Insect-derived bacteria as biocontrol tool and a potent suppressor of plant pathogenic fungi in tomato cultivation.

Sustainable agriculture is increasingly emphasized, focusing on microorganisms' role in maintaining soil fertility and inhibiting plant pathogens. Seeking novel sources of plant-beneficial bacteria, our study explores insects due to their established associations with plants and bacteria. The insect gut, hosting various bacteria, may hold microbes protecting against fungal infections, particularly plant pathogens. Traditional sources of plant growth-promoting bacteria are the rhizosphere and host plant tissues; however, insects serve as diverse bacterial reservoirs in the environment. This study aimed to identify insect-gut-derived bacteria with antifungal properties and cellulase enzyme production, predicting high plant tissue colonization abilities. Cellulase, crucial for breaking down cellulose, is essential for both industry and the environment. We sought to assess the potential of these bacteria as biocontrol agents against plant pathogenic fungi, with a focus on tomato plants. Bacterial isolates from insect bodies, including Lactococcus lactis, Pantoea ananatis, and Serratia liquefaciens, exhibited robust antifungal properties and cellulase activity. In vitro tests and glasshouse tests, confirmed their ability to inhibit the growth of plant-pathogenic fungi, indicating potential for biological control. Moreover, selected strains demonstrated high cellulase enzyme activity, vital for nutrient competition and rapid colonization of plant surfaces. The study introduces insect-gut-derived bacteria as promising biocontrol agents against plant pathogenic fungi. The identified strains, capable of inhibiting fungal growth and producing cellulase, offer sustainable alternatives to synthetic fungicides for protecting tomato plants. The findings advance agricultural practices by harnessing insect-associated bacteria, contributing to eco-friendly and efficient pest management strategies in modern agriculture.