Abstract
Mitigation strategies based on plant–microbe interactions to increase the performance of plants under water-deficit conditions are well documented. However, little is known about a suitable consortium of bacterial inoculants and underlying physiological and enzymatic events to improve drought tolerance in maize. We performed laboratory and pot experiments to understand the synergistic interactions among plant growth-promoting bacteria to alleviate the drought-induced damages in maize. Initially, ten bacterial strains were evaluated for their osmotic stress tolerance capacity by growing them in a media containing 0, 10, 20, and 30% polyethylene glycol (PEG-6000). Also, the seeds of a drought tolerant (NK-6654) and sensitive (SD-626) maize cultivar were inoculated with these bacterial strains in the first pot experiment to determine their effects on the growth and physiological processes. Later, in the second pot experiment, the best performing inoculants were selected to study the individual and synergistic effects of bacterial inoculation to confer drought tolerance in maize. Our findings showed that the inoculation with tolerant strains resulted in higher photosynthetic activity (25–39%), maintenance of leaf water status (14–18%) and pigments (27–32%), and stimulation of antioxidant machinery (28–38%) than no inoculation in water-stressed maize seedlings. Moreover, the treatment with bacteria consortia further stimulated the drought protective mechanisms and resulted in higher efficiency of photosynthetic (47–61%) and antioxidant systems (42–62%) than the individual inoculants under water-deficit conditions. We conclude that the inoculation with microbial consortia regulates water uptake, photosynthetic performance, and stress metabolites to minimize drought-induced damages in maize.
Highlights
Improving crop productivity to feed the burgeoning global population is a complex and challenging issue (Buono 2020)
The response of bacterial strains varied at different concentrations and the negative effects of PEGinduced osmotic stress on growth increased by increasing PEG concentrations in comparison to control without the osmotic agent (− 0.04 MPa)
Our results indicate that the bacterial strains vary in their response to drought stress, and the use of tolerant inoculants could be a viable, effective strategy to improve maize growth under water-deficit conditions
Summary
Improving crop productivity to feed the burgeoning global population is a complex and challenging issue (Buono 2020). The recurrent occurrence of climatic extremes has made it more difficult to obtain optimum yields in important food crops including maize. Like most plants facing water shortage, maize plants are able to sustain growth by the increased uptake of water and nutrients and the regulation of stress metabolites such as antioxidative enzymes under arid conditions (Naeem et al 2018). Breeding for drought tolerant, high-yielding maize genotypes could be one of the solutions to confront the challenges of food security; it is a time-consuming and labor-intensive process. It possess ecological risks and the transgenic crops may face little acceptability by the consumers. The use of microbial inoculants provides an alternative and economically viable solution to support maize growth under water-deficit conditions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
