A 69 kbp Deletion at the Berry Color Locus Is Responsible for Berry Color Recovery in Vitis vinifera L. Cultivar ‘Riesling Rot’

Abstract

‘Riesling Weiss’ is a white grapevine variety famous worldwide for fruity wines with higher acidity. Hardly known is ‘Riesling Rot’, a red-berried variant of ‘Riesling Weiss’ that disappeared from commercial cultivation but has increased in awareness in the last decades. The question arises of which variant, white or red, is the original and, consequently, which cultivar is the true ancestor. Sequencing the berry color locus of ‘Riesling Rot’ revealed a new VvmybA gene variant in one of the two haplophases called VvmybA3/1RR. The allele displays homologous recombination of VvmybA3 and VvmybA1 with a deletion of about 69 kbp between both genes that restores VvmybA1 transcripts. Furthermore, analysis of ‘Riesling Weiss’, ‘Riesling Rot’, and the ancestor ‘Heunisch Weiss’ along chromosome 2 using SSR (simple sequence repeat) markers elucidated that the haplophase of ‘Riesling Weiss’ was inherited from the white-berried parent variety ‘Heunisch Weiss’. Since no color mutants of ‘Heunisch Weiss’ are described that could have served as allele donors, we concluded that, in contrast to the public opinion, ‘Riesling Rot’ resulted from a mutational event in ‘Riesling Weiss’ and not vice versa.

Breeding new seedless table grapevines for a more sustainable viticulture in Mediterranean climate

“…Such variability is not surprising in table grape, a crop in which crosses between different varieties are widespread resulting in extensive gene recombination. In grapevine, differences in berry color are generally due to somatic mutations associated with the VvMybA gene family, which is highly polymorphic and determines the variation in anthocyanin content in berries (Lijavetzky et al, 2006;Fournier-Level et al, 2009;Carbonell-Bejerano et al, 2017;Ferreira et al, 2020;Röckel et al, 2022). Here, too, it is likely that minor loci also play a role, which would explain the controversial results especially for the varieties BLACK MAGIC, MOSCATO, and RED GLOBE.…”

Characterization of Simple Sequence Repeat (SSR) Markers Mined in Whole Grape Genomes

“…Riesling was once thought to be a wild vine native to the Rhine area, although there is little evidence to back up this statement. According to DNA fingerprinting, one of Riesling’s parents is ‘Gouais blanc’ [ 60 ]. Similar to ‘Gouais blanc’, ‘Kyoho’ and ‘Muscat Hamburg’ are related to many important varieties.…”