Carbon,nitrogen and pH regulate the production and activity of a polygalacturonase isozyme produced by Penicillium expansum |
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| Authors: | Wayne M Jurick II Ivana Vico Verneta L Gaskins Kari A Peter Eunhee Park Wojciech J Janisiewicz |
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| Institution: | 1. Food Quality Laboratory , USDA-ARS , Beltsville , Maryland Wayne.Jurick@ars.usda.gov;3. Food Quality Laboratory , USDA-ARS , Beltsville , Maryland;4. Department of Phytomedicine , University of Belgrade , Belgrade , Serbia;5. Food Quality Laboratory , USDA-ARS , Beltsville , Maryland;6. Appalachian Fruit Research Station , USDA-ARS , Kearneysville , West Virginia |
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| Abstract: | The influence of carbon, nitrogen and pH on polygalacturonase (PG) activity produced by Penicillium expansum were investigated. P. expansum mycelial growth was greatest on lyophilized lyophilised fruit tissue and the highest PG activity occurred in apple pectin medium. Nitrogen source influenced PG activity and was highest with ammonia while the greatest mycelial mass was supported by glutamate or glutamine. PG activity and mycelial mass peaked 5 five days after inoculation as polyuronide content decreased and the pH and ammonium levels increased in apple pectin medium. A single active PG isozyme with an isoelectric point of ～7.6 was produced in apple pectin medium and a partial cDNA clone was obtained that was most homologous to the pggII gene from Penicillium. griseoroseum. The results from this study indicate that P. expansum can modulate the activity of PG in response to nutrient sources and ambient pH through signalling pathways that modulate nutrient acquisition, uptake and metabolism. |
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| Keywords: | blue mold postharvest decay virulence factor nutrient sensing polygalacturonase P expansum |
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