Molecular responses of legumes to abiotic stress: post-translational modifications of proteins and redox signaling.

Manuel A Matamoros,Manuel Becana,Christine Foyer

doi:10.1093/jxb/erab008

Abstract

Legumes include several major crops that can fix atmospheric nitrogen in symbiotic root nodules, thus reducing the demand for nitrogen fertilizers and contributing to sustainable agriculture. Global change models predict increases in temperature and extreme weather conditions. This scenario might increase plant exposure to abiotic stresses and negatively affect crop production. Regulation of whole plant physiology and nitrogen fixation in legumes during abiotic stress is complex, and only a few mechanisms have been elucidated. Reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS) are key players in the acclimation and stress tolerance mechanisms of plants. However, the specific redox-dependent signaling pathways are far from understood. One mechanism by which ROS, RNS, and RSS fulfil their signaling role is the post-translational modification (PTM) of proteins. Redox-based PTMs occur in the cysteine thiol group (oxidation, S-nitrosylation, S-glutathionylation, persulfidation), and also in methionine (oxidation), tyrosine (nitration), and lysine and arginine (carbonylation/glycation) residues. Unraveling PTM patterns under different types of stress and establishing the functional implications may give insight into the underlying mechanisms by which the plant and nodule respond to adverse conditions. Here, we review current knowledge on redox-based PTMs and their possible consequences in legume and nodule biology.

Highlights

Crops provide the vast majority of global food requirements
Bacterial nitrogenase c activity injects around 40 million tons of nitrogen into agricultural systems every year, reducing s the demand for nitrogen fertilizers and contributing to sustainable agriculture (Udvardi and Poole, u 2013; Gresshoff et al, 2015). n Mankind is confronted with environmental challenges that are predicted to worsen in the upcoming a decades
The same post-translational modification (PTM) may have different effects depending on the modification site, and a specific PTM can have opposed effects on different proteins

Summary

Introduction

Crops provide the vast majority of global food requirements. modern agriculture relies greatly on the supply of fertilizers, especially nitrogen, and the demand is expected to rise due to population growth. In L. japonicus and M. truncatula, glutathione peroxidases (Gpxs), an enzyme family closely related to Prxs, are S-nitrosylated in vitro and in vivo, which resulted in the partial inhibition of their enzyme activities (Matamoros et al, 2015; Castella et al, 2017) These results strongly suggest an important role for NO signaling in the regulation of SNF, a possible function under stress conditions awaits investigation. The physiological implications of these discoveries are not Ac clear yet, but probably S-glutathionylation of proteins increases under abiotic stresses that perturb the cellular redox state This PTM may protect the protein from irreversible oxidative deactivation and/or regulate its activity as part of signaling events that control cell metabolism. In M. truncatula only one GLXII gene is up-regulated in response to c drought conditions (Fig. 4), suggesting that either the glyoxalase system is not regulated under stress Aconditions or that it relies on post-transcriptional control for its activation

Conclusions and perspectives

A Indeterminate nodules ep c p vb en Determinate nodules