Plant growth‐promoting endophytic bacteria augment growth and salinity tolerance in rice plants

Abstract

• Salt stress negatively affects growth and development of plants. However, it is hypothesized that plant growth-promoting endophytic bacteria can greatly alleviate the adverse effects of salinity and can promote growth and development of plants. In the present research, we aimed to isolate endophytic bacteria from halotolerant plants and evaluate their capacity for promoting crop plant growth. • The bacterial endophytes were isolated from selected plants inhabiting sand dunes at Pohang beach, screened for plant growth-promoting traits and applied to rice seedlings under salt stress (NaCl; 150 mM). • Out of 59 endophytic bacterial isolates, only six isolates, i.e. Curtobacterium oceanosedimentum SAK1, Curtobacterium luteum SAK2, Enterobacter ludwigii SAK5, Bacillus cereus SA1, Micrococcus yunnanensis SA2, Enterobacter tabaci SA3, resulted in a significant increase in the growth of Waito-C rice. The cultural filtrates of bacterial endophytes were tested for phytohormones, including indole-3-acetic acid, gibberellins and organic acids. Inoculation of the selected strains considerably reduced the amount of endogenous ABA in rice plants under NaCl stress, however, they increased GSH and sugar content. Similarly, these strains augmented the expression of flavin monooxygenase (OsYUCCA1) and auxin efflux carrier (OsPIN1) genes under salt stress. • In conclusion, the pragmatic application of the above selected bacterial strains alleviated the adverse effects of NaCl stress and enhanced rice growth attributes by producing various phytohormones.

The Halotolerant Rhizobacterium—Pseudomonas koreensis MU2 Enhances Inorganic Silicon and Phosphorus Use Efficiency and Augments Salt Stress Tolerance in Soybean (Glycine max L.)

“…This trend of expression level could be attributed to the interaction of MU2 with soybean plants thus, producing hormones and organic acids, which help reduce osmotic stress through the mediation of the antioxidant biosynthetic pathway and osmolytes, activating stress hormones, antioxidant systems, and ion regulating genes leading to salt tolerance, thereby improving salt tolerance in soybean plants. These findings agree with Bharti et al [ 68 ] and Khan et al [ 5 ] who reported the beneficial role of Dietzia natronolimnaea and Arthrobacter woluwensis in mitigating salt stress by demonstrating the expression of various ion transporters and antioxidant-enzymes regulating genes.…”

“…Higher concentration of soil salinity causes ionic imbalance and leads to osmotic stress, ion toxicity, and mineral imbalance [ 5 ]. Ion toxicity induces the efflux of cytosolic Ca ++ and K + thereby disrupting cellular homeostasis, retarding growth, and causing several physiological and morphological disorders in many crops [ 53 ].…”

“…Plants acquire several strategies to tolerate salt stress, and ionic adjustment is the major one. Here, plants avoid the influx of Na + and Cl − , which causes ionic toxicity and accumulation of K + [ 5 ]. This adverse effect on the ions-utilizing system alters the biochemical and metabolic processes of plants when the intake of Na + exceeds its efflux through the plasma membrane channels [ 6 ].…”

WITHDRAWN: Plant growth promoting Bipolaris sp. CSL-1 mitigate salinity stress in soybean via altering endogenous phytohormonal level, antioxidants and genes expression

“…Soil salinity has been reported to limit crops productivity by impairing the root growth, nutrient uptake and affect metabolic processes [4][5][6]. Salinity stress affect various physiological, morphological and biochemical process which results in reduction of crops biomass and productivity [6,7]. Morphological changes observed under salinity stress on all growth stages including germination, seedling, vegetative and maturity stages [8,9].…”

Phosphate-Solubilizing Enterobacter ludwigii AFFR02 and Bacillus megaterium Mj1212 Rescues Alfalfa’s Growth under Post-Drought Stress

“…Various environmental stresses, including drought stress, lead to decreased water availability and osmotic stress that promote the synthesis of endogenous ABA phytohormonal regulation and different antioxidant systems [23,78,79]. It was also observed that alfalfa plants inoculated with AFFR02 and MJ1212 induced drought stress tolerance by reducing water loss (Figure 4A).…”