Hydrogen Sulfide-Mediated Activation of O-Acetylserine (Thiol) Lyase and l/d-Cysteine Desulfhydrase Enhance Dehydration Tolerance in Eruca sativa Mill.

M Khan,Asma Al-Huqail,Hayssam M Ali,Hafiz Al-Haque,Fahad Alzuaibr,Manzer Siddiqui,Mohammed Al-Muwayhi

doi:10.3390/ijms19123981

Abstract

Hydrogen sulfide (H2S) has emerged as an important signaling molecule and plays a significant role during different environmental stresses in plants. The present work was carried out to explore the potential role of H2S in reversal of dehydration stress-inhibited O-acetylserine (thiol) lyase (OAS-TL), l-cysteine desulfhydrase (LCD), and d-cysteine desulfhydrase (DCD) response in arugula (Eruca sativa Mill.) plants. Dehydration-stressed plants exhibited reduced water status and increased levels of hydrogen peroxide (H2O2) and superoxide (O2•−) content that increased membrane permeability and lipid peroxidation, and caused a reduction in chlorophyll content. However, H2S donor sodium hydrosulfide (NaHS), at the rate of 2 mM, substantially reduced oxidative stress (lower H2O2 and O2•−) by upregulating activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and increasing accumulation of osmolytes viz. proline and glycine betaine (GB). All these, together, resulted in reduced membrane permeability, lipid peroxidation, water loss, and improved hydration level of plants. The beneficial role of H2S in the tolerance of plants to dehydration stress was traced with H2S-mediated activation of carbonic anhydrase activity and enzyme involved in the biosynthesis of cysteine (Cys), such as OAS-TL. H2S-treated plants showed maximum Cys content. The exogenous application of H2S also induced the activity of LCD and DCD enzymes that assisted the plants to synthesize more H2S from accumulated Cys. Therefore, an adequate concentration of H2S was maintained, that improved the efficiency of plants to mitigate dehydration stress-induced alterations. The central role of H2S in the reversal of dehydration stress-induced damage was evident with the use of the H2S scavenger, hypotaurine.

Highlights

Climate change is the main factor triggering various environmental stresses, affecting agriculture productivity in almost all the areas of the world
The results show that plants exposed to dehydration stress (DS) exhibited a reduction of 35.1% in Leaf Relative Water Content (LRWC) over the control (Figure 1A)
Addition of HT, an H2S scavenger, to the incubation medium suppressed the effect of H2S on dehydration, and LRWC was further reduced to 13.1% and rate of water loss was increased by 38.5% in stressed seedlings treated with H2S (Figure 1A,B)

Summary

Introduction

Climate change is the main factor triggering various environmental stresses, affecting agriculture productivity in almost all the areas of the world. Drought stress, a slow-onset hazard, has been considered as the most devastating, causing severe losses to crop plants in arid and semi-arid regions of the world [1]. High temperature, low rainfall, high light intensity, dry wind, and fast evaporation of water from soil, cause drought stress [2]. Cumulative effects of drought culminate in reduced crop production and loss of livestock that makes agriculture a high-risk endeavor, and can stifle investment, pushing the country into a cycle of underproduction, low income, and persistent poverty. It has been estimated that 83 percent of all the damage and loss to agriculture were caused by drought alone [3]. Between 2005 and 2015, drought caused 30 percent of agricultural loss in developing countries, which amounted to over USD 29 billion, and caused losses of over 11 million human lives, and more than 2 billion have been affected by drought since 1900 [3]

Methods

Results

Discussion

Conclusion