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

Abstract

Salinity is one of the principal abiotic stresses that limit the growth and productivity of crops. The use of halotolerant plant growth‐promoting rhizobacteria (PGPR) that increase the growth of salt‐stressed crops is an environmentally friendly alternative to promote plant yield under salinity. The aim of this study was to test native PGPR, isolated according to their tolerance to NaCl, and to evaluate their influence on morphological, physiological, and biochemical traits promoted by salt stress in tomato plants. Enterobacter 64S1 and Pseudomonas 42P4 were selected as the most efficient strains in terms of salt tolerance. Both strains were classified as moderately resistant to salinity (NaCl) and maintained their plant growth‐promoting activities, such as nitrogen fixation and phosphate solubilization, even in the presence of high levels of salt. The results of a greenhouse experiment demonstrated that PGPR inoculation increased root and shoot dry weight, stem diameter, plant height, and leaf area compared to control noninoculated plants under nonsaline stress conditions, reversing the effects of salinity. Inoculated plants showed increased tolerance to salt conditions by reducing electrolyte leakage (improved membrane stability) and lipid peroxidation and increasing chlorophyll quantum efficiency (Fv/Fm) and the performance index. Also, inoculation increased the accumulation of proline and antioxidant nonenzymatic compounds, such as carotenes and total phenolic compounds. The catalase and peroxidase activities increased with salinity, but the effect was reversed by Enterobacter 64S1. In conclusion, Enterobacter 64S1 and Pseudomonas 42P4 isolated from salt‐affected regions have the potential to alleviate the deleterious effects of salt stress in tomato crops.

Melatonin production by rhizobacteria native strains: Towards sustainable plant growth promotion strategies

“…The native PGPR inoculation in Arabidopsis plants under drought demonstrated their beneficial effects by increasing leaf area and plant weight levels (Figure 3). Similarly, previous work by our group reported the ability of 64S1 and 42P4 strains to promote plant growth in tomato and pepper plants and alleviate the negative symptoms of saline stress (Lobato Ureche et al, 2021; Pérez‐Rodriguez et al, 2022; Pérez‐Rodriguez, Piccoli, et al, 2020a). Moreover, PGPR such as P. fluorescens , Proteus mirabilis , and B. amyloliquefaciens , stimulated plant growth in tomato, maize, and Vitis labrusca under drought and salt stress (Jiao et al, 2016; Mekureyaw et al, 2022; Vishnupradeep et al, 2022).…”

Tomato responses to salinity stress: From morphological traits to genetic changes

“…In BHU-AV3-inoculated plant leaves superoxide content, cell death and lipid peroxidation were significantly reduced (Vaishnav et al, 2020). Enterobacter 64S1 and Pseudomonas 42P4 under salt stress reduced electrolyte leakage and lipid peroxidation and increased chlorophyll quantum efficiency (Fv/Fm), proline and antioxidant nonenzymatic compounds (carotenes and total phenolic compounds) contents in tomato leaves (Peŕez-Rodriguez et al, 2022). A combination of arbuscular mycorrhizal fungi (Claroideoglomus etunicatum, Funneliformis mosseae, Glomus aggregatum, Rhizophagus intraradices), bacteria and fungi (Trichoderma, Streptomyces, Bacillus, Pseudomonas) improved the tomato fruit quality and the antioxidant content of 'Pixel F1' tomato cultivar exposed to soils electrical conductivity of 1.5, 3.0, 4.5, and 6.0 (Sellitto et al, 2019).…”

“…auxin, cytokinin, and abscisic acid), ACCdeaminase, ammonia, IAA, extracellular polymeric substance (EPS), induction of synthesis of plant osmolytes and antioxidant activity, increasing the essential nutrient uptake or/and by reducing ethylene production (Kumar et al, 2020). Sphingobacterium BHU-AV3 (Vaishnav et al, 2020), Bacillus megaterium strain A12 (Akram et al, 2019), Enterobacter 64S1 and Pseudomonas 42P4 (Peŕez-Rodriguez et al, 2022), Bacillus aryabhattai H19-1 and Bacillus mesonae H20-5 (Yoo et al, 2019) are some of the PGPB that have been proved to increase tomato tolerance to salt stress. For example, inoculation of tomato cv.…”

Synergic mitigation of saline-alkaline stress in wheat plant by silicon and Enterobacter sp. FN0603

“…High salinity and alkalinity greatly limit plant growth and production, especially when the adverse alkaline conditions are caused by Na 2 CO 3 or NaHCO 3 and occur during the initial phase of the plant life cycle (e.g., seedling; Liu et al, 2022 ; Pérez-Rodriguez et al, 2022 ). Chemical treatment of seeds with silicon or inoculation with a biological agent such as PGPR could eliminate salt damage to the plants ( Kubi et al, 2021 ), but the effects of treating seeds with a combination of silicon and PGPR on plants under saline-alkaline stress are less clear.…”