Magnolia biondii Pamp. (Magnoliaceae, magnoliids) is a phylogenetically, economically, and medicinally important ornamental tree species widely grown and cultivated in the north-temperate regions of China. Determining the genome sequence of M. biondii would help resolve the phylogenetic uncertainty of magnoliids and improve the understanding of individual trait evolution within the Magnolia genus. We assembled a chromosome-level reference genome of M. biondii using ~67, ~175, and ~154 Gb of raw DNA sequences generated via Pacific Biosciences single-molecule real-time sequencing, 10X Genomics Chromium, and Hi-C scaffolding strategies, respectively. The final genome assembly was ~2.22 Gb, with a contig N50 value of 269.11 kb and a BUSCO complete gene percentage of 91.90%. Approximately 89.17% of the genome was organized into 19 chromosomes, resulting in a scaffold N50 of 92.86 Mb. The genome contained 47,547 protein-coding genes, accounting for 23.47% of the genome length, whereas 66.48% of the genome length consisted of repetitive elements. We confirmed a WGD event that occurred very close to the time of the split between the Magnoliales and Laurales. Functional enrichment of the Magnolia-specific and expanded gene families highlighted genes involved in the biosynthesis of secondary metabolites, plant–pathogen interactions, and responses to stimuli, which may improve the ecological fitness and biological adaptability of the lineage. Phylogenomic analyses revealed a sister relationship of magnoliids and Chloranthaceae, which are sister to a clade comprising monocots and eudicots. The genome sequence of M. biondii could lead to trait improvement, germplasm conservation, and evolutionary studies on the rapid radiation of early angiosperms.

中文翻译：

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Magnolia biondii Pamp 的基因组。深入了解木兰目的进化和萜类化合物的生物合成

玉兰潘普。（木兰科，木兰科）是我国北温带地区广泛种植和栽培的一种系统发育、经济和药用重要的观赏树种。确定基因组序列米.比昂迪将有助于解决木兰的系统发育不确定性，并提高对个体性状进化的理解。木兰属。我们组装了一个染色体水平的参考基因组M. biondii分别使用通过 Pacific Biosciences 单分子实时测序、10X Genomics Chromium 和 Hi-C 支架策略生成的约 67、约 175 和约 154 Gb 的原始 DNA 序列。最终的基因组组装约为 2.22 Gb，contig N50 值为 269.11 kb，BUSCO 完整基因百分比为 91.90%。大约 89.17% 的基因组被组织成 19 条染色体，导致支架 N50 为 92.86 Mb。基因组包含47,547个蛋白质编码基因，占基因组长度的23.47%，而66.48%的基因组长度由重复元素组成。我们确认了 WGD 事件发生在非常接近 Magnoliales 和 Laurales 分裂的时间。功能丰富木兰特定和扩展的基因家族突出了参与次生代谢物生物合成、植物-病原体相互作用和对刺激反应的基因，这可能会提高谱系的生态适应性和生物适应性。系统基因组分析揭示了木兰科植物和绿藻科的姐妹关系，它们是由单子叶植物和真双子叶植物组成的进化枝的姐妹关系。基因组序列M. biondii可能导致性状改进、种质保存和早期被子植物快速辐射的进化研究。