BSocial Tool Deciphers Highly Functional Plant Growth-Promoting Bacterial Consortia

The application of microbial consortia in biotechnological areas has proven to be much more efficient than that of single microorganisms; however, the main difficulty lies in the large number of communities to be tested. The use of models to predict functional efficiency on a high-throughput scale is key to incorporating greater diversity. The BSocial tool (http://m4m.ugr.es/BSocial.html) assigns a social behaviour to each strain based on its contribution to the overall growth of the consortium through a statistical analysis, defining a 'social consortium'. To determine the effectiveness of the BSocial tool for designing a biofertilizer, the social behaviour of 8 plant growth-promoting microorganisms belonging to Azospirillum, Bacillus, Bradyrhizobium, Ensifer and Pseudomonas, as well as 3 plant growth-promoting traits (siderophore production, phosphate solubilisation and indole acetic acid production) of the complete combinatorial (255 communities) were analysed. We selected 3 social consortia (X22, X93 and X149) with a diversity of 2-4 species, two of which presented high performance for more than one plant growth-promoting trait evaluated. Functional stability, following the increase in diversity, was observed in all functions except for siderophore production. Overall, the results show the effectiveness of the BSocial tool in selecting plant growth-promoting consortia to formulate efficient biofertilizers.