Chromosome-scale Genome Assembly of An Important Coniferous Defoliator from Pine Forests, Dendrolimus houi. Dendrolimus houi isolate:FUJIAN-N1

The Yunnan pine caterpillar, Dendrolimus houi Lajonquiere (Lepidoptera: Lasiocampidae), is a common caterpillar species infesting Gymnosperm trees in Southeast Asia. It exhibits high resistance to abiotic and biotic stress due to its host preference, tolerance to extreme temperatures, and geographic isolation. However, little is known about the genomic characterization of this species' unique ecological characteristics. Here, we present a high-quality reference genome for D.houi at the chromosome level. The final assembly was 663.13 Mb (contig N50 = 23.43 Mb), with 99.33% of contigs anchored onto 30 chromosomes. This genome contains 14,687 functionally annotated protein-coding genes out of a total of 93.39% genes identified. Additionally, it includes repetitive sequences (432.16 Mb), pseudogenes (1392), motifs (664), tRNAs (422), rRNAs (163), and miRNAs (39). Phylogenetic analysis showed that D.houi and D. punctatus had a mutual ancestor during the Neogene, and Lasiocampidae appeared around 96.14 million years ago. Compared with their mutual-ancestor, D.houi has expanded in 86 gene families and shows significant enrichment in the Longevity regulating pathway, with core genes including FoxO, Sod2, RPS6, and mTOR. This may explain why D.houi eggs can tolerate low temperatures and pupae can withstand high temperature stress. Expanding the P450 gene family of D.houi may potentially enhance its detoxification efficacy of secondary substances from host plants. This high-quality, chromosome-level reference genome will be a valuable resource for understanding the adaptation mechanism of D.houi under acute abiotic stress.