Hydrogen Sulfide: A Gaseous Molecule in Postharvest Freshness

Hydrogen sulfide (H2S), as signaling molecule, is involved in the regulation of growth and development in plants. Recent studies have indicated that H2S also plays important roles in regulating postharvest senescence of horticultural products. The focus of this review was to summarize the synthesis of H2S in plants and its potential roles in alleviating the senescence of cut flowers, fruits and vegetables during postharvest storage. During postharvest of horticultural products, H2S could scavenge reactive oxygen species (ROS) via promoting the activity of antioxidant enzymes, thereby sustaining the integrity of membrane. In fruits, H2S effectively enhanced the tolerance of chilling by increasing the content of proline and polyphenol compounds. During postharvest storage of perishable fruits and vegetables, H2S significantly alleviated decay which was caused by fungal through inhibiting the growth of fungi spores. Moreover, H2S interacted with other molecules synergistically (NO) or antagonistically (ethylene) to alleviate senescence of horticultural products. At transcription level, H2S regulated the expression of senescence-related genes which were related to degradation of proteins and chlorophyll to delay the senescence of horticultural products. Thus, H2S does not only possess positive anti-oxidize and anti-fungal properties but also significantly regulates the senescence related-gene during postharvest of horticultural products. The future study of H2S in postharvest storage should focus on its molecular mechanism in the post-translational modifications of proteins as well as its safety attributes in treated fruits and vegetables.