1093/abbs/gmq034
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发表时间：
2010-06
影响因子：
3.7
通讯作者：
Yiwen Wang;Ji Xu;Aimin Chen;Yan-Zhang Wang;Jiabi Zhu;Guan-qiao Yu;Ling Xu;L. Luo
中科院分区：
文献类型：
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作者：
Yiwen Wang;Ji Xu;Aimin Chen;Yan-Zhang Wang;Jiabi Zhu;Guan-qiao Yu;Ling Xu;L. Luo
二磷酸鸟苷（bis-（3 '，5'）-cyclic dimeric guanosine monophosphate，c-di-GMP）是一种新的细菌第二信使，通常由含有GGDEF或谷氨酸-丙氨酸-亮氨酸（glutamate-alanine-leucine，EAL）结构域的蛋白质合成或分解。它们通常作为c-di-GMP的环化酶或磷酸二酯酶，并且根据已知的基因组DNA序列，它们的基因分布在几乎所有的细菌中。然而，GGDEF和EAL基因的系统鉴定在根瘤菌中仍然不清楚，根瘤菌是与相容的豆科植物相互作用形成固氮根瘤的土壤细菌。本研究通过生物信息学分析，在苜蓿中华根瘤菌（Sinorhizobium meliloti）中鉴定了19个GGDEF和EAL基因（编码5个GGDEF蛋白、4个EAL蛋白和10个GGDEF和EAL双结构域蛋白）。通过系统的质粒插入，构建了14个基因的突变体。所有14个基因突变体在基本培养基中表现出缺陷的生长和缺陷的运动，和11个基因突变体产生了很多胞外多糖和表现出较低的竞争性分泌宿主植物，苜蓿。我们的研究结果表明，GGDEF和EAL蛋白可能在S.苜蓿草的生理学，虽然它们含有保守的催化（GGDEF或EAL）结构域。我们的发现也暗示c-di-GMP可能在该根瘤菌与其宿主植物之间的相互作用中发挥重要作用，以建立有效的共生关系。
A new bacterial secondary messenger, bis-(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP), is usually synthesized or decomposed by proteins containing GGDEF or glutamate-alanine-leucine (EAL) domain. They often act as cyclase or phosphodiesterase of c-di-GMP and their genes are distributed among almost all bacteria according to known genomic DNA sequences. However, the systematic identification of GGDEF and EAL genes remains unclear in rhizobia, soil bacteria that interact with compatible legumes to form nitrogen-fixing nodules. In this study, 19 putative GGDEF and EAL genes were identified in a model rhizobium, Sinorhizobium meliloti, by bioinformatic analysis (encoding 5 GGDEF proteins, 4 EAL proteins, and 10 GGDEF and EAL double-domain proteins). Null mutants of 14 genes were constructed through systematic plasmid insertion. All 14 gene mutants showed deficient growth in minimal medium and defective motility, and 11 gene mutants produced a lot more exopolysaccharide and displayed less competitive nodulation on the host plant, alfalfa. Our results suggested that GGDEF and EAL proteins may play different roles in the control of S. meliloti physiology, although they contain conserved catalytic (GGDEF or EAL) domains. Our finding also implied that c-di-GMP may play an important role in the interactions between this rhizobium and its host plants to establish efficient symbiosis.