Nitric Oxide in Plant Cold Stress: Functions, Mechanisms and Challenges

Abstract

Cold stress, as an environmental factor that seriously restricts the growth, production and survival of plants, has received extensive attention in recent years. Nitric oxide (NO), as an important bioactive molecule, has emerged as a research focus in the domain of alleviating plant cold damage. In this review, the role of NO in enhancing plant cold tolerance and its underlying mechanisms, including interactions with signaling molecules, are discussed more extensively, and novel research directions and prospects are proposed according to existing research gaps. Interestingly, exogenous NO mitigates cold stress by strengthening antioxidant defense mechanisms, raising proline levels, enhancing photosynthetic capacity, and regulating glucose metabolism. More importantly, NO also interacts with cytoplasmic calcium ions (Ca2+), reactive oxygen species (ROS), glutathione (GSH), melatonin (MT), abscisic acid (ABA), ethylene (ETH) and hydrogen sulfide (H2S). At the same time, in the process of NO alleviating cold stress, it regulates the expression of NO synthesis genes, cold response genes and antioxidant related genes, thereby improving the cold tolerance of plants, which may involve epigenetic reprogramming. This paper also points out the problems existing in the current research and the potential of NO in agricultural practice, and provides relevant theoretical references for future research in this field.