The effect of oregano and thyme essential oils on Glycine max seeds infected with Pseudomonas spp. causing bacterial blight of soybean

Abstract

Pseudomonas savastanoi pv. glycinea is the causal agent of bacterial blight in Glycine max. Seeds constitute one of the main transmission vectors of this pathogen. Therefore, treating seeds with compounds that reduce bacterial proliferation represents an appealing solution to prevent production losses. Currently, studies focus on searching for natural products from aromatic plants with antimicrobial properties as efective and environmentally prudent alternatives. This study investigates the eicacy of oregano and thyme essential oils (EOs) in treating seeds infected with P. savastanoi pv. glycinea B076 and Pseudomonas syringae M7-C1. In a previous study, greenhouse trials were performed using only thyme oil. In this research, the same studies were made for oregano essential oil, adding in vivo field trials for both oils. Non-phytotoxic concentration of 0.89 mg/ml was determined for oregano. Both EOs reduced the number of bacterial cells in the seeds, as well as disease Incidence and severity. Among them, thyme EO was more efective in reducing disease under both controlled and ield conditions. This study demonstrates the efficacy of oregano and thyme Eos in reducing pathogenic bacteria on seeds, representing a promising natural alternative for managing these microorganisms.