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Abstract：
The ladybird beetle Propylea japonica is an important natural enemy in agro-ecological systems. Studies on the strong tolerance of P. japonica to high temperatures and insecticides, and its population and phenotype diversity have recently increased. However, abundant genome resources for obtaining insights into stress-resistance mechanisms and genetic intra-species diversity for P. japonica are lacking. Here, we constructed the P. japonica genome maps using Pacific Bioscience (PacBio) and Illumina sequencing technologies. The genome size was 850.90 Mb with a contig N50 of 813.13 kb. The Hi-C sequence data were used to upgrade draft genome assemblies; 4,777 contigs were assembled to 10 chromosomes; and the final draft genome assembly was 803.93 Mb with a contig N50 of 813.98 kb and a scaffold N50 of 100.34 Mb. Approximately 495.38 Mb of repeated sequences was annotated. The 18,018 protein-coding genes were predicted, of which 95.78% were functionally annotated, and 1,407 genes were species-specific. The phylogenetic analysis showed that P. japonica diverged from the ancestor of Anoplophora glabripennis and Tribolium castaneum ~ 236.21 million years ago. We detected that some important gene families involved in detoxification of pesticides and tolerance to heat stress were expanded in P. japonica, especially cytochrome P450 and Hsp70 genes. Overall, the high-quality draft genome sequence of P. japonica will provide invaluable resource for understanding the molecular mechanisms of stress resistance and will facilitate the research on population genetics, evolution and phylogeny of Coccinellidae. This genome will also provide new avenues for conserving the diversity of predator insects.
摘要：
瓢虫甲虫Propyleajaponica是农业生态系统中的重要天敌。日本紫花苜蓿对高温和杀虫剂的强耐受性研究，其种群和表型多样性最近有所增加。然而,缺乏丰富的基因组资源，无法深入了解粳稻的抗逆机制和遗传种内多样性。这里,我们使用太平洋生物科学（PacBio）和Illumina测序技术构建了P.japonica基因组图谱。基因组大小为850.90Mb，重叠群N50为813.13kb。Hi-C序列数据用于升级草图基因组组装；将4,777个重叠群组装到10个染色体上；最终的基因组组装草图为803.93Mb，重叠群N50为813.98kb，支架N50为100.34Mb。注释了大约495.38Mb的重复序列。预测了18018个蛋白质编码基因，其中95.78%是功能注释的，和1,407个基因是物种特异性的。系统发育分析表明，粳稻与2.3621万年前的无孔雀和栗树的祖先不同。我们检测到一些参与农药解毒和对热胁迫耐受性的重要基因家族在粳稻中得到扩展，特别是细胞色素P450和Hsp70基因。总的来说,优质基因组序列草案将为理解抗逆的分子机制提供宝贵的资源，并将促进群体遗传学研究，球藻科的进化和系统发育。该基因组还将为保护捕食者昆虫的多样性提供新的途径。
