ARC Training Centre for Innovative Wine Production publications

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Browsing ARC Training Centre for Innovative Wine Production publications by Author "Barril, C."

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    Expression patterns of genes encoding sugar and potassium transport proteins are simultaneously upregulated or downregulated when carbon and potassium availability is modified in Shiraz (Vitis vinifera L.) berries
    (Oxford University Press, 2019) Coetzee, Z.A.; Walker, R.R.; Liao, S.; Barril, C.; Deloire, A.J.; Clarke, S.J.; Tyerman, S.D.; Rogiers, S.Y.
    A link between the accumulation of sugar and potassium has previously been described for ripening grape berries. The functional basis of this link has, as of yet, not been elucidated, but could potentially be associated with the integral role that potassium has in phloem transport. An experiment was conducted on Shiraz grapevines in a controlled environment. Berry sugar accumulation was curtailed by reducing the leaf photoassimilation rate and the availability of potassium was increased through soil fertilisation. The study characterises the relationship between the accumulation of sugar and potassium into the grape berry and describes how their accumulation patterns are related to the expression patterns of their transporter proteins. A strong connection was observed between sugar and potassium accumulation in the grape berry pericarp, irrespective of the treatment. The relative expression of proteins associated with sugar and potassium transport across the tonoplast and plasma membrane were closely correlated, suggesting transcriptional co-regulation leading to the simultaneous translocation and storage of potassium and sugar in the grape berry cell.
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    Impact of reduced atmospheric CO₂ and varied potassium supply on carbohydrate and potassium distribution in grapevine and grape berries (Vitis vinifera L.)
    (Elsevier Masson SAS, 2017) Coetzee, Z.; Walker, R.; Deloire, A.; Barril, C.; Clarke, S.; Rogiers, S.
    To assess the robustness of the apparent sugar-potassium relationship during ripening of grape berries, a controlled-environment study was conducted on Shiraz vines involving ambient and reduced (by 34%) atmospheric CO₂ concentrations, and standard and increased (by 67%) soil potassium applications from prior to the onset of ripening. The leaf net photoassimilation rate was decreased by 35% in the reduced CO₂ treatment. The reduction in CO₂ delayed the onset of ripening, but at harvest the sugar content of the berry pericarp was similar to that of plants grown in ambient conditions. The potassium content of the berry pericarp in the reduced CO₂ treatment was however higher than for the ambient CO₂. Berry potassium, sugar and water content were strongly correlated, regardless of treatments, alluding to a ternary link during ripening. Root starch content was lower under reduced CO₂ conditions, and therefore likely acted as a source of carbohydrates during berry ripening. Root carbohydrate reserve replenishment could also have been moderated under reduced CO₂ at the expense of berry ripening. Given that root potassium concentration was less in the vines grown in the low CO₂ atmosphere, these results point toward whole-plant fine-tuning of carbohydrate and potassium partitioning aimed at optimising fruit ripening.
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    Spatiotemporal changes in the accumulation of sugar and potassium within individual 'Sauvignon Blanc' (Vitis vinifera L.) berries
    (Julius Kühn-Institut, 2017) Coetzee, Z.A.; Walker, R.R.; Deloire, A.; Clarke, S.J.; Barril, C.; Rogiers, S.Y.
    It has been speculated that there may be a link between the transport of sugar and potassium into grape berries during ripening as they exhibit similar accumulation patterns. It is unclear if this proposed link is apparent in individual grape berries and in the grape berry compartments. Single grape berries were therefore analysed for sugar and potassium content and concentration within the skin, seeds and the pulp from pre-véraison until harvest. Sugar and potassium had similar accumulation patterns and positive relationships were confirmed between the sugar and potassium content within individual berries and compartments. The sugar content in the grape berry, however, increased 5-fold during ripening whereas the potassium content only doubled. Both sugar and potassium increased with berry size, suggesting a ternary relationship with berry water. The high variability in sugar and potassium contents between berries however affirms plasticity in their accumulation within individual berries.