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 (HS) 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 HS on improving plant cold resistance, which makes up for the gaps in the existing literature. In general, HS 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, HS 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 HS, gene expression related to HS 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 HS in agricultural practice, and provides relevant theoretical references for future research in this field.