Aspergillus niger Control on Strawberries by Recombinant Tobacco Osmotin for Extending Shelf-life

Abstract

Osmotin, a pathogenesis-related (PR) protein, possesses antimicrobial activity. The objectives of this study were: 1) to determine the stability of the recombinant tobacco osmotin (rOSM), 2) to define the antimicrobial profiles of rOSM, and 3) to control Aspergillus niger on strawberries by rOSM. The rOSM was expressed in Escherichia coli and stored at -20, 4, and 25 °C for stability study. The antimicrobial activities of rOSM were tested against A. niger, Penicillium aurantiogriseum, Cryptococcus neoformans and 26 foodborne pathogenic bacteria. Strawberries were inoculated with A. niger spores and treated with rOSM. The infection rates of strawberries were recorded daily at 25 °C for 8 days. The rOSM was stable for 6 months at -20, 4, and 25 °C. The antimicrobial activity of rOSM was dose and microorganism related. The rOSM treated strawberries showed longer shelf-life. These results indicated that rOSM has a potential use in foods for food safety.