title: Potential preadaptation to anthropogenic pollution: evidence from a common quantitative trait locus for zinc and cadmium tolerance in metallicolous and nonmetallicolous accessions of Arabidopsis halleri.
abstract: As a drastic environmental change, metal pollution may promote the rapid evolution of genetic adaptations contributing to metal tolerance. In Arabidopsis halleri, genetic bases of zinc (Zn) and cadmium (Cd) tolerance have been uncovered only in a metallicolous accession, although tolerance is species-wide. The genetic determinants of Zn and Cd tolerance in a nonmetallicolous accession were thus investigated for the first time. The genetic architecture of tolerance was investigated in a nonmetallicolous population (SK2) by using first backcross progeny obtained from crosses between SK2 and Arabidopsis lyrata petraea, a nonmetallophyte species. Only one significant and common quantitative trait locus (QTL) region was identified explaining 22.6% and 31.2% of the phenotypic variation for Zn and Cd tolerance, respectively. This QTL co-localized with HEAVY METAL ATPASE 4 (AhHMA4), which was previously validated as a determinant of Zn and Cd tolerance in a metallicolous accession. Triplication and high expression of HMA4 were confirmed in SK2. In contrast, gene duplication and high expression of METAL TOLERANT PROTEIN 1A (MTP1A), which was previously associated with Zn tolerance in a metallicolous accession, were not observed in SK2. Overall, the results support the role of HMA4 in tolerance capacities of A. halleri that may have pre-existed in nonmetallicolous populations before colonization of metal-polluted habitats. Preadaptation to metal-contaminated sites is thus discussed.
authors: Laboratoire Physiologie et Génétique Moléculaire des Plantes, Université Libre de Bruxelles, Boulevard du Triomphe, Campus Plaine, B-1050, Brussels, Belgium.
authors: Claire-Lise
authors: CL
authors: Meyer
authors: Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F-59655, Villeneuve d'Ascq, France.
authors: Maxime
authors: M
authors: Pauwels
authors: Laboratoire Physiologie et Génétique Moléculaire des Plantes, Université Libre de Bruxelles, Boulevard du Triomphe, Campus Plaine, B-1050, Brussels, Belgium.
authors: Loic
authors: L
authors: Briset
authors: Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F-59655, Villeneuve d'Ascq, France.
authors: Cécile
authors: C
authors: Godé
authors: Laboratoire Physiologie et Génétique Moléculaire des Plantes, Université Libre de Bruxelles, Boulevard du Triomphe, Campus Plaine, B-1050, Brussels, Belgium.
authors: Piétro
authors: P
authors: Salis
authors: Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F-59655, Villeneuve d'Ascq, France.
authors: Angélique
authors: A
authors: Bourceaux
authors: Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F-59655, Villeneuve d'Ascq, France.
authors: Dima
authors: D
authors: Souleman
authors: Université de Lille - Sciences et Technologies, CNRS, UMR 8198 Evo-Eco-Paleo, F-59655, Villeneuve d'Ascq, France.
authors: Hélène
authors: H
authors: Frérot
authors: Laboratoire Physiologie et Génétique Moléculaire des Plantes, Université Libre de Bruxelles, Boulevard du Triomphe, Campus Plaine, B-1050, Brussels, Belgium.
authors: Nathalie
authors: N
authors: Verbruggen
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D060146:Ecotype; D004787:Environmental Pollution; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D006802:Human Activities; D006801:Humans; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015032:Zinc / Q000633:toxicity*
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D002104:Cadmium; D015032:Zinc
keywords: constitutive tolerance; genetic architecture; metal pollution; preadaptation; pseudometallophytes; rapid evolution