title: The Petal-Specific InMYB1 Promoter Functions by Recognizing Petaloid Cells.
abstract: The InMYB1 gene in Japanese morning glory (Ipomoea nil) is a member of the MYB transcription factor family. The promoter of InMYB1 has been reported to induce petal-specific gene expression in Arabidopsis and Eustoma, and has the same function in several other dicotyledonous plants. Most flowers consist of sepals, petals, stamens and a carpel, whose identity establishment is explained by the ABC model. The establishment of the identity of petals is determined by the expression of class A and B genes in whorl 2. The aim of this study was to clarify whether the InMYB1 promoter functions by recognizing whorl position or petal identity by examining its activity in various mutant and transgenic Arabidopsis thaliana plants in which genes related to the ABC model have been modified. In plants defective in class C gene function, the InMYB1 promoter functioned not only in petals generated in whorl 2 but also in petaloid organs generated in whorl 3; while in the plants defective in class B gene function, the InMYB1 promoter did not function in the sepaloid organs generated in whorl 2. Plants overexpressing class A, B and E genes set flowers with petaloid sepals in whorl 1, i.e. the lateral parts were white and looked like petals, while the central parts were green and looked like sepals. The InMYB1 promoter functioned in the lateral white parts but not in the central green parts. These results show that the InMYB1 promoter functions by recognizing petal identity at the cellular level rather than the whorl position. The petal-specific function of the InMYB1 promoter could be used as a marker to identify petaloid cells.
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan.
authors: Mirai
authors: M
authors: Azuma
authors: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi, Tsukuba, 305-8566 Japan.
authors: Nobutaka
authors: N
authors: Mitsuda
authors: Research Institute for Biological Sciences, Okayama Prefectural Technology Center for Agriculture, Forestry, and Fisheries, Yoshikawa, Kibi-chuo, Okayama, 716-1241 Japan.
authors: Koji
authors: K
authors: Goto
authors: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi, Tsukuba, 305-8566 Japan.
authors: Yoshimi
authors: Y
authors: Oshima
authors: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi, Tsukuba, 305-8566 Japan Institute for Environmental Science and Technology, Saitama University, Sakura, Saitama, 338-8570 Japan.
authors: Masaru
authors: M
authors: Ohme-Takagi
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan.
authors: Shungo
authors: S
authors: Otagaki
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan.
authors: Shogo
authors: S
authors: Matsumoto
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan shira@agr.nagoya-u.ac.jp.
authors: Katsuhiro
authors: K
authors: Shiratake
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology; D035264:Flowers / Q000033:anatomy & histology* / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D049915:Ipomoea nil / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics; D059828:Plant Cells / Q000378:metabolism*; D019441:Plant Epidermis / Q000166:cytology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic
chemical_list: D010940:Plant Proteins
keywords: ABC model; Flower morphology; MYB promoter; Petal identity; Petal-specific promoter