Revitalization of bacterial endophytes and rhizobacteria for nutrients bioavailability in degraded soils to promote crop production

Abstract

The diverse community of endophyte and rhizobacteria is a critical resource in enhancing plant growth and resistance against abiotic and biotic stress. These microbes include various bacterial communities dominated by Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. They inhabit and proliferate in plant tissues forming beneficial associations compared to other microbes residing in the exospheric region. Despite the demonstration of the presence of bacterial endophytes in crops, their role in supporting nutrient bioavailability and acquisition in degraded soils is largely unexplored. In addition, the practical application of these microbial communities in the field has not been demonstrated. A comprehensive understanding of plant-endophyte interactions will help restore degraded soils and plant nutrient acquisition in resource-limiting field environments. Anthropogenic farming practices such as the use of chemical fertilizers to restore degraded soils have proved to be detrimental to soil structure, function and soil biodiversity. Recent studies in soil and root structure suggest that the rhizosphere and endophytic bacterial communities could potentially be used to enhance crop production. Other studies have shown that endophytic microbes play a key role in modulation of metabolism in plants, stimulation of plant growth, and aid in plant adaptation to environmental stress using phytohormone signaling. The use of rhizosphere and endophytic bacteria can significantly reduce the amount of agrochemicals that contribute to environmental pollution. In the context of the changing climatic conditions, some beneficial rhizospheric and endophytic bacterial communities enhance adaptation and resilience, thereby promoting sustainable farming systems. The current review addresses the concepts, challenges, and roles of the bacterial endophytes and rhizobacteria as components of the plant microbiota, and their prospective use in reclamation of degraded soil environments.

Keywords

• plant growth-promoting rhizobacteria
• bacterial endophytes
• soil fertility
• rhizobacteria
• sustainable agriculture