Abstract：Many phytopathogens use N-acylhomoserine lactone (AHL) as quorum sensing (QS) signals, inducing the expression of virulence factors to destroy plant. N-acylhomoserine lactonase (AiiA) can degrade AHL, resulting in the disruption of AHL-mediated QS system in gram-negative bacteria. In this study, auto inducer inactivation A(aiiA) gene was firstly inserted into the shuttle expression vector of pPICZαB and introduced to GS115 strain of Pichia pastoris, resulting in a recombinant yeast strain GS115-pPICZαB-aiiA. On the other hand, codon optimized aiiA gene, named as MaiiA, was carried out by using site-directed mutagenesis to adapt to P. pastoris expression system betterly, and was also inserted into the expression vector and introduced into yeast, and constructed GS115-pPICZαB-MaiiA. Both GS115-pPICZαB-aiiA and GS115-pPICZαB-MaiiA were successfully induced to express secreted AiiA proteins by the addition of 1% methanol at 28 ℃. Antimicrobial activity analysis showed that the AiiA protein inhibited the virulence of Erwinia carotovora. The expression of secreted AiiA protein in P. pastoris, broadening the acquisition route of AiiA protein, provides a theoretical basis and new idea for AiiA industrialization. Codon optimization provides a new way of thinking for the future reconstruction and the efficient expression of AiiA protein.
