230T Poster - Population Genetics
Thursday June 09, 8:30 PM - 9:15 PM

A two-step adaptive walk rewires nutrient transport in a challenging edaphic environment


Authors:
Emmanuel Tergemina 1; Ahmed F. Elfarargi 1; Paulina Flis 2; Andrea Fulgione 1; Mehmet Göktay 1; Célia Neto 1; Marleen Scholle 3; Pádraic Flood 1; Sophie-Asako Xerri 1; Johan Zicola 1; Nina Döring 1; Herculano Dinis 4,5; Ute Krämer 3; David Salt 2; Angela M. Hancock 1

Affiliations:
1) Max Planck Institute for Plant Breeding Research, Cologne, DE; 2) Future Food Beacon of Excellence and the School of Biosciences, University of Nottingham, Sutton Bonington Campus, Nr Loughborough, LE12 5RD, United Kingdom; 3) Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801 Bochum, Germany; 4) Parque Natural do Fogo, Direção Nacional do Ambiente, 115 Chã d’Areia, Praia, Santiago, Cabo Verde; 5) Associação Projecto Vitó, 8234, Xaguate, Cidade de São Filipe, Fogo, Cabo Verde

Keywords:
Natural selection

Most well-characterized cases of adaptation involve single genetic loci. Theory suggests multi-locus adaptive walks should be common, but these are challenging to identify in natural populations. Here, we combine trait mapping with population genetic modeling to show that a two-step process rewired nutrient homeostasis in a population of Arabidopsis as it colonized the base of an active stratovolcano characterized by extremely low soil manganese (Mn). First, a variant that disrupted the primary iron (Fe) uptake transporter (IRT1) swept quickly to fixation in a hard selective sweep, increasing Mn but limiting Fe in the leaves. Second, multiple independent tandem duplications occurred at NRAMP1 and rose to near-fixation in a soft selective sweep, compensating IRT1 loss by improving iron homeostasis. This study provides a well-resolved case of a two-locus adaptive walk and reveals how adaptive genetic variants reshaped a phenotype and spread over space and time.