Journal Article

Blue‐light dependent reactive oxygen species formation by Arabidopsis cryptochrome may define a novel evolutionarily conserved signaling mechanism

Martino, Carlos, Ahmad, Margaret, Consentino, Laurent, Bouchet, Pierre‐Etienne, Witczak, Jacques, Jourdan, Nathalie, Corbineau, Francoise, Lambert, Stefan, d'Harlingue, Alain, Castello, Pablo, El‐Esawi, Mohamed

2015

Overview

Cryptochromes are widespread blue‐light absorbing flavoproteins with important signaling roles. In plants they mediate de‐etiolation, developmental and stress responses resulting from interaction with downstream signaling partners such as transcription factors and components of the proteasome. Recently, it has been shown that Arabidopsis cry1 activation by blue light also results in direct enzymatic conversion of molecular oxygen (O₂) to reactive oxygen species (ROS) and hydrogen peroxide (H₂O₂) in vitro. Here we explored whether direct enzymatic synthesis of ROS by Arabidopsis cry1 can play a physiological role in vivo. ROS formation resulting from cry1 expression was measured by fluorescence assay in insect cell cultures and in Arabidopsis protoplasts from cryptochrome mutant seedlings. Cell death was determined by colorimetric assay. We found that ROS formation results from cry1 activation and induces cell death in insect cell cultures. In plant protoplasts, cryptochrome activation results in rapid increase in ROS formation and cell death. We conclude that ROS formation by cryptochromes may indeed be of physiological relevance and could represent a novel paradigm for cryptochrome signaling.

• Publisher: Academic Press,New Phytologist Trust,Wiley Subscription Services, Inc,Wiley
• Subject: Apoptosis / Arabidopsis / Arabidopsis - drug effects / Arabidopsis - metabolism / Arabidopsis - radiation effects / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Biological Evolution / blue light / Cell activation / Cell culture / Cell death / Cell Death - drug effects / Cell Survival - drug effects / Cell Survival - radiation effects / Cellular Biology / Colorimetry / cryptochrome / Cryptochromes / Cryptochromes - metabolism / Downstream effects / Electromagnetic absorption / Enzymatic synthesis / Etiolation / Flavoproteins / Fluorescence / Hydrogen peroxide / Insects / Life Sciences / Light / Mortality / mutants / oxidative stress / Oxygen / Oxygen - pharmacology / photomorphogenesis / photoreceptor / Physiology / proteasome endopeptidase complex / Proteasomes / Protoplasts / Protoplasts - drug effects / Protoplasts - metabolism / Reactive oxygen species / reactive oxygen species (ROS) signaling / Reactive Oxygen Species - metabolism / Recombination, Genetic - genetics / Seedlings / Sf9 Cells / Signal Transduction - drug effects / Signal Transduction - radiation effects / Signaling / Stress response / Subcellular Fractions - drug effects / Subcellular Fractions - metabolism / Transcription / Transcription factors / Vegetal Biology