COP1 destabilizes DELLA proteins in Arabidopsis

BLANCO-TOURIÑÁN, NOEL*; COSTIGLIOLO ROJAS, CECILIA *; GARCIA-LEON, MARTA; TIM BLOMEIER; DAVID ESTEVE-BRUNA; HENNING FRERIGMANN; VICENTE RUBIO; DAVID ALABADί; MINGUET, EUGENIO G*; INIESTO, ELISA; HEUCKEN, NICOLE; MARTIN CERNÝ; BřETISLAV BRZOBOHATÝ; STEVE A. KAY; CASAL, JORGE J.; LEGRIS, MARTINA*; NOHALES, MARIA A.; MANUEL PACIN; ANTONELLA LOCASCIO; MÓNICA DÍEZ-DÍAZ; MATίAS D. ZURBRIGGEN; MIGUEL A. BLÁZQUEZ

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Lugar: Washington DC, USA; Año: 2020

0027-8424

DELLA proteins are plant-specific transcriptional regulators that act as signaling hubs at the interface between the environment and the transcriptional networks that control growth. The growth-promoting hormone gibberellin destabilizes DELLAs. Here we describe an alternative pathway to destabilize these proteins. We show that DELLAs are substrate of COP1, an E3 ubiquitin ligase that increases its activity to promote growth in response to shade or warmth. Our results show that COP1, and not changes in gibberellin levels, mediates the rapid destabilization of DELLAs in response to environmental cues.DELLA transcriptional regulators are central components in the control of plant growth responses to the environment. This control is considered to be mediated by changes in the metabolism of the hormones gibberellins (GAs), which promote the degradation of DELLAs. However, here we show that warm temperature or shade reduced the stability of a GA-insensitive DELLA allele in Arabidopsis thaliana. Furthermore, the degradation of DELLA induced by the warmth preceded changes in GA levels and depended on the E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). COP1 enhanced the degradation of normal and GA-insensitive DELLA alleles when coexpressed in Nicotiana benthamiana. DELLA proteins physically interacted with COP1 in yeast, mammalian, and plant cells. This interaction was enhanced by the COP1 complex partner SUPRESSOR OF phyA-105 1 (SPA1). The level of ubiquitination of DELLA was enhanced by COP1 and COP1 ubiquitinated DELLA proteins in vitro. We propose that DELLAs are destabilized not only by the canonical GA-dependent pathway but also by COP1 and that this control is relevant for growth responses to shade and warm temperature.