The Functional Interplay between Ethylene, Hydrogen Sulfide, and Sulfur in Plant Heat Stress Tolerance

Plants encounter several abiotic stresses, among which heat stress is gaining paramount attention because of the changing climatic conditions. Severe heat stress conspicuously reduces crop productivity through changes in metabolic processes and in growth and development. Ethylene and hydrogen sulfide (H₂S) are signaling molecules involved in defense against heat stress through modulation of biomolecule synthesis, the antioxidant system, and post-translational modifications. Other compounds containing the essential mineral nutrient sulfur (S) also play pivotal roles in these defense mechanisms. As biosynthesis of ethylene and H₂S is connected to the S-assimilation pathway, it is logical to consider the existence of a functional interplay between ethylene, H₂S, and S in relation to heat stress tolerance. The present review focuses on the crosstalk between ethylene, H₂S, and S to highlight their joint involvement in heat stress tolerance.