Bacteria of the genus Xanthomonas cause serious diseases in more than 400 plant species and lead to significant yield losses.1][2][3] AvrBs2 family effectors are among the most important virulence factors of these bacteria.[1][2] AvrBs2 is a synthetase derived from glycerophosphodiesterase that catalyzes the uridine 5'-diphosphate-α-D-galactose to a sugar phosphodiester called xanthosan, specifically bis-(1,6)-cyclic dimeric α-D-galactose phosphate.[1][2][3] Xanthosan is synthesized by AvrBs2 in host cells and released into apoplastic compartments.[1][2][3] Xanthomonas bacteria take up xanthosan via the XanT transporter and hydrolyze it by the phosphodiesterase XanP for nutrition.1][2][3] AvrBs2, XanT and XanP form a "generation-absorption-utilization" system of xanxosan that provides a specific nutritional strategy for these bacteria.[1][2][3] The discovery of this virulence mechanism inspired the development of an "anti-nutritional" strategy to control various diseases caused by Xanthomonas.[1][2][3] The discovery of this virulence mechanism inspired the development of an "anti-nutritional" strategy to control a variety of Xanthomonas diseases.[1][2][3] The discovery of the "anti-nutritional" strategy inspired the development of the Xanthomonas