Spatiotemporal profiling of bioactive metabolites in a resilient plant species and its antifungal potential against plant pathogens

Abstract

Concerns about the ecological and health risks of indiscriminate use of pesticides have increased interest in natural alternatives that are less harmful yet still effective. Resilient species from harsh environments are a valuable source of active compounds. However, intraspecific chemical variability resulting from the interaction between local growing condition and plant developmental stage is often underestimated, despite its relevance for identifying superior raw materials. Azorella prolifera, a widely dominant species in arid and semiarid areas of South America, is a valuable model for addressing this purpose. This study aimed to carry out a spatiotemporal characterization of bioactive metabolite profiling of A. prolifera, considering different provenances and phenological stages of the plant material. The antifungal activity of A. prolifera essential oils and hydrolats against nine plant fungal pathogens was also assessed. This species exhibited a rich secondary metabolite profile, containing at least 31 (poly)phenols (4.1 ± 1.4 g/100 g of dry weight) and up to 55 volatiles. A. prolifera essential oils showed a promising performance against Fusarium graminearum (a devastating crop pathogen), with minimum inhibitor and fungicide concentrations between 250 and 500 μg/mL. Variability in both chemical profiling and antifungal effectiveness within this species was revealed. Natural populations from 41◦08'S - 71◦08'W provide an additional value, as their hydrolats exhibited fungistatic activity against A. fumigatus and B. cinerea fungi. Our results highlight the potential of A. prolifera for biofungicide formulation and demonstrate the importance of spatiotemporal chemical screening of raw materials to identify superior ones.