The Role of ATP-binding Cassette (ABC) Transporters in Bacterial Phytopathogenesis
Bacteria use selective membrane transporting strategies to support cell survival in different environments. Of the membrane transport systems, ATP-binding cassette (ABC) transporters, which utilize the energy of ATP hydrolysis to deliver substrate across the cytoplasmic membrane, are the largest and most diverse superfamily. These transporters import nutrients, export substrates, and are required for diverse cell functions, including cell division and morphology, gene regulation, surface motility, chemotaxis, and interspecies competition. Phytobacterial pathogens may encode numerous ABC transporter homologs compared to related non-phytopathogens, with up to 160 transporters per genome, suggesting that plant pathogens must be able to import or respond to a greater number of molecules than saprophytes or animal pathogens. Despite their importance, ABC transporters have been little examined in plant pathogens. And yet, to understand bacterial phytopathogenesis and evolution, we need to understand the roles that ABC transporters play in plant-microbe interactions. In this review, we outline a multitude of roles that bacterial ABC transporters play, using both plant and animal pathogens as examples, to emphasize the importance of exploring these transporters in phytobacteriology.