Xanthomonas campestris Overcomes Arabidopsis Stomatal Innate Immunity through a DSF Cell-to-Cell Signal-Regulated Virulence Factor
Xanthomonas campestris Overcomes Arabidopsis Stomatal Innate Immunity through a DSF Cell-to-Cell Signal-Regulated Virulence Factor
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DOI：
10.1104/pp.108.126870
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发表时间：
2009-02-01
期刊：
影响因子：
7.4
通讯作者：
Vojnov, Adrian A.
中科院分区：
文献类型：
--
作者：
Gudesblat, Gustavo E.;Torres, Pablo S.;Vojnov, Adrian A.
病原菌诱导的气孔关闭是植物先天免疫反应的一部分。利用气孔作为进入叶片途径的植物病原体必须避开寄主的气孔反应。在本文中，我们描述了细菌性植物病原体野油菜黄单胞菌野油菜致病变种（Xcc）分泌的一种因子，能够干扰细菌或脱落酸（阿坝）诱导的气孔关闭。我们发现，活XCC，以及乙酸乙酯提取物从XCC培养上清液，能够恢复气孔关闭诱导的细菌，脂多糖，或阿坝。XCC乙酸乙酯提取物还补充了假单胞菌番茄致病变种（Pst）的冠状病毒毒素，这是需要克服气孔防御的生产缺陷的突变体的感染性。相比之下，XCC的rpfF和rpfC突变株，这是无法分别合成或感知的扩散分子参与细菌细胞到细胞的信号传导，是无法恢复气孔关闭，表明抑制气孔反应XCC需要一个完整的rpf/扩散信号因子系统。此外，我们还发现保卫细胞特异性的拟南芥（Arabidopsis thaliana）丝裂原活化蛋白激酶3（MPK 3）反义突变体对细菌或脂多糖促进气孔关闭的作用不敏感，而对Pst冠状蛋白缺陷突变体的作用更敏感，表明MPK 3是气孔免疫应答所必需的。此外，我们发现，与野生型拟南芥不同，ABA诱导的MPK 3反义突变体气孔关闭不受Xcc或Xcc培养上清液提取物的影响，这表明Xcc因子可能靶向MPK 3相同途径中的一些信号传导成分。
Pathogen-induced stomatal closure is part of the plant innate immune response. Phytopathogens using stomata as a way of entry into the leaf must avoid the stomatal response of the host. In this article, we describe a factor secreted by the bacterial phytopathogen Xanthomonas campestris pv campestris (Xcc) capable of interfering with stomatal closure induced by bacteria or abscisic acid (ABA). We found that living Xcc, as well as ethyl acetate extracts from Xcc culture supernatants, are capable of reverting stomatal closure induced by bacteria, lipopolysaccharide, or ABA. Xcc ethyl acetate extracts also complemented the infectivity of Pseudomonas syringae pv tomato (Pst) mutants deficient in the production of the coronatine toxin, which is required to overcome stomatal defense. By contrast, the rpfF and rpfC mutant strains of Xcc, which are unable to respectively synthesize or perceive a diffusible molecule involved in bacterial cell-to-cell signaling, were incapable of reverting stomatal closure, indicating that suppression of stomatal response by Xcc requires an intact rpf/diffusible signal factor system. In addition, we found that guard cell-specific Arabidopsis ( Arabidopsis thaliana) Mitogen-Activated Protein Kinase3 (MPK3) antisense mutants were unresponsive to bacteria or lipopolysaccharide in promotion of stomatal closure, and also more sensitive to Pst coronatine-deficient mutants, showing that MPK3 is required for stomatal immune response. Additionally, we found that, unlike in wild-type Arabidopsis, ABA-induced stomatal closure in MPK3 antisense mutants is not affected by Xcc or by extracts from Xcc culture supernatants, suggesting that the Xcc factor might target some signaling component in the same pathway as MPK3.