Genomic analysis reveals the major driving forces of bacterial life in the rhizosphere.
Genomic analysis reveals the major driving forces of bacterial life in the rhizosphere.
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DOI：
10.1186/gb-2007-8-9-r179
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发表时间：
2007
期刊：
影响因子：
12.3
通讯作者：
Ramos-González MI
中科院分区：
文献类型：
--
作者：
Matilla MA;Espinosa-Urgel M;Rodríguez-Herva JJ;Ramos JL;Ramos-González MI
在与玉米根的相互作用过程中进行的恶臭假单胞菌基因表达的全球分析揭示了细菌种群如何调整其遗传程序以适应这种生活方式的特定条件。与根瘤菌和豆科植物之间的相互作用相比，植物和细菌（通常是假单胞菌）之间的相互作用更为人所知，假单胞菌在根和邻近的土壤区域（根际）定居。对恶臭假单胞菌与玉米根相互作用期间表达的基因进行的全球分析揭示了细菌种群如何调整其遗传程序以适应这种生活方式。通过比较根际定殖群体与三个不同的控制，涵盖了各种营养物质，生长阶段和生活方式（反硝化和固着）的差异表达的基因进行了鉴定。90根际上调基因，这是诱导相对于所有三个控制，进行了鉴定，而没有共同的实验之间的抑制基因。参与芳香族化合物的氨基酸吸收和代谢的基因在根际中优先表达，这反映了根分泌物中特定营养物质的可利用性。外排泵和谷胱甘肽代谢酶的诱导表明，适应不利条件和应激（氧化）反应是细菌在这种环境中生活的关键。在诱导基因中发现GGDEF/EAL结构域反应调节器表明次级信使c-diGMP在根定殖中的周转作用。几个突变体在竞争性根定殖中表现出降低的适应性。我们的研究结果表明，两种不同性质的选择性力量殖民根际的重要性：压力适应和特定营养物质的可用性。我们还确定了新的特性，赋予细菌在这个利基生存，并开辟了一条途径，以表征特定的信号和监管过程，管理植物假单胞菌协会。
A global analysis of Pseudomonas putida gene expression performed during the interaction with maize roots revealed how a bacterial population adjusts its genetic program to the specific conditions of this lifestyle. Mutualistic interactions less well known than those between rhizobia and legumes are commonly found between plants and bacteria, frequently pseudomonads, which colonize roots and adjacent soil areas (the rhizosphere). A global analysis of Pseudomonas putida genes expressed during their interaction with maize roots revealed how a bacterial population adjusts its genetic program to this lifestyle. Differentially expressed genes were identified by comparing rhizosphere-colonizing populations with three distinct controls covering a variety of nutrients, growth phases and life styles (planktonic and sessile). Ninety rhizosphere up-regulated (rup) genes, which were induced relative to all three controls, were identified, whereas there was no repressed gene in common between the experiments. Genes involved in amino acid uptake and metabolism of aromatic compounds were preferentially expressed in the rhizosphere, which reflects the availability of particular nutrients in root exudates. The induction of efflux pumps and enzymes for glutathione metabolism indicates that adaptation to adverse conditions and stress (oxidative) response are crucial for bacterial life in this environment. The finding of a GGDEF/EAL domain response regulator among the induced genes suggests a role for the turnover of the secondary messenger c-diGMP in root colonization. Several mutants in rup genes showed reduced fitness in competitive root colonization. Our results show the importance of two selective forces of different nature to colonize the rhizosphere: stress adaptation and availability of particular nutrients. We also identify new traits conferring bacterial survival in this niche and open a way to the characterization of specific signalling and regulatory processes governing the plant-Pseudomonas association.