Genetic determinants of swarming in Rhizobium etli
Genetic determinants of swarming in Rhizobium etli
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DOI：
10.1007/s00248-007-9250-1
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发表时间：
2008-01-01
影响因子：
3.6
通讯作者：
Michiels, Jan
中科院分区：
文献类型：
--
作者：
Braeken, Kristien;Daniels, Ruth;Michiels, Jan
群集运动被认为是一种社会现象，使细菌群体能够在固体表面上协调移动。分化的蜂群细胞群嵌入细胞外粘液层中，这种现象以前与生物膜形成和毒力有关。革兰氏阴性固氮土壤细菌Rhizobium etli CNPAF512先前显示在软琼脂平板上显示群集行为。为了寻找新的群集行为的遗传决定因素，对700个R.进行了etli。24个突变体的缺陷，在群集或显示异常群集模式进行了鉴定，并可分为三组的基础上，他们的群集模式。14个突变体是完全群集缺陷，5个突变体表现出非典型的群集模式，没有完全光滑的边缘和局部挤出，和5个突变体显示中间群集表型。序列分析表明，突变体可能在群体感应，多糖组成或出口，运动，氨基酸和多胺代谢的影响。几个鉴定的突变体显示出降低的共生固氮活性。
Swarming motility is considered to be a social phenomenon that enables groups of bacteria to move coordinately atop solid surfaces. The differentiated swarmer cell population is embedded in an extracellular slime layer, and the phenomenon has previously been linked with biofilm formation and virulence. The gram-negative nitrogen-fixing soil bacterium Rhizobium etli CNPAF512 was previously shown to display swarming behavior on soft agar plates. In a search for novel genetic determinants of swarming, a detailed analysis of the swarming behavior of 700 miniTn5 mutants of R. etli was performed. Twenty-four mutants defective in swarming or displaying abnormal swarming patterns were identified and could be divided into three groups based on their swarming pattern. Fourteen mutants were completely swarming deficient, five mutants showed an atypical swarming pattern with no completely smooth edge and local extrusions, and five mutants displayed an intermediate swarming phenotype. Sequence analysis of the targeted genes indicated that the mutants were likely affected in quorum-sensing, polysaccharide composition or export, motility, and amino acid and polyamines metabolism. Several of the identified mutants displayed a reduced symbiotic nitrogen fixation activity.