Figure 2.

Schematic representation of the regulatory interaction between ethylene and H₂S biosynthesis for stress tolerance through the S-assimilation pathway. Different arrow types shown above indicate different possible mechanisms. ACC, 1-aminocyclopropane-1-carboxylic acid; ACO, ACC oxidase; ACS, ACC synthase; APR, APS reductase; APS, adenosine 5-phosphosulfate; ATPS, ATP-sulfurylase; Cys, cysteine; DCD, D-cysteine desulfhydrase; LCD, L-cysteine desulfhydrase; ET, ethylene; H₂S, hydrogen sulfide; NH₃, ammonia; S, sulfur; SAM, S-adenosyl methionine; SO₄²⁻, sulfate; SO₃²⁻, sulfite; S²⁻, sulfide; SiR, sulfide reductase; OASTL, O-acetylserine (thiol)-lyase.