Associations between the 1-deoxy- d -xylulose-5-phosphate synthase gene and aroma in different grapevine varieties

Linalool, α-terpineol, citronellol, nerol, geraniol, and geraniol acid are the main monoterpenes in the grapevine (Vitis vinifera L.) with the concentrations of these substances differing in different varieties. This research performed association analyses using a core collection of 92 grape accessions to identify causal SNPs in the gene 1-deoxy-d-xylulose-5-phosphate synthase (VvDXS), a regulator of monoterpene metabolism. We evaluated the free linalool, α-terpineol, citronellol, nerol, geraniol, and geraniol acid content of 92 grape varieties in two consecutive years (2014 and 2015). Twenty-two SNPs were found in the VvDXS coding region and were used in an association analysis. We found that the linalool, α-terpineol, nerol, and geraniol acid levels were higher in varieties with a G/T genotype at P852 than in varieties with other genotypes at this site. Additionally, we found a novel polymorphism site P1678 (A/G) with a functional effect on terpenoid content that was related to the regulation of gene transcription. This study revealed the relationship between VvDXS and aroma, with the identified polymorphism site potentially assisting in the screening of aroma compounds at early stages in fruit development in grapevines.