Prospective evaluation of individual and consortia plant growth promoting rhizobacteria for drought stress amelioration in rice (Oryza sativa L.)

Abstract

Rice (Oryza sativa L.) being the most important crop for human population in Asia region, accounts for 23% of the world’s caloric intake. Due to the changing climatic conditions, the agricultural crops are experiencing vagaries of the weather more frequently leading to yield losses and even crop failure. The objective of this study was to find out a suitable consortium of bacterial inoculants which can make the crop resilient to drought stress. Bacterial isolates from different habitats were characterized for salt tolerance and multiple plant growth promoting traits. Four separate treatments were formulated, with two treatments having individual bacterial strain as PGPR and the rest two having consortia of three bacterial isolates as PGPR. High yielding variety MTU1010 was selected for pot experiments and treated with individual as well as consortium of isolates. Drought was imposed for 10 days to different batch of the rice crop (variety MTU1010) at two stages of crop growth i.e., pre-flowering and flowering stages. Results indicated amelioration of drought stress with higher biomass accumulation, increased grain yield and reversal of stress indicators in plants inoculated with PGPR. The antioxidant enzyme activity of SOD, CAT, and GPOX declined by 24%, 20.5% and 20% in plants treated with bacterial inoculum as compared to un-inoculated control. This study indicates that the plant beneficial microorganisms can be used to induce systematic tolerance to rice plants under drought stress and furthermore, application of consortium of PGPR has better probability to improve the coping capacity of the plants exposed to stress conditions.