Abstract
Small signalling peptides have emerged as important cell to cell messengers in plant development and stress responses. However, only a few of the predicted peptides have been functionally characterized. Here, we present functional characterization of two members of the IDA-LIKE (IDL) peptide family in Arabidopsis thaliana, IDL6 and IDL7. Localization studies suggest that the peptides require a signal peptide and C-terminal processing to be correctly transported out of the cell. Both IDL6 and IDL7 appear to be unstable transcripts under post-transcriptional regulation. Treatment of plants with synthetic IDL6 and IDL7 peptides resulted in down-regulation of a broad range of stress-responsive genes, including early stress-responsive transcripts, dominated by a large group of ZINC FINGER PROTEIN (ZFP) genes, WRKY genes, and genes encoding calcium-dependent proteins. IDL7 expression was rapidly induced by hydrogen peroxide, and idl7 and idl6 idl7 double mutants displayed reduced cell death upon exposure to extracellular reactive oxygen species (ROS). Co-treatment of the bacterial elicitor flg22 with IDL7 peptide attenuated the rapid ROS burst induced by treatment with flg22 alone. Taken together, our results suggest that IDL7, and possibly IDL6, act as negative modulators of stress-induced ROS signalling in Arabidopsis.
Highlights
Plants cannot escape their environment, and are exposed to herbivore grazing, pathogen attacks, and other environmental perturbations such as drought, temperature changes, and high salinity
The protein fusions were transiently expressed in N. benthamiana leaves, and the subcellular localization was examined by confocal microscopy
In this study we describe two new putative peptide ligands belonging to the extended family of IDA and IDL peptides (Vie et al, 2015) and show evidence suggesting that they act as negative modulators of reactive oxygen species (ROS) responses
Summary
Plants cannot escape their environment, and are exposed to herbivore grazing, pathogen attacks, and other environmental perturbations such as drought, temperature changes, and high salinity. NADPH oxidases, often referred to as respiratory burst oxidase homologues (Rbohs), are transmembrane proteins responsible for the production of extracellular superoxide (O2·−) upon pathogen attack (Torres et al, 2002) or abiotic stresses (Kwak et al, 2003; Miller et al, 2009). Both abiotic and biotic stresses trigger a systemic autopropagating wave of ROS, mediated by the NADPH oxidase RBOHD, that travels rapidly in the apoplast from the affected tissue to the entire plant and activates a systemic response to the stress (Miller et al, 2009; Dubiella et al, 2013; Gilroy et al, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
