Kemampuan Bacillus sp. penghasil AHL-Laktonase dalam menghambat proses quorum sensing patogenisitas bakteri fitopatogen

Abstract

Quorum Sensing (QS) is a process that bacteria are be able to communicate using a secreted signal molecule called autoinducer (AI). AI molecule of Gram negative bacteria is N-acylhomoserine lactone (AHL). The AHL can be degraded by an enzyme called Acyl Homoserine Lactonase (AHL-Lactonase). AHL-laktonase is an anti-QS compound can be used as to control bacterial pathogen virulence. This study aimed to test the ability of Bacillus sp. producing AHL lactonase in inhibiting QS processes of phytopatogenic bacteria. The highest inhibition index of violacein production by Chromobacterium violaceum was achieved by Bacillus sp. SGT3g with a value of 0.33. Inhibition test of QS process in Erwinia chrysanthemi showed that Bacillus sp. INT1c could inhibit its virulence in potatoes. Test in tobacco plants also showed that Bacillus sp. NTT3a, NTT3e, SGT3g and INT1c was able to inhibit the emergence of necrotic leaf tissue symptoms of Ralstonia solanacearum, Pseudomonas syringae pv. glycines, Pseudomonas fluorescens, dan Xanthomonas oryzae. Inhibition percentage inhibition of necrotic symptoms by the four Bacillus isolates was up to 99%.