Capsicum annuum WRKY transcription factor d (CaWRKYd) regulates hypersensitive response and defense response upon Tobacco mosaic virus infection

• Published in: Plant science (Limerick) 2012-12, Vol.197, p.50-58
• Main Authors: Huh, Sung Un, Choi, La Mee, Lee, Gil-Je, Kim, Young Jin, Paek, Kyung-Hee
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis; Biological and medical sciences; Capsicum - genetics; Capsicum - immunology; Capsicum - metabolism; Capsicum - virology; Capsicum annuum; Capsid Proteins - metabolism; Cell Death; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Gene Silencing; genes; Host-Pathogen Interactions; Hypersensitive response; leaves; microarray technology; pepper; Phylogeny; Phytopathology. Animal pests. Plant and forest protection; Plant Diseases - immunology; Plant Diseases - virology; Plant Growth Regulators - pharmacology; Plant Leaves - genetics; Plant Leaves - immunology; Plant Leaves - metabolism; Plant Leaves - microbiology; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plant viruses and viroids; rice; Sequence Alignment; Tobacco mosaic virus; Tobacco Mosaic Virus - physiology; transcription (genetics); transcription factors; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription Factors - metabolism; vector control; WRKY
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/j.plantsci.2012.08.013

WRKY transcription factors regulate biotic, abiotic, and developmental processes. In terms of plant defense, WRKY factors have important roles as positive and negative regulators via transcriptional regulation or protein–protein interaction. Here, we report the characterization of the gene encoding Capsicum annuum WRKY transcription factor d (CaWRKYd) isolated from microarray analysis in the Tobacco mosaic virus (TMV)-P0–inoculated hot pepper plants. CaWRKYd belongs to the WRKY IIa group, a very small clade in the WRKY subfamily, and WRKY IIa group has positive/negative regulatory roles in Arabidopsis and rice. CaWRKYd transcripts were induced by various plant defense-related hormone treatments and TMV-P0 inoculation. Silencing of CaWRKYd affected TMV-P0-mediated hypersensitive response (HR) cell death and accumulation of TMV-P0 coat protein in local and systemic leaves. Furthermore, expression of some pathogenesis-related (PR) genes and HR-related genes was reduced in the CaWRKYd-silenced plants compared with TRV2 vector control plants upon TMV-P0 inoculation. CaWRKYd was confirmed to bind to the W-box. Thus CaWRKYd is a newly identified Capsicum annuum WRKY transcription factor that appears to be involved in TMV-P0-mediated HR cell death by regulating downstream gene expression.