The results of this research show that COP1 regulates the levels of DELLA proteins in response to environmental changes.

Researchers of the Plant Molecular and Cellular Biology Institute (IBMCP), mixed centre of Valencia’s Polytechnic University (UPV) and the Spanish National Research Council (CSIC), have identified a new mechanism that regulates the DELLA proteins, which control the growth of plants depending on their environment. The results of this research, which increases the knowledge available on how plants respond to environmental changes, have been published in journal Proceedings of the National Academy of Sciences.

Plants can adopt different morphologies depending on the surroundings they live in. This plastic behaviour is modulated through highly interconnected signalling pathways that include numerous control points. The light and temperature are among the environmental variables that most affect plant growth. For example, the light that reaches them after bouncing off neighbouring plants, or which filters through the vegetation cover, as well as high environmental temperature, accelerate stem and leaf petiole growth to avoid the shade and improve plant cooling.

David Alabadí, researcher of the CSIC at the IBMCP, explains that “plants have a type of proteins called DELLA that act as an interface between the environment and the cellular mechanisms that promote growth. Until now it was believed that the levels of DELLA proteins were exclusively regulated by gibberellin hormones. We have discovered that COP1, an E3 ubiquitin ligase involved in protein degradation, also fulfils a key role controlling the levels of DELLA proteins in response to certain environmental changes.”

The IBMCP researchers have conducted experiments with plant Arabidopsis thaliana, and have verified that COP1 plays a pivotal role when regulating the levels of DELLA proteins in response to environmental stimuli such as shade and heat in the short term, instead of the levels of gibberellin hormone.

The results of this study therefore show an alternative cellular mechanism that regulates plant response to environmental stimuli. The centres that worked on this project were the Leloir Institute of Buenos Aires (Argentina), the University of Southern California (USA), the National Biotechnology Centre of the CSIC, the University of Buenos Aires (Argentina), the University of Düsseldorf (Germany), Mendel University of Brno (Czech Republic), the Catholic University of Valencia and the Max Planck Institute (Germany).

Reference:

Noel Blanco-Touriñán, Martina Legris, Eugenio G. Minguet, Cecilia Costigliolo-Rojas, Marίa A. Nohales, Elisa Iniesto, Marta Garcίa-Leόn, Manuel Pacίn, Nicole Heucken, Tim Blomeier, Antonella Locascio, Martin Černý, David Esteve-Bruna, Mόnica Dίez-Dίaz, Břetislav Brzobohatý, Henning Frerigmann, Matίas D. Zurbriggen, Steve A. Kay, Vicente Rubio, Miguel A. Blázquez, Jorge J. Casal y David Alabadί. COP1 destabilizes DELLA proteins in Arabidopsis. PNAS first published May 29, 2020. DOI: https://doi.org/10.1073/pnas.1907969117