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Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
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Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System

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Phylogenetic analysis reveals an ancient gene duplication as the origin of the MdtABC efflux pump

Kamil Górecki1, Megan M McEvoy1,2,3

  • 1Institute for Society & Genetics, University of California, Los Angeles, California, United States of America.

Plos One
|February 13, 2020
PubMed

Insights

The MdtABC efflux pump in Gram-negative bacteria evolved from a single gene duplication event early in Proteobacteria evolution. This ancient duplication event predates major bacterial class divergences, highlighting stable bacterial pump evolution.

Area of Science:

  • Microbiology
  • Evolutionary Biology
  • Molecular Biology

Background:

  • Resistance-Nodulation-Division (RND) efflux pumps are crucial for intrinsic antibiotic resistance in Gram-negative bacteria.
  • The MdtABC pump is unique within the RND family due to its two homologous inner membrane components, MdtB and MdtC.

Purpose of the Study:

  • To investigate the evolutionary origins and phylogenetic context of the MdtBC inner membrane components within the RND family.
  • To determine the duplication event's timing and its implications for RND efflux pump evolution.

Main Methods:

  • Phylogenetic analysis of MdtBC pumps.
  • Comparative analysis with other RND efflux pumps across bacterial species.

Main Results:

  • The MdtB and MdtC inner membrane components are conserved across Proteobacterial species, originating from a single gene duplication.
  • This gene duplication event is ancient, occurring before the divergence of Alpha-, Beta-, and Gamma-Proteobacteria.
  • The MdtABC and MexMN pumps share a common ancestor, suggesting MexMN also arose from a gene duplication event.

Conclusions:

  • The MdtABC pump system has ancient evolutionary origins within the RND family.
  • Gene duplication events have played a significant role in the diversification of RND efflux pumps.
  • Core bacterial efflux pump repertoires appear evolutionarily stable.

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