Horizontal transfer of two operons coding for hydrogenases between bacteria and archaea

Area of Science:

• Microbiology
• Genetics
• Evolutionary Biology

Background:

• Horizontal gene transfer (HGT) is a significant evolutionary mechanism.
• Membrane-bound (NiFe) hydrogenases play vital roles in microbial energy metabolism.
• Understanding HGT of metabolic genes provides insights into genome evolution.

Purpose of the Study:

• To identify and characterize instances of horizontal gene transfer involving hydrogenase gene clusters.
• To investigate the phylogenetic origins and potential functions of transferred hydrogenase operons.

Main Methods:

• Phylogenetic analysis of bacterial and archaeal genomes.
• Identification of large gene clusters, specifically operons (mbx and ech).
• Comparative genomics to trace gene origins and transfer events.

Main Results:

• Three putative horizontal gene transfers involving large gene clusters were identified between bacterial and archaeal species.
• The mbx operon (13 genes) was likely transferred to Thermotoga maritima from a Pyrococcus-related species.
• The ech operon (6 genes) was independently transferred to Thermoanaerobacter tengcongensis and Desulfovibrio gigas from a Methanosarcina-related species.

Conclusions:

• The identified horizontal gene transfers involved operons encoding multisubunit membrane-bound (NiFe) hydrogenases.
• These transfers impacted genes central to energy metabolism in the recipient genomes.
• The study contributes to the known cases of HGT involving hydrogenases, highlighting their role in microbial evolution.