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Communications Biology：拟南芥GCN2激酶作用于ABA内稳态和气孔免疫

已有 3379 次阅读 2019-8-11 15:26 |个人分类:每日摘要|系统分类:论文交流

Arabidopsis GCN2 kinase contributes to ABA homeostasis and stomatal immunity

First author: Xiaoyu Liu; Affiliations: University of Alabama at Birmingham (阿拉巴马大学伯明翰分校): Birmingham, USA

Corresponding author: Karolina M. Pajerowska-Mukhtar

General Control Non-derepressible 2 (GCN2) is an evolutionarily conserved serine/threonine kinase that modulates amino acid homeostasis in response to nutrient deprivation (营养缺乏) in yeast, human and other eukaryotes. However, the GCN2 signaling pathway in plants remains largely unknown. Here, we demonstrate that in Arabidopsis, bacterial infection activates AtGCN2-mediated phosphorylation of eIF2α and promotes TBF1 translational derepression. Consequently, TBF1 regulates a subset of abscisic acid signaling components to modulate pre-invasive (侵入前) immunity. We show that GCN2 fine-tunes abscisic acid accumulation and signaling during both pre-invasive and post-invasive stages of an infection event. Finally, we also demonstrate that AtGCN2 participates in signaling triggered by phytotoxin coronatine (冠菌素) secreted by P. syringae (丁香假单胞菌). During the preinvasive phase, AtGCN2 regulates stomatal immunity by affecting pathogen-triggered stomatal closure and coronatine-mediated stomatal reopening. Our conclusions support a conserved role of GCN2 in various forms of immune responses across kingdoms, highlighting GCN2’s importance in studies on both plant and mammalian immunology.

GCN2是一个演化上十分保守的丝氨酸/苏氨酸激酶，其在酵母、人类和其他真核生物中的作用是在响应于营养缺乏时调节氨基酸的内稳态。然而，目前我们对于植物中的GCN2信号转导通路还所知甚少。本文中，作者揭示了在拟南芥中细菌侵染会激活AtGCN2介导的eIF2α磷酸化，并促进TBF1的翻译脱抑制作用。因此，TBF1调控一系列脱落酸ABA信号组份，从而调节植株的侵入前免疫。作者的研究显示GCN2在侵染事件发生时的侵入前和侵入后阶段均能够精确调控ABA的积累和信号转导。最终，本文的研究显示AtGCN2参与了由丁香假单胞菌分泌的植物毒素冠菌素所诱导的信号转导。在侵入前阶段，AtGCN2通过影响病原菌诱导的气孔闭合以及冠菌素介导的气孔重新张开调控气孔免疫。本文的研究结果支持GCN2在不同生物圈的各种免疫响应系统中具有非常保守的功能，说明GCN2在哺乳动物和植物的免疫研究中都十分重要。