Investigating functional and genetic characteristics of beneficial seed bacteria

<p dir="ltr">Plant-beneficial bacteria have the potential to enhance agricultural productivity via their capacity to improve plant tolerance to biotic and abiotic stress and increase nutrient availability. Seeds of native plants house diverse microbiomes and are a potential source of beneficial bacteria which may also be capable of aiding growth and stress tolerance in crop plant species. In this work functional and genomic characterisation was performed on 18 bacterial isolates from native <i>Acacia </i>seeds. Whole genome sequencing showed eight strains were highly novel with all 18 encoding suites of genes involved in predicted plant beneficial traits, including plant colonisation, biotic/abiotic stress tolerance and competitive exclusion. Phenotypic assays identified multiple isolates with tolerance to high salinity, acidic and alkaline pH conditions, however all isolates were sensitive to physiological drought. Highly salt tolerant isolates (<i>Leclercia</i>, <i>Pseudomonas </i>and <i>Variovorax sp</i>.) were selected and applied to sterile soybean seeds to determine their impact on seed emergence and growth under salinity stress and non-stress conditions. Improved rates of seed emergence and seedling survival, compared to no-inoculant controls, were observed with <i>Pseudomonas </i>and <i>Variovorax </i>isolates under some conditions. This study suggests that native seed-associated bacteria have the potential to improve growth and stress tolerance of agriculturally important plants.</p>