From a model to a crop species: constans is involved in aerial morphogenesis of lucerne
Résumé
The development of genomics tools and knowledge in model species can be used for genetic analyses in crop species. QTL detection in the model legume Medicago truncatula was carried out for flowering date and stem height, two traits related to aerial morphogenesis. A strong QTL was detected, and after a fine mapping step and bioanalysis of BAC sequences, six candidate genes were listed. One of these genes, Constans, was proved to be differentially expressed among two parental lines differing for flowering date. Constans was sequenced in a population of lucerne (Medicago sativa) genotypes that were phenotyped for flowering date and stem height. The low rate of polymorphism of Constans in lucerne shows that this gene is not neutral. Sequence polymorphism was associated to phenotypic variation. Constans is thus involved in flowering date and stem height genetic determinism.