Ação antifúngica sobre fitopatógenos e atividade de enzimas relacionadas a defesa em trigo pelo extrato etanólico de própolis

Abstract

Propolis is widely known for its antimicrobial effects and used in the area of human health, it has been tested in the control of plant diseases, but there is still little information about its efficiency. Thus, this study aimed to evaluate the action of propolis ethanolic extract (EEP) on wheat phytopathogens Pyricularia grisea (brusone), Fusarium graminearum (hence), Bipolaris sorokiniana (helminthosporiosis) and Puccinia triticina (wheat rust), fungal diseases that affect the wheat crop and cause significant losses in crop productivity. The EEP was obtained by maceration for 15 days in 70% ethanol. Regarding the phytopathogens, concentrations of 0, 0.1, 0.5, 1 and 2% were evaluated, where the mycelial growth of the colonies was evaluated, with the exception of rust, where the germination of spores and the size of the germ tubes were evaluated, because it is a biotrophic pathogen. In an experiment under a greenhouse, the activity of peroxidases and polyphenoloxidases enzymes was evaluated in wheat plants submitted to the application of concentrations of 0, 0.1, 0.5, 1 and 2% of EEP and in times of 0, 24, 48, 72 and 96 hours after application. EEP showed a dose-dependent inhibitory effect on Pyricularia grisea, Fusarium graminearum, Bipolaris sorokiniana and Puccinia triticina, although there was no total growth inhibition. For peroxidases and polyphenoloxidases there was no significant effect (p<0.05) by the application of propolis in the different concentrations and times analyzed. The results demonstrate the potential of propolis in controlling wheat diseases, as well as the importance of greater understanding in field studies.