terclim by ICS banner
IVES 9 IVES Conference Series 9 International Congress on Grapevine and Wine Sciences 9 2ICGWS-2023 9 Identification of loci associated with specialised metabolites in Vitis vinifera

Identification of loci associated with specialised metabolites in Vitis vinifera

Abstract

Secondary (or specialised) metabolites such as terpenes and phenolic compounds are produced by plants for various roles which include defence against pathogens and herbivores, protection against abiotic stress, and plant signalling. Additionally, these metabolites influence grapevine quality traits such as colour, aroma, taste, and nutritional value. However, the biosynthesis of these metabolites is often complex and controlled by multiple genes which in grapevine are predominantly uncharacterised. This study therefore aimed to identify novel loci associated with grapevine volatile organic and phenolic compounds. Chemical analysis of these compound classes was performed via GC-MS and UPLC analysis in a grapevine mapping population, and the quantified metabolites used for quantitative trait loci (QTL) analysis.  Several significant QTLs associated with terpenes and phenolic compounds were identified, and the underlying genomic regions were investigated. For phenolic compounds, a novel locus associated with caftaric acid biosynthesis was identified, and a hydroxycinnamoyltransferase (VvHCT) was investigated as a candidate gene. Several terpene synthases (VvTPSs) co-localised with QTLs associated with monoterpenes and sesquiterpenes. Notably, loci on chromosomes 12 and 13 were shown to be associated with geraniol and cyclic monoterpene accumulation, respectively. The locus on chromosome 12 was shown to contain a geraniol synthase gene (VvGer), while the locus on chromosome 13 contained an a-terpineol synthase gene (VvTer). Further molecular and genomic investigation of VvGer and VvTer found that these genes appear in tandemly duplicated clusters, with high levels of hemizygosity which was further supported by genomic data from recently published diploid grapevine genomes. Interestingly, copy number analysis demonstrated that VvTer gene copy number correlated with both VvTerexpression and the accumulation of cyclic monoterpenes, highlighting the impact of VvTPS gene duplication and copy number variation on terpene accumulation in grapevine.

DOI:

Publication date: October 3, 2023

Issue: ICGWS 2023

Type: Article

Authors

Robin Bosman*1 and Justin Graham Lashbrooke2

1South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, South Africa
2 Department of Genetics, Stellenbosch University, South Africa.

Contact the author*

Keywords

terpenes, TPS, grapevine, gene copy number, genomics, QTL, phenolics

Tags

2ICGWS | ICGWS | ICGWS 2023 | IVES Conference Series

Citation

Related articles…

Control of bacterial growth in carbonic maceration winemaking through yeast inoculation

Controlling the development of the bacterial population during the winemaking process is essential for obtaining correct wines[1]. Carbonic Maceration (CM) wines are recognised as high-quality young wines. However, due to its particularities, CM winemaking implies a higher risk of bacterial growth: lower SO2 levels, enrichment of the must in nutrients, oxygen trapped between the clusters… Therefore, wines produced by CM have slightly higher volatile acidity values than those produced by the destemming/crushing method[2].

Quantification of polysaccharides of variety Pomaces of the D.O.Ca Rioja

Pomace is one of the main residues generated by the wine industry and represents an environmental problem. Currently, there is a growing interest in the revaluation of these products because different bioactive compounds can be obtained from them, such as polyphenols, grape seed oils and polysaccharides. Red grape pomace can be an important source of polysaccharides, but they are currently little studied and even less with viable and environmental extraction processes (green extraction), such as flash extraction. The residual amount of the fraction rich in pectin (residual pulp) and component rich in hemicellulose in the pomace and the strength of association of the pectin with the cellulose-xyloglucan network depend on the degree of extractability of the polysaccharides in red winemaking and on the winemaking conditions.

Phenotyping bud break and trafficking of dormant buds from grafted vine

In grapevine, phenology from bud break to berry maturation, depends on temperature and water availability. Increases in average temperatures accelerates initiation of bud break, exposing newly formed shoots to detrimental environmental stresses. It is therefore essential to identify genotypes that could delay phenology in order to adapt to the environment. The use of different rootstocks has been applied to change scion’s characteristics, to adapt and resist to abiotic and biotic stresses[1].

Effect of ultraviolet B radiation on pathogenic molds of grapes

The fungicidal effect of UV-C radiation (100-280 nm wavelength) is well known, but its applicability for the control of pathogenic molds of grapes is conditioned by its effect on the host and by the risks inherent in its handling[1].
As an alternative, the effect in vitro of UV-B radiation (280-315 nm) on the main pathogenic molds of grapes has been studied: Botrytis cinerea, Aspergillus niger, Penicillium expansum and Rhizopus stolonifer.

Sparkling wines and atypical aging: investigating the risk of refermentation

Sparkling wine (SW) production entails a two-steps process where grape must undergoes a primary fermentation to produce a base wine (BW) which is then refermented to become a SW. This process allows for the development of a new physicochemical profile characterized by the presence of foam and a different organoleptic profile.