P-344 - Utilizing microbial consortia to enhance soybean drought tolerance and resistance to Rhizoctonia solani

Soybean productivity in Louisiana has significantly declined due to increased occurrence of drought conditions, exacerbated by infection from the fungal pathogen Rhizoctonia solani. Limited research has addressed seed biopriming for alleviating drought and pathogen stresses. Seed biopriming, an eco-friendly strategy utilizing beneficial microbes, has emerged as a sustainable approach to enhance soybean stress resilience. This study aimed to isolate soybean-associated beneficial bacteria, formulate microbial consortia, and evaluate their efficacy against drought stress and R. solani AG-4 infection. Approximately 100 bacteria isolated from drought-stressed soybean fields were screened for growth-promoting and stress-tolerating traits like EPS production, phosphate solubilization, nitrogen fixation, and siderophore production. Nine isolates were identified by 16S rRNA sequencing as Pseudomonas, Acinetobacter, Enterobacter, and Stenotrophomonas. Greenhouse trials demonstrated that two bacterial consortia Set2 and Setm4, as well as individual isolates, significantly enhanced soybean growth, biomass, and root water content under drought conditions. Set2 and Setm4 treatments also significantly reduced lesion lengths after R. solani infection, with Setm4 enhancing defense-related gene expression. This research highlights seed biopriming as an effective and eco-friendly strategy to improve soybean resilience to abiotic and biotic stresses.