Biocontrol of fungal decay of citrus fruit by Pichia pastoris recombinant strains expressing cecropin A

Cecropin A gene was cloned into the expression vector pPIC9k and was successfully expressed in methylotrophic yeast, Pichia pastoris GS115. The yeast had effective antimicrobial activity on Geotrichum citri-aurantii spores by the thiazolyl blue (MTT) assay. There was no large growth difference between nontransformed strain GS115 and recombinant strain GS115/CEC in citrus fruits wounds. Yeast transformants could significantly inhibit growth of germinated G. citri-aurantii spores and inhibited decay development caused by G. citri-aurantii in citrus fruits compared to the yeast strain GS115/pPIC. This study demonstrates the potential of expression of an antifungal peptide in yeast for enhancing suppression of postharvest diseases and represents a new approach for the biological control of postharvest diseases.