Comparative Analyses of the Order Enterobacterales Support the Importance of Methyl-Accepting Chemotaxis Proteins and ATP-Binding Cassette Transporters in the Pathogenicity of Soft Rot Pectobacteriaceae

Methyl-accepting chemotaxis proteins (MCPs) are bacterial chemoreceptors that sense environmental and intracellular signals and regulate flagellar rotation through interactions with Che proteins. Some MCPs interact with ATP-binding cassette (ABC) transporters, which import and export various compounds across cell membranes. Using annotated prokaryotic genome assemblies, we assessed the abundance and organization of MCPs and ABC transporters in plant pathogenic Pectobacteriaceae and compared these features with those in other members of the Enterobacterales order, including Escherichia, Yersinia, Pectobacterium, Salmonella, Erwinia, and Sodalis. Soft rot Pectobacteriaceae encode at least 20 MCP genes per strain and contain diverse ligand-binding domains, including TarH, 4HB, HBM, NIT, dCache-1, sCache_2, Cache_3-Cache_2, FIST, Chase3, CZB, NIT, and Pas domains. Their genomes are also enriched in ABC transporters that transport sugars, peptides, amino acids, iron-siderophores, and the family 5, 6 and 9 transporters compared to other Enterobacterales. Some MCPs are clustered in Pectobacteriaceae, and some are collocated with ABC transporters. A subset of substrate-binding proteins of ABC transporters that bind to sugar, amino acid, mineral salt, iron, and polyamine may interact with MCPs in Pectobacterium to co-sense signals. Our findings suggest that soft rot Pectobacteriaceae are enriched in both MCPs and ABC transporters relative to many other members of Enterobacterales, supporting the potential importance of these proteins in adaptation to diverse environments and pathogenesis within the context of shared phylogenetic history. MCPs and ABC transporters therefore provide candidates for future functional studies of soft rot pathogenesis and may help identify strategies for plant disease management.