Hydrogen sulfide: a luminous future in the postharvest preservation of fruits and vegetables

Abstract

Hydrogen sulfide (H₂S) has emerged as a signaling molecule that plays a crucial role in the postharvest preservation of fruits and vegetables. This review summarizes the various functions of H₂S such as delaying ripening and senescence, enhancing the resistance to cold and disease, and emphasizes the underlying mechanisms. Appropriate concentrations of H₂S primarily operate through stimulating the antioxidant system, while showing positive effects on physiological metabolism relevant to storage quality and shelf life including energy, sugar, proline, phenolic, membrane lipid and cell wall metabolism. Moreover, H₂S may reduce storage loss by modulating the expression patterns of senescence-related genes, like those linked to ethylene. The coordination of H₂S and nitric oxide (NO) combats ethylene-derived negative effects during ripening and senescence. High concentrations of H₂S not only act as a regulator to induce disease resistance, but also as a fungicide to inhibit the growth and pathogenicity of fungi. The intricate crosstalk between H₂S and other molecules exists via synergistic and antagonistic roles based on protein persulfidation, which is the major signaling process of H₂S and appears to compete with other post-translational modifications (PTMs) for the same cysteine residues. This review summarizes H₂S synthesis pathways and also discusses the correlation between the signals of H₂S, Ca²⁺ and ABA, while highlighting the intrinsic mechanisms of H₂S performing its functions in postharvest preservation.