The 13 rhizobacterial isolates selected were screened for the
production of the quorum sensing signal acyl-homoserine lactone (AHL) using the biosensor mutant Chromobacterium violaceum.
Only strain PP3WT produced the blue pigment violacein on LB agar
medium at the point of contact between isolate PP3WT and the
biosensor strain and inhibited production of pigment by the indicator
strain C. violaceum ATCC12472 in the quorum sensing inhibition
(QSI) test (Table. 3).