Large-Scale Integration of Amplicon Data Reveals Massive Diversity within , Mostly Originating from Saline Environments.

The order , a group of bacteria involved in complex degradation pathways, comprises three officially described families: , , and . These collectively contain 17 genera and 31 species. The current knowledge on diversity is the product of traditional isolation methods, with the inherited limitations of culture-based approaches. This study utilized the extensive information available in public sequence repositories combined with recent analytical tools to evaluate the global evidence-based diversity of the order. Our analysis resulted in 1183 novel molecular families, 15,033 novel molecular genera, and 188 K novel molecular species. Of those, 7 novel families, 464 novel genera, and 1565 species appeared in abundances at ≥0.1%. were detected in various environments, such as saline water, freshwater, soil, various hosts, wastewater treatment plants, and other bioreactors. Overall, saline water was the environment showing the highest prevalence of , with bioreactors and wastewater treatment plants being the environments where they occurred with the highest abundance. was the family containing the majority of the most prevalent species detected, while was the family with the majority of the most abundant species found. This analysis should prime researchers to further explore, in a more targeted way, the proportion of microbial dark matter.