AHL-type quorum sensing and its regulation on symplasmata formation in Pantoea agglomerans YS19
AHL-type quorum sensing and its regulation on symplasmata formation in Pantoea agglomerans YS19
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DOI：
10.1002/jobm.201400472
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发表时间：
2015-05-01
影响因子：
3.1
通讯作者：
Feng, Yongjun
中科院分区：
文献类型：
--
作者：
Jiang, Jing;Wu, Suisui;Feng, Yongjun
成团泛菌（Pantoea agglomerans）YS 19是从水稻中分离到的一株内生固氮菌，其特征是形成多细胞聚集体，即共质体，这种共质体不仅赋予细菌强大的抗逆性，而且有助于内生菌与宿主的特异性适应。酰基高丝氨酸内酯（Acyl-homoserine lactones，AHLs）是革兰氏阴性菌群体感应（quorum sensing，QS）系统中的重要信号分子，对细菌的运动、聚集等行为具有重要的调控作用。本文研究了成团毕赤酵母YS 19产生阿勒及其对共质体形成的调控。结果表明，在LB培养基中，YS 19的阿勒产生始于对数生长期，此后在稳定生长期达到高峰。经MALDI-TOF-MS分析，确定阿勒为N-3-氧代辛酰基-L-高丝氨酸内酯（OOHL）。克隆了YS 19的阿勒合成基因pagI和受体基因pagR，系统发育分析表明，这两个基因在成团毕赤酵母种间高度保守。结果表明，阿勒促进细菌生长和共质体形成的YS 19。同时，阿勒还增强了YS 19在寄主植物上的定殖能力和促生作用。这些结果有力地表明了AHL型QS系统在菌株内生生活中的多效性作用。
Pantoea agglomerans YS19, an endophytic diazotrophic bacterium isolated from rice, is characterized by the formation of multicellular aggregate structure called symplasmata, which not only bestow the strong stress-resistance of the bacterium, but also contribute to the specific adaptation in the endophyte-host association. Acyl-homoserine lactones (AHLs), as the important signal molecule in the quorum sensing (QS) system of gram-negative bacteria, were demonstrated to regulate motility, cell-aggregation, and other bacterial behaviors. Here, the production of AHL by P. agglomerans YS19 and its regulation on the symplasmata formation were studied. It was revealed that the production of AHL by YS19 was initiated at the exponential growth stage and from then on, reached the peak values at the stationary growth stage in LB medium. The AHL was identified as N-3-oxooctanoyl-L-homoserine lactone (OOHL) by MALDI-TOF-MS analysis. The AHL synthesis gene pagI and receptor gene pagR in YS19 were cloned and phylogenetic analysis showed that they were high conservative among strains in species of P. agglomerans. It was revealed that AHL promoted the bacterial growth and symplasmata formation of YS19. Meanwhile, the colonization ability and growth-promoting effect of YS19 on the host plant were also enhanced by AHL. These results strongly suggest the pleiotropic effects of the AHL-type QS system in endophytic life of the strain.