Metagenomic Analysis of Freshwater Bacterial and Viral Biodiversity Using Shotgun Sequencing

Introduction

The microorganisms are ubiquitous and are found in almost all environments ranging from the gut of an animal to the geothermal hot springs. Microbial diversity refers to the variety of unicellular organisms, bacteria, archaea, protists, and fungi that exist. The microbes thrive all across the biosphere, defining the boundaries of life and fostering the survival and evolution of other living things. The microbes are distinguished by their distinct cellular metabolism, physiology, and morphology, as well as their diverse ecological distributions and activities, as well as their distinct genomic structure, expression, and evolution. Although the diversity of microorganisms now existing on the Earth is well recognized and assumed to be immense, the exact amount of the microbial diversity is mostly unknown. New molecular technologies are allowing researchers to quickly investigate the diversity of microorganisms, as well as their evolutionary links and history. The major difficulty in studying these microbes is that only a few of them are culturable using artificial media, whereas in the conventional culturing methods most of the bacterial community remains unidentified. Bacterial and viral communities in the freshwater bodies are important components of the freshwater ecosystem. They play a major role in maintaining the balance of the ecosystem and based on their diversity and richness, various parameters of the freshwater including metabolism, water quality can be studied. A study of the complete profile of bacterial biodiversity is difficult using the conventional methods, there is a need for other methods to study the biodiversity associated with the freshwater ecosystem. So, the metagenomics-based study has been found as a boon to study the environmental samples like freshwater and identify the microbial biodiversity based on their genomic data. Since this method is based on genomic information of the microbes in the sample, almost all the microbes can be identified by metagenomic analysis.

The sustainable development of freshwater environments is a worldwide concern. Bacteria and viruses are not only the essential components of food webs, but they also play a critical role in the freshwater ecosystem water quality control and regulation. The most important bacterial groups include Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, and Verrucomicrobia. Freshwater bacteria and virus research has been primarily focused on the processes in which they are involved, such as water quality and elemental biogeochemical cycles. Despite the efforts over the last ten years, knowledge of the diversity and function of freshwater bacterial and viral communities is still quite restricted. Freshwater biodiversity is still a relatively new field of study, which limits people's ability to learn more about the microbial communities in freshwater settings.