Wild Carrot Differentiation in Europe and Selection at DcAOX1 Gene?

PLoS One. 2016 Oct 21;11(10):e0164872. doi: 10.1371/journal.pone.0164872. eCollection 2016.

Abstract

By definition, the domestication process leads to an overall reduction of crop genetic diversity. This lead to the current search of genomic regions in wild crop relatives (CWR), an important task for modern carrot breeding. Nowadays massive sequencing possibilities can allow for discovery of novel genetic resources in wild populations, but this quest could be aided by the use of a surrogate gene (to first identify and prioritize novel wild populations for increased sequencing effort). Alternative oxidase (AOX) gene family seems to be linked to all kinds of abiotic and biotic stress reactions in various organisms and thus have the potential to be used in the identification of CWR hotspots of environment-adapted diversity. High variability of DcAOX1 was found in populations of wild carrot sampled across a West-European environmental gradient. Even though no direct relation was found with the analyzed climatic conditions or with physical distance, population differentiation exists and results mainly from the polymorphisms associated with DcAOX1 exon 1 and intron 1. The relatively high number of amino acid changes and the identification of several unusually variable positions (through a likelihood ratio test), suggests that DcAOX1 gene might be under positive selection. However, if positive selection is considered, it only acts on some specific populations (i.e. is in the form of adaptive differences in different population locations) given the observed high genetic diversity. We were able to identify two populations with higher levels of differentiation which are promising as hot spots of specific functional diversity.

MeSH terms

  • Aldehyde Oxidase / metabolism*
  • Cell Differentiation*
  • Daucus carota / cytology*
  • Daucus carota / genetics
  • Europe
  • Phylogeny

Substances

  • Aldehyde Oxidase

Grants and funding

TN was supported by a Marie Curie Career Integration grant (FP7-PEOPLE-2012-CIG ref. 321725) and a Foundation for Science and Technology (FCT, Portugal) fellowship (SFRH/BCC/52187/2013). MO thanks FCT for the support given under the program UID/MAT/04674/2013 (CIMA). This work is funded by National Funds through FCT under the Project UID/AGR/00115/2013. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.