Comparative analyses of the banded alder borer (Rosalia funebris) and Asian longhorned beetle (Anoplophora glabripennis) genomes reveal significant differences in genome architecture and gene content among these and other Cerambycidae.

Abstract

Rosalia funebris (RFUNE; Cerambycidae), the banded alder borer, is a longhorn beetle whose larvae feed on the wood of various economically and ecologically significant trees in western North America. Adults are short-lived and not known to consume plant material substantially. We sequenced, assembled, and annotated the RFUNE genome using HiFi and RNASeq data. We documented genome architecture and gene content, focusing on genes putatively involved in plant feeding (phytophagy). Comparisons were made to the well-studied genome of the Asian longhorned beetle (AGLAB; Anoplophora glabripennis) and other Cerambycidae. The 814 Mb RFUNE genome assembly was distributed across 42 contigs, with an N50 of 30.18 Mb. Repetitive sequences comprised 60.27% of the genome, and 99.0% of expected single-copy orthologous genes were fully assembled. We identified 12,657 genes, fewer than in the four other species studied, and 46.4% fewer than for Aromia moschata (same subfamily as RFUNE). Of the 7,258 orthogroups shared between RFUNE and AGLAB, 1,461 had more copies in AGLAB and 1,023 had more copies in RFUNE. We identified 240 genes in RFUNE that putatively arose via horizontal transfer events. The RFUNE genome encoded substantially fewer putative plant cell wall degrading enzymes than AGLAB, which may relate to the longer-lived plant-feeding adults of the latter species. The RFUNE genome provides new insights into cerambycid genome architecture and gene content and provides a new vantage point from which to study the evolution and genomic basis of phytophagy in beetles.