Hazelnut is popular for its flavor, and it has also been suggested that hazelnut is beneficial to cardiovascular health because it is rich in oleic acid. Here, we report the first high-quality chromosome-scale genome for the hazelnut species Corylus mandshurica (2n = 22), which has a high concentration of oleic acid in its nuts. The assembled genome is 367.67 Mb in length, and the contig N50 is 14.85 Mb. All contigs were assembled into 11 chromosomes, and 28,409 protein-coding genes were annotated. We reconstructed the evolutionary trajectories of the genomes of Betulaceae species and revealed that the 11 chromosomes of the hazelnut genus were derived from the most ancestral karyotype in Betula pendula, which has 14 protochromosomes, by inferring homology among five Betulaceae genomes. We identified 96 candidate genes involved in oleic acid biosynthesis, and 10 showed rapid evolution or positive selection. These findings will help us to understand the mechanisms of lipid synthesis and storage in hazelnuts. Several gene families related to salicylic acid metabolism and stress responses experienced rapid expansion in this hazelnut species, which may have increased its stress tolerance. The reference genome presented here constitutes a valuable resource for molecular breeding and genetic improvement of the important agronomic properties of hazelnut.

中文翻译：

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毛榛基因组为桦木科基因组进化和榛子育种提供了见解

榛子因其味道而广受欢迎，也有人认为榛子有益于心血管健康，因为它富含油酸。在这里，我们报告了榛子物种的第一个高质量染色体规模基因组毛榛(2n= 22），其坚果中含有高浓度的油酸。组装后的基因组长度为 367.67 Mb，重叠群 N50 为 14.85 Mb。所有重叠群被组装成 11 条染色体，并注释了 28,409 个蛋白质编码基因。我们重建了桦木科物种基因组的进化轨迹，揭示了榛子属的11条染色体来源于最古老的核型。悬垂桦，通过推断五个桦木科基因组之间的同源性，它具有 14 条原染色体。我们鉴定了 96 个参与油酸生物合成的候选基因，其中 10 个表现出快速进化或正选择。这些发现将帮助我们了解榛子中脂质合成和储存的机制。与水杨酸代谢和应激反应相关的几个基因家族在该榛子物种中经历了快速扩增，这可能提高了其应激耐受性。这里提供的参考基因组为榛子重要农艺特性的分子育种和遗传改良提供了宝贵的资源。