The effect of Uncinula necator (powdery mildew) and Botrytis cinerea infection of grapes on the levels of haze-forming pathogenesis-related proteins in grape juice and wine |
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Authors: | TERESA GIRBAU BELINDA E STUMMER KENNETH F POCOCK GAYLE A BALDOCK EILEEN S SCOTT ELIZABETH J WATERS |
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Affiliation: | Nutricio i Bromatologia, Centre de Referencia en Tecnologia dels Aliments (CeRTA), Facultat de Farmacia, Universitat de Barcelona, Av. Joan XXIII s/n, 08028 Barcelona, Spain;Cooperative Research Centre for Viticulture, PO Box 154, Glen Osmond, SA 5064, Australia;Discipline of Plant and Pest Science, School of Agriculture and Wine, University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia;The Australian Wine Research Institute, PO Box 197, Glen Osmond, SA 5064, Australia |
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Abstract: | Powdery mildew on Chardonnay grapes resulted in increased levels of a grape thaumatin-like protein, VvTL2, in the free run juice compared to that from uninfected grapes. These increased levels persisted through winemaking and at the highest level of infection (> 30% of bunches infected) had a significant impact on the haziness in the wine following a heat test. Infection of Cabernet Sauvignon grapes (1–20% of bunches infected) did not affect the protein concentration of free run juice, and only traces of pathogenesis-related (PR) proteins remained detectable in the Cabernet Sauvignon wines from either infected or healthy grapes. In contrast, infection of Chardonnay or Semillon grapes by Botrytis cinerea in the vineyard resulted in decreased levels of all PR proteins in the free run juice and in a total protein extract from infected berries compared to that from uninfected grapes. Similar trends were observed when B. cinerea was grown in the laboratory on surface-sterilised berries or in filter-sterilised juice. |
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Keywords: | umatin-like proteins chitinases PR proteins Uncinula necator Botrytis cinerea oidium heat-induced haze Vitis vinifera |
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