RING-type E3 ligase PROTEOLYSIS1 from Syntrichia caninervis targets ABI3 for degradation and modulates plant stress responses

Abstract

Ubiquitin-mediated protein degradation is crucial for plants to respond to environmental stresses, with E3 ligases being particularly important in regulating responses to abiotic stresses. This study focused on the role of E3 ubiquitin ligase in osmotic stress response in desiccation-tolerant mosses. We identified PROTEOLYSIS1 (PRT1), a RING-type E3 ligase, in Syntrichia caninervis. Our in vivo and in vitro assays confirmed that ScPRT1 actively targets the abscisic acid-insensitive 3 (ABI3) protein for degradation. Overexpressing ScPRT1 in Arabidopsis and S. caninervis reduced their tolerance to salt and drought stresses. Transcriptome analysis showed that ScPRT1 overexpression downregulates ABI3 and suppresses genes in the ERFs and DREBs subfamilies, leading to impaired stress resistance. This research enhances our understanding of abiotic stress responses in bryophytes and highlights the significance of protein ubiquitination in these plants.