Analysis of the expression of selected genes encoding differentially expressed proteins. A significant difference in expression was detected by qRT-PCR between planktonic and biofilm conditions for selected genes confirming their expression during X. a. pv. citri biofilm formation. Black bars indicate the expression levels of X. a. pv. citri transcripts in biofilm compared to a reference planktonic growth (white bars). As a reference gene, a fragment of 16S rRNA was amplified. Values represent the means of four independent experiments. Error bars indicate standard deviations. Data were statistically analyzed using one-way ANOVA (p < 0.05) and Student t-test (p < 0.05).