Comparative genomic analyses provide new insights into phylogenetic and functional diversification in genus Fenollaria.

The genus Fenollaria has gained attention due to its associations with human prostate cancer, colorectal cancer and other diseases. The higher abundance of Fenollaria was believed to be associated with biochemical recurrence of prostate cancer but remission of colorectal cancer. Owing to the fastidious growth requirements of Fenollaria species in laboratory isolation and culture, the genomes of isolated strains is rarely available. Consequently, only limited comparative genomic studies have been conducted, leaving knowledge gap regarding the genomic diversity, distribution of functional genes, and evolutionary relationships, which hindered the understanding of ecological adaptation and mechanism exploration of Fenollaria. Here, a large-scaled genomic investigation of Fenollaria genus was performed using four high quality MAGs generated in this study and publicly available genomic data. The four MAGs were constructed from urine metagenome samples from bladder cancer patients, which were under conditions of oligotrophy and limited oxygen. Four mono-clades were revealed by phylogenomic analysis, representing for three previously described species (i.e., F. massiliensis, F. timonensis, and F. sporofastidiosus) as well as a novel proposed Fenollaria species. The divergences among these clades were also supported by genome-wide G + C content, ANI and AAI values. The functional difference between clades were revealed by the distribution of clade-specific genes in COG categories, as well as the biased distribution of ARGs, VFs, and CRISPR-Cas systems.