Abstract
Plant growth-promoting rhizobacteria (PGPR) are beneficial soil microorganisms that can stimulate plant growth and increase tolerance to biotic and abiotic stresses. Some PGPR are capable of secreting exopolysaccharides (EPS) to protect themselves and, consequently, their plant hosts against environmental fluctuations and other abiotic stresses such as drought, salinity, or heavy metal pollution. This review focuses on the enhancement of plant abiotic stress tolerance by bacterial EPS. We provide a comprehensive summary of the mechanisms through EPS to alleviate plant abiotic stress tolerance, including salinity, drought, temperature, and heavy metal toxicity. Finally, we discuss how these abiotic stresses may affect bacterial EPS production and its role during plant-microbe interactions.
Highlights
Crop productivity is influenced by nutrient availability, pathogen diseases, and climatic and agronomic factors, such as radiation, temperature, or water quantity and quality
Ashraf et al [52] proposed that amelioration of salt stress on wheat plants by plant growth-promoting rhizobacteria (PGPR)-producing EPS was probably caused by a reduced passive flow of Na+ into the stele due to the higher proportion of the root zones covered with soil sheaths in PGPRinoculated plants
These results suggest a direct effect of EPS to alleviate heat stress in PGPRs, which may be related to a protecting role of the surrounding matrix produced by EPS around the roots that might act as a dampen agent against heat and improve water retention [125], alleviating the effects of the heat shock in the plant
Summary
Crop productivity is influenced by nutrient availability, pathogen diseases, and climatic and agronomic factors, such as radiation, temperature, or water quantity and quality. Advances in whole genome sequencing have improved breeding programs and permit to find genome variations in wild crop relatives to obtain and select environmentally adapted and climate-resilient crops [2,3]. This strategy is limited to species with a high-quality reference genomic sequence available and populations of wild relatives that grow in diverse environments [4], in addition to the technical difficulties that tend to be labor-intense, highly costly, and poorly welcomed by consumers. To provide an overview of PGPR EPS-mediated tolerance to abiotic stress, we consider how external environmental changes influence bacterial EPS composition and structure during plant-bacteria interactions and their effect on stress mitigation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
