Fig 4.
Relative alkaline phosphatase activity reflecting the induction of the hxfA promoter in a X. fastidiosa WT strain and its ΔrpfF derivative as well as the rpfFN strain (kanamycin resistant) and its rpfF* mutant derivative with changes in the DSF catalytic site, each harboring an hxfA′::phoA transcriptional fusion, after 96 h of growth in PD3 broth in the presence or absence of 10 μM 2(Z)-tetradecenoic acid (XfDSF). Error bars represent the standard deviations of the means (n = 6). Statistically significant differences (P < 0.05) between samples are represented by the letters “a” and “b.”