UV-B as a Potential Regulator of Horticultural Crop Quality: From Signal Perception to Metabolic Reprogramming

Abstract

UV-B (280–315 nm) is an ultraviolet waveband in the solar spectrum, which can act as both an abiotic stressor and a signal regulator. This band could be used in protected horticulture and containerized plant growth conditions. Under modern protected cultivation, the enclosed growing environment often lacks natural UV-B radiation, which may have an impact on vegetative growth, degrade nutritional quality, and weaken disease resistance in certain cases; however, such effects are not universal and depend on crop species, cultivars, developmental stages, and cultivation systems. Therefore, UV-B deficiency or supplementation should not be viewed as universally beneficial or harmful. Previous studies have mostly focused on the adverse stress effects of high-intensity UV-B, such as damage to plant cell membranes and photosynthetic apparatus. However, under specific conditions and at appropriate low doses, UV-B irradiation can activate plant-specific light signaling cascades, modulate plant growth and secondary metabolite biosynthesis, and has shown potential to improve the morphological traits, nutritional accumulation, and postharvest storability of certain horticultural crops. This paper reviews the molecular mechanisms underlying UV-B perception and signal transduction in plants. It summarizes the regulatory patterns of UV-B on morphogenesis, vegetative growth, and overall quality of horticultural crops. Bottlenecks in current knowledge are discussed in the context of the use of precise UV-B radiation for commercial application. By synthesizing scattered evidence on dose-dependent responses, this review extracts practical parameters—irradiation timing, intensity thresholds, and species-specific sensitivities—that are directly relevant to containerized and protected cultivation. This framework aims to support the development of more efficient, quality-oriented green cultivation systems.