Fig. 7. Summary of floral phenotypes and model of the role of UFO during flower development. (A) Effect on the flower morphology of the timing of UFO induction (blue shading in bars represents the window of UFO expression) in the ufo-2 35S::UFO_ind line. In the floral diagrams, green represents sepals, white petals, yellow stamens, red carpels, blue filaments and black ovules. Bi-color represent chimeric organs. (1) In the absence of UFO induction or expression later than late stage 6, flowers with a mutant phenotype are produced. (2) Ubiquitous induction of UFO during the floral stage 4/5 or early 6 leads to stamen identity restoration and partial restoration of petal identity. An extra whorl of stamens, carpel fusion defects and abnormal ovules are observed in some flowers. (3) Ubiquitous UFO expression from the floral stage 3 onwards leads to full restoration of petal and stamen identities. The organ primordia and the floral patterning are however misaligned. An extra whorl of stamens, carpel fusion defects and abnormal ovules are observed in some flowers. (4) Ubiquitous UFO expression starting at floral stage 2 leads to complete restoration of petal and stamen development. Pistils show occasional increased carpel number or fusion defect. (5) Transient ubiquitous UFO expression from early floral stage 2 onwards or earlier leads to normal stamen development but absence of petal growth. Pistils are normal. Petaloid sepals develop occasionally. (B) Diagram of the early stages of flower development with the domain of UFO expression shown in blue. The timing of the different role of UFO is represented below. Proper patterning of the primordia in the three inner whorls requires UFO expression during the floral stage 2. The B function activity requires UFO expression during stage 2 and/or 3 but can be induced as late as stage 6 by ectopic UFO expression (dotted line). Proper petal growth requires later UFO expression.

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