Genetic control of flower morphogenesis in Arabidopsis thaliana:: a logical analysis

Motivation: A large number of molecular mechanisms at the basis of gene regulation have been described during the last few decades, it is now becoming possible to address questions dealing with both the structure and the dynamics of genetic regulator?: networks, at least in the case of some of the best-characterized organisms. Most recent attempts to address these questions deal with microbial or animal model systems. In contrast, we analyze here a gene network involved in the control of the morphogenesis of flowers in a model plant, Arabidopsis thaliana, Results: The genetic control of flower morphogenesis ill Arabidopsis involves a large number of genes, of which 10 are considered here. The network topology has been derived from published genetic and molecular data, mainly relying on mRNA expression patterns under wild-type and mutant backgrounds, Using a 'generalized logical formalism', bile provide a qualitative model ann derive the parameter constraints accounting for the different patterns of gene expression found in the four floral organs of Arabidopsis (sepals, petals, stamens and carpels), pins a 'non-floral' state. This model also allows the simulation or the prediction of various mutant phenotypes. On the basis of our model analysis; we predict rite existence of a sixth stable pattern of gene expression, yet to be characterized experimentally Moreover; pur dynamical analysis leads to the prediction of at least orae more regulator of the gene LFY, likely to be involved in the transition from the non-flowering state to the flowering pathways. Finally, this work, together with other theoretical and experimental considerations, leads us to propose some general conclusions about the structure of gene networks controlling development. Contact: lams@servidor.unam.mx; denis@dbm.ulb.ac.be; abuylla@servidor:unam.mx