title: Capsicum annuum WRKY protein CaWRKY1 is a negative regulator of pathogen defense.
abstract: Plants respond to pathogens by regulating a network of signaling pathways that fine-tune transcriptional activation of defense-related genes. The aim of this study was to determine the role of Capsicum annuum WRKY zinc finger-domain transcription factor 1 (CaWRKY1) in defense. In previous studies, CaWRKY1 was found to be rapidly induced in C. annuum (chili pepper) leaves by incompatible and compatible pathogen inoculations, but the complexity of the network of the WRKY family prevented the function of CaWRKY1 in defense from being elucidated. Virus-induced gene silencing of CaWRKY1 in chili pepper leaves resulted in decreased growth of Xanthomonas axonopodis pv. vesicatoria race 1. CaWRKY1-overexpressing transgenic plants showed accelerated hypersensitive cell death in response to infection with tobacco mosaic virus and Pseudomonas syringe pv. tabaci. Lower levels of pathogenesis-related gene induction were observed in CaWRKY1-overexpressing transgenic plants following salicylic acid (SA) treatments. This work suggests that the newly characterized CaWRKY1, which is strongly induced by pathogen infections and the signal molecule SA, acts as a regulator to turn off systemic acquired resistance once the pathogen challenge has diminished and to prevent spurious activation of defense responses at suboptimal concentrations of SA.
authors.affiliation: Plant Genome Research Center, KRIBB, P.O. Box 115, Yusung, Daejeon 305-600, Korea.
authors.forename: Sang-Keun
authors.initials: SK
authors.lastname: Oh
authors.affiliation: Department of Plant Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Kwang-Hyun
authors.initials: KH
authors.lastname: Baek
authors.affiliation: Plant Genome Research Center, KRIBB, P.O. Box 115, Yusung, Daejeon 305-600, Korea.
authors.forename: Jeong Mee
authors.initials: JM
authors.lastname: Park
authors.affiliation: Plant Genome Research Center, KRIBB, P.O. Box 115, Yusung, Daejeon 305-600, Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Yi
authors.affiliation: Laboratory of Plant Pathology, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Seung Hun
authors.initials: SH
authors.lastname: Yu
authors.affiliation: Department of Plant Pathology, OARDC, The Ohio State University, Wooster, OH 44691-4096, USA.
authors.forename: Sophien
authors.initials: S
authors.lastname: Kamoun
authors.affiliation: Plant Genome Research Center, KRIBB, P.O. Box 115, Yusung, Daejeon 305-600, Korea.|Department of Plant Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Doil
authors.initials: D
authors.lastname: Choi
mesh_terms: D000595:Amino Acid Sequence; D002212:Capsicum / Q000187:drug effects / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D020868:Gene Silencing; D005801:Genes, Homeobox; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D020156:Salicylic Acid