Figure 2 Phenotype of sep1 sep2 sep3 triple mutants. a, Wild-type flower consisting of four sepals, four petals, six stamens and two fused carpels. b, sep1 sep2 sep3 triple mutant flower in which the four petals and six stamens are replaced by sepaloid organs and carpels are replaced by a new flower that repeats this same phenotype. In addition, there is internode elongation between internal flowers, presumably because of a functional ERECTA gene. c, Dissected sep1 sep2 sep3 triple mutant flower with first-whorl sepals (top), second and third whorl sepaloid organs (middle), and a new flower (bottom) that replaces the carpels. d, pi ag (bc) double mutant that reiterates the same sepal, sepal, sepal phenotype. e, Abaxial surface of wild-type sepal. f, Abaxial surface of wild-type petal. g, Abaxial surface of sep1 sep2 sep3 second-whorl sepaloid organ. h, Abaxial surface of sep1 sep2 sep3 third-whorl sepaloid organ. Arrows indicate several stomata. Scale bar in e–h: 50 µm.
Figure 3 Phenotypes of triply and quadruply transgenic plants. a, Sixteen-day-old 35S::SEP3 plant showing a severe phenotype. b, Three-week-old 35S::PI;35S::AP3 plant displaying the curled leaf phenotype. c, Three-week-old 35S::PI;35S::AP3;35S::SEP3 plant. Cotyledons (C) are rather normal, but true leaves are transformed into petaloid organs. Numbers show the order of leaf development. S, stamens; TF, terminal flower. d, Three-week-old 35S::PI;35S::AP3;35S::AP1 plant. A cauline leaf (CL) is transformed into a petaloid organ. e–h, Cryo-scanning electron micrograph (cryo-SEM) of the adaxial surface of a 35S::SEP3 rosette leaf (e) which is similar to rosette and cauline leaves of the wild type; a wild-type petal (f); a petaloid 35S::PI;35S::AP3;35S::SEP3 rosette leaf (g); and a petaloid 35S::PI;35S::AP3;35::AP1 cauline leaf (h). The epidermis of vegetative leaves consists of irregular 'jigsaw-puzzle-shaped' cells with interspersed stomata (e), whereas petal epidermis consists of conical ridged cells and lacks stomata (f–h). i, Cauline leaves (CL) and lateral flowers (F) of 35S::PI;35S::AP3;35S::AG;35S::SEP3 quadruply transgenic plants. Not only all floral organs but also cauline leaves are transformed into stamens or staminoid organs. Arrowheads show branched trichomes. j–o, Cryo-SEM of staminoid cauline leaves of quadruply transgenic plants (j, l, n). For comparison, an anther (k), filament (m) and basal region of a cauline leaf (o) of wild-type are indicated. Wild-type cauline leaves lack a petiole and have irregularly shaped epidermal cells (o). Transformed cauline leaves of quadruply transgenic plants consist two distinct regions whose epidermal cells exhibit a morphology similar to that of wild-type anthers and filaments, respectively (k–n). p, q, Flowers of quadruply transgenic (p) and 35S::PI;35S::AP3;35S::AG (q) plants. Asterisks show petaloid first whorl organs which are often incompletely converted into staminoid organs. Scale bars, 1 mm (a-c); 0.5 mm (d, i, p, q); 50 µm (e–h, j–o).
Figure 2 AP3::GUS expression in the transgenic plants. a, b, AP3::GUS in 35S::PI;35S::AP3 plants (a) and in 35S::AP1 plants (b). GUS activity was observed only in the flowers and floral buds (arrowheads). c, AP3::GUS in 35S::PI;35S::AP3;35S::AP1 triply transgenic plants. GUS activity was observed not only in floral organs (arrowheads), but also in roots, cotyledons, rosette and cauline leaves. d, AP3::GUS in a 3-week-old 35S::SEP3 plant. This line shows a severe phenotype. GUS expression is restricted to the floral organs (arrowheads). e, AP3::GUS in 17-day-old 35S::PI;35S::AP3;35S::SEP3 plants. GUS activity was observed in the whole plant. C; cotyledons. Scale bars, 5 mm (a–c); 1 mm (d, e).