title: Temperature and water loss affect ADH activity and gene expression in grape berry during postharvest dehydration.
abstract: Clusters of Aleatico wine grape were picked at 18°Brix and placed at 10, 20, or 30°C, 45% relative humidity (RH) and 1.5m/s of air flow to dehydrate the berries up to 40% of loss of initial fresh weight. Sampling was done at 0%, 10%, 20%, 30%, and 40% weight loss (wl). ADH (alcohol dehydrogenase) gene expression, enzyme activity, and related metabolites were analysed. At 10°C, acetaldehyde increased rapidly and then declined, while ethanol continued to rise. At 20°C, acetaldehyde and ethanol increased significantly with the same pattern and declined at 40%wl. At 30°C, acetaldehyde did not increase but ethanol increased rapidly already at 10%wl. At the latter temperature, a significant increase in acetic acid and ethyl acetate occurred, while at 10°C their values were low. At 30°C, the ADH activity (ethanol to acetaldehyde direction), increased rapidly but acetaldehyde did not rise because of its oxidation to acetic acid, which increased together with ethyl acetate. At 10°C, the ADH activity increased at 20%wl and continued to rise even at 40%wl, meaning that ethanol oxidation was delayed. At 20°C, the behaviour was intermediate to the other temperatures. The relative expression of the VvAdh2 gene was the highest at 10°C already at 10%wl in a synchrony with the ADH activity, indicating a rapid response likely due to low temperature. The expression subsequently declined. At 20 and 30°C, the expression was lower and increased slightly during dehydration in combination with the ADH activity. This imbalance between gene expression and ADH activity at 10°C, as well as the unexpected expression of the carotenoid cleavage dioxygenase 1 (CCD1) gene, opens the discussion on the stress sensitivity and transcription event during postharvest dehydration, and the importance of carefully monitoring temperature during dehydration.
authors.affiliation: Department of Agriculture, Forestry, Nature and Energy, University of Tuscia, Viterbo, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Cirilli
authors.affiliation: Department of Environment, Food, and Forestry Innovative Systems, Postharvest Lab, University of Tuscia, Viterbo, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bellincontro
authors.affiliation: Department of Environment, Food, and Forestry Innovative Systems, Postharvest Lab, University of Tuscia, Viterbo, Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: De Santis
authors.affiliation: Department of Environment, Food, and Forestry Innovative Systems, Postharvest Lab, University of Tuscia, Viterbo, Italy.
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Botondi
authors.affiliation: Department of Agriculture, Forestry, Nature and Energy, University of Tuscia, Viterbo, Italy.
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Colao
authors.affiliation: Department of Agriculture, Forestry, Nature and Energy, University of Tuscia, Viterbo, Italy.
authors.forename: Rosario
authors.initials: R
authors.lastname: Muleo
authors.affiliation: Department of Environment, Food, and Forestry Innovative Systems, Postharvest Lab, University of Tuscia, Viterbo, Italy. Electronic address: mencarel@unitus.it.
authors.forename: Fabio
authors.initials: F
authors.lastname: Mencarelli
mesh_terms: D000079:Acetaldehyde / Q000032:analysis; D019342:Acetic Acid / Q000032:analysis; D000426:Alcohol Dehydrogenase / Q000235:genetics* / Q000378:metabolism*; D003890:Desiccation / Q000379:methods; D000431:Ethanol / Q000032:analysis; D005511:Food Handling / Q000379:methods; D005638:Fruit / Q000737:chemistry / Q000201:enzymology*; D015870:Gene Expression; D010084:Oxidation-Reduction; D013696:Temperature; D027843:Vitis; D014867:Water / Q000032:analysis*
chemical_list: D014867:Water; D000431:Ethanol; D000426:Alcohol Dehydrogenase; D000079:Acetaldehyde; D019342:Acetic Acid
keywords: ADH activity; ADH gene expression; Dehydration; Grape; Temperature; Volatile compounds