Colonization of Solanaceous crops by endophytic and rhizospheric plant growth-promoting bacteria from the native Solanaceae Solanum hindsianum Benth

Plant-associated bacteria are an important tool for sustainable agriculture since the have been shown to play a significant role in the health and productivity of plants through various mechanisms. However, commercial inoculants often fail to produce desired effects due to colonization issues and lack of adaptation to local conditions. In this study, we aimed to evaluate the potential of plant growth-promoting bacteria (PGPB) isolated from Solanum hindsianum, a native plant from the Sonoran Desert, to colonize and promote growth in Solanaceae crops under different irrigation conditions. First, endophytic bacteria were screened for various plant growth-promoting traits, and selected strains were identified as Bacillus, Brevibacillus, Pseudomonas, Acinetobacter, and Siccibacter. Then, endophytic and rhizospheric Pseudomonas isolates, were tested for their tolerance to salinity and osmotic stress and for their ability to induce auxin-responsive gene expression and promote plant development in Arabidopsis. All strains induced strong expression of an auxin reporter gene, while significantly improving root and plant morphology, and showed tolerance to osmotic and salinity stress. In colonization experiments, these strains successfully colonized the root crown and rhizosphere of chili, tomatillo, and tomato plants. However, the endophytic strain showed better colonization ability, especially under low irrigation conditions. Overall, this study demonstrates the potential of native PGPR strains to colonize and promote growth in Solanaceae crops under specific environmental conditions. [Display omitted] •Endophytic bacteria from Solanum hindsianum exhibit plant growth-promoting and pathogen suppression traits.•Pseudomonas strains for colonization assays tagged with Tn7 transposon carrying sGFP2 gene.•Pseudomonas Isolates colonize crown and rhizosphere as epiphytes and endophytes.•Colonization efficacy is influenced by irrigation, with endophytic strains performing better under low irrigation.