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Proc Natl Acad Sci U S A. 2018 Mar 27;115(13):3416-3421. doi: 10.1073/pnas.1709141115. Epub 2018 Mar 14.

Adaptive diversification of growth allometry in the plant Arabidopsis thaliana.

Author information

1
Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany; franc.vasseur@gmail.com weigel@weigelworld.org.
2
Centre d'Ecologie Fonctionnelle et Evolutive (CEFE), CNRS, Université Paul Valéry Montpellier 3, Ecole Pratique des Hautes Etudes (EPHE), Institut de Recherche pour le Développement (IRD), 34090 Montpellier, France.
3
Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, UMR759, 34060 Montpellier, France.
4
Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.
5
Programa de Recursos Genéticos y Productividad (RGP)-Fisiología Vegetal, Colegio de Postgraduados, 56230 Texcoco, Mexico.
6
Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721.
7
The Santa Fe Institute, Santa Fe, NM 87501.

Abstract

Seed plants vary tremendously in size and morphology; however, variation and covariation in plant traits may be governed, at least in part, by universal biophysical laws and biological constants. Metabolic scaling theory (MST) posits that whole-organismal metabolism and growth rate are under stabilizing selection that minimizes the scaling of hydrodynamic resistance and maximizes the scaling of resource uptake. This constrains variation in physiological traits and in the rate of biomass accumulation, so that they can be expressed as mathematical functions of plant size with near-constant allometric scaling exponents across species. However, the observed variation in scaling exponents calls into question the evolutionary drivers and the universality of allometric equations. We have measured growth scaling and fitness traits of 451 Arabidopsis thaliana accessions with sequenced genomes. Variation among accessions around the scaling exponent predicted by MST was correlated with relative growth rate, seed production, and stress resistance. Genomic analyses indicate that growth allometry is affected by many genes associated with local climate and abiotic stress response. The gene with the strongest effect, PUB4, has molecular signatures of balancing selection, suggesting that intraspecific variation in growth scaling is maintained by opposing selection on the trade-off between seed production and abiotic stress resistance. Our findings suggest that variation in allometry contributes to local adaptation to contrasting environments. Our results help reconcile past debates on the origin of allometric scaling in biology and begin to link adaptive variation in allometric scaling to specific genes.

KEYWORDS:

GWAS; fitness trade-off; local adaptation; metabolic scaling theory

PMID:
29540570
PMCID:
PMC5879651
DOI:
10.1073/pnas.1709141115
[Indexed for MEDLINE]
Free PMC Article

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