title: Evidence of divergent selection for drought and cold tolerance at landscape and local scales in Abies alba Mill. in the French Mediterranean Alps.
abstract: Understanding local adaptation in forest trees is currently a key research and societal priority. Geographically and ecologically marginal populations provide ideal case studies, because environmental stress along with reduced gene flow can facilitate the establishment of locally adapted populations. We sampled European silver fir (Abies alba Mill.) trees in the French Mediterranean Alps, along the margin of its distribution range, from pairs of high- and low-elevation plots on four different mountains situated along a 170-km east-west transect. The analysis of 267 SNP loci from 175 candidate genes suggested a neutral pattern of east-west isolation by distance among mountain sites. F(ST) outlier tests revealed 16 SNPs that showed patterns of divergent selection. Plot climate was characterized using both in situ measurements and gridded data that revealed marked differences between and within mountains with different trends depending on the season. Association between allelic frequencies and bioclimatic variables revealed eight genes that contained candidate SNPs, of which two were also detected using F(ST) outlier methods. All SNPs were associated with winter drought, and one of them showed strong evidence of selection with respect to elevation. Q(ST)-F(ST) tests for fitness-related traits measured in a common garden suggested adaptive divergence for the date of bud flush and for growth rate. Overall, our results suggest a complex adaptive picture for A. alba in the southern French Alps where, during the east-to-west Holocene recolonization, locally advantageous genetic variants established at both the landscape and local scales.
authors.affiliation: Conservation Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Straße, Marburg, 35032, Germany.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Roschanski
authors.affiliation: INRA, UR629, Ecologie des Forêts Méditerranéennes (URFM), Avignon Cedex 9, 84914, France.
authors.forename: Katalin
authors.initials: K
authors.lastname: Csilléry
authors.affiliation: Conservation Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Straße, Marburg, 35032, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Liepelt
authors.affiliation: INRA, UR629, Ecologie des Forêts Méditerranéennes (URFM), Avignon Cedex 9, 84914, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Oddou-Muratorio
authors.affiliation: Conservation Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Straße, Marburg, 35032, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Ziegenhagen
authors.affiliation: INRA, AGROCLIM, Avignon Cedex 9, 84914, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Huard
authors.affiliation: Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Straße, Marburg, 35032, Germany.
authors.forename: Kristian K
authors.initials: KK
authors.lastname: Ullrich
authors.affiliation: Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy.|Institute of Biosciences and Bioresources, National Research Council (CNR), Via Madonna del Piano 10, Sesto Fiorentino (Firenze), 50019, Italy.|National Institute of Forest Research and Development (INCDS), Simeria Research Station, Str. Biscaria 1, Simeria, 335900, Romania.
authors.forename: Dragos
authors.initials: D
authors.lastname: Postolache
authors.affiliation: Institute of Biosciences and Bioresources, National Research Council (CNR), Via Madonna del Piano 10, Sesto Fiorentino (Firenze), 50019, Italy.
authors.forename: Giovanni G
authors.initials: GG
authors.lastname: Vendramin
authors.affiliation: INRA, UR629, Ecologie des Forêts Méditerranéennes (URFM), Avignon Cedex 9, 84914, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fady
mesh_terms: D028202:Abies / Q000235:genetics* / Q000502:physiology; D000222:Adaptation, Physiological / Q000235:genetics; D001499:Bayes Theorem; D002980:Climate; D003080:Cold Temperature; D018744:DNA, Plant / Q000235:genetics; D055864:Droughts; D005602:France; D005787:Gene Frequency; D005828:Genetics, Population; D008969:Molecular Sequence Data; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D014197:Trees / Q000235:genetics
chemical_list: D018744:DNA, Plant
keywords: European silver fir; candidate gene; isolation by environment; landscape genomics; microclimate; selection