GWAS on the Attack by Aspen Borer Saperda calcarata on Black Cottonwood Trees Reveals a Response Mechanism Involving Secondary Metabolism and Independence of Tree Architecture

Black cottonwood (Populus trichocarpa) is a species of economic interest and an outstanding study model. The aspen borer (Saperda calcarata) causes irreversible damage to poplars other riparian in North America. insect can produce multiple effects ranging from the presence some galleries stem tree death. Despite ecological commercial importance this tree–insect interaction, genetic mechanisms underlying response P. trichocarpa S. calcarata are scarcely understood. In study, common garden trial provenances, established Davis, California, was assessed at second year growth, regarding infestation natural outbreak. A genome-wide association (GWAS) conducted using 629k exonic SNPs assess relationship between genomic variation attack. Tree architecture, terms number per plant, wood metabolome were also included. Insect attack independent stems tree. performed GWAS identified three significantly associated SNP markers (q-value < 0.2) belonging same gene models, encoding proteins involved signal transduction secondary metabolite production, including that R-mandelonitrile lyase, Chromodomain-helicase-DNA-binding family protein, Leucine-rich repeat protein. These results aligned with current knowledge defensive pathways plants trees, helping expand understanding black against insects.