Choi Du Seok, Kim Nak Hyun, Hwang Byung Kook
Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea
Plant Physiol. 2014 Nov;166(3):1298-311. doi: 10.1104/pp.114.246736. Epub 2014 Sep 18.
Formate dehydrogenase (FDH; EC 1.2.1.2) is an NAD-dependent enzyme that catalyzes the oxidation of formate to carbon dioxide. Here, we report the identification and characterization of pepper (Capsicum annuum) mitochondrial FDH1 as a positive regulator of cell death and defense responses. Transient expression of FDH1 caused hypersensitive response (HR)-like cell death in pepper and Nicotiana benthamiana leaves. The D-isomer -: specific 2-hydroxyacid dehydrogenase signatures of FDH1 were required for the induction of HR-like cell death and FDH activity. FDH1 contained a mitochondrial targeting sequence at the N-terminal region; however, mitochondrial localization of FDH1 was not essential for the induction of HR-like cell death and FDH activity. FDH1 silencing in pepper significantly attenuated the cell death response and salicylic acid levels but stimulated growth of Xanthomonas campestris pv vesicatoria. By contrast, transgenic Arabidopsis (Arabidopsis thaliana) overexpressing FDH1 exhibited greater resistance to Pseudomonas syringae pv tomato in a salicylic acid-dependent manner. Arabidopsis transfer DNA insertion mutant analysis indicated that AtFDH1 expression is required for basal defense and resistance gene-mediated resistance to P. syringae pv tomato infection. Taken together, these data suggest that FDH1 has an important role in HR-like cell death and defense responses to bacterial pathogens.
甲酸脱氢酶（FDH；EC 1.2.1.2）是一种依赖烟酰胺腺嘌呤二核苷酸（NAD）的酶，可催化甲酸氧化为二氧化碳。在此，我们报告了辣椒（Capsicum annuum）线粒体FDH1的鉴定和特性，它是细胞死亡和防御反应的正向调节因子。FDH1的瞬时表达在辣椒和本氏烟草叶片中引发了类似过敏反应（HR）的细胞死亡。FDH1的D-异构体特异性2-羟基酸脱氢酶特征是诱导类似HR的细胞死亡和FDH活性所必需的。FDH1在N端区域含有一个线粒体靶向序列；然而，FDH1的线粒体定位对于诱导类似HR的细胞死亡和FDH活性并非必不可少。辣椒中FDH1基因沉默显著减弱了细胞死亡反应和水杨酸水平，但促进了野油菜黄单胞菌疮痂致病变种的生长。相比之下，过表达FDH1的转基因拟南芥（Arabidopsis thaliana）以水杨酸依赖的方式对丁香假单胞菌番茄致病变种表现出更强的抗性。拟南芥转移DNA插入突变体分析表明，AtFDH1的表达是基础防御以及抗性基因介导的对丁香假单胞菌番茄致病变种感染的抗性所必需的。综上所述，这些数据表明FDH1在类似HR的细胞死亡以及对细菌病原体的防御反应中具有重要作用。
