What does Arabidopsis natural variation teach us (and does not teach us) about adaptation in plants?

Sessile organisms such as plants have to develop adaptive responses to face environmental change. In Arabidopsis thaliana populations, natural variation for stress responses have been observed at different levels of integration and the genetic bases of those variations have been analysed using two strategies: classical linkage and association (LD) mapping. The strength of Arabidopsis resides in the huge amount of genomic data and molecular tools available leading to the identification of many polymorphisms responsible for phenotypic variation. Remaining limitations to clearly understand how Arabidopsis adapts to its environment, that is the complexity of the genetic architecture and the lack of ecological data, should be partially solved thanks to the development of new methods and the acquisition of new data.

► Quantitative genetics is exploiting the complementary techniques of linkage mapping and association mapping.
► High-throughput accurate phenotyping is required to study the complex genetic architecture of physiological responses to abiotic factors.
► A weak allele of a sodium transporter – responsible for enhanced salt tolerance – is shown to be more frequent in populations from saline areas.
► More ecological considerations are needed to be able to draw conclusions on adaptation.