Exploring the Genomes of Symbiotic Diazotrophs with Relevance to Biological Nitrogen Fixation

Abstract

Nitrogen fixation is an important process for the conversion of atmospheric nitrogen to its biologically available form, cutting across various ecosystems. Biological nitrogen fixation (BNF) is accomplished by a group of microorganisms, known as diazotrophs through the catalytic action of nitrogenase enzyme system. N-fixing microbes exhibit a wide diversity in terms of their habitat. Some are free-living, whereas others form symbiotic associations with higher plants. Symbiotic nitrogen fixation is particularly relevant in context of sustainable agriculture. Recent advances in next-generation sequencing technology have ensured the availability of thousands of complete genomes including those of symbiotic diazotrophs. Genomic approaches together with bioinformatics tools are now being used to define and understand the complex molecular relationships that underpin symbiotic nitrogen fixation. Accessibility of new computational tools for genomic and proteomic analysis has accelerated nitrogen fixation research predominantly in the areas of comparative genomics, protein chemistry, and phylogenetic analysis of nitrogen fixation genes. Alternative phylogenetic approaches and protein structure-based studies may prove to be quite prolific to divulge the unfamiliar aspects of symbiotic nitrogen fixation.