Hermaphroditic (perfect) flowers were a key trait in grapevine domestication, enabling a drastic increase in yields due to the efficiency of self-pollination in the domesticated grapevine (Vitis vinifera L. ssp. vinifera). In contrast, all extant wild Vitis species are dioecious, each plant having only male or female flowers. In this study, we identified the male (M) and female (f) haplotypes of the sex-determining region (SDR) in the wild grapevine species V. cinerea and confirmed the boundaries of the SDR. We also demonstrated that the SDR and its boundaries are precisely conserved across the Vitis genus using shotgun resequencing data of 556 wild and domesticated accessions from North America, East Asia, and Europe. A high linkage disequilibrium was found at the SDR in all wild grape species, while different recombination signatures were observed along the hermaphrodite (H) haplotype of 363 cultivated accessions, revealing two distinct H haplotypes, named H1 and H2. To further examine the H2 haplotype, we sequenced the genome of two grapevine cultivars, 'Riesling' and 'Chardonnay'. By reconstructing the first two H2 haplotypes, we estimated the divergence time between H1 and H2 haplotypes at ∼6 million years ago, which predates the domestication of grapevine (∼8,000 y ago). Our findings emphasize the important role of recombination suppression in maintaining dioecy in wild grape species and lend additional support to the hypothesis that at least two independent recombination events led to the reversion to hermaphroditism in grapevine.

雌雄同体（完美）花是葡萄树驯化的一个关键性状，由于驯化葡萄树 ( Vitis vinifera L. ssp. vinifera )的自花授粉效率，使产量大幅增加。相比之下，所有现存的野生葡萄种都是雌雄异株的，每株植物都只有雄花或雌花。在这项研究中，我们确定了野生葡萄品种V. cinerea 中性别决定区 (SDR) 的雄性 (M) 和雌性 (f) 单倍型，并确认了 SDR 的边界。我们还证明了 SDR 及其边界在Vitis中精确保守使用来自北美、东亚和欧洲的 556 个野生和驯化种质的鸟枪重测序数据对属进行了分析。在所有野生葡萄物种的 SDR 处都发现了高度连锁不平衡，而沿着 363 个栽培种质的雌雄同体 (H) 单倍型观察到了不同的重组特征，揭示了两种不同的 H 单倍型，命名为 H1 和 H2。为了进一步检查 H2 单倍型，我们对两个葡萄品种“雷司令”和“霞多丽”的基因组进行了测序。通过重建前两个 H2 单倍型，我们估计 H1 和 H2 单倍型之间的分歧时间在大约 600 万年前，早于葡萄树的驯化（大约 8,000 年前）。