DET1 and COP1 Modulate the Coordination of Growth and Immunity in Response to Key Seasonal Signals in Arabidopsis

Sreeramaiah N Gangappa,S Vinod Kumar

doi:10.1016/j.celrep.2018.08.096

Abstract

SummaryPlant growth and development and outcomes of plant-microbe interactions are defined by coordinated responses to seasonal signals. The mechanisms that control the coordinated regulation of growth and immunity are not well understood. Here, we show that a common signaling module integrates environmental signals, such as photoperiod and temperature, to regulate the growth-defense balance. Key light-signaling components De-Etiolated 1 (DET1) and Constitutive Photomorphogenic 1 (COP1) negatively regulate immunity and are essential for immune modulation by photoperiod and temperature. Our results show that this is regulated by the transcription factor Phytochrome Interacting Factor 4 (PIF4), suggesting that the DET1/COP1-PIF4 module acts as a central hub for the control of growth and immunity in response to seasonal signals. These findings provide a regulatory framework for environmental signal integration.

Highlights

Perception and integration of seasonal signals and diurnal fluctuations into biological processes define plant phenology and adaptation (Møller and Chua, 1999; Vert and Chory, 2011)
Disease Resistance Is Influenced by Photoperiod To dissect the influence of light on defense responses, we studied the disease resistance of Arabidopsis to the bacterial pathogen Pseudomonas syringae pv. tomato (Pto) DC3000 at different photoperiods
Plants grown at LL showed significantly enhanced resistance as opposed to those grown at LD (Figures 1A and S1A), confirming that plant immunity and disease resistance to Pto DC3000 is strongly influenced by day length

Summary

Introduction

Perception and integration of seasonal signals and diurnal fluctuations into biological processes define plant phenology and adaptation (Møller and Chua, 1999; Vert and Chory, 2011). Key seasonal signals such as photoperiod and temperature have been shown to strongly influence plant processes such as growth and development, as well as plant-pathogen interactions (Alcazar and Parker, 2011; Ballare , 2014; Dietrich et al, 1994; Hua, 2013). Photoperiod strongly influences plant phenological and physiological responses (Fraser et al, 2016; Song et al, 2013) and it has been well understood (Song et al, 2013) It plays a key role in modulating plant defense responses that are exemplified by the modulation of lesion-mimic mutant phenotypes (Dietrich et al, 1994; Chaouch et al, 2010) and resistance to pathogens (Roden and Ingle, 2009; Hua, 2013). Beyond fundamental biology, elucidating the underlying mechanisms that modulate plant immunity in response to diurnal and seasonal signals is of great significance for sustainable productivity, especially in the wake of climate change (Battisti and Naylor, 2009; Gornall et al, 2010)

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