Homeosis and delayed floral meristem termination could account for abnormal flowers in cultivars of Delphinium  (Ranunculaceae) and Aquilegia (Ranunculaceae) cultivars

Espinosa, Felipe; Damerval, Catherine; Le Guilloux, Martine; Deroin, Thierry; Wang​, Wei; Pinedo-Castro, Myreya; Nadot, Sophie; Jabbour, Florian,

Homeosis and delayed floral meristem termination could account for abnormal flowers in cultivars of Delphinium (Ranunculaceae) and Aquilegia (Ranunculaceae) cultivars

2020

Floral mutants display various deviant phenotypes and, as such, they are appropriate material with which to addressthe origin and the building of morphological variation. To identify the pivotal developmental stages at which floralvariation may originate and to infer the putative associated genetic causes, we studied abnormal flowers in ninecultivars of Aquilegia and Delphinium of Ranunculaceae, a family displaying a high range of floral diversity. Wildtype flowers of the two genera are pentamerous and spurred, but they differ in their overall symmetry (actinomorphyvs. zygomorphy). Floral morphology of their cultivars at different developmental stages up to anthesis was observed,and the putative identity of the perianth organs and vascularization was inferred. Our results show that in thefloral mutants in both genera, phyllotaxis was generally conserved, whereas floral organization, vascularization andsymmetry were modified. Most of the morphological and anatomical deviations impacted the perianth, includingorgan number, identity and (spur) elaboration, and also led to the formation of mosaic organs. We hypothesized thatthe phenotypes of floral mutants in Aquilegia and Delphinium result from genetic alterations affecting frontiersbetween sets of organs of different identity, homeosis and length of floral meristem activity.

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