Fig 1.

(A) Alkaline phosphatase activity indicative of induction of the hxfA promoter in cells of WT X. fastidiosa (circles) or a ΔrpfF strain (squares) harboring an hxfA′::phoA transcriptional fusion during 4 days of growth in PD3 broth in the presence (open symbols) or absence (filled symbols) of 10 μM 2(Z)-tetradecenoic acid (XfDSF) (n = 3). Growth of the bacterial strains is shown in the inset. (B) qRT-PCR analysis of hxfB expression in X. fastidiosa WT and ΔrpfF strains after 3 days of growth in PD3 broth in the presence or absence of 10 μM XfDSF (n = 3). Expression is expressed as the ratio between mRNA levels in the mutant and those in the WT strain or as the ratio between mRNA levels in the presence and those in the absence of XfDSF in each of the strains. Vertical bars are standard deviations of the means.