Data from: Genome assembly and annotation of the medicinal plant Calotropis gigantea, a producer of anticancer and antimalarial cardenolides

Calotropis gigantea produces specialized secondary metabolites known as cardenolides which have anti-cancer and anti-malarial properties. Although transcriptomic studies have been conducted in other cardenolide-producing species, no nuclear genome assembly for an Asterid cardenolide-producing species has been reported to date. A high quality de novo assembly was generated for C. gigantea, representing 157,284,427 bp with an N50 scaffold size of 805,959 bp, for which quality assessments indicated a near complete representation of the genic space. Transcriptome data in the form of RNA-sequencing libraries from a developmental tissue series was generated to aid in annotation and construction of a gene expression atlas. Using an ab initio and evidence-driven gene annotation pipeline, 18,197 high confidence genes were annotated. Homologous and syntenic relationships between C. gigantea and other species within the Apocynaceae family confirmed previously identified evolutionary relationships and suggest the emergence or loss of the specialized cardenolide metabolites after the divergence of the Apocynaceae subfamilies. The C. gigantea genome assembly, annotation, and RNA-sequencing data provide a novel resource to study the cardenolide biosynthesis pathway especially for understanding the evolutionary origin of cardenolides and engineering of cardenolide production in heterologous organisms for existing and novel pharmaceutical applications.牛角瓜（Calotropis gigantea）可产生一类被称为强心甾类化合物（cardenolides）的特化次生代谢产物，该类物质兼具抗癌与抗疟活性。尽管学界已在其他产强心甾类化合物的物种中开展了转录组学研究，但截至目前，尚无关于菊亚纲（Asterid）产强心甾类化合物物种的核基因组组装的相关报道。本研究针对牛角瓜完成了高质量的从头组装（de novo assembly），组装基因组总长度为157,284,427 bp，支架N50（Scaffold N50）长度达805,959 bp；质量评估结果显示，该组装几乎完整覆盖了基因组的基因空间。为辅助基因组注释并构建基因表达图谱，研究团队还生成了以RNA测序（RNA-sequencing）文库形式存在的、覆盖不同发育阶段组织系列的转录组数据。通过采用从头预测结合证据支持的基因注释流程，本研究共注释得到18,197个高置信度基因。对牛角瓜与夹竹桃科（Apocynaceae）其他物种间的同源性及共线性关系进行分析，验证了此前已确定的演化关系，同时提示特化的强心甾类代谢产物的出现或丢失事件发生在夹竹桃科各亚科分化之后。本研究获得的牛角瓜基因组组装结果、基因注释信息以及RNA测序数据，为强心甾类化合物的生物合成通路研究提供了全新的研究资源，尤其有助于解析强心甾类化合物的演化起源，以及在异源生物中工程化改造强心甾类化合物的生产能力，以支撑现有及新型药物的研发与应用。