Expansion of LINEs and species-specific DNA repeats drives genome expansion in Asian gypsy moths

Authors: HEBERT, FRANCOIS - Laval University; FRESCHI, LUCA - Laval University; BLACKBURN, GWYLIM - Laval University; BELIVEAU, CATHERINE - Canadian Forest Service; DEWAR, KEN - Genome Quebec; BOYLE, BRIAN - Laval University; Gundersen-Rindal, Dawn; Sparks, Michael; CUSSON, MICHEL - Canadian Forest Service; HAMELIN, RICHARD - University Of British Columbia; LEVESQUE, ROGER - Laval University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2019
Publication Date: 11/11/2019
Publication URL: https://handle.nal.usda.gov/10113/6829266
Citation: Hebert, F.O., Freschi, L., Blackburn, G., Beliveau, C., Dewar, K., Boyle, B., Gundersen, D.E., Sparks, M., Cusson, M., Hamelin, R.C., Levesque, R.C. 2019. Expansion of LINEs and species-specific DNA repeats drives genome expansion in Asian gypsy moths. Scientific Reports. 9:16413.

Interpretive Summary: The term "Asian gypsy moth" (AGM) refers to two lepidopteran subspecies, Lymantria dispar asiatica and L. dispar japonica, and is distinctive from the "European gypsy moth" (EGM), consisting only of L. dispar dispar. In particular, AGM females have flight capabilities not present in EGMs, the latter of which became established in North America roughly 130 years ago and have since caused considerable economic damages. As such, AGM has even greater capacity to rapidly expand its host range and is one of the most significant forest invasive alien threats in North America today. Despite decades of research on the ecology and biology of this pest, limited AGM-specific genomic resources are currently available. Here, we report on the genome sequences and functional genic content of each AGM subspecies. At 921 and 999 megabases, the genomes of L. dispar asiatica and L. dispar japonica are the largest lepidopteran genomes sequenced to date, and this appears to be due to accumulation of specific types of repetitive elements. Genome-wide metabolic pathway reconstructions suggest strong genomic signatures of energy-related pathways in both subspecies, dominated by metabolic functions related to thermogenesis. The genome sequences reported here will provide tools for probing the molecular mechanisms underlying phenotypic traits believed to confer enhanced invasiveness to AGM as compared to some of its close relatives. This will help develop better strategies to prevent accidental introductions and/or mitigate realized outbreaks.

Technical Abstract: The Asian gypsy moth (AGM), comprising the lepidopteran subspecies, Lymantria dispar asiatica and L. dispar japonica, is one of the most significant forest invasive alien threat in North America. Despite decades of research on the ecology and biology of this pest, limited AGM-specific genomic resources are currently available. Here, we report on the genome sequences and functional content of each AGM subspecies. At 921 and 999 megabases, the genomes of L. dispar asiatica and L. dispar japonica are the largest lepidopteran genomes sequenced to date. High genome size is here driven by the accumulation of specific classes of repeats. Genome-wide metabolic pathway reconstructions suggest strong genomic signatures of energy-related pathways in both subspecies, dominated by metabolic functions related to thermogenesis. The genome sequences reported here will provide tools for probing the molecular mechanisms underlying phenotypic traits believed to confer enhanced invasiveness to AGM as compared to some of its close relatives. This will help develop better strategies to prevent accidental introductions and/or abate potential outbreaks.