The Genome of Candidatus Liberibacter asiaticus (CLas) revealed the presence of luxR that encodes LuxR protein, one of the two components typical of bacterial “quorum sensing” or cell-to-cell communication systems. Interestingly, the genome lacks the second components; luxI that produce Acyl-Homoserine Lactones (AHLs) suggesting that CLas has a solo LuxR system. In the current project, we will test the effect of AHL-producing citrus plants on the pathogencity of CLas. Although the postdoctoral researcher has joined our lab two months later than the proposed starting date, we have selected different Lux-I genes from different bacteria expressing different AHLs. The selected genes included TraI (accession number: L22207.1) from Agrobacterium tumefaciens, AhyI (accession number: CAA61653) from Aeromonas hydrophilia, AYsI (accession number: DQ058009) from Agrobacterium vitis, CepI (accession number: AF019654.1) from Burkholderia cepacia, CviI (accession number: AY277257.1) from Chromobacterium violaceum, EsaI (accession number: L32183) from Panteoa stewartii, ExpI (Accession number: AY507108.1) from Pectobacterium carotovorum, LasI (protein ID: AHW72185.1) from Pseudomonas aeruginosa, RhlI (accession number: U11811.1) from Pseudomonas aeruginosa, PhzI (accession number: AAC18898.1) from Pseudomonas fluorescens, CinI (accession number: AF210630) from Rhizobium leguminosarum bv. Viciae, RhiI (protein ID: CAK10388) from Rhizobium leguminosarum bv. Viciae, RaiI (accession number: AJ427969) from Rhizobium leguminosarum bv. Viciae, CerI (accession number: AF016298) from Rhodobacter sphaeroides, SwrI (accession number: U22823.1) from Serratia liquifaciens, SinI (Protein ID: CAC46418.1) from Sinorhizobium meliloti, VanI (accession number: U69677) from Vibrio anguillarum, LuxI (protein ID: AAD48474.1) from Vibrio fischeri, LuxM (accesion number: L13940) from Vibrio harveyi, Yenl (accession number: X76082.1) from Yersinia enterocolitica, YpsI (accession number: AF079973.1) from Yersinia pseudotuberculosis, and YtbI (accession number: AF079136.2) from Yersinia pseudotuberculosis. Currently, we are synthesizing the genes in order to insert them in CTV-based vector prior to the infiltration inside citrus trees.