The spruce budworm genome: Reconstructing the evolutionary history of antifreeze proteins

Sunday, November 13, 2022

4:06 PM – 4:18 PM PT

Location: Vancouver Convention Centre, Meeting Room 215/216

Presenting Author(s)

Michel Cusson (he/him/his)

Research Scientist
Natural Resources Canada
Québec City, Québec, Canada

Co-Author(s)

CB

Catherine Béliveau

Natural Resources Canada
Québec, Québec, Canada
PG

Patrick Gagné

Natural Resources Canada
Québec, Québec, Canada
SP

Sandrine Picq

Natural Resources Canada
Québec, Québec, Canada
Christopher I. Keeling

Research Scientist in Forest Genomics/Professeur associé
Natural Resources Canada
Québec, Québec, Canada
OV

Oksana Vernygora

University of Kentucky
Lexington, Kentucky
DD

Daniel Doucet

Natural Resources Canada
Sault Ste.Marie, Ontario, Canada
JJ

J. Spencer Johnston

Texas A&M University
College Station, Texas
HM

Halim Maaroufi

Université Laval
Québec, Québec, Canada
Felix Sperling

Professor
University of Alberta
Edmonton, Alberta, Canada

Insects have developed various adaptations to survive winter conditions. Among freeze-intolerant species, some produce “antifreeze proteins” (AFPs) that bind to nascent ice crystals and inhibit ice growth. Such is the case of the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae), a destructive North American conifer pest that can withstand temperatures below -30°C. Despite the potential importance of AFPs in the adaptive diversification of Choristoneura, genomic tools to explore their origins have until now been limited. Here we present a chromosome-scale genome assembly for C. fumiferana, which we used to conduct comparative genomic analyses aimed at reconstructing the evolutionary history of tortricid AFPs. The budworm genome features 16 genes homologous to previously reported CfAFPs, 15 of which map to a single region on chromosome 18. Fourteen of these were also detected in five congeneric species, indicating Choristoneura AFP diversification occurred before the speciation event that led to C. fumiferana. Although budworm AFPs were previously considered unique to the genus Choristoneura, a search for homologs targeting recently sequenced tortricid genomes identified seven CfAFP-like genes in the distantly related Notocelia uddmanniana. High structural similarity between Notocelia and Choristoneura AFPs suggests a common origin, despite the absence of homologs in three related tortricids. Interestingly, one Notocelia AFP formed the C-terminus of a “zonadhesin-like” protein, possibly representing the ancestral condition from which tortricid AFPs evolved. Future work should clarify the evolutionary path of AFPs between Notocelia and Choristoneura and assess the role of the “zonadhesin-like” protein as precursor of tortricid AFPs.