P-213 - Synthetic rhizosphere community confers drought tolerance in barley

Under assumed climate change scenarios for temperate agroecosystems in Europe, prolonged drought poses a significant threat to barley production, requiring novel strategies to ensure growth under future conditions. One approach is to enhance drought resistance through plant-beneficial rhizobacteria, but studies on this strategy have been limited. We isolated and screened a culture collection of drought-tolerant bacteria from the barley rhizosphere. From this, we assembled a 16-member consortium based on their relative abundance in the rhizosphere after drought and in vitro osmotic stress tolerance (Drought Tolerant Synthetic microbial Community/“DT-SynCom”). Genome analyses revealed genes associated with plant growth promotion, and in vitro assays confirmed auxin production, ACC deaminase activity, inorganic phosphorus solubilization, as well as cellulase and chitinase activity for individual members. DT-SynCom bacteria were mutually compatible and showed neutral or beneficial effects on barley shoot and root growth in vitro. Greenhouse experiments showed DT-SynCom improved drought tolerance of barley, but soil type and added heat stress strongly influenced its beneficial effects. The results highlight microbial consortia as a sustainable strategy to boost crop resilience under future climates. Ongoing work investigates the bacterial and plant factors behind this increased drought tolerance and the DT-SynCom’s effect on disease resistance in barley.