Background A key step in domestication of the grapevine was the transition from separate sexes (dioecy) in wild Vitis vinifera ssp. sylvestris (V. sylvestris) to hermaphroditism in cultivated Vitis vinifera ssp. sativa (V. vinifera). It is known that V. sylvestris has an XY system and V. vinifera a modified Y haplotype (Yh) and that the sex locus is small, but it has not previously been precisely characterized. Results We generate a high-quality de novo reference genome for V. sylvestris, onto which we map whole-genome re-sequencing data of a cross to locate the sex locus. Assembly of the full X, Y, and Yh haplotypes of V. sylvestris and V. vinifera sex locus and examining their gene content and expression profiles during flower development in wild and cultivated accessions show that truncation and deletion of tapetum and pollen development genes on the X haplotype likely causes male sterility, while the upregulation of a Y allele of a cytokinin regulator (APRT3) may cause female sterility. The downregulation of this cytokinin regulator in the Yh haplotype may be sufficient to trigger reversal to hermaphroditism. Molecular dating of X and Y haplotypes is consistent with the sex locus being as old as the Vitis genus, but the mechanism by which recombination was suppressed remains undetermined. Conclusions We describe the genomic and evolutionary characterization of the sex locus of cultivated and wild grapevine, providing a coherent model of sex determination in the latter and for transition from dioecy to hermaphroditism during domestication.

中文翻译：

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野生葡萄基因组序列提供了对葡萄驯化过程中从雌雄同体到雌雄同体的转变的见解

背景 葡萄树驯化的一个关键步骤是从野生 Vitis vinifera ssp 中的不同性别（雌雄异株）过渡。sylvestris (V. sylvestris) 对栽培 Vitis vinifera ssp 中的雌雄同体。苜蓿（V. vinifera）。众所周知，V. sylvestris 具有 XY 系统，而 V. vinifera 具有修饰的 Y 单倍型 (Yh)，并且性别基因座很小，但之前尚未对其进行精确表征。结果我们生成了一个高质量的从头参考基因组 sylvestris，我们在上面绘制了一个杂交的全基因组重测序数据以定位性别基因座。V. sylvestris 和 V. 的完整 X、Y 和 Yh 单倍型的组装。vinifera 性位点并检查其在野生和栽培种质花发育过程中的基因含量和表达谱表明，X 单倍型上绒毡层和花粉发育基因的截断和缺失可能导致雄性不育，而细胞分裂素调节因子的 Y 等位基因的上调(APRT3) 可能导致女性不育。Yh 单倍型中这种细胞分裂素调节剂的下调可能足以触发雌雄同体的逆转。X 和 Y 单倍型的分子年代与与葡萄属一样古老的性别基因座一致，但抑制重组的机制仍未确定。结论 我们描述了栽培和野生葡萄藤性别基因座的基因组和进化特征，