Polygenic adaptation of rosette growth in Arabidopsis thaliana
Wieters, Benedict (University of Cologne. Institute of Botany (Germany))
Steige, Kim A. (University of Cologne. Institute of Botany (Germany))
He, Fei (University of Cologne. Institute of Botany (Germany))
Koch, Evan M. (Harvard Medical School. Department of Biomedical Informatics (USA))
Ramos-Onsins, Sebastian (Centre de Recerca en Agrigenòmica)
Gu, Hongya (Peking University. State Key Laboratory for Protein and Plant Gene Research (China))
Guo, Ya-Long (Chinese Academy of Sciences. Institute of Botany. State Key Laboratory of Systematic and Evolutionary Botany (China))
Sunyaev, Shamil (Harvard Medical School. Department of Biomedical Informatics (USA))
de Meaux, Juliette (University of Cologne. Institute of Botany (Germany))

Data:	2021
Resum:	The rate at which plants grow is a major functional trait in plant ecology. However, little is known about its evolution in natural populations. Here, we investigate evolutionary and environmental factors shaping variation in the growth rate of Arabidopsis thaliana. We used plant diameter as a proxy to monitor plant growth over time in environments that mimicked latitudinal differences in the intensity of natural light radiation, across a set of 278 genotypes sampled within four broad regions, including an outgroup set of genotypes from China. A field experiment conducted under natural conditions confirmed the ecological relevance of the observed variation. All genotypes markedly expanded their rosette diameter when the light supply was decreased, demonstrating that environmental plasticity is a predominant source of variation to adapt plant size to prevailing light conditions. Yet, we detected significant levels of genetic variation both in growth rate and growth plasticity. Genome-wide association studies revealed that only 2 single nucleotide polymorphisms associate with genetic variation for growth above Bonferroni confidence levels. However, marginally associated variants were significantly enriched among genes with an annotated role in growth and stress reactions. Polygenic scores computed from marginally associated variants confirmed the polygenic basis of growth variation. For both light regimes, phenotypic divergence between the most distantly related population (China) and the various regions in Europe is smaller than the variation observed within Europe, indicating that the evolution of growth rate is likely to be constrained by stabilizing selection. We observed that Spanish genotypes, however, reach a significantly larger size than Northern European genotypes. Tests of adaptive divergence and analysis of the individual burden of deleterious mutations reveal that adaptive processes have played a more important role in shaping regional differences in rosette growth than maladaptive evolution. The rate at which plants grow is a major functional trait in plant ecology. However, little is known about its genetic variation in natural populations. Here, we investigate genetic and environmental factors shaping variation in the growth rate of Arabidopsis thaliana and ask whether genetic variation in plant growth contributes to adaptation to local environmental conditions. We grew plants under two light regimes that mimic latitudinal differences in the intensity of natural light radiation, and measured plant diameter as it grew over time. When the light supply was decreased, plant diameter grew more slowly but reached a markedly larger final size, confirming that plants can adjust their growth to prevailing light conditions. Yet, we also detected significant levels of genetic variation both in growth rate and in how the growth dynamics is adjusted to the light conditions. We show that this variation is encoded by many loci of small effect that are hard to locate in the genome but overall significantly enriched among genes associated with growth and stress reactions. We further observe that Spanish genotypes tended to reach, on average, a significantly larger rosette size than Northern European genotypes. Tests of adaptive divergence indicate that these differences may reflect adaptation to local environmental conditions.
Ajuts:	European Commission 648617 Ministerio de Economía y Competitividad AGL2016-78709-R Ministerio de Economía y Competitividad SEV-2015-0533
Nota:	Altres ajuts: CERCA Programme/Generalitat de Catalunya
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	PLoS Genetics, Vol. 17, Issue 1 (January 2021) , art. e1008748, ISSN 1553-7404

DOI: 10.1371/journal.pgen.1008748
PMID: 33493157

27 p, 1.9 MB

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