The pepper RNA-binding protein CaRBP1 functions in hypersensitive cell death and defense signaling in the cytoplasm.
The regulation of gene expression via post-transcriptional modification by RNA-binding proteins is crucial for plant disease and innate immunity. Here, we report the identification of the pepper (Capsicum annuum) RNA-binding protein1 gene (CaRBP1) as essential for hypersensitive cell death and defense signaling in the cytoplasm. CaRBP1 contains an RNA recognition motif and is rapidly and strongly induced in pepper by avirulent Xanthomonas campestris pv. vesicatoria (Xcv) infection. CaRBP1 displays in vitro RNA- and DNA-binding activity and in planta nucleocytoplasmic localization. Transient expression of CaRBP1 in pepper leaves triggers cell-death and defense responses. Notably, cytoplasmic localization of CaRBP1, mediated by the N-terminal region of CaRBP1, is essential for the hypersensitive cell-death response. Silencing of CaRBP1 in pepper plants significantly enhances susceptibility to avirulent Xcv infection. This is accompanied by compromised hypersensitive cell death, production of reactive oxygen species in oxidative bursts, expression of defense marker genes and accumulation of endogenous salicylic acid and jasmonic acid. Over-expression of CaRBP1 in Arabidopsis confers reduced susceptibility to infection by the biotrophic oomycete Hyaloperonospora arabidopsidis. Together, these results suggest that cytoplasmic localization of CaRBP1 is required for plant signaling of hypersensitive cell-death and defense responses.
Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713, Korea.
Dong Hyuk
DH
Lee
Dae Sung
DS
Kim
Byung Kook
BK
Hwang
D017360:Arabidopsis / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D002212:Capsicum / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology*; D016923:Cell Death; D018548:Cotyledon / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D003517:Cyclopentanes / Q000032:analysis; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions; D009868:Oomycetes / Q000472:pathogenicity; D054883:Oxylipins / Q000032:analysis; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology; D010937:Plant Growth Regulators / Q000032:analysis; D057865:Plant Immunity; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D044224:Pseudomonas syringae / Q000472:pathogenicity; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D020156:Salicylic Acid / Q000032:analysis; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D016959:Xanthomonas campestris / Q000472:pathogenicity
D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C011006:jasmonic acid; D020156:Salicylic Acid