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A genetic framework for floral patterning.

Abstract

The initial steps of flower development involve two classes of consecutively acting regulatory genes. Meristem-identity genes, which act early to control the initiation of flowers, are expressed throughout the incipient floral primordium. Homeotic genes, which act later to specify the identity of individual floral organs, are expressed in distinct domains within the flower. The link between the two classes of genes has remained unknown so far. Here we show that the meristem-identity gene LEAFY has a role in controlling homeotic genes that is separable from its role in specifying floral fate. On the basis of our observation that LEAFY activates different homeotic genes through distinct mechanisms, we propose a genetic framework for the control of floral patterning.

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BibTeXRIS

F Parcy, O Nilsson, M A Busch, I Lee, D Weigel. 1998-10-08. A genetic framework for floral patterning.. https://doi.org/10.1038/26903

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A molecular link between stem cell regulation and floral patterning in Arabidopsis.

The homeotic gene AGAMOUS (AG) has dual roles in specifying organ fate and limiting stem cell proliferation in Arabidopsis flowers. We show that the floral identity protein LEAFY (LFY), a transcription factor expressed throughout the flower, cooperates with the homeodomain protein WUSCHEL (WUS) to activate AG in the center of flowers. WUS was previously identified because of its role in maintaining stem cell populations in both shoot and floral meristems. The unsuspected additional role of WUS in regulating floral homeotic gene expression supports the hypothesis that floral patterning uses a general meristem patterning system that was present before flowers evolved. We also show that AG represses WUS at later stages of floral development, thus creating a negative feedback loop that is required for the determinate growth of floral meristems.

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