Abordagem ambientalmente sustentável da própolis brasileira a partir de estudos in vitro e in vivo frente a fitopatógenos

Abstract

Phytopathogens are microorganisms that infect agricultural crops, reducing the quality of plants and fruits. In this sense, Brazilian Green, Red, and Brown Propolis have been gaining prominence due to their numerous biological properties, mainly antimicrobial, making them a promising option against these microorganisms. To this end, this study evaluated the antibacterial and antibiofilm potential, as well as the ability to inhibit pathogenicity and infection, of crude hydroalcoholic extracts of Brazilian red, green, and brown propolis against relevant phytopathogens. The studies were conducted using strains of Pantoea ananatis, Pectobacterium carotovorum, Ralstonia solanacearum, and Burkholderia cepacia, together with crude hydroalcoholic extracts of green, red, and brown propolis. Initially, the Minimum Inhibitory Concentration (MIC) was determined, with results ranging from 1 mg/mL to 2 mg/mL, as well as the Minimum Bactericidal Concentration (MBC), where it was observed that the red propolis extract demonstrated bactericidal activity against some strains. Based on the results obtained in the MIC test, the most promising values (1 mg/mL) were selected for the evaluation of synergistic activity, Minimum Inhibitory Concentration of Biofilm (MICB50), and in vivo antibacterial activity in plants. Red propolis did not show synergistic activity with streptomycin. However, red propolis at concentrations of 1 and 2 mg/mL was able to reduce both the biomass and cell viability of the biofilm of P. ananatis and R. solanacearum. In the in vivo assay, red propolis significantly reduced the size of symptoms on corn leaves infected with P. ananatis and R. solanacearum when used both as prevention and as treatment for infection. In the future, extracts from Brazilian propolis, especially red propolis, may be a promising alternative for the control of phytopathogenic bacteria in agriculture.