The Pepper Calmodulin Gene CaCaM1 Is Involved in Reactive Oxygen Species and Nitric Oxide Generation Required for Cell Death and the Defense Response
The Pepper Calmodulin Gene CaCaM1 Is Involved in Reactive Oxygen Species and Nitric Oxide Generation Required for Cell Death and the Defense Response
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DOI：
10.1094/mpmi-22-11-1389
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发表时间：
2009-11-01
影响因子：
3.5
通讯作者：
Hwang, Byung Kook
中科院分区：
文献类型：
--
作者：
Choi, Hyong Woo;Lee, Dong Hyuk;Hwang, Byung Kook
钙信号已成为高等植物响应生物和非生物胁迫的重要信号转导途径。钙调素（CaM）通过激活特异性靶点在应激信号的解码和转导中起着关键作用。在这里，我们分离和功能特性的病原体响应钙调素基因，辣椒钙调素I（CaCaM 1），从辣椒（C。annuum）植物。CaCaM 1的细胞功能通过Agrobacterium spp.-介导辣椒中的瞬时表达和拟南芥中的转基因过表达。农杆菌属-介导的CaCaM 1的瞬时表达激活了辣椒叶片中的活性氧（ROS）、一氧化氮（NO）产生和过敏反应（HR）样细胞死亡，最终导致对野油菜黄单胞菌致病变种的局部获得性抗性。囊膜CaCaM 1过表达（OX）的拟南芥表现出对假单胞菌和寄生透明霜霉的抗性增强，并伴随着ROS和NO的产生以及HR样细胞死亡。用钙通道阻滞剂处理抑制了辣椒和拟南芥中由CaCaM 1表达引发的氧化和NO爆发和HR样细胞死亡，这表明钙内流是激活植物中CaCaM 1介导的防御反应所必需的。在用CaM拮抗剂处理后，毒力P. p.番茄诱导的NO生成也受到损害CaCaM 1-OX叶片。总之，这些结果表明，CaCaM 1基因在ROS和NO生成中的功能是植物细胞死亡和防御反应所必需的。
Calcium signaling has emerged as an important signal transduction pathway of higher plants in response to biotic and abiotic stresses. Ca2+-bound calmodulin (CaM) plays a critical role in decoding and transducing stress signals by activating specific targets. Here, we isolated and functionally characterized the pathogen-responsive CaM gene, Capsicum annuum calmodulin I (CaCaM1), from pepper (C. annuum) plants. The cellular function of CaCaM1 was verified by Agrobacterium spp.-mediated transient expression in pepper and transgenic overexpression in Arabidopsis thaliana. Agrobacterium spp.-mediated transient expression of CaCaM1 activated reactive oxygen species (ROS), nitric oxide (NO) generation, and hypersensitive response (HR)-like cell death in pepper leaves, ultimately leading to local acquired resistance to Xanthomonas campestris pv. vesicatoria. CaCaM1-overexpression (OX) Arabidopsis exhibited enhanced resistance to Pseudomonas syringae and Hyaloperonospora parasitica, which was accompanied by enhanced ROS and NO generation and HR-like cell death. Treatment with the calcium-channel blocker suppressed the oxidative and NO bursts and HR-like cell death that were triggered by CaCaM1 expression in pepper and Arabidopsis, suggesting that calcium influx is required for the activation of CaCaM1-mediated defense responses in plants. Upon treatment with the CaM antagonist, virulent P syringae pv. tomato-induced NO generation was also compromised in CaCaM1-OX leaves. Together, these results suggest that the CaCaM1 gene functions in ROS and NO generation are essential for cell death and defense responses in plants.