Genomic Analysis of the Yet-Uncultured Binatota Reveals Broad Methylotrophic, Alkane-Degradation, and Pigment Production Capacities.

ABSTRACT

The recent leveraging of genome-resolved metagenomics has generated an enormous number of genomes from novel uncultured microbial lineages yet left many clades undescribed. Here, we present a global analysis of genomes belonging to Binatota (UBP10), a globally distributed, yet-uncharacterized bacterial phylum. All orders in Binatota encoded the capacity for aerobic methylotrophy using methanol, methylamine, sulfomethanes, and chloromethanes as the substrates. Methylotrophy in Binatota was characterized by order-specific substrate degradation preferences, as well as extensive metabolic versatility, i.e., the utilization of diverse sets of genes, pathways, and combinations to achieve a specific metabolic goal. The genomes also encoded multiple alkane hydroxylases and monooxygenases, potentially enabling growth on a wide range of alkanes and fatty acids. Pigmentation is inferred from a complete pathway for carotenoids (lycopene, ß- and γ-carotenes, xanthins, chlorobactenes, and spheroidenes) production. Further, the majority of genes involved in bacteriochlorophyll a, c, and d biosynthesis were identified, although absence of key genes and failure to identify a photosynthetic reaction center preclude proposing phototrophic capacities. Analysis of 16S rRNA databases showed the preferences of Binatota to terrestrial and freshwater ecosystems, hydrocarbon-rich habitats, and sponges, supporting their potential role in mitigating methanol and methane emissions, breakdown of alkanes, and their association with sponges. Our results expand the lists of methylotrophic, aerobic alkane-degrading, and pigment-producing lineages. We also highlight the consistent encountering of incomplete biosynthetic pathways in microbial genomes, a phenomenon necessitating careful assessment when assigning putative functions based on a set-threshold of pathway completion.IMPORTANCE A wide range of microbial lineages remain uncultured, yet little is known regarding their metabolic capacities, physiological preferences, and ecological roles in various ecosystems. We conducted a thorough comparative genomic analysis of 108 genomes belonging to the Binatota (UBP10), a globally distributed, yet-uncharacterized bacterial phylum. We present evidence that members of the order Binatota specialize in methylotrophy and identify an extensive repertoire of genes and pathways mediating the oxidation of multiple one-carbon (C1) compounds in Binatota genomes. The occurrence of multiple alkane hydroxylases and monooxygenases in these genomes was also identified, potentially enabling growth on a wide range of alkanes and fatty acids. Pigmentation is inferred from a complete pathway for carotenoids production. We also report on the presence of incomplete chlorophyll biosynthetic pathways in all genomes and propose several evolutionary-grounded scenarios that could explain such a pattern. Assessment of the ecological distribution patterns of the Binatota indicates preference of its members to terrestrial and freshwater ecosystems characterized by high methane and methanol emissions, as well as multiple hydrocarbon-rich habitats and marine sponges.