Giovannini - The “genes for flowering” and their involvement in ornamental applied research

Annalisa Giovannini
CRA Istituto Sperimentale per la Floricoltura, corso Inglesi 508, 18038 Sanremo (IM)

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Key words: Arabidopsis thaliana, agricultural biotechnology, flowering-time genes, meristem-identity genes, organ-identity genes.

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Abstract

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Classical breeding together with the most advanced techniques in molecular biology have been applying to a wide variety of species, contributing to the elucidation of molecular mechanisms in plant development. The recent discoveries of the mechanisms of flowering in the model plants Antirrhinum majus, Arabidopsis thaliana and Petunia hybrida allowed new sets of genes to be available. These include genes which affect flowering time and flower architecture, commonly named: flowering-time genes, meristem-identity genes and organ-identity genes. Studies in Arabidopsis have led to the identification of components within individual signaling pathways that affect flowering and to their positioning within molecular hierarchies. Currently four genetic pathways have been identified: the light-dependent, the autonomous, the vernalization and the gibberellin pathway, all integrated by the function of regulatory genes at the integration pathway. Furthermore, distinct signaling pathways are known to converge on the activation of the same integrator genes. This convergence of pathways on a common set of genes may enable the integration of different responses, so that the plant can produce a coordinated flowering response under conditions in which multiple environmental and endogenous parameters are changing simultaneously. The possibility of using molecular techniques to transfer genes in major ornamentals has greatly increased the resources available to plant breeders. Flower induction genes could affect flowering in species unrelated to the plant from which they were isolated. Moreover, native genes can be overexpressed or suppressed. In the near future plant biotechnologists and plant breeders will continue to work alongside to improve floricultural plants.

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