Selection of symbiotic efficient and high salt-tolerant rhizobia strains by gamma irradiation

Abstract

Gamma irradiation was used on Rhizobium tropici CIAT 899 and Mesorhizobium ciceri 835 nodulating, respectively, common bean and chickpea in order to select individual rhizobia mutant highly tolerant to salt and symbiotically effective. Radiosensibility analysis showed that 800 Gy was the highest dose of gamma rays supported by tested strains. The irradiated clones at 700 and 800 Gy were more tolerant to salt stress and phosphorus deficiency compared to control strains, which proved that gamma irradiation was effective in changing physiological and phenotypic characteristics via random mutations. Likewise, biochemical analysis showed that tested clones had a variable superoxide dismutase and catalase activities especially in Mesorhizobium ciceri 835. The increase of antioxidant enzyme activities in some mutants was related to tolerance acquisition that protects effective symbiosis against oxidative damage induced by abiotic stresses. Thus, efficient symbiotic nitrogen fixation rhizobia under salt stress were identified.

Biochar and Chitosan Regulate Antioxidant Defense and Methylglyoxal Detoxification Systems and Enhance Salt Tolerance in Jute (Corchorus olitorius L.)

“…Salt stress decreases the hydraulic conductivity of plant cells due to the excessive amount of soluble and exchangeable ions in the soil solution. Thus, water adsorption capacity and the influx of water into cells decreases, thereby hampering cell expansion and reducing plant growth [ 42 ]. Chlorophyll, which is responsible for net photosynthesis activity, also declines in level during salt stress, causing lower photosynthetic assimilate production and biomass accumulation by salt-stressed plants [ 43 ].…”

Implications of seed irradiation with γ-rays on the growth parameters and grain yield of faba bean

“…Based on the findings of Soliman and Abd-ElHamid (2003), germination of kidney bean seeds and growth parameters increased significantly with seed irradiation at relatively low doses of gamma rays. Probably, seed irradiation, at low doses, increases the symbiotic relationship between soil biota and the host plants (Challougui Fatnassi et al, 2011). Accordingly, translocation of fixed atmospheric N to the grown plants increases.…”

Proteomic analysis of free-living Bradyrhizobium diazoefficiens: highlighting potential determinants of a successful symbiosis

“…Salinity leads to loss of intracellular water, resulting in osmotic disturbances that can influence a range of metabolic activities [ 80 ]. Indeed, several negative effects in rhizobia-plant symbioses have been attributed to salinity; e.g.…”