Comparative genomic analysis identifies potential adaptive variation in Mycoplasma ovipneumoniae

Area of Science:

• Bacteriology
• Genomics
• Evolutionary Biology

Background:

• Mycoplasma ovipneumoniae causes respiratory disease in wild and domestic Caprinae.
• Disease outcomes vary significantly across host species and geographic locations.

Purpose of the Study:

• To investigate the phylogenetic structure of M. ovipneumoniae.
• To understand the mechanisms of pathogenicity and adaptation in M. ovipneumoniae.

Main Methods:

• Comparative genomics of 99 M. ovipneumoniae samples from 6 countries and 4 host species.
• Core genome sequencing and pangenome analysis.
• Identification of clade-associated and accessory genes.

Main Results:

• Two distinct phylogenetic clades of M. ovipneumoniae were identified, originating from separate host species (domestic sheep and goats).
• Bighorn sheep and caribou genomes clustered within these two clades, indicating host-species spillover events.
• High accessory gene content (91.4%) suggests adaptability; homologous recombination in carbon metabolism genes indicates adaptation.
• A divergent subclade in asymptomatic Alaskan caribou lacked 23 genes, many involved in carbon metabolism.

Conclusions:

• M. ovipneumoniae adaptation is driven by evolution in carbon metabolism and associated virulence mechanisms.
• Genetic variations, particularly in metabolism pathways, may explain diverse disease outcomes in Caprinae.
• Identified genes offer potential targets for understanding and managing M. ovipneumoniae infections.