Project description:TCP transcription factors from the CYC2-class are involved in the development of monosymmetric flowers in all core eudicot species analysed so far. In Antirrhinum majus, the CYC2/TCP transcription factor CYCLOIDEA (CYC) is the molecular key regulator driving the development of flower monosymmetry (Luo D, Carpenter R, Vincent C, Copsey L, Coen E: Origin of floral asymmetry in Antirrhinum. Nature 1996, 383:794-799). In the Brassicaceae Iberis amara, a stronger expression of the CYC2 gene IaTCP1 in the small adaxial petals likely leads to the reduced petal size in comparison to large abaxial petals, with hardly any IaTCP1 expression. This results in the formation of the monosymmetric Iberis flower (Busch A, Zachgo S: Control of corolla monosymmetry in the Brassicaceae Iberis amara. PNAS 2007, 104:16714-16719). In contrast, the orthologous TCP/CYC2 transcription factor TCP1 from Arabidopsis thaliana, which forms equally sized and shaped petal pairs, only shows an early and transient expression in the adaxial area of floral primordia. This implies that monosymmetry in the Brassicaceae evolved through a heterochronic expression shift of the TCP/CYC2 key regulator gene IaTCP1. Transgenic Arabidopsis plants overexpressing IaTCP1 and TCP1 develop smaller petals whereas transgenic plants overexpressing CYC from Antirrhinum majus produce larger flowers. In any case, petal size is affected. To compare the effects of the three CYC2 TCP transcription factors on downstream (regulatory) networks in Arabidopsis thaliana, a microarray analysis was conducted.
Project description:Investigation of gene expression level changes in snapdragon petals and sepals during flower development The flower developmental stages analyzed in this study are representative of distinct developmental events: (i) preanthesis, (ii) anthesis, (iii) maturation and (iv) presenescence and are further described in the accompanying article. A 24 chip study using total RNA recovered from samples of petal and sepal tissue of Antirrhinum majus cv. Maryland True Pink harvested at four different stages of flower development, namely (i) preanthesis (three days before flower opening=d-3), (ii) anthesis (day of flower opening=d1), (iii) maturation (four days after flower opening=d4) and (iv) presenescence (seven days after flower opening=d7). Three separate samples were extracted per tissue and developmental stages. Each chip measures the expression level of 11,959 ESTs from Antirrhinum majus cv. Maryland True Pink with up to six 60-mer probes per target.