Articles
The Pinotage old vine story – lessons learnt for future genetics research in Chenin blanc
Article number
1430_5
Pages
25 – 38
Language
English
Abstract
In many parts of the world there is a newfound interest in old vines and vineyards, and the exceptional wines produced from them.
Such wines are generally considered as having more depth and complexity than young-vineyard wines, thus often the term old vine are used on wine labels as an indication of a superior, high-quality wine.
In South Africa, two of the most prominent cultivars used for the production of old-vine wines are Chenin blanc and Pinotage.
However, there is only anecdotal evidence that these wines are truly of a higher standard.
This study is the first genetic research into the so-called old-vine wine character, aiming to determine any significant differences in gene expression in leaves and berries of young (7 years) and old (GROTERDAN40 years) clonal Pinotage vines, as well as the viral populations (viromes) present in these young and old plants.
Genome sequencing, as well as RNA-seq, allowed for the identification of 925 genes differentially expressed between young and old Pinotage vines.
Many of these genes are involved in metabolic pathways active during fruit ripening, and a general trend was observed towards delayed berry ripening in old vines.
Berries of these vines also had a lower sugar concentration and higher titratable acids at the time of harvest, compared to young-vine berries.
Collectively, these results suggest that berries of old Pinotage vines take longer to ripen, possibly allowing for the accumulation of volatile aromas that influence berry flavour.
A comparison of the viruses present in these plants revealed that old plants not only harboured a more diverse collection of grapevine viruses and viroids, but also higher concentrations of these.
The obvious question that arises is if similar trends exist in a classical white cultivar like Chenin blanc, especially since chemical and sensory analyses of young- and old-vine Chenin blanc wines have been done before.
Comparing these results to those obtained from such differential gene expression and virome studies in young and old clonal Chenin blanc vines could potentially tie genotype and phenotype together in a unique way for grapevine research.
Such wines are generally considered as having more depth and complexity than young-vineyard wines, thus often the term old vine are used on wine labels as an indication of a superior, high-quality wine.
In South Africa, two of the most prominent cultivars used for the production of old-vine wines are Chenin blanc and Pinotage.
However, there is only anecdotal evidence that these wines are truly of a higher standard.
This study is the first genetic research into the so-called old-vine wine character, aiming to determine any significant differences in gene expression in leaves and berries of young (7 years) and old (GROTERDAN40 years) clonal Pinotage vines, as well as the viral populations (viromes) present in these young and old plants.
Genome sequencing, as well as RNA-seq, allowed for the identification of 925 genes differentially expressed between young and old Pinotage vines.
Many of these genes are involved in metabolic pathways active during fruit ripening, and a general trend was observed towards delayed berry ripening in old vines.
Berries of these vines also had a lower sugar concentration and higher titratable acids at the time of harvest, compared to young-vine berries.
Collectively, these results suggest that berries of old Pinotage vines take longer to ripen, possibly allowing for the accumulation of volatile aromas that influence berry flavour.
A comparison of the viruses present in these plants revealed that old plants not only harboured a more diverse collection of grapevine viruses and viroids, but also higher concentrations of these.
The obvious question that arises is if similar trends exist in a classical white cultivar like Chenin blanc, especially since chemical and sensory analyses of young- and old-vine Chenin blanc wines have been done before.
Comparing these results to those obtained from such differential gene expression and virome studies in young and old clonal Chenin blanc vines could potentially tie genotype and phenotype together in a unique way for grapevine research.
Authors
B. Coetzee, K. Oosthuizen, H.J. Maree, J.T. Burger
Keywords
grapevine, RNA-seq, differential gene expression, berry ripening, virome
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