Genomic characterization of Serratia liquefaciens TN503 with the ability to promote growth and mitigate salt stress in tomatoes

Abstract

Abstract Salinity is an abiotic factor of soil degradation that limits the development of plants and reduces agricultural competitiveness. Our purpose was to evaluate the effect of four rhizobacteria (TN503, TN106, TN333 y TN26) on growth and mitigation of abiotic stress in tomato. For this, initially the production of indole-3-acetic acid, (IAA), and phosphate solubilization by the bacteria were determined. The saline stress mitigation test was evaluated in tomato variety Rio Grande exposed to 100 and 200 mM NaCl. The rhizobacteria with the best response to stress conditions and growth promotion were selected for genomic analysis, and the genotypic identification of rhizobacteria was performed by the 16S ribosomal RNA. The rhizobacteria were identified as Serratia liquefaciens (TN503), Serratia plymuthica (TN106), Serratia sp (TN333) and Enterobacter sp (TN26). Plant inoculation showed that TN106 and TN503 rhizobacteria promoted tomato growth by up to 61.6% compared to the control without inoculum. The total dry weight of the plant was favored by the TN503 strain with an increase of 68.9 and 37.64% at 100 and 200 mM NaCl respectively, compared to the control. On the other hand, all strains produced indoles (0.50 to 4.44 µg ml− 1) and solubilized phosphate (32.03 to 35.5 mg ml− 1). Genomic analysis shows that TN503 could colonize tomato rhizosphere, promote plant growth and mitigate salt stress through genes associated with biofilm formation, siderophores, IAA, solubilization of phosphate, osmolytes and antioxidant, among others. The inoculation of PGPR in tomato crops represents a biotechnological alternative for sustainable agriculture, minimizing the use of agrochemicals.