Understanding the regulation of VvDXS gene expression
Some of the most relevant wine odor constituents are monoterpenoids which have been demonstrated to be produced via the plastid-located methyl-erythritol- phosphate (MEP) pathway in grapevine. The MEP pathway biosynthetic gene 1- deoxy-D-xylulose 5-phosphate synthase (VvDXS), maps to a major QTL responsible for monoterpenoid accumulation in 'Muscat' grape varieties. Recent results suggest that gain-of-function mutations that affect the enzymatic or regulatory properties of the VvDXS protein appear to be the major determinants of terpenoid accumulation. The 5'upstream region of VvDXS alleles cloned and sequenced to characterize the promoter and several cis-elements putatively involved in the regulation of the gene were identified. This information was then used to screen a transcription factor library using a transient expression dual-luciferase assay in tobacco. It is also known that genomic DNA can be compacted into chromatin to form limit accessibility of transcription factor binding to DNA target elements. Antibodies that recognize specific histone amino acid methylation patterns that are associated with heterochromatin or euchromatin allow us to determine epigenetic profiles. Preliminary results suggest chromatin modification differs within the coding region or promoters of VvDXS gene depending on grapevine variety and on the stage of berry development. Furthermore, two clones of 'Chardonnay' that exhibit dramatic differences in monoterpenoid accumulation and berry flavor have been characterized. They represent an ideal comparison to identify rare alleles of genes controlling biosynthesis of aromatic compounds.
Battilana, J., Emanuelli, F., Lorenzi, S., Lin-Wang, K., Allan, A.C., Grando, M.S. and Boss, P.K. (2017). Understanding the regulation of VvDXS gene expression. Acta Hortic. 1157, 283-288
ChIP analysis, promoter, region characterization, monoterpenoids, grapevine