Transcriptome profiling of a Sinorhizobium meliloti fadD mutant reveals the role of rhizobactin 1021 biosynthesis and regulation genes in the control of swarming.
Transcriptome profiling of a Sinorhizobium meliloti fadD mutant reveals the role of rhizobactin 1021 biosynthesis and regulation genes in the control of swarming.
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DOI：
10.1186/1471-2164-11-157
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发表时间：
2010-03-08
期刊：
影响因子：
4.4
通讯作者：
Soto MJ
中科院分区：
文献类型：
--
作者：
Nogales J;Domínguez-Ferreras A;Amaya-Gómez CV;van Dillewijn P;Cuéllar V;Sanjuán J;Olivares J;Soto MJ
群聚是一种多细胞现象，其特征是细菌在半固体表面上协调而快速地移动。在苜蓿中华根瘤菌中，已经在FADD突变体中描述了这种类型的运动性。为了深入了解根瘤菌聚集过程的机制，我们比较了在聚集诱导条件下(半固体培养)和在非聚集条件下生长的细胞(肉汤和固体培养)下生长的苜蓿链霉菌FADD突变体的转录组。有一千多个基因被鉴定为与琼脂表面生长有关的差异表达基因，包括代谢活性基因、铁吸收基因、趋化性基因、运动基因和胁迫相关基因。在群体特有的条件下，最显著的反应是铁相关基因的上调。我们证明了pSymA质粒，特别是铁载体根瘤蛋白1021的生物合成所需的基因是苜蓿根瘤菌野生型菌株聚集所必需的，但在FADD突变体中不是。此外，高铁条件抑制了野生型菌株的聚集，但在缺乏铁限制反应调节因子RIRA或FADD的突变体中则不抑制。目前的工作是第一次转录研究根瘤菌在表面的生长，包括集群诱导条件。结果表明，与液体培养相比，生长在表面上的苜蓿细胞在生理上发生了重大变化。此外，对响应集群诱导条件的基因的分析表明，铁和参与根瘤菌素1021合成的基因在苜蓿链霉菌的表面运动性中发挥作用，这可以在FADD突变体中规避。这项工作为识别根瘤菌聚集所涉及的新特征和调控网络开辟了一条途径。
Swarming is a multicellular phenomenom characterized by the coordinated and rapid movement of bacteria across semisolid surfaces. In Sinorhizobium meliloti this type of motility has been described in a fadD mutant. To gain insights into the mechanisms underlying the process of swarming in rhizobia, we compared the transcriptome of a S. meliloti fadD mutant grown under swarming inducing conditions (semisolid medium) to those of cells grown under non-swarming conditions (broth and solid medium). More than a thousand genes were identified as differentially expressed in response to growth on agar surfaces including genes for several metabolic activities, iron uptake, chemotaxis, motility and stress-related genes. Under swarming-specific conditions, the most remarkable response was the up-regulation of iron-related genes. We demonstrate that the pSymA plasmid and specifically genes required for the biosynthesis of the siderophore rhizobactin 1021 are essential for swarming of a S. meliloti wild-type strain but not in a fadD mutant. Moreover, high iron conditions inhibit swarming of the wild-type strain but not in mutants lacking either the iron limitation response regulator RirA or FadD. The present work represents the first transcriptomic study of rhizobium growth on surfaces including swarming inducing conditions. The results have revealed major changes in the physiology of S. meliloti cells grown on a surface relative to liquid cultures. Moreover, analysis of genes responding to swarming inducing conditions led to the demonstration that iron and genes involved in rhizobactin 1021 synthesis play a role in the surface motility shown by S. meliloti which can be circumvented in a fadD mutant. This work opens a way to the identification of new traits and regulatory networks involved in swarming by rhizobia.
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影响因子：
4.2
作者：
van Dillewijn P;Sanjuán J;Olivares J;Soto MJ
通讯作者：
Soto MJ
影响因子：
3.6
作者：
Braeken, Kristien;Daniels, Ruth;Michiels, Jan
通讯作者：
Michiels, Jan
影响因子：
4.1
作者：
Dondrup, M;Goesmann, A;Meyer, F
通讯作者：
Meyer, F
影响因子：
3.2
作者：
Inoue, Tetsuyoshi;Shingaki, Ryuji;Fukui, Kazuhiro
通讯作者：
Fukui, Kazuhiro
影响因子：
3.5
作者：
FELLAY, R;FREY, J;KRISCH, H
通讯作者：
KRISCH, H