title: The pepper GNA-related lectin and PAN domain protein gene, CaGLP1, is required for plant cell death and defense signaling during bacterial infection.
abstract: Carbohydrate-binding proteins, commonly referred to as lectins or agglutinins, function in defense responses to microbial pathogens. Pepper (Capsicum annuum) GNA-related lectin and PAN-domain protein gene CaGLP1 was isolated and functionally characterized from pepper leaves infected with Xanthomonas campestris pv. vesicatoria (Xcv). CaGLP1 contained an amine-terminus prokaryotic membrane lipoprotein lipid attachment site, a Galanthus nivalis agglutinin (GNA)-related lectin domain responsible for the recognition of high-mannose N-glycans, and a carboxyl-terminus PAN/apple domain. RNA gel blot and immunoblot analyses determined that CaGLP1 was strongly induced in pepper by compatible and incompatible Xcv infection. CaGLP1 protein localized primarily to the plasma membrane and exhibited mannose-binding specificity. CaGLP1-silenced pepper plants were more susceptible to compatible or incompatible Xcv infection compared with that of non-silenced control plants. CaGLP1 silencing in pepper leaves did not accumulate H2O2 and induce cell death during incompatible Xcv infection. Defense-related CaDEF1 (defensin) gene expression was significantly reduced in CaGLP1-silenced pepper plants. CaGLP1-overexpression in Arabidopsis thaliana enhanced resistance to Pseudomonas syringae pv. tomato. Defense-related AtPDF1.2 expression was elevated in CaGLP1-overexpression lines. Together, these results suggest that CaGLP1 is required for plant cell death and defense responses through the reactive oxygen species burst and downstream defense-related gene expression in response to bacterial pathogen challenge.
authors.affiliation: Department of Biology, The University of North Carolina at Chapel Hill, NC 27599-3280, USA.
authors.forename: Nak Hyun
authors.initials: NH
authors.lastname: Kim
authors.affiliation: Department of Plant Pathology, University of California Davis, Davis, CA 95616-8751, USA.
authors.forename: Dong Hyuk
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Plant Pathology and Microbiology, University of California Riverside, Riverside, CA 92521, USA.
authors.forename: Du Seok
authors.initials: du S
authors.lastname: Choi
authors.affiliation: Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea. Electronic address: bkhwang@korea.ac.kr.
authors.forename: Byung Kook
authors.initials: BK
authors.lastname: Hwang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D002212:Capsicum / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D016923:Cell Death; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity; D018515:Plant Leaves / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D044224:Pseudomonas syringae / Q000502:physiology; D015398:Signal Transduction; D016959:Xanthomonas campestris / Q000502:physiology
chemical_list: D010940:Plant Proteins
keywords: Capsicum annuum; Defense response; Galanthus nivalis agglutinin (GNA)-related lectin and PAN domain protein; Pathogens; Transgenic Arabidopsis; Virus-induced gene silencing