Unraveling the Genomic and Environmental Diversity of the Ubiquitous Solirubrobacter

Solirubrobacter a genus within the Actinobacteriota phylum, is commonly found in soils and rhizospheres yet remains unexplored despite its widespread presence and diversity, as revealed through metagenomic studies. Previously recognized as a prevalent soil bacterium, our study delved into phylogenomics, pangenomics, environmental diversity, and bacterial interactions of Solirubrobacter. Analyzing the limited genomic sequences available for this genus, we uncovered a pangenome consisting of 19,645 protein families, with 2,644 constituting a strict core genome. While reported isolates do not exhibit motility, we intriguingly discovered the presence of flagellin genes, albeit with an incomplete flagellum assembly pathway. Our examination of 16S ribosomal genes unveiled a considerable diversity (3,166 operational taxonomic units OTUs) of Solirubrobacter in Mexican soils, and co-occurrence network analysis indicated its extensive connectivity with other bacterial taxa. Through phylogenomic analysis, we delved into the relatedness of sequenced strains and notably dismissed ASM999324v1 as a member of this genus. Our investigation extended to the metagenomic diversity of Solirubrobacter across various environments, affirming its pervasive presence in rhizospheres and certain soils. This broader pangenomic view revealed genes linked to transcription, signal transduction, defense mechanisms, and carbohydrate metabolism, highlighting Solirubrobacter's adaptability. We observed that Solirubrobacter's prevalence in rhizospheres is geographically indiscriminate, prompting intriguing questions about its potential interactions with plants and the biotic and abiotic determinants of its soil occurrence. Given its richness and diversity, Solirubrobacter might be a versatile yet overlooked keystone species in its environments, meriting further recognition and study. ### Competing Interest Statement The authors have declared no competing interest.