Phytoparasitica (2004) 32, 187-188

Y. Hadas, O. Pines, I. Goldberg and D. Prusky (2004)
The role of organic acid secretions during the pathogenesis of Penicillium spp.
Phytoparasitica 32 (2), 187-188
lecture presented at the 25th Congress of the Israeli Phytopathological Society, Febr. 2004, Bet Dagan, Israel
Abstract: The phytopathogenic fungus Penicillium expansum acidifies the host tissue during the Penicillium attack. The acidification is achieved by secretion of organic acids combined with the uptake of ammonia. The tissue acidification induces the expression of the gene pepg1, which encodes for the pectolytic enzyme polygalacturonase involved in the maceration of the host tissue. P. expansum isolates with increased pathogenicity, accumulated higher amounts of gluconic acid and reduced the Phytoparasitica apple tissue pH to lower values than isolates with reduced pathogenicity. Glucose oxidase (GOX) activity, involved in gluconic acid production, was detected in P. expansum decayed tissue but not in the healthy tissue of the same fruit. Growth of the fungi at reduced oxygen levels reduced the activity of GOX, decreased the accumulation of gluconic acid in the medium and delayed development of decay. Our present results suggest that the secretion of gluconic acid and acidification of the host tissue is a first stage leading to the secretion of pectolytic enzyme and decay development.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Dov Prusky

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Penicillium expansum