The effect of rhizosphere bacteria isolated from halophyte plants on some growth characteristics of Triticum aestivum L. (var. Narin).

Increasing world population, along with climate change and environmental stresses, has posed a serious challenge to adequate food supply. Salinity is one of the most important stresses affecting the reduction of agricultural products. In recent years, the use of new strategies for sustainable production of food products under salinity stress has been considered, including plant growth promoting rhizosphere bacteria. Due to the strategic importance of wheat in food security, this study was designed and conducted with the aim of increasing the salinity resistance of wheat (Var. Narin) using plant growth promoting rhizosphere bacteria isolated from the rhizosphere of several halophyte plants in Yazd province.

Plant growth promoting traits such as ability to produce auxin, siderophore, hydrogen cyanide, and phosphate solubility and salinity resistance of isolated bacteria from rhizosphere of halophyte plants (Atriplex lentiformis, Seidlitzea rosmarinus, Halostachys belangeriana and tamarix ramossima) in their habitats in Chahafzal in Yazd Province were investigated. Then, wheat seeds were inoculated with the best three bacteria in terms of plant growth-promoting traits and salinity resistance, and then was irrigated with water with salinities of 4, 8 and 16 ds/m. After the growth period, the ion content of sodium, potassium, calcium and phosphorus in the leaves as well as some vegetative growth indices including stem length, stem and root dry weight and total biomass were measured.

The studied bacteria including Bacillus safensis, B. pumilus and Zhihengliuella halotolerans had the ability to produce auxin, siderophore, hydrogen cyanide, 1-aminocyclopropane-1-carboxylic acid deaminase (ACC deaminase) and phosphate solubility. The highest amount of auxin production was measured in B. safensis (29.72 μg/ml) and the highest amount of hydrogen cyanide production and phosphate solubility was in Z. halotolerans. The highest amount of ACC deaminase was measured in B. pumilus (8 μmol of α-ketobutyrate h–1 mg–1 protein). The results of wheat leaf analysis showed that at salinity stress levels, sodium content increased and other measured items decreased compared to the control. The use of bacteria reduced the sodium content by 142 percentage and increased the content of potassium, calcium and phosphorus in wheat leaf under salinity stress by 70, 92 and 295 percentage, respectively, compared to the control. Also, stem length, stem dry weight, root dry weight and total biomass in treatments under salinity stress and inoculated with bacterial isolates increased to 44, 56, 117 and 61 percentage, respectively, compared to the control

Plant growth promoting rhizosphere bacteria in this experiment significantly improved the resistance of wheat to salinity stress. B. safensis, more than the other two bacterial isolates, improved the growth indices of wheat var. Narin under salinity stress. These results also show that the rhizosphere of halophytic rangeland plants can be a good source for the isolation of salinity-resistant bacteria to improve the resistance of wheat plants to salinity.