College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
Forest Breeding Institute, Zhejiang Academy of Forestry, Hangzhou, 310023, China.
Commun Biol. 2022 Aug 4;5(1):786. doi: 10.1038/s42003-022-03751-9.
The Chinese tallow tree (Triadica sebifera) can produce oil with high content of unsaturated fatty acids in seeds and shows attractive leaf color in autumn and winter. Here, the 739 Mb chromosome-scale genome sequence of the Chinese tallow tree was assembled and it reveals the Chinese tallow tree is a tetraploid. Numerous genes related to nutrition assimilation, energy utilization, biosynthesis of secondary metabolites and resistance significantly expanded or are specific to the Chinese tallow tree. These genes would enable the Chinese tallow tree to obtain high adaptability. More genes in fatty acids biosynthesis in its genome, especially for unsaturated fatty acids biosynthesis, and higher expression of these genes in seeds would be attributed to its high content of unsaturated fatty acids. Cyanidin 3-O-glucoside was identified as the major component of anthocyanin in red leaves. All structural genes in anthocyanin biosynthesis show significantly higher expression in red leaves than in green leaves. Transcription factors, seven MYB and one bHLH, were predicted to regulate these anthocyanin biosynthesis genes. Collectively, we provided insight into the polyploidization, high adaptability and biosynthesis of the high content of unsaturated fatty acids in seeds and anthocyanin in leaves for the Chinese tallow tree.
乌桕（Triadica sebifera）的种子含有丰富的不饱和脂肪酸，叶子在秋冬季节呈现出吸引人的颜色。在这里，我们组装了乌桕的 739Mb 染色体规模基因组序列，结果表明乌桕是一个四倍体。许多与营养吸收、能量利用、次生代谢物生物合成和抗性相关的基因显著扩张或特属于乌桕。这些基因使乌桕具有高度的适应性。其基因组中脂肪酸生物合成的基因较多，特别是不饱和脂肪酸生物合成的基因较多，种子中这些基因的表达水平较高，这导致了乌桕中不饱和脂肪酸含量较高。在红叶中鉴定出矢车菊素 3-O-葡萄糖苷是花色素苷的主要成分。花色素苷生物合成的所有结构基因在红叶中的表达水平明显高于绿叶。预测有七个 MYB 和一个 bHLH 转录因子来调节这些花色素苷生物合成基因。总的来说，我们深入了解了乌桕的多倍体化、高度适应性以及种子中不饱和脂肪酸和叶子中花色素苷的高含量的生物合成。
