AtsPLA₂-α nuclear relocalization by the Arabidopsis transcription factor AtMYB30 leads to repression of the plant defense response

• Published in: Proceedings of the National Academy of Sciences - PNAS 2010-08, Vol.107 (34), p.15281-15286
• Main Authors: Froidure, Solène, Canonne, Joanne, Daniel, Xavier, Jauneau, Alain, Brière, Christian, Roby, Dominique, Rivas, Susana
• Format: Article
• Language: English
• Subjects: Active Transport, Cell Nucleus; Arabidopsis - genetics; Arabidopsis - microbiology; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Base Sequence; Biological Sciences; Cellular Biology; DNA Primers - genetics; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Genes, Plant; Genetic Complementation Test; Life Sciences; Mutation; Nicotiana - genetics; Nicotiana - microbiology; Nicotiana - physiology; Phospholipases A2, Secretory - genetics; Phospholipases A2, Secretory - metabolism; Plant Diseases - genetics; Plant Diseases - microbiology; Plants, Genetically Modified; Pseudomonas syringae - pathogenicity; RNA, Plant - genetics; RNA, Plant - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Two-Hybrid System Techniques
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1009056107

The hypersensitive response (HR), characterized by a rapid and localized cell death at the inoculation site, is one of the most efficient resistance reactions to pathogen attack in plants. The transcription factor AtMYB30 was identified as a positive regulator of the HR and resistance responses during interactions between Arabidopsis and bacteria. Here, we show that AtMYB30 and the secreted phospholipase AtsPLA₂-α physically interact in vivo, following the AtMYB30-mediated specific relocalization of AtsPLA₂-α from cytoplasmic vesicles to the plant cell nucleus. This protein interaction leads to repression of AtMYB30 transcriptional activity and negative regulation of plant HR. Moreover, Atspla₂-α mutant plants are more resistant to bacterial inoculation, whereas AtsPLA₂-α overexpression leads to decreased resistance, confirming that AtsPLA₂-α is a negative regulator of AtMYB30-mediated defense. These data underline the importance of cellular dynamics and, particularly, protein translocation to the nucleus, for defense-associated gene regulation in plants.