The harlequin ladybird, Harmonia axyridis (Pallas), is a well‐known model organism for genetic studies and is also a well‐studied natural enemy used for pest control. It became an invasive species after being introduced to North America and Europe as a pest control agent. Though two genome assemblies for this insect have been previously reported, a high‐quality genome assembly at the chromosome level is still not available. Here, we obtained a new chromosome‐level genome assembly of H. axyridis by combining various sequencing technologies, namely Illumina short reads, PacBio long reads, 10X Genomics and Hi‐C. The chromosome‐level genome assembly is 423 Mb with a scaffold N50 of 45.92 Mb. Using Hi‐C data 1,897 scaffolds were anchored to eight chromosomes. A total of 730,068 repeat sequences were identified, making up 51.2% of the assembled genome. After masking these repeat sequences, we annotated 22,810 protein‐encoding genes. The X chromosome and Y‐linked scaffolds were also identified by resequencing male and female genomes and calculating the male to female coverage ratios. Two gene families associated with environmental adaptation, odorant receptor and cytochrome P450, were analysed and showed no obvious expansion in H. axyridis. We successfully constructed a putative biosynthesis pathway of harmonine, a defence compound in the haemolymph of H. axyridis, which is a key factor for H. axyridis strong immunity. The chromosome‐level genome assembly of H. axyridis is a helpful resource for studies of beetle biology and invasive biology.

中文翻译：

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丑角瓢虫 Harmonia axyridis 的染色体水平组装作为研究甲虫和入侵生物学的基因组资源

丑角瓢虫Harmonia axyridis (Pallas) 是一种众所周知的遗传研究模式生物，也是一种经过充分研究的用于害虫防治的天敌。它作为害虫控制剂被引入北美和欧洲后成为入侵物种。尽管之前已经报道了这种昆虫的两个基因组组装，但仍然没有在染色体水平上进行高质量的基因组组装。在这里，我们获得了H的新染色体水平基因组组装。 木犀草通过结合各种测序技术，即 Illumina 短读长、PacBio 长读长、10X Genomics 和 Hi-C。染色体水平的基因组组装为 423 Mb，支架 N50 为 45.92 Mb。使用 Hi-C 数据将 1,897 个支架锚定在 8 条染色体上。共鉴定出 730,068 个重复序列，占组装基因组的 51.2%。在掩盖这些重复序列后，我们注释了 22,810 个蛋白质编码基因。还通过对男性和女性基因组进行重新测序并计算男性与女性的覆盖率来鉴定 X 染色体和 Y 连锁支架。分析了与环境适应相关的两个基因家族，气味受体和细胞色素 P450，在H 中没有明显的扩增。 木犀草. 我们成功地构建了一个假定的生物合成途径 Harmonine，这是H血淋巴中的一种防御化合物。 axyridis，这是H的关键因素。 axyridis免疫力强。H的染色体水平基因组组装。 axyridis是研究甲虫生物学和侵入性生物学的有用资源。