Understanding the process of Prunus species floral development is crucial for developing strategies to manipulate bloom time and prevent crop loss due to climate change. Here, we present a detailed examination of flower development from initiation until bloom for early- and late-blooming sour cherries (Prunus cerasus) from a population segregating for a major bloom time QTL on chromosome 4. Using a new staging system, we show floral buds from early-blooming trees were persistently more advanced than those from late-blooming siblings. A gDNA coverage analysis revealed the late-blooming haplotype of this QTL, k, is located on a subgenome originating from the late-blooming P. fruticosa progenitor. Transcriptome analyses identified many genes within this QTL as differentially expressed between early- and late-blooming trees during the vegetative-to-floral transition. From these, we identified candidate genes for the late bloom phenotype, including multiple transcription factors homologous to REproductive Meristem (REM) B3 domain-containing proteins. Additionally, we determined the basis of k in sour cherry is likely separate from candidate genes found in sweet cherry – suggesting several major regulators of bloom time are located on Prunus chromosome 4.

中文翻译：

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酸樱桃休眠前的遗传因素影响来年春天的开花时间

了解李属植物花卉发育的过程对于制定控制开花时间和防止气候变化造成的作物损失的策略至关重要。在这里，我们对早花和晚花酸樱桃 (Prunus cerasus) 的花发育从起始到开花进行了详细检查，这些樱桃来自在 4 号染色体上分离主要开花时间 QTL 的群体。使用新的分期系统，我们展示了花的发育过程。早开花树的芽始终比晚开花树的芽提前。 gDNA 覆盖度分析揭示了该 QTL k 的晚花单倍型位于源自晚花 P. fruticosa 祖先的亚基因组上。转录组分析发现，该 QTL 内的许多基因在营养到花的转变过程中，早花树和晚花树之间的表达存在差异。由此，我们确定了晚花表型的候选基因，包括与含有生殖分生组织 (REM) B3 结构域的蛋白质同源的多个转录因子。此外，我们确定酸樱桃中 k 的基础可能与甜樱桃中发现的候选基因不同，这表明开花时间的几个主要调节因子位于李属 4 号染色体上。