Seed Bio inoculation with Plant Growth-Promoting Bacteria Improves Drought Performance in Model and Crop Species

Drought stress poses a major threat to plant health and agricultural productivity, with increasing frequency and severity anticipated under future climate scenarios. Consequently, sustainable strategies are required to mitigate its impact on crop performance. Bioaugmentation with plant growth-promoting bacteria (PGPB) represents a promising approach to enhance plant resilience under water-limited conditions.
In this PhD, we evaluated a panel of bacterial strains exhibiting key PGP traits such as proline production and phosphate solubilisation, for their potential as bioinoculants. Specifically, Pseudomonas fluorescens, P. putida, P. capeferrum, P. protegens, and Mucilaginibacter gossypiicola were assessed for their ability to improve drought tolerance in both barley (Hordeum vulgare L.) and Arabidopsis thaliana. Seed inoculation assays during early seedling development revealed that under osmotic stress, P. capeferrum and M. gossypiicola significantly enhanced barley seedling growth. In Arabidopsis, inoculation with P. fluorescens and M. gossypiicola increased germination rates.
Subsequent soil-based experiments demonstrated that M. gossypiicola significantly improved both root and shoot biomass in barley following one week of drought stress, with growth promotion persisting even after rewatering. Comparable effects were observed in Arabidopsis. Ongoing work aims to elucidate the mechanisms underpinning these responses using multi-omics approaches and targeted disruption of hormone signalling pathways. We are also working to evaluate whether these bioinoculants can establish and persist in the bulk soil and rhizosphere of these different plant families.