Abstract: Numerous gram negative bacterial plant pathogens use a cooperative cell to cell communication system known as quorum sensing to synchronize expression of genes essential for survival and virulence. N-Acyl-L-Homoserine Lactone (AHL) is the diffusible density-dependent signal molecule that is used in quorum sensing and is responsible for pathogenicity in most species of plant pathogenic bacteria including the papaya dieback disease pathogen, Erwinia mallotivora. Quorum quenching enzymes such as N-acyl-L-homoserine lactonase found in rhizosphere soil bacteria have the ability to degrade AHL and eliminate bacterial virulence therefore are key targets for disease control in plants. AHL inactivation genes coding for AHL lactonase were cloned from five Bacillus species isolated from tomato rhizosphere soil in Malaysia. Analysis of nucleotide sequences revealed an Open Reading Frame (ORF) of 753 bp which encodes a polypeptide of 250 amino acids with a predicted molecular weight of 28 kDa. BLAST analysis showed that the 753 bp nucleotide sequence was homologous with the AHL lactonase gene (aiiA) from Bacillus species in the GenBank database with 88-99% nucleotide sequence identity. The deduced AHL-lactonases have 90-100% amino acid identity with Bacillus aiiA proteins and belong to the group of metallo-beta-lactamase superfamily proteins.
Noriha Mat Amin, Mohd. Yusof Nor Rahim, Rohaiza Ahmad Redzuan, Amin Asyraf Tamizi and Hamidun Bunawan, 2016. Acyl Homoserine Lactonase Genes from Bacillus Species Isolated from Tomato Rhizosphere Soil in Malaysia. Research Journal of Applied Sciences, 11: 656-659.