Drought and UV-B radiation modulate Adenanthera pavonina leaf metabolite profile and physiology

Adenanthera pavonina is a medicinal species, which economic value depends on the richness of its phytocompounds. Extreme climatic conditions are becoming frequent worldwide, but despite their impact on plant productivity these weather events also modulate plants’ metabolism increasing the production of important phytocompounds. We aimed to characterize the physiological and metabolite adjustments in A. pavonina leaves induced by drought and UV-B radiation. Plants were exposed to drought (DS), UV-B radiation (UV-B), and drought + UV-B (DS + UV-B), and photosynthesis, lipophilic metabolites, and antioxidant status were evaluated. The stress conditions compromised the photosynthetic performance and induced oxidative stress (DS and UV-B plants). However, plants activated protective mechanisms (increased antioxidant activity and flavonoids in all treatments, total phenols in DS and DS + UV-B, and catechols in UV-B and DS + UV-B) and modulated their lipophilic profiles (accumulation of fatty acids and TCA cycle-related metabolites, and reduction of carbohydrates) to cope with the stress. We demonstrate for the first time that DS and UV-B radiation can enrich A. pavonina leaves with antioxidants and fatty acids increasing their medicinal value.