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United States Department of Agriculture

Agricultural Research Service

Research Project: Developing Sustainable Cropping Systems to Improve Water Productivity and Protect Water and Soil Quality in Irrigated Agriculture

Location: Water Management Research

Title: Inhibitory effect of selenium against Penicillium expansum and its possible mechanisms of action

Authors
item Wu, Z -
item Yin, X -
item Lin, Z -
item Banuelos, Gary
item Yuan, L -
item Liu, Y -
item Li, M -

Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 9, 2014
Publication Date: N/A

Interpretive Summary: Penicillium expansum is a widely spread fungal pathogen that causes blue mold rot in a variety of fruit. Management of decay caused by P. expansum has become important for ensuring the quality and safety of fruit. For this, the disease is mainly controlled by the intensive use of synthetic fungicides. However, the use of fungicides is becoming increasingly restricted because of concerns for environment and health, as well as the development of fungicide resistance by pathogens. As an alternative fungicide, selenium (selenium sulfide) has been shown to inhibit a yeast thought to play a pathogenic role in seborrheic dermatitis and dandruff, and other fungi. In the present study, the effects of Se on the control of blue mold diseases in apple plants were investigated. The results showed that Se strongly inhibited spore germination, germ tube elongation, and the mycelial spread of P. expansum. The inhibitory effects were positively related to the concentration of Se. These results suggest that Se might serve as a potential alternative to synthetic fungicides for the control of postharvest diseases of fruit and vegetables caused by P. expansum.

Technical Abstract: Penicillium expansum is a widely spread fungal pathogen that causes blue mold rot in a variety of fruits. This pathogen not only induces blue mold rot but also produces patulin in affected apple fruit, a secondary metabolite that is toxic to humans and animals. Currently, diseases caused by P. expansum are mainly controlled by synthetic fungicides. There is interest and practical scientific investigations on the use of selenium (Se) to inhibit growth of pityrosporum, a yeast. In this study the fungal pathogen P. expansum was used. The culture medium was supplemented with different concentrations of sodium selenate at 0, 5, 10, 15 and 20 mg/L. After 9 hours of incubation, spores were examined microscopically. The following parameters were determined; germ tube length, mycelial growth, intracellular reactive oxygen species, membrane integrity, cellular leakage and cellular enzymatic activity. Results showed that Se had an inhibitory effect on spore germination and germ tube elongation, increased amount of oxidizing molecules detected, decreased membrane integrity, and increased leakage of proteins and carbohydrates. Selenium clearly and directly inhibited the growth of P. expansum (in vitro). This observation suggests that Se might serve as a potential alternative to synthetic fungicides for the control of postharvest diseases caused by P. expansum in fruit and vegetables.

Last Modified: 7/31/2014
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