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Abstract

The grapevine meristem contains at least two distinct cell layers, L1 and L2, which can bear different genotypes and give rise to chimeric tissues and organs. Grape skin epidermal and internal tissues derive from L1 and L2 cell layers, respectively. Grapevine Tempranillo variants known as Tempranillo Gris produce berries with a gray color due to the presence of deletions leading to the absence of functional VviMybA genes in the L2 meristem cell layer (Royo et al., 2019). VviMYBA transcription factor genes are responsible for the regulation of anthocyanin biosynthesis and pigmentation of the berry skin. We addressed direct somatic embryogenesis methods in Tempranillo Gris to obtain embryos of unicellular origin. In this way, embryos from L1 layer would give rise to plants generating black berries (functional VviMybA locus), while embryos from L2 layer would develop into plants producing white berries (null VviMybA locus). Somatic embryogenesis induction from stamen filaments of Tempranillo Gris was tested using an induction medium containing different combinations of thidiazuron (TDZ) and 2,4-dichlorophenoxyacetic acid (2,4-D) growth regulators.