Natural genetic transformation by agrobacterium rhizogenes . Annual flowering in two biennials, belgian endive and carrot
Genetic transformation of Belgian endive (Cichorium intybus) and carrot (Daucus carota) by Agrobacterium rhizogenes resulted in a transformed phenotype, including annual flowering. Back-crossing of transformed (R1) endive plants produced a line that retained annual flowering in the absence of the other traits associated with A. rhizogenes transformation. Annualism was correlated with the segregation of a truncated transferred DNA (T-DNA) insertion. During vegetative growth, carbohydrate reserves accumulated normally in these annuals, and they were properly mobilized prior to anthesis. The effects of individual root-inducing left-hand T-DNA genes on flowering were tested in carrot, in which rolC (root locus) was the primary promoter of annualism and rolD caused extreme dwarfism. We discuss the possible adaptive significance of this attenuation of the phenotypic effects of root-inducing left-hand T-DNA.
Limami
MA
Institut National de la Recherche Agronomique, Federation Nationale de Producteurs d'Endive and Laboratoire du Metabolisme et de la Nutrition des Plantes, Institut National de la Recherche Agronomique, 78026, Versailles, cedex, France.
Sun
LY
Douat
C
Helgeson
J
Tepfer
D