Recombinant expression of antimicrobial peptides in Pichia pastoris: A strategy to inhibit the Penicillium expansum in pears

The alteration of safety-secured yeast is a crucial step before scale applications. Based on previous studies, Pichia pastoris showed great potential and value to improve its biocontrol ability. The original sequences of antimicrobial peptide Ac-AMP2 and MiAMP1 were optimized according to the preference of Pichia pastoris and ligated into pPICZαA plasmid which is emerged as a high-performance vector for transformation and expression. The results of RT-qPCR and Western blotting could imply that pPICZαA/Ac-AMP2 and pPICZαA/MiAMP1 were successfully overexpressed in Pichia pastoris GS115. The peptide concentration of GS115/Ac-AMP2 reached a maximum value of 210 mg L−1 at 60 h while GS115/MiAMP1 was 220 mg L−1 at 96 h. The biocontrol experiment indicated that the recombinant strain GS115/Ac-AMP2 and GS115/MiAMP1 could highly suppress the pathogen Penicillium expansum in vivo, which was respectively 42 % (GS115/Ac-AMP2) and 29.2 % (GS115/MiAMP1) of incidence disease lower than the sterile distilled water treatment. In the case of the experimental results considered, the modified GS115/Ac-AMP2 and GS115/MiAMP1 might be promising biological agent in postharvest applications.