UVR8-mediated UV-B signaling and its regulation of horticultural traits: from Arabidopsis to application.

Ultraviolet-B (UV-B, 280-315 nm) radiation acts as a key environmental signal that regulates plant development and acclimation responses. The UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) plays a central role in perceiving and transducing these signals. In the absence of UV-B, UVR8 exists predominantly as a homodimer in the cytoplasm. Upon UV-B absorption, UVR8 dissociates into active monomers that translocate to the nucleus, where they initiate downstream signaling via interactions with core regulatory components. In this review, we systematically elaborate on the UVR8-mediated UV-B signal transduction cascade and the origin and diversification of UVR8, with a focus on the regulatory effects of UV-B on the nutritional quality, stress resilience, and reproductive traits of horticultural plants. We further propose future directions for the genetic improvement of horticultural crops and the development of light-environment manipulation technologies based on the UVR8 signaling network. This review aims to provide a theoretical reference for enhancing the economic value of horticultural products and advancing green, efficient horticultural production.