Development of a plant growth-promoting bacterial EcoBiome derived from desert soil isolates

The study of the application of plant growth-promoting (PGP) bacteria has increased due to their potential to enhance crop yield, improve nutrient acquisition, and increase plant tolerance to biotic and abiotic stresses. Developing synthetic microbial consortia represents a promising strategy, as it can enhance colonization success and functional synergy within the rhizosphere. In this study, we designed a stable EcoBiome derived from a synthetic community (SynCom) of 17 bacterial isolates obtained from three desert environments. We evaluated their PGP traits, including siderophore production, indoleacetic acid synthesis, phosphate solubilization, and nitrogen fixation. Using Oxford Nanopore Technologies (ONT), we sequenced 16S rRNA genes and tracked changes in relative abundance across successive subcultures under four temperature conditions. From this analysis, Erwinia rhapontici 1SR, Pseudomonas yamanorum RZ5, and Plantibacter sp. RU18 were identified as dominant isolates and subsequently selected to construct the EcoBiome. Functional characterization showed that these isolates exhibited complementary PGP traits, biofilm formation capacity, and tolerance to water deficit, both individually and jointly. These findings highlight the potential of desert-derived bacterial consortia as microbial resources for developing biostimulants to enhance plant resilience under environmental stress conditions.

This study demonstrates that desert-derived bacterial isolates can be rationally assembled into a stable and functionally complementary EcoBiome with plant growth-promoting traits. By integrating phenotypic screening with community dynamics across environmental conditions, we demonstrate that simplified bacterial consortia derived from synthetic communities (SynCom) can retain key ecological traits, such as persistence, biofilm formation, and water deficit tolerance. These findings expand our knowledge of how bacterial molecular resources adapted to desert environments can be harnessed as biostimulants and provide a framework for the development of EcoBiomes aimed at improving plant resilience to abiotic stress.