Preharvest application of antagonistic yeast Rhodosporidium paludigenum induced resistance against postharvest diseases in mandarin orange.

摘要

Preharvest application of biocontrol agents has been employed as a preferred strategy to minimize a wide range of postharvest decays. Rhodosporidium paludigenum as a novel biocontrol yeast significantly inhibited the development of various postharvest fruit diseases. However, whether preharvest treatment with R. paludigenum might suppress postharvest pathogens has not been investigated. This study was conducted to evaluate the efficacy of preharvest applications of R. paludigenum against postharvest diseases in mandarin orange. Our results showed that preharvest applications of R. paludigenum significantly reduced postharvest decays of mandarin orange caused by Penicillium digitatum and Penicillium italicum, by 20.8% and 30.7% reduction in disease percentage, and by 14.6% and 37.3% reduction in disease severity, respectively. The population growth of R. paludigenum on the mandarin orange surface did not show any significant changes compared with the initial concentration during 20 days of storage after harvest. Moreover, it was found that the activities of some defense-related enzymes, comprising beta -1,3-glucanase, phenylalanine ammonia-lyase, peroxidase and polyphenoloxidase, increased significantly in response to preharvest application of R. paludigenum. In addition, preharvest treatment of R. paludigenum did not impair fruit quality during postharvest storage. Therefore, the preharvest application of yeast antagonist R. paludigenum would be a useful biocontrol strategy to reduce the fungal diseases of harvested mandarin orange.