Single-Cell Transcriptomes and Phylogenomic Analysis of Uncultivated Oxymonads

Area of Science:

• Microbiology
• Evolutionary Biology
• Protistology

Background:

• Oxymonads are anaerobic protists inhabiting animals, known for complex morphology but limited molecular data.
• Existing classification of oxymonads into five families lacks robust molecular support for interrelationships.
• Only a few oxymonad species have sequenced genomes or transcriptomes, hindering evolutionary studies.

Purpose of the Study:

• To conduct the first phylogenomic analysis of oxymonads incorporating all five families.
• To resolve the evolutionary relationships among oxymonad families using molecular data.
• To establish a robust phylogenetic framework for studying oxymonad evolution.

Main Methods:

• Single-cell transcriptomics was employed on six species from five genera.
• Phylogenomic analysis was performed using the generated transcriptomic data.
• The study included representatives from all five established oxymonad families.

Main Results:

• A major phylogenetic division was identified between Polymastigidae/Streblomastigidae and Saccinobaculidae/Oxymonadidae/Pyrsonymphidae.
• Oxymonadidae and Pyrsonymphidae were resolved as sister clades within the latter group.
• The phylogenomic tree provided stronger support for nodes compared to SSU rRNA trees and suggested a new root.

Conclusions:

• The study provides the first comprehensive phylogenomic framework for oxymonads.
• The resolved phylogeny offers a basis for reconstructing the evolution of oxymonad traits.
• This work facilitates testing hypotheses about new lineages and their classification within oxymonads.