Native bacteria isolated from roots and rhizosphere of Solanum lycopersicum L. increase tomato seedling growth under a reduced fertilization regime

Abstract

In semiarid regions is important to use native strains best adapted to these environments to optimize plant-PGPR interaction. We aimed to isolate and characterize PGPR from roots and rhizosphere of a tomato crop, as well as studying the effect of its inoculation on tomato seedlings growth. We selected four strains considering their effectiveness of fixing nitrogen, solubilizing phosphate, producing siderophores and indole acetic acid. They belong to the genera Enterobacter, Pseudomonas, Cellulosimicrobium, and Ochrobactrum. In addition, we also analyzed the ability to solubilize Ca3(PO4)2, FePO4 and AlPO4 and the presence of one of the genes encoding the cofactor PQQ in their genome. Enterobacter 64S1 and Pseudomonas 42P4 showed the highest phosphorus solubilizing activity and presence of pqqE gene. Furthermore, in a tomato-based bioassay in speed-bed demonstrated that a sole inoculation at seedling stage with the strains increased dry weight of roots (49–88%) and shoots (39–55%), stem height (8–13%) and diameter (5–8%) and leaf area (22–31%) and were equal or even higher than fertilization treatment. Leaf nitrogen and chlorophyll levels were also increased (50–80% and 26–33%) compared to control. These results suggest that Enterobacter 64S1 and Pseudomonas 42P4 can be used as bio-inoculant in order to realize a nutrient integrated management.

Okra Growth, Yield and Rhizosphere Microbiome Responses to the Encapsulated Bioinoculant Application under Reduced Fertilization Regime

“…As a result, the amount of OH − released was minimal, resulting in a pH drop in the soil. These findings are consistent with the literature associated with effects of bioinoculants on plants under a reduced fertilization regime [ 44 , 48 ].…”

“…application resulted in a consistent increase in SAP along with an increase in soil bacterial viable cells. Pérez-Rodriguez et al [ 44 ] supports this finding, as they confirmed the presence of a pqq -encoding gene in the genomic DNA of Enterobacter sp., which is responsible for P solubilization as a cofactor in glucose extracellular oxidation to gluconic acid via glucose-dehydrogenase-mediated processes. This data concurs with our prior observation that strain 40a generated a huge amount of gluconic acid during P and K solubilization [ 23 ].…”

Halotolerant native bacteria Enterobacter 64S1 and Pseudomonas 42P4 alleviate saline stress in tomato plants

“…The NaCl tolerance was assessed in four bacterial strains ( Enterobacter 64S1, Pseudomonas 42P4, Ochrobactrum 53F, and Cellulosimicrobium 60I1) previously isolated from roots and the rhizosphere of tomato (Pérez‐Rodriguez et al, 2020). These bacteria are able to solubilize different sources of inorganic phosphate to fix N 2 , to produce siderophores and indole acetic acid (Pérez‐Rodriguez et al, 2020). Salt tolerance was determined in solid Luria‐Broth medium (LB, Sigma Chem.…”

“…In a previous study, we isolated and identified four PGPR strains that increase tomato seedling growth (Pérez-Rodriguez et al, 2020).…”

“…In a previous study, we isolated and identified four PGPR strains that increase tomato seedling growth (Pérez‐Rodriguez et al, 2020). The aim of the present study was to characterize the native PGPR, isolated according to their salt tolerance, and to evaluate their physiological and biochemical ability to counteract salt stress in tomato plants.…”