Nitric oxide–centred signaling networks in plants: from growth to postharvest
Nitric oxide (NO) has emerged as a versatile signaling molecule that regulates plant development, stress responses, and redox homeostasis through interactions with reactive oxygen species (ROS), phytohormones, and other bioactive compounds. In horticulture, postharvest losses remain a major challenge due to ongoing metabolic activity associated with ripening and senescence. Increasing evidence identifies NO as a key regulator capable of mitigating these processes and extending shelf life. This Mini Review provides a concept-driven synthesis positioning NO as a central integrator of plant signaling networks. We highlight its role as a redox–hormonal hub coordinating interactions with ROS and phytohormones. Special emphasis is placed on the dual role of NO as both a signaling molecule and a modulator of nitro-oxidative stress during plant growth, fruit ripening, and postharvest physiology. We further discuss key molecular mechanisms underlying postharvest responses, together with current controversies related to NO biosynthesis, concentration-dependent effects, and practical application strategies.