Tung tree (Vernicia fordii) is an economically important woody oil plant that produces tung oil rich in eleostearic acid. Here, we report a high-quality chromosome-scale genome sequence of tung tree. The genome sequence was assembled by combining Illumina short reads, Pacific Biosciences single-molecule real-time long reads, and Hi-C sequencing data. The size of tung tree genome is 1.12 Gb, with 28,422 predicted genes and over 73% repeat sequences. The V. fordii underwent an ancient genome triplication event shared by core eudicots but no further whole-genome duplication in the subsequent ca. 34.55 million years of evolutionary history of the tung tree lineage. Insertion time analysis revealed that repeat-driven genome expansion might have arisen as a result of long-standing long terminal repeat retrotransposon bursts and lack of efficient DNA deletion mechanisms. The genome harbors 88 resistance genes encoding nucleotide-binding sites; 17 of these genes may be involved in early-infection stage of Fusarium wilt resistance. Further, 651 oil-related genes were identified, 88 of which are predicted to be directly involved in tung oil biosynthesis. Relatively few phosphoenolpyruvate carboxykinase genes, and synergistic effects between transcription factors and oil biosynthesis-related genes might contribute to the high oil content of tung seed. The tung tree genome constitutes a valuable resource for understanding genome evolution, as well as for molecular breeding and genetic improvements for oil production.

中文翻译：

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桐树（Vernicia fordii）基因组提供了了解基因组进化和提高石油产量的资源。

桐树（Vernicia fordii）是一种经济上重要的木本植物，可生产富含硬脂酸的桐油。在这里，我们报告高质量的桐树染色体规模的基因组序列。通过组合Illumina短读，Pacific Biosciences单分子实时长读和Hi-C测序数据来组装基因组序列。桐树基因组的大小为1.12 Gb，具有28,422个预测基因和超过73％的重复序列。佛氏弧菌经历了一个古老的基因组三倍复制事件，由核心真双子叶植物共享，但在随后的ca.中没有进一步的全基因组复制。桐树谱系的进化史为3455万年。插入时间分析表明，重复驱动的基因组扩展可能是由于长期存在的长末端重复逆转录转座子爆发和缺乏有效的DNA缺失机制而引起的。基因组包含88个编码核苷酸结合位点的抗性基因。这些基因中的17个可能参与了枯萎病抗性的早期感染阶段。此外，鉴定出651个与油有关的基因，其中88个被预测直接与桐油的生物合成有关。磷酸烯醇丙酮酸羧激酶基因相对较少，转录因子与油脂生物合成相关基因之间的协同作用可能有助于桐籽的高油脂含量。桐树基因组是了解基因组进化的宝贵资源，