Hybrid crop varieties have been repeatedly demonstrated to produce significantly higher yields than their parental lines; however, the low efficiency and high cost of hybrid seed production has limited the broad exploitation of heterosis for cotton production. One option for increasing the yield of hybrid seed is to improve pollination efficiency by insect pollinators. Here, we report the molecular cloning and characterization of a semidominant gene, Beauty Mark (BM), which controls purple spot formation at the base of flower petals in the cultivated tetraploid cotton species Gossypium barbadense. BM encodes an R2R3 MYB113 transcription factor, and we demonstrate that GbBM directly targets the promoter of four flavonoid biosynthesis genes to positively regulate petal spot development. Introgression of a GbBM allele into G. hirsutum by marker-assisted selection restored petal spot formation, which significantly increased the frequency of honeybee visits in G. hirsutum. Moreover, field tests confirmed that cotton seed yield was significantly improved in a three-line hybrid production system that incorporated the GbBM allele. Our study thus provides a basis for the potentially broad application of this gene in improving the long-standing problem of low seed production in elite cotton hybrid lines.

中文翻译：

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陆地棉美丽标记介导的花卉访问量和杂交种子产量增加

杂交作物品种已被反复证明其产量明显高于其亲本品系；然而，杂交种子生产的低效率和高成本限制了在棉花生产中广泛利用杂种优势。提高杂交种子产量的一种选择是提高昆虫传粉者的授粉效率。在这里，我们报告了半显性基因Beauty Mark ( BM )的分子克隆和表征，该基因控制栽培的四倍体棉花品种Gossypium barbadense花瓣基部的紫色斑点形成。BM编码一个 R2R3 MYB113 转录因子，我们证明 GbBM 直接靶向四个类黄酮生物合成基因的启动子以正向调节花瓣斑的发育。通过标记辅助选择将GbBM等位基因渗入陆地棉中恢复了花瓣斑点的形成，这显着增加了蜜蜂在陆地棉中的访问频率。此外，田间试验证实，在包含GbBM等位基因的三系杂交生产系统中，棉籽产量显着提高。因此，我们的研究为该基因在改善优良棉花杂交系中种子产量低的长期问题中的潜在广泛应用提供了基础。