Light affects motility and infectivity of Agrobacterium tumefaciens
Light affects motility and infectivity of Agrobacterium tumefaciens
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DOI：
10.1111/j.1462-2920.2008.01618.x
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发表时间：
2008-08-01
影响因子：
5.1
通讯作者：
Lamparter, Tilman
中科院分区：
文献类型：
--
作者：
Oberpichler, Inga;Rosen, Ran;Lamparter, Tilman
对光条件变化的反应涉及多种受体，这些受体可以调节基因表达、酶活性和/或运动性。为了研究根癌农杆菌的光调控效应，我们使用了一种全球性的分析方法-蛋白质组学-并比较了黑暗和光照生长的细菌的蛋白质模式。这些分析显示，当细胞在光照下生长时，鞭毛蛋白FlaA和FlaB显著减少。用分离的鞭毛通过SDS-PAGE证实了光效应。定量PCR实验表明，flaA，flaB和flaC的转录水平在20分钟内增加了10倍后，从光转移到黑暗。电子显微镜显示，这些分子事件导致每个细胞的鞭毛数量的光诱导减少。这些变化具有关于运动性的主要生理后果，运动性随着暴露于光而显著降低。光对运动的抑制作用不是A.在根瘤菌科的其他物种中也发现了这种现象。前人的研究表明，鞭毛的功能对细菌与植物的相互作用和细菌的毒力具有重要意义。在我们的研究中，光减少了A.根癌农杆菌对番茄根的毒性以及黄瓜感染测定中细菌的毒力。
Response to changes in light conditions involves a variety of receptors that can modulate gene expression, enzyme activity and/or motility. For the study of light-regulated effects of Agrobacterium tumefaciens, we used a global analysis approach - proteomics - and compared the protein patterns of dark- and light-grown bacteria. These analyses revealed a significant reduction of FlaA and FlaB - proteins of the flagellum - when the cells were grown in light. The light effect was confirmed by SDS-PAGE with isolated flagella. Quantitative PCR experiments showed a 10-fold increase of the transcription level of flaA, flaB and flaC within 20 min after the transfer from light to darkness. Electron microscopy revealed that these molecular events result in a light-induced reduction of the number of flagella per cell. These changes have major physiological consequences regarding motility, which is considerably reduced with exposure to light. The inhibitory effect of light on the motility is not unique to A. tumefaciens and was also seen in other species of the Rhizobiaceae. Previous studies suggested that the flagella function is significant for bacteria-plant interactions and bacterial virulence. In our studies, light reduced the attachment of A. tumefaciens to tomato roots and the virulence of the bacteria in a cucumber infection assay.