Plant Growth-Promoting Rhizobacteria and Salinity Stress: A Journey into the Soil

Abstract

A large number of studies have indicated that salinity stress and saline soils are cruel environmental limiting factors that retard the growth of crop plants. Present scenario of climate change will further increase the border of the area affected by saline soils, and therefore this phenomenon will threaten the productivity of crops leading to depletion of food sources of human societies. Various strategies including soil quality management policies, improving crop resistance against salinity stress, detoxification of noxious ions, improving the quality of irrigation water, and many other effects need to be examined to decrease the detrimental consequences associated with saline soils. In this context, the use of microorganisms especially plant growth-promoting rhizobacteria (PGPR) has been proposed as a sustainable way to fortify the quality of soils to help crop plants grow under salinity stress. Recent advances in molecular soil biology studies suggested that PGPR are involved in the important physiological process associated with plant growth and development. Among the other mechanisms, improvement in water and nutrient uptake, decrease in the toxicity of hazardous ions, amelioration of photosynthesis, improvement in nitrogen fixation, regulation/modulation of physiological signaling networks are the common features exhibited by PGPR to enhance the growth of plants in saline soils. Thus, it should be noted that these miracle bacterial species are legendary soil guards to protect both soil texture and crop plants from salinity stress in the light of present and upcoming global climate changes.