Biosolutions
Current agricultural practices intensely use synthetic fertilizers and pesticides leading to soil degradation. Microbes are valuable assets towards tackling these challenges by helping plants grow and protect against pathogens. This study aims to identify beneficial microbes that promote the growth of the model plant Arabidopsis thaliana under three conditions: high salinity, water deficiency, and no stress. In each condition, the effects of 57 endophytic microbial strains and two synthetic communities—isolated from plants like olive trees and halophytes were evaluated based on phenotypic traits of the plant. Some of these strains, particularly under saline stress, had a positive impact on plant traits—including those related to reproduction. Both synthetic microbial communities promoted plant growth, with one showing consistent benefits across all tested conditions. Microbial genera like Paenibacillus, Bacillus, Pantoea, Neorhizobium and Bosea, showed their known ability to help plants grow, with Bosea strain being beneficial across all tested conditions. This study also reports, for the first time, plant growth- promoting activity of microbes isolated from Tetraena alba, Euphorbia paralias, and Teucrium capitatum. This suggests that native and halophytic plants could be good sources of diverse microbes, that might assist sustainable agriculture. The findings support the selection of strains for further genomic and functional studies toward agricultural applications.