APS Homepage

POSTERS: Molecular plant-microbe interactions

Identification of putative FliA sigma factor motifs in methyl-accepting chemotaxis protein genes of Dickeya dianthicola
Afnan Shazwan Nasaruddin - Colorado State University. Amy Charkowski- Colorado State University

Dickeya dianthicola, a member of the Pectobacteriaceae family, has caused significant losses in the US potato production since 2014. Genomic comparison of the Pectobacteriaceae with closely related animal pathogens in the order Enterobacteriales identified an elevated number of methyl-accepting chemotaxis protein (mcp) genes in this family. For instance, Escherichia coli has 5 mcp, while D. dianthicola has 42. The high number of chemotaxis genes in plant pathogenic bacteria compared to animal pathogens suggests that chemotaxis is important for Pectobacteriaceae in navigating their environments and host plants. The purpose of this study is to determine how mcp are regulated in D. dianthicola. The alternative sigma factor FliA (?28) is the only sigma factor required for transcription of chemotaxis and motility-related genes in E. coli. Based on the consensus motif of FliA (5’-TAAAG-N14-GCCGATA-3’), we analyzed the 500-bp upstream region of mcp in D. dianthicola to identify putative FliA binding sites. Out of the 42 mcp, 15 were identified to have a FliA consensus binding site upstream of the coding sequence. The remaining 27 mcp lack a putative FliA binding site. Our results suggest that other sigma factors besides FliA activate transcription of these 27 chemotaxis genes.