Hydrogen sulfide in plant cold stress: functions, mechanisms, and challenge

Cold stress is an environmental factor that seriously restricts the growth, production and survival of plants, and has received extensive attention in recent years. Hydrogen sulfide (H₂S) is an ubiquitous gas signaling molecule, and its role in alleviating plant cold stress has become a research focus in recent years. This paper reviews for the first time the significant effect of H₂S on improving plant cold resistance, which makes up for the gaps in the existing literature. In general, H₂S improves plant tolerance to cold stress by activating antioxidant reaction and promoting the accumulation of metabolic substances such as chlorophyll, flavonoids, proline, sucrose and total soluble sugar in plants. Interestingly, H₂S also interacts with nitric oxide (NO), auxin, jasmonic acid (JA), salicylic acid (SA), and ethylene (ETH) to alleviate cold stress. More importantly, in the process of alleviating cold stress with H₂S, gene expression related to H₂S synthesis, cold response and antioxidant is up-regulated or down-regulated, leading to the improvement of plant cold resistance. This paper also points out the problems existing in the current research and the potential of H₂S in agricultural practice, and provides relevant theoretical references for future research in this field.