Ethylene-Induced Hydrogen Sulfide Negatively Regulates Ethylene Biosynthesis by Persulfidation of ACO in Tomato Under Osmotic Stress.

Honglei Jia,Xiaofeng Wang,Jisheng Li,Jun Yang,Juan Wang,Cong Shi,Meijuan Ren,Sisi Chen,Dan Liu,Wei Shi,Johannes Liesche

doi:10.3389/fpls.2018.01517

Abstract

A number of recent studies identified hydrogen sulfide (H2S) as an important signal in plant development and adaptation to environmental stress. H2S has been proven to participate in ethylene-induced stomatal closure, but how the signaling pathways of H2S and ethylene interact is still unclear. Here, we reveal how H2S controls the feedback-regulation of ethylene biosynthesis in tomato (Solanum lycopersicum) under osmotic stress. We found that ethylene induced the production of H2S in guard cells. The supply of hypotaurine (HT; a H2S scavenger) or DL-pro-pargylglycine (PAG; a synthetic inhibitor of H2S) removed the effect of ethylene or osmotic stress on stomatal closure. This suggests that ethylene-induced H2S is a downstream component of osmotic stress signaling, which is required for ethylene-induced stomatal closure under osmotic stress. We further found that H2S inhibited ethylene synthesis through inhibiting the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidases (ACOs) by persulfidation. A modified biotin-switch method (MBST) showed that H2S can induce persulfidation of LeACO1 and LeACO2 in a dose-dependent manner, and that persulfidation inhibits the activity of LeACO1 and LeACO2. We also found that LeACO1 is persulfidated at cysteine 60. These data suggested that ethylene-induced H2S negatively regulates ethylene biosynthesis by persulfidation of LeACOs. In addition, H2S was also found to inhibit the expression of LeACO genes. The results provide insight on the general mode of action of H2S and contribute to a better understanding of a plant’s response to osmotic stress.

Highlights

Hydrogen sulfide (H2S) is recognized as the third endogenous gasotransmitter, following the discovery of nitric oxide and carbon monoxide (Tan et al, 2010)
NaHS treatment inhibited the activity of ACC oxidase under control and osmotic stress conditions (Figure 3B). These results suggest that H2S may inhibit ethylene biosynthesis through negatively regulating ACC oxidase activity
These results strongly suggested that H2S is an important signal molecule involved in ethylene signal, at least in the osmotic stress response of guard cells

Summary

Introduction

Hydrogen sulfide (H2S) is recognized as the third endogenous gasotransmitter, following the discovery of nitric oxide and carbon monoxide (Tan et al, 2010). H2S Negatively Regulates Ethylene Biosynthesis (D-CDES) degrade Cys to H2S, pyruvate, and ammonia and are responsible for the release of H2S into the cell (Kopriva, 2006). H2S has been recognized as a major signaling compound, involved in stress responses to osmotic stress, high salinity, drought, heavy metals, and oxidative stress (Christou et al, 2013; Li et al, 2014; Jia et al, 2016; Fang et al, 2016; Guo et al, 2017). H2S seems to generally act via the modulation of hormone action, namely of ethylene, auxin, and abscisic acid (Hou et al, 2013; Scuffi et al, 2014; Jia et al, 2015). Is the molecular mechanism of how H2S can affect hormone action

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Conclusion