A highly-contiguous genome assembly of the Eurasian spruce bark beetle, Ips typographus, provides insight into a major forest pest

Daniel Powell,Ewald Groβe-Wilde,Amrita Chakraborty,Heiko Vogel,Christer Löfstedt,Martin N Andersson,Paal Krokene,Fredrik Schlyter,Amit Roy

doi:10.1038/s42003-021-02602-3

Abstract

Conifer-feeding bark beetles are important herbivores and decomposers in forest ecosystems. These species complete their life cycle in nutritionally poor substrates and some can kill enormous numbers of trees during population outbreaks. The Eurasian spruce bark beetle (Ips typographus) can destroy >100 million m3 of spruce in a single year. We report a 236.8 Mb I. typographus genome assembly using PacBio long-read sequencing. The final phased assembly has a contig N50 of 6.65 Mb in 272 contigs and is predicted to contain 23,923 protein-coding genes. We reveal expanded gene families associated with plant cell wall degradation, including pectinases, aspartyl proteases, and glycosyl hydrolases. This genome sequence from the genus Ips provides timely resources to address questions about the evolutionary biology of the true weevils (Curculionidae), one of the most species-rich animal families. In forests of today, increasingly stressed by global warming, this draft genome may assist in developing pest control strategies to mitigate outbreaks.

Highlights

Conifer-feeding bark beetles are important herbivores and decomposers in forest ecosystems
Conifer-feeding bark beetles (Coleoptera; Curculionidae; Scolytinae) are keystone species in forest ecosystems, contributing to wood decomposition and nutrient recycling through direct feeding and the action of beetle-associated microbiota[1]
Beetle mass-attacks on trees are coordinated by an aggregation pheromone, which is produced by males as they initiate boring in suitable host trees and attracts large numbers of both sexes[10]

Summary

Introduction

Conifer-feeding bark beetles are important herbivores and decomposers in forest ecosystems. These species complete their life cycle in nutritionally poor substrates and some can kill enormous numbers of trees during population outbreaks. We reveal expanded gene families associated with plant cell wall degradation, including pectinases, aspartyl proteases, and glycosyl hydrolases This genome sequence from the genus Ips provides timely resources to address questions about the evolutionary biology of the true weevils (Curculionidae), one of the most species-rich animal families. The Eurasian spruce bark beetle (Ips typographus [L.]) is the most serious pest of Norway spruce (Picea abies [L.] Karst) and other spruce species in the beetle’s range, currently causing unprecedented forest destruction across the Palearctic region (Fig. 1). Beetles (Coleoptera) constitute the largest order of the Metazoa, only 11 Coleoptera genomes have been published, of which only two belong to members of the 6,000 species strong

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