Use of Plant Growth-Promoting Rhizobacteria to Alleviate Salinity Stress in Plants

Abstract

Salinization of soil is one of the main threats for the development and maintenance of agricultural systems. Climate change will even increase soil salinity further. Soil salinity affects the establishment, growth, and development of crops and can result in severe yield reduction. Fortunately, the plant root contains beneficial microbes. These microbes, including plant growth-promoting rhizobacteria (PGPR) are able to promote plant growth and protect plants against various soilborne pathogens and can help plants to adapt to a number of environmental stresses. The mechanisms of alleviation of salt stress and plant growth promotion by PGPR include the production of phytohormones and the enzyme ACC deaminase, and competition for nutrient and niches. Increasing our understanding of the modes of action of these mechanisms will open new doors for proposing strategies to improve the efficacy of PGPR. For example, more detailed studies are needed on the role of abiotic factors in altering the activity of rhizobacteria and on managing plant–microbe interactions with respect to their adaptability to extreme conditions. This chapter provides a brief overview of our present knowledge of the alleviation of salt stress in plants by PGPR and the action modes of these PGPR under salt-stressed conditions.