During the last decades, substantial advancements have been made in identifying soil characteristics that impact the composition of the soil microbiome. However, the impacts of microorganisms on their respective soil habitats have received less attention, with the majority of prior research focusing on the contributions of microbes to the dynamics of soil carbon and nitrogen. Soil microbiome plays a critical role in soil habitats by influencing soil fertility, crop yields, and biotic and abiotic stress tolerance. In addition to their roles in nutrient cycling and organic matter transformations, soil microorganisms affect the soil environment via many biochemical and biophysical mechanisms. For instance, the soil microbiome plays an essential role in soil mechanical stability and pore connectivity and regulates the flow of nutrients, oxygen, and water. Similarly, soil microbiomes perform various critical functions in an ecosystem, which leads to carbon stabilization for a long time and could serve as microbiome engineering targets for global climate change mitigation. In this review, considering soil structure, hydrology, and chemistry, we outline how microorganisms alter the soil ecosystem. Further, this study investigates the mechanisms by which feedback loops can be generated between microorganisms and soil. Moreover, we analyze the potential of microbially mediated modifications of soil properties as a viable strategy to address soil threats and global climate challenges. In addition, the current study propose a deep learning-based approach to develop a synthetic microbial consortium to improve soil health and mitigate climate change.

Linlu Qiu, Peter Shaw, Panupong Pasupat, Pawel Nowak, Tal Linzen, Fei Sha, Kristina Toutanova. Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies. 2022.

Introduction Clostridioides (Clostridium) difficile infection, the leading cause of healthcare-associated diarrhea, represents a significant burden on global healthcare systems. Despite being a global issue, information on C. difficile from a global perspective is lacking. The aim of this study is to model the global phylogeography of clinical C. difficile. Methods Using samples collected from the MODIFY I and II studies (NCT01241552, NCT01513239), we performed whole-genome sequencing of 1501 clinical isolates including 37 novel sequence types (STs), representing the largest worldwide collection to date. Results Our data showed ribotypes, multi-locus sequence typing clades, and whole-genome phylogeny were in good accordance. The clinical C. difficile genome was found to be more conserved than previously reported (61% core genes), and modest recombination rates of 1.4–5.0 were observed across clades. We observed a significant continent distribution preference among five C. difficile clades (Benjamini-Hochberg corrected Fisher’s exact test P < 0.01); moreover, weak association between geographic and genetic distance among ribotypes suggested sources beyond healthcare-related transmission. Markedly different trends of antibiotic susceptibility among lineages and regions were identified, and three novel mutations (in pyridoxamine 5′-phosphate oxidase family protein: Tyr130Ser, Tyr130Cys, and a promoter SNP) associated with metronidazole-reduced susceptibility were discovered on a nim-related gene and its promotor by genome-wide association study. Toxin gene polymorphisms were shown to vary within and between prevalent ribotypes, and novel severe mutations were found on the tcdC toxin regulator protein. Conclusion Our systematic characterization of a global set of clinical trial C. difficile isolates from infected individuals demonstrated the complexity of the genetic makeup of this pathogenic organism. The geographic variability of clades, variability in toxin genes, and mutations associated with antibiotic susceptibility indicate a highly complex interaction of C. difficile between host and environment. This dataset will provide a useful resource for validation of findings and future research of C. difficile.