Microbial Adaptation to Climate Change Stressors Revealed by Environmental Metagenomics: Insights and Perspectives

Abstract

The microorganisms play a central role in the regulation of the ecosystems on the Earth, controlling the cycles of nutrients, carbon storage and ecosystem stability. Nevertheless, increasing speed of climate change exposes microbial communities to numerous stressors, which include warming, changes in precipitation, drought, salt levels, and ocean acidity, as well as, the buildup of pollutants, which have significant impacts on microbial community structure and functionality. Knowing how microbes can respond to these stressors is crucial to understanding how the ecosystem will react and how climate change can be reduced. Environmental metagenomics has become an innovative instrument of investigating the genetic potential, evolutionary approaches, and functional resilience of microorganisms in a variety of environments, such as soils, freshwater, oceans, and harsh environments. The review is a synthesis of the recent developments in the field of metagenomic applications to reveal the microbial mechanism of adaption to stress by the expression of stress-response genes, horizontal gene transfer, mobile genetic elements, and metabolic restructuring as a response to climate-related perturbation. We put emphasis on case studies to show how microbial community structure changes, functional genes become enriched, and biogeochemical feedbacks change due to environmental change. These methodological frameworks are shotgun metagenomics, metagenome-assembled genomes (MAGs), and multi-omics methods, all critically reviewed in order to highlight their limitations and strengths. In addition, such issues as unfinished functional annotation, sampling bias, and computational limitation are also addressed in the context of extrapolating microbial understanding to predictive ecosystems. In the future, we highlight the need to combine environmental metagenomics with longitudinal surveillance, machine learning, and synthetic biology and improve our knowledge of microbial resilience, ecosystem stability, and climate adaptation mechanisms.