G418-Resistance as a Dominant Selectable Marker for Heterogenous Gene Expression in Antagonist Pichia membranefaciens

Pichia membranefaciens, which was isolated from the surface of peach fruits, showed effective biocontrol capabilityagainst rhizopus rot of peach fruits. Aminoglycoside antibiotic G418 can inhibit the growth of P. membranefaciens. Theminimal inhibitory concentration of G418 to P. membranefaciens in YPD medium was 100g mL-1. We constructed aphosphoglycerate kinase (PGK) promoter-driven neoR expression cassette, which was called pFL61-neo. The biocontrolyeast P. membranefaciens was transformed with pFL61-neo by lithium acetate method. Expression vector pFL61-neoconferred P. membranefaciens drug resistance to 100g mL-1 G418. The transformant could keep a high percentage ofplasmid-containing of transformant with 67.87% after 50 generations in non-selective medium. The result showed that P.membranefaciens could recognize the promoter and terminator of PGK and direct the expression of heterologous neoRgene. Expression vector pFL61-neo could exist stably in P. membranefaciens. Therefore, it is feasible to utilize G418-resistance as a dominant selectable marker for heterogenous gene expression in antagonist P. membranefaciens.