FIGURE 4.

Correlation between motility and HAA production: a bacterial cell is shown with the flagella required for motility and with the four-tiered flagellar regulatory hierarchy and HAA production. FleQ transcriptionally activates FleSR, which is required for site selection and formation of hook and basal body complex formation. After the complete formation of hook and basal body complex, an anti-sigma factor is secreted through it (indicated in red dashed box and line), releases the FliA inhibition which directs the genetic expression of FliC (flagellin) and chemotaxis proteins, and controls the flagellar motor rotation. FleQ also controls the HAA formation from the acylated precursors by the transcriptional activity of rhlA. HAA is transported outside through cell membrane (shown with orange dashed line). Flagella synthesis depicts that the early flagellar assembly activates HAA production, but the late stages including fliC activation and flagellar maturation restrict the HAA production (Adapted from (Xu et al., 2012)).