Vineyard in the Barossa Valley
Miniature oxygen probe measuring oxygen in a Shiraz grape.   Image: The University of Adelaide

Miniature oxygen probe measuring oxygen in a Shiraz grape.
Image: © The University of Adelaide

University of Adelaide researchers have discovered how grapes “breathe”, and that shortage of oxygen leads to cell death in the grape.

The discovery raises many questions about the potentially significant impacts on grape and wine quality and flavour and vine management, and may lead to new ways of selecting varieties for warming climates.

“In 2008 we discovered the phenomenon of cell death in grapes, which can be implicated where there are problems with ripening, and we’ve since been trying to establish what causes cell death,” says Professor Steve Tyerman, Chair of Viticulture at the University of Adelaide’s Waite campus.

 

“Although there were hints that oxygen was involved, until now we’ve not known of the role of oxygen and how it enters the berry.”

 

Professor Tyerman and PhD student Zeyu Xiao from the University’s Australian Research Council (ARC) Training Centre for Innovative Wine Production have identified that during ripening, grapes suffer internal oxygen shortage. The research was in collaboration with Dr Victor Sadras, South Australian Research and Development Institute, and Dr Suzy Rogiers, NSW Department of Primary Industries, Wagga Wagga.

Published in the Journal of Experimental Botany, the researchers describe how grape berries suffer internal oxygen shortage during ripening.  With the use of a miniature oxygen measuring probe – the first time this has been done in grapes – they compared oxygen profiles across the flesh inside grapes of Chardonnay, Shiraz and Ruby Seedless table grape.

They found that the oxygen shortage profile closely correlated with cell death within the grapes. Respiration measurements indicated that this would be made worse by high temperatures during ripening – expected to happen more frequently with global warming.

“By manipulating oxygen supply we discovered that small pores on the surface of the berry stem were vital for oxygen supply, and if they were blocked this caused increased cell death within the berry of Chardonnay; essentially suffocating the berry. We also used micro X-ray computed tomography (CT) to show that air canals connect the inside of the berry with the small pores on the berry stem,” says Mr Xiao.

X-ray micro computer tomography (CT) of the inside of a single grape berry showing the air spaces and air canals.   Image: The University of Adelaide

X-ray micro computer tomography (CT) of the inside of a single grape berry showing the air spaces and air canals.
Image: The University of Adelaide

 

“Shiraz has a much smaller area of these oxygen pores on the berry stem which probably accounts for its greater sensitivity to temperature and higher degree of cell death within the berry.”

 

 

 

Professor Vladimir Jiranek, Director of the ARC Training Centre for Innovative Wine Production, says: “This breakthrough on how grapes breathe will provide the basis for further research into berry quality and cultivar selection for adapting viticulture to a warming climate.”

The study was supported by the Australian Government through the Australian Research Council‘s Industrial Transformation Research Program (project IC1301100005) with support from Wine Australia and industry partners.

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The ARC TC-IWP would like to congratulate PhD students:

Zeyu Xiao who submitted his thesis ‘Hypoxia and Cell Death in Grape Berries (Vitis vinifera L.)’ on 21st February 2018 and Ana Hranilovic who submitted her thesis: ‘Managing ethanol and sensory compounds by non-Saccharomyces yeasts’ on 23rd February 2018.

image2Ana submits thesis 23 Feb 2018_2 (002)

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Rocco Dec 2017

ARC TC-IWP would like to congratulate PhD student Rocco Longo (CSU) who submitted his thesis on the 11th of December 2017. The title of his thesis is: “Effects of harvest timing and technological approaches on volatile compounds and sensory profiles of lower alcohol wines“.

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The ARC TC-IWP would like to congratulate PhD students Lieke van der Hulst and Sijing Li who submitted their thesis on respectively the 17th of November and the 1st of December. The title of Lieke’s thesis is: The analysis of grapevine response to smoke exposure. Sijing’s work is titled: Selective use of winemaking supplements to […]

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PhD Student Ana Hranilovic has published her work on the yeast Lachancea thermotolerans (formerly Kluyveromyces thermotolerans) as a species with remarkable, yet underexplored, biotechnological potential. To gain an insight into L. thermotolerans population diversity and structure, 172 isolates sourced from diverse habitats worldwide were analysed using a set of 14 microsatellite markers. The resultant clustering revealed that the evolution of L. thermotolerans has been […]

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Phd Student Rocco Longo and dr Leigh Schmidtke have produced two technical notes on their work on the production of lower alcohol wines. The notes can be found here.

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A/Prof David Jeffery and Dr Renata Ristic presented at the ‘From Fermentation to Fume Hood: the Chemistry of Wine’ Symposium, at the 254th American Chemical Society National Meeting & Exposition, held in Washington, DC, 20-24 August 2017. The ACS meetings are the largest international chemistry conferences, and routinely host more than 10,000 attendees and over […]

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The last workshop for the first round of the ARC TC-IWP was held last Monday the 7th of August with presentations from all PhD students and Post docs at the Charles Hawker Conference Centre at the Waite Campus. Industry partners and academic colleagues gathered to listen to the presentations and discuss the outcomes of several […]

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ARC TC-IWP would like to congratulate PhD student Zelmari Coetzee who submitted her thesis on the 4th of August 2017. The title of her thesis is: The sugar-potassium nexus within the grape berry.    

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The ARC TC-IWP would like to congratulate PhD student Bora Qesja who submitted her thesis on the 31st of July 2017. The title of her thesis is: Innovating Traditional Products: Product Authenticity vs. Perceived Sacrifice from the Innovation.    

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