High-resolution lac insect genome assembly provides genetic insights into lac synthesis and evolution of scale insects

Lac insect is an important resource insect with great commercial value. However, the lack of its genome information restricts the fundamental biological research and applied studies of this species. Here, we first assembled the contig of Kerria lacca using Illumina and Nanopore sequencing by Hi-C and T2T techniques to obtain the genome of K. lacca at the chromosome 0 gap level. The genome of K. lacca was 256.62 Mb and the Scaffold N50 was 28.53 Mb. A total of 56.94 Mb of repeat sequences, constituting 22.19% of the assembled genome, were identified. We annotated 10,696 protein-encoding geneswith 89.74% annotated. By horizontal gene transfer analysis, we obtained a putative gene Isoprenyl diphosphate synthase (IPPS), a key enzyme in the isoprene synthesis pathway in the regulation of lac biosynthesis that transferred horizontally from bacteria to the genome of K. lacca. Meanwhile, we constructed the lac synthesis biosynthetic pathway and screened 25 putative key genes in the synthesis pathway by transcriptome analysis in different developmental stages and tissues. It provides new research ideas to reveal the molecular mechanism of lac biosynthesis and regulation. The high-quality chromosomal-level genome of lac insect will provide a basis for the study of development, genetics, and the evolution of scale insects.