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