title: Pepper mitochondrial FORMATE DEHYDROGENASE1 regulates cell death and defense responses against bacterial pathogens.
abstract: 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.
authors.affiliation: Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
authors.forename: Du Seok
authors.initials: DS
authors.lastname: Choi
authors.affiliation: Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
authors.forename: Nak Hyun
authors.initials: NH
authors.lastname: Kim
authors.affiliation: Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea bkhwang@korea.ac.kr.
authors.forename: Byung Kook
authors.initials: BK
authors.lastname: Hwang
mesh_terms: D000429:Alcohol Oxidoreductases / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D002212:Capsicum / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology*; D016923:Cell Death; D018506:Gene Expression Regulation, Plant; D008928:Mitochondria / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology / Q000821:virology*; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism; D044224:Pseudomonas syringae / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism; D016959:Xanthomonas campestris / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D000429:Alcohol Oxidoreductases; C083779:2-hydroxyacid dehydrogenase; D020156:Salicylic Acid