A perspective on ecologically relevant plant-UV research and its practical application

Abstract

Plants perceive ultraviolet-B (UV-B) radiation through the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8), and initiate regulatory responses via associated signalling networks, gene expression and metabolic pathways. Various regulatory adaptations to UV-B radiation enable plants to harvest information about fluctuations in UV-B irradiance and spectral composition in natural environments, and to defend themselves against UV-B exposure. Given that UVR8 is present across plant organs and tissues, knowledge of the systemic signalling involved in its activation and function throughout the plant is important for understanding the context of specific responses. Fine-scale understanding of both UV-B irradiance and perception within tissues and cells requires improved application of knowledge about UV-attenuation in leaves and canopies, warranting greater consideration when designing experiments. In this context, reciprocal crosstalk among photoreceptor-induced pathways also needs to be considered, as this appears to produce particularly complex patterns of physiological and morphological response. Through crosstalk, plant responses to UV-B radiation go beyond simply UV-protection or amelioration of damage, but may give cross-protection over a suite of environmental stressors. Overall, there is emerging knowledgeshowing how information captured by UVR8 is used to regulate molecular and physiological processes, although understanding of upscaling to higher levels of organisation, i.e. organisms, canopies and communities remains poor. Achieving this will require further studies using model plant species beyond Arabidopsis, and that represent a broad range of functional types. More attention should also be given to plants in natural environments in all their complexity, as such studies are needed to acquire an improved understanding of the impact of climate change in the context of plant-UV responses. Furthermore, broadening the scope of experiments into the regulation of plant-UV responses will facilitate the application of UV radiation in commercial plant production. By considering the progress made in plant-UV research, this perspective highlights prescient topics in plant-UV photobiology where future research efforts can profitably be focussed. This perspective also emphasises burgeoning interdisciplinary links that will assist in understanding of UV-B effects across organisational scales and gaps in knowledge that need to be filled so as to achieve an integrated vision of plant responses to UV-radiation.

Seasonal Patterns in Spectral Irradiance and Leaf UV-A Absorbance Under Forest Canopies

“…Many questions on the ecological role of UV responses remain unanswered (Barnes, 2016c;Robson et al, 2019), including how plant secondary metabolite responses controlling UV absorbance may be modified by climatic and environmental factors. This consideration is particularly relevant for forest understorey species whose growth may be limited by the light environment (Valladares, 2003;Heberling et al, 2019).…”

Phenolic characteristics acquired by berry skins of Vitis vinifera cv. Tempranillo in response to close‐to‐ambient solar ultraviolet radiation are mostly reflected in the resulting wines

“…Solar ultraviolet (UV) radiation is divided into UV‐C (100–280 nm), UV‐B (280–315 nm) and UV‐A (315–400 nm) bands, although only wavelengths greater than 290 nm reach the biosphere. UV radiation represents a minor fraction of total solar radiation, with UV‐A and UV‐B photons being equivalent to around 5% and 0.33% of photosynthetically active radiation photons (PAR) (400–700 nm) at ground level . However, UV causes significant effects on the morphology, physiology and gene expression of plants.…”

“…However, UV causes significant effects on the morphology, physiology and gene expression of plants. Although traditionally considered as a stressor, UV radiation (particularly UV‐B) may lead to both damage and acclimation responses, which depend on the irradiance and dose received, and can be notably different under controlled and field conditions . High UV doses, frequently artificial and unrealistic, may cause DNA damage and alterations in the photosynthetic machinery, leading to plant distress (permanent damage), although real ambient UV levels rather cause acclimation responses (eustress), including DNA repair, growth modulation and induction of antioxidant defenses, as well as potential protection of secondary metabolites .…”

Characterization of Ethyl Acetate and Trichloromethane Extracts from Phoebe zhennan Wood Residues and Application on the Preparation of UV Shielding Films

“…Since ultraviolet (UV) photons are very energetic in reaching the Earth's surface and thus able to break chemical bonds and rearrange molecular structures [23], UV light can cause skin lesions [24], paper yellowing [25], plastic aging [26] and promote the oxidative degradation of foods [27]. Therefore, the development of UV shielding materials has attracted great interest; for example, a transparent TiO 2 xerogel has been fabricated to protect wood from discoloration and degradation [28].…”