Pepper Arginine Decarboxylase Is Required for Polyamine and γ-Aminobutyric Acid Signaling in Cell Death and Defense Response
Pepper Arginine Decarboxylase Is Required for Polyamine and γ-Aminobutyric Acid Signaling in Cell Death and Defense Response
复制标题
DOI：
10.1104/pp.113.217372
复制
发表时间：
2013-08-01
期刊：
影响因子：
7.4
通讯作者：
Hwang, Byung Kook
中科院分区：
文献类型：
--
作者：
Kim, Nak Hyun;Kim, Beom Seok;Hwang, Byung Kook
野油菜黄单胞菌水泡致病变种（Xcv）效应子AvrBsT诱导辣椒（Capsicum annuum）中的过敏性细胞死亡。然而，AvrBsT触发细胞死亡的分子机制尚未完全清楚。在这里，我们确定辣椒精氨酸脱羧酶（CaADC 1）作为一个AvrBsT相互作用的蛋白，这是早期和强烈诱导不兼容的辣椒Xcv的相互作用。双分子荧光互补和免疫共沉淀试验表明，CaADC 1-AvrBsT复合物定位于细胞质。CaADC 1与avrBsT在本氏烟草叶中的瞬时共表达特异性地增强了AvrBsT触发的细胞死亡，伴随着多胺、一氧化氮（NO）和过氧化氢（H2 O2）爆发的积累。在多胺中，精胺的应用强烈诱导NO和H2 O2的爆发，最终导致细胞死亡。CaADC 1沉默辣椒叶片显着损害NO和H2 O2的积累和细胞死亡诱导，导致增强的无毒Xcv感染过程中的增长。水杨酸，多胺，γ-氨基丁酸（GABA）的水平，以及在无毒Xcv感染的防御反应基因的表达，在CaADC 1沉默的植物明显低于空载体对照植物。GABA的应用显着抑制无毒Xcv生长在CaADC 1沉默的叶片和空载体对照植物。总之，这些结果表明，CaADC 1可能作为一个关键的防御和细胞死亡调节剂，通过介导的多胺和GABA代谢。
The Xanthomonas campestris pv vesicatoria (Xcv) effector AvrBsT induces a hypersensitive cell death in pepper (Capsicum annuum). However, the molecular mechanisms underlying AvrBsT-triggered cell death are not fully understood. Here, we identified pepper arginine decarboxylase (CaADC1) as an AvrBsT-interacting protein, which is early and strongly induced in incompatible pepper-Xcv interactions. Bimolecular fluorescence complementation and coimmunoprecipitation assays showed that the CaADC1-AvrBsT complex was localized to the cytoplasm. Transient coexpression of CaADC1 with avrBsT in Nicotiana benthamiana leaves specifically enhanced AvrBsT-triggered cell death, accompanied by an accumulation of polyamines, nitric oxide (NO), and hydrogen peroxide (H2O2) bursts. Among the polyamines, spermine application strongly induced NO and H2O2 bursts, ultimately leading to cell death. CaADC1 silencing in pepper leaves significantly compromised NO and H2O2 accumulation and cell death induction, leading to the enhanced avirulent Xcv growth during infection. The levels of salicylic acid, polyamines, and gamma-aminobutyric acid (GABA), and the expression of defense response genes during avirulent Xcv infection, were distinctly lower in CaADC1-silenced plants than those in the empty vector control plants. GABA application significantly inhibited avirulent Xcv growth in CaADC1-silenced leaves and the empty vector control plants. Together, these results suggest that CaADC1 may act as a key defense and cell death regulator via mediation of polyamine and GABA metabolism.