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

Abstract

Aim 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. Methods 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 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 uninoculated control. Conclusions 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.

The Contrivance of Plant Growth Promoting Microbes to Mitigate Climate Change Impact in Agriculture

“…Lower content of antioxidant enzymes compared to control conditions may indicate drought stress amelioration. For instance, rice inoculated with Bacillus sp., as well as with a particular PGPB consortium, resulted in decreased levels of GPOX (20%), CAT (20.5%) and SOD (24%) in plants compared to those untreated, under drought stress [200]. Pseudomonas putida H-2-3 Soybean (Glycine max L.) [201] Increased plant biomass IAA, GA, SA production, ACC activity by bacteria.…”

Co-inoculation With Tropical Strains of Azospirillum and Bacillus Is More Efficient Than Single Inoculation for Improving Plant Growth and Nutrient Uptake in Maize.

“…In fact, all strains produced high concentrations of this phytohormone, especially the Azospirillum strains, which resulted in positive effects on root growth. Various plant species inoculated with IAA producing bacteria reported increased root growth and/or enhanced formation of lateral roots and root hairs, which further increases the surface area and length of lateral and adventitious roots (Mohite, 2013;Joshi et al 2020). In general, plant-associated bacteria use the tryptophan present in plant exudates as a precursor for IAA biosynthesis.…”

“…Bacillus and Azospirillum strains have been described as e cient PGPBs in different crops, soil, and climatic conditions. For example, the use of a combination of six Bacillus strains, either individually or in consortia, enhanced growth in rice and improved plant resilience to abiotic environmental stresses (Joshi et al 2020). Genes involved in the production of low molecular weight organic acids, P and N metabolism were identi ed in the genome of Bacillus strains (Velloso et al 2020) and they have also been described as bene cial to plant growth for their e ciency in phosphate solubilization and organic acid production (Gomes et al 2014;Abreu et al 2017;Ribeiro et al 2018).…”

Alternative Strategies for Multi-Stress Tolerance and Yield Improvement in Millets

“…There are several possible approaches to increase the stress tolerance and productivity of millets. For example, application of PGPRs has been used to improve yield and stress tolerance in wheat [ 39 , 40 , 41 ] and rice [ 42 , 43 , 44 ], but it remains to be tested in millets. Another approach for trait improvement is via genome editing, which has recently gained tremendous attentions due to its specific allele manipulation potential.…”