Flower development of Phalaenopsis orchid involves functionally divergent SEPALLATA-like genes.
Bottom Line: The tepal became a leaf-like organ when PeSEP3 was silenced by virus-induced silencing, with alterations in epidermis identity and contents of anthocyanin and chlorophyll.Silencing of the E-class genes PeSEP2 and PeSEP3 resulted in the downregulation of B-class PeMADS2-6 genes, which indicates an association of PeSEP functions and B-class gene expression.These findings reveal the important roles of PeSEP in Phalaenopsis floral organ formation throughout the developmental process by the formation of various multiple protein complexes.
Affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.Show MeSH
Related in: MedlinePlus
Mentions: To determine whether the identities of floral organs of the three PeSEP-silenced lines were affected, we quantified several characteristics, including flower size, cell density, shape, height and length (Fig.6). The mean flower size was smaller in PeSEP3- and PeSEP2/3-silenced plants than in mock-treated and PeSEP2-silenced plants (Fig.6a), whereas the epidermal cell size was decreased in both height and width in sepals and petals (Fig.6c,d), together with increased cell density (Fig.6b). Although the PeSEP2-silenced floral morphological features, especially the lip and column, were almost unaffected and indistinguishable from mock-treated features (Fig.5p,t), we observed slight changes in the epidermis. Similar phenotype changes were observed in the independent experiment with P. I-Hsin Sunrise Cinderella (Figs S4, S5). Therefore, morphological changes were stronger for PeSEP3- than PeSEP2/3-silenced plants. No noticeable changes in PeSEP2-silenced plants suggested that PeSEP2 has redundant functions in floral organ identity.
Affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.