Bacterial Outer Membrane Vesicles Induce Plant Immune Responses
Bacterial Outer Membrane Vesicles Induce Plant Immune Responses
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DOI：
10.1094/mpmi-12-15-0270-r
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发表时间：
2016-05-01
影响因子：
3.5
通讯作者：
Ronald, Pamela C.
中科院分区：
文献类型：
--
作者：
Bahar, Ofir;Mordukhovich, Gideon;Ronald, Pamela C.
革兰氏阴性细菌不断地夹断其外膜的一部分，释放出膜囊泡。这些外膜囊泡 (OMV) 参与多个过程，包括细胞间通讯、生物膜形成、应激耐受、水平基因转移和毒力。 OMV 也是已知的哺乳动物免疫反应调节剂。尽管 OMV 在哺乳动物-细菌通讯中的作用已有充分记录，但它们与植物的相互作用尚未得到充分研究。为了检查植物病原体的 OMV 是否调节植物免疫反应，我们从四种不同的植物病原体中纯化了 OMV，并将其用于治疗拟南芥。 OMV 分别在拟南芥叶盘、细胞培养物和幼苗中迅速诱导活性氧爆发、培养基碱化和防御基因表达。蛋白质印迹分析显示 EF-Tu 存在于 OMV 中，并且以这种形式充当植物免疫反应的诱导子。我们的结果进一步表明免疫辅助受体 BAK1 和 SOBIR1 介导 OMV 感知和反应。总而言之，我们的结果表明植物可以通过激活其免疫系统来检测和响应 OMV 相关分子，揭示了植物与细菌相互作用的新方面。
Gram-negative bacteria continuously pinch off portions of their outer membrane, releasing membrane vesicles. These outer membrane vesicles (OMVs) are involved in multiple processes including cell-to-cell communication, biofilm formation, stress tolerance, horizontal gene transfer, and virulence. OMVs are also known modulators of the mammalian immune response. Despite the well-documented role of OMVs in mammalian-bacterial communication, their interaction with plants is not well studied. To examine whether OMVs of plant pathogens modulate the plant immune response, we purified OMVs from four different plant pathogens and used them to treat Arabidopsis thaliana. OMVs rapidly induced a reactive oxygen species burst, medium alkalinization, and defense gene expression in A. thaliana leaf discs, cell cultures, and seedlings, respectively. Western blot analysis revealed that EF-Tu is present in OMVs and that it serves as an elicitor of the plant immune response in this form. Our results further show that the immune coreceptors BAK1 and SOBIR1 mediate OMV perception and response. Taken together, our results demonstrate that plants can detect and respond to OMV-associated molecules by activation of their immune system, revealing a new facet of plant-bacterial interactions.