Physiological response of tomato plant to chitosan-immobilized aggregated CBMB20 inoculation under salinity stress.

The use of plant growth promoting bacteria as bioinoculant to alleviate salt stress is a sustainable and eco-friendly approach in agriculture. However, the maintenance of the bacterial population in the soil for longer period is a major concern. In the present study, chitosan-immobilized aggregated CBMB20 was used as a bioinoculant to improve tomato plant ( Mill.) growth under salt stress. The chitosan-immobilized aggregated CBMB20 was able to enhance plant dry weight, nutrient uptake (N, P, K and Mg), photosynthetic efficiency and decrease electrolyte leakage under salt stress conditions. The oxidative stress exerted by elevated levels of salt stress was also alleviated by the formulated bioinoculant, as it up-regulated the antioxidant enzyme activities and enhanced the accumulation of proline which acts as an osmolyte. The chitosan-immobilized aggregated CBMB20 was able to decrease the excess Na influx into the plant cells and subsequently decreasing the Na/K ratio to improve tomato plant growth under salt stress conditions. Therefore, it is proposed that the chitosan-immobilized aggregated . CBMB20 could be used as a bioinoculant to promote the plant growth under salt stress conditions.