Nitrogen (N) is one of the vital elements required for proper growth and development of plants. In the earth’s atmosphere, N is available in the form of nitrogen gas (N2) and mostly plants utilize N in the form nitrate (NO3-) and ammonium ion (NH4+) which are fixed through the biological process known as N2 fixation. As N is one of the elements most likely to be limiting to plant growth, this phenomenon provides an alternative to the implementations of chemical fertilizers as source of nutrients which have resulted in the ammonia volatilization, leading to significant impact on global warming in the atmosphere which, further, diverts the focus of scientist to find out eco-friendly technology. Globally, the demand for introducing eco-friendly practices for improving sustainable agriculture productivity has been increased. Since long time, microbes play an important role in providing pollution-free environment. Endophytic microbes being present inside the specific tissues of plants mostly empower in the growth of plants. The endophytic nitrogen-fixing microbe has been well characterized from leguminous as well non-legume crops. Endophytic bacteria belong to different phyla such as Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. The predominant N2-fixing endophytic Burkholderia, Rhizobium, Pseudomonas, Bradyrhizobium, Bacillus, Frankia, Enterobacter, and Azospirillum have been reported from different host plant. Nitrogen-fixing endophytic bacteria has a wide variety of application for maintaining growth of plant, crop yield, and health of soil for sustainable agriculture. The present review focuses on major developments on biodiversity of N-fixing endophytic microbiomes and their role for plant growth promotion and soil health for agroenvironmental sustainability.
Key words: Biological nitrogen fixation, Endophytic bacteria, Plant growth promoting attributes, Sustainable Agriculture