Color Intensity of the Red-Fleshed Berry Phenotype ofVitis viniferaTeinturier Grapes Varies Due to a 408 bp Duplication in the Promoter ofVvmybA1

Grapevine (Vitis vinifera) teinturier cultivars are characterized by their typical reddish leaves and red-fleshed berries due to ectopic anthocyanin formation. Wines of these varieties have economic importance as they can be used for blending to enhance the color of red wines. The unique and heritable mutation has been known for a long time but the underlying genetic mechanism still is not yet understood. Here we describe the association of the red-fleshed berry phenotype with a 408 bp repetitive DNA element in the promoter of theVvmybA1gene (grapevine color enhancer, GCE). Three different clones of 'Teinturier' were discovered with two, three and five allelic GCE repeats (MybA1t2,MybA1t3andMybA1t5). All three clones are periclinal chimeras; these clones share the same L1 layer, but have distinct L2 layers with different quantities of GCE repeats. Quantitative real time PCR and HPLC analysis of leaf and berry samples showed that the GCE repeat number strongly correlates with an increase of the expression ofVvmybA1itself and theVvUFGTgene regulated by it and the anthocyanin content. A model is proposed based on autoregulation ofVvmybA1tto explain the red phenotype which is similar to that of red-fleshed apples. This study presents results about the generation and modes of action of threeMybA1talleles responsible for the red-fleshed berry phenotype of teinturier grapevines.