Dragon fruits are tropical fruits economically important for agricultural industries. As members of the family ofCactaceae, they have evolved to adapt to the arid environment. Here we report the draft genome ofHylocereus undatus, commercially known as the white-fleshed dragon fruit. The chromosomal level genome assembly contains 11 longest scaffolds corresponding to the 11 chromosomes ofH. undatus. Genome annotation ofH. undatusfound ~29,000 protein-coding genes, similar toCarnegiea gigantea(saguaro). Whole-genome duplication (WGD) analysis revealed a WGD event in the last common ancestor ofCactaceaefollowed by extensive genome rearrangements. The divergence time betweenH. undatusandC. giganteawas estimated to be 9.18 MYA. Functional enrichment analysis of orthologous gene clusters (OGCs) in sixCactaceaeplants found significantly enriched OGCs in drought resistance. Fruit flavor-related functions were overrepresented in OGCs that are significantly expanded inH. undatus. TheH. undatusdraft genome also enabled the discovery of carbohydrate and plant cell wall-related functional enrichment in dragon fruits treated with trypsin for a longer storage time. Lastly, genes of the betacyanin (a red-violet pigment and antioxidant with a very high concentration in dragon fruits) biosynthetic pathway were found to be co-localized on a 12 Mb region of one chromosome. The consequence may be a higher efficiency of betacyanin biosynthesis, which will need experimental validation in the future. TheH. undatusdraft genome will be a great resource to study various cactus plants.

中文翻译：

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火龙果的染色体水平基因组揭示了甜菜青素生物合成基因的全基因组复制和染色体共定位


火龙果是对农业具有重要经济意义的热带水果。作为家庭成员仙人掌科，它们已经进化到适应干旱的环境。在这里，我们报告了基因组草案火龙果，商业上称为白肉火龙果。染色体水平的基因组组装包含11个最长的支架，对应于11条染色体乌达斯。基因组注释乌达斯发现了约 29,000 个蛋白质编码基因，类似于巨卡内基（仙人掌）。全基因组重复（WGD）分析揭示了最后一个共同祖先的WGD事件仙人掌科随后进行广泛的基因组重排。之间的分歧时间乌达斯和巨茶估计为 9.18 MYA。六个直系同源基因簇（OGC）的功能富集分析仙人掌科植物发现显着富集的OGCs具有抗旱能力。与水果风味相关的功能在 OGC 中被过度体现，这些功能在乌达斯。这乌达斯基因组草案还发现，经过胰蛋白酶处理并延长储存时间的火龙果中碳水化合物和植物细胞壁相关的功能富集。最后，β花青素（一种红紫色色素和抗氧化剂，在火龙果中含量非常高）生物合成途径的基因被发现共定位于一条染色体的 12 Mb 区域。其结果可能是甜菜花青素生物合成效率更高，这需要未来的实验验证。这H. 乌达图斯基因组草案将成为研究各种仙人掌植物的重要资源。