Unravelling wild carrot differentiation in Europe – preliminary data on a candidate gene approach

Carrot is an outcrossing species and levels of gene flow between populations, and even between wild and domesticated relatives, are expected to be high. Cases of natural hybridization and introgression of crops and wild relatives have been reported. Have these events diluted any putative habitat-adapted genotypes? In other words, can we still find a correlation between wild carrot genotypes and regional/local environment? We have chosen to start addressing this question using a member of the alternative oxidase (AOX) gene family. AOX genes seem to be linked to all kinds of abiotic and biotic stress reactions. Wild carrots were sampled in an environmental gradient across Western Europe. This gradient included sampling points with more deviating conditions, such as Sierra de Guadarrama or the central Pyrenees and the French Massif Central. Phylogenetic reconstruction on this molecular marker is to be combined with geographic, climatic, and ecological evidence. So far, the preliminary results suggest the existence of a biogeographical barrier at the Pyrenees, and higher gene diversity than initially expected. From an applied point of view, diversity of functional traits is much more relevant than species diversity. Gene transfer from wild to cultivated plants has contributed to the evolution of crop species. Providing that deterioration of genetic resources and biodiversity loss have not been drastic, gene transfer from wild plants has the potential to further contribute to a (targeted) improvement of cultivars.