Confocal laser scanning microscopy analysis X. a . pv . citri in vitro biofilms. Representative photographs of laser scanning confocal analysis of GFP-expressing X. a. pv. citri cells cultured in static liquid XVM2 in 24-well PVC plates for one, three and seven days (upper panels). Serial images were taken at 0.5 μm distances (z-stack). White arrows point to cell aggregations and dotted white arrows point to network channels. Scale bars: 30 μm. For a better visualization, the lower panels are images of biofilm channels and cell aggregates at 7 days.