Biocontrol of Postharvest Decay on Cherry Tomatoes by Recombinant Strain GS115/CEC and Its Possible Mechanism

Due to cecropin A's effective antifungal effects against Alternaria alternata (A. alternata), recombinant Pichia pastoris expressing cecropin A could control incidence of the black rot in cherry tomatoes caused by A. alternata, when compared with fruits inoculated with sterile water or plasmid without the gene insertion. Observations using a scanning electron microscope and a transmission electron microscope showed that when treated with the recombinant yeast, obvious changes in the morphology and inner structure of the A. alternata were induced leading to some cell abnormality and lysing. In order to further clarify the molecular mechanism of action, the binding properties exerted by GS115/CEC on DNA and RNA of A. alternata fungal cells were examined. The results showed that DNA and RNA of the A. alternata fungal cells were degraded by the recombinant yeast GS115/CEC. Furthermore, the recombinant strain GS115/CEC could induce the expression of the pathogenesis-related protein in order to decrease postharvest decay in cherry tomatoes.