title: Landscape genomics and a common garden trial reveal adaptive differentiation to temperature across Europe in the tree species Alnus glutinosa.
abstract: The adaptive potential of tree species to cope with climate change has important ecological and economic implications. Many temperate tree species experience a wide range of environmental conditions, suggesting high adaptability to new environmental conditions. We investigated adaptation to regional climate in the drought-sensitive tree species Alnus glutinosa (Black alder), using a complementary approach that integrates genomic, phenotypic and landscape data. A total of 24 European populations were studied in a common garden and through landscape genomic approaches. Genotyping-by-sequencing was used to identify SNPs across the genome, resulting in 1990 SNPs. Although a relatively low percentage of putative adaptive SNPs was detected (2.86% outlier SNPs), we observed clear associations among outlier allele frequencies, temperature and plant traits. In line with the typical drought avoiding nature of A. glutinosa, leaf size varied according to a temperature gradient and significant associations with multiple outlier loci were observed, corroborating the ecological relevance of the observed outlier SNPs. Moreover, the lack of isolation by distance, the very low genetic differentiation among populations and the high intrapopulation genetic variation all support the notion that high gene exchange combined with strong environmental selection promotes adaptation to environmental cues.
authors.affiliation: Plant Conservation and Population Biology, Department of Biology, University of Leuven, Kasteelpark Arenberg 31, Heverlee, B-3001, Belgium.
authors.forename: Hanne
authors.initials: H
authors.lastname: De Kort
authors.forename: Katrien
authors.initials: K
authors.lastname: Vandepitte
authors.forename: Hans Henrik
authors.initials: HH
authors.lastname: Bruun
authors.forename: Déborah
authors.initials: D
authors.lastname: Closset-Kopp
authors.forename: Olivier
authors.initials: O
authors.lastname: Honnay
authors.forename: Joachim
authors.initials: J
authors.lastname: Mergeay
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D029661:Alnus / Q000235:genetics*; D001499:Bayes Theorem; D057231:Climate Change; D018744:DNA, Plant / Q000235:genetics; D005060:Europe; D005787:Gene Frequency; D005828:Genetics, Population; D023281:Genomics / Q000379:methods; D005838:Genotype; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D018744:DNA, Plant
keywords: adaptation; climate change; contemporary evolution; natural selection; quantitative genetics