Synechococcus elongatus PCC 7942 Genome sequencing

A spontaneous mutation arose in an O-GlcNAc transferase deletion mutant that suppressed several mutant phenotypes, including enhanced cell settling and aggregation. Whole genome sequencing of the wild type, OGT deletion, and suppressor strains identified a missense mutation in the pilA gene of the suppressor strains. PilA is a subunit of type four pili (fimbriae), which are frequently found on the surfaces of gram-negative bacteria. Fimbriae are involved in virulence, DNA uptake, twitching motility, and adhesion. Glycosylation of extra-cellular appendages, such as flagella and cilia has been widely reported. Pili are also known substrates of glycosylation and glycosylation states have been reported to be important in the function of pili.