“…Confocal microscopy and promoter-probe vectors carrying fluorescent protein-reporter genes are classical tools that have been used to monitor biofilm formation, structure, and development [ 76 , 77 , 78 , 79 , 80 , 81 , 82 ]. They are also powerful tools for localizing and quantifying the AHL-based communication of various plant-associated Gram-negative bacteria [ 57 , 83 , 84 , 85 , 86 , 87 , 88 ]. We used the fine detection capacity of the P. atrosepticum 6276-EI AHL biosensor to show that R. rhizogenes strain 5520 T produces AHLs in the biofilm context ( Figure 3 ).…”