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ABSTRACT: We identified a Torenia fournieri Lind. mutant (no. 252) that exhibited a sepaloid phenotype in which the second whorls were changed to sepal-like organs. This mutant had no stamens, and the floral organs consisted of sepals and carpels. Although the expression of a torenia class B MADS-box gene, GLOBOSA (TfGLO), was abolished in the 252 mutant, no mutation of TfGLO was found. Among torenia homologs such as APETALA1 (AP1), LEAFY (LFY), and UNUSUAL FLORAL ORGANS (UFO), which regulate expression of class B genes in Arabidopsis, only accumulation of the TfUFO transcript was diminished in the 252 mutant. Furthermore, a missense mutation was found in the coding region of the mutant TfUFO. Intact TfUFO complemented the mutant phenotype whereas mutated TfUFO did not; in addition, the transgenic phenotype of TfUFO-knockdown torenias coincided with the mutant phenotype. Yeast two-hybrid analysis revealed that the mutated TfUFO lost its ability to interact with TfLFY protein. In situ hybridization analysis indicated that the transcripts of TfUFO and TfLFY were partially accumulated in the same region. These results clearly demonstrate that the defect in TfUFO caused the sepaloid phenotype in the 252 mutant due to the loss of interaction with TfLFY.
The Plant Journal 05/2012; 71(6):1002-14. · 6.16 Impact Factor
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ABSTRACT: While heavy-ion beam irradiation is becoming popular technology for mutation breeding in Japan, the combination with genetic manipulation makes it more convenient to create greater variation in plant phenotypes. We have succeeded in producing over 200 varieties of transgenic torenia (Torenia fournieri Lind.) from over 2,400 regenerated plants by this procedure in only 2 years. Mutant phenotypes were observed mainly in flowers and showed wide variation in colour and shape. Higher mutation rates in the transgenics compared to those in wild type indicate the synergistic effect of genetic manipulation and heavy-ion beam irradiation, which might be advantageous to create greater variation in floral traits.
Methods in molecular biology (Clifton, N.J.) 01/2012; 847:275-89.
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ABSTRACT: Homeotic class B genes GLOBOSA (GLO)/PISTILLATA (PI) and DEFICIENS (DEF)/APETALA3 (AP3) are involved in the development of petals and stamens in Arabidopsis. However, functions of these genes in the development of floral organs in torenia are less well known. Here, we demonstrate the unique floral phenotypes of transgenic torenia formed due to the modification of class B genes, TfGLO and TfDEF. TfGLO-overexpressing plants showed purple-stained sepals that accumulated anthocyanins in a manner similar to that of petals. TfGLO-suppressed plants showed serrated petals and TfDEF-suppressed plants showed partially decolorized petals. In TfGLO-overexpressing plants, cell shapes on the surfaces of sepals were altered to petal-like cell shapes. Furthermore, TfGLO- and TfDEF-suppressed plants partially had sepal-like cells on the surfaces of their petals. We isolated putative class B gene-regulated genes and examined their expression in transgenic plants. Three xyloglucan endo-1,4-beta-D: -glucanase genes were up-regulated in TfGLO- and TfDEF-overexpressing plants and down-regulated in TfGLO- and TfDEF-suppressed plants. In addition, 10 anthocyanin biosynthesis-related genes, including anthocyanin synthase and chalcone isomerase, were up-regulated in TfGLO-overexpressing plants and down-regulated in TfGLO-suppressed plants. The expression patterns of these 10 genes in TfDEF transgenic plants were diverse and classified into several groups. HPLC analysis indicated that sepals of TfGLO-overexpressing plants accumulate the same type of anthocyanins and flavones as wild-type plants. The difference in phenotypes and expression patterns of the 10 anthocyanin biosynthesis-related genes between TfGLO and TfDEF transgenic plants indicated that TfGLO and TfDEF have partial functional divergence, while they basically work synergistically in torenia.
MGG Molecular & General Genetics 11/2010; 284(5):399-414. · 2.58 Impact Factor
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ABSTRACT: The white petals of chrysanthemum (Chrysanthemum morifolium Ramat.) are believed to contain a factor that inhibits the accumulation of carotenoids. To find this factor, we performed polymerase chain reaction-Select subtraction screening and obtained a clone expressed differentially in white and yellow petals. The deduced amino acid sequence of the protein (designated CmCCD4a) encoded by the clone was highly homologous to the sequence of carotenoid cleavage dioxygenase. All the white-flowered chrysanthemum cultivars tested showed high levels of CmCCD4a transcript in their petals, whereas most of the yellow-flowered cultivars showed extremely low levels. Expression of CmCCD4a was strictly limited to flower petals and was not detected in other organs, such as the root, stem, or leaf. White petals turned yellow after the RNAi construct of CmCCD4a was introduced. These results indicate that in white petals of chrysanthemums, carotenoids are synthesized but are subsequently degraded into colorless compounds, which results in the white color.
Plant physiology 12/2006; 142(3):1193-201. · 6.53 Impact Factor
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ABSTRACT: When anthocyanins in plants make complexes with copigments such as flavones or flavonols (copigmentation), the visible absorption maximum of the flowers is shifted so that it becomes longer: that is, the flowers look bluer. In an earlier study, our group reported the modification of flower color in torenia (Torenia fournieri Lind.) by re-introduction of the dihydroflavonol-4-reductase (DFR) gene or the chalcone synthase (CHS) gene. Our initial observation of torenia transformants was that plants with the antisense DFR gene produced bluer flowers than plants with the antisense CHS gene. In the present study we found that inactivation of the DFR gene by genetic transformation caused the accumulation of flavones — possible copigments — and that the resulting copigmentation likely to make the torenia flowers bluer. This method could be applied to other plant species to produce bluer flowers.
Plant Science 01/2001; · 2.94 Impact Factor
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ABSTRACT: Modification of flower colour in torenia (Torenia fournieri Lind.) by reintroduction of the chalcone synthase (CHS) or dihydroflavonol-4-reductase genes has been reported (Aida et al., 2000.Plant Science153: 33–42). The typical modified phenotype among plants with an introduced antisense gene is a uniformly lighter-coloured corolla. Of the 67 plants in which an antisense CHS gene was introduced, only a single line (411-7) showed a wavy pattern on the flower lip. In flowers of this plant, the inner part of the corolla lip was pigmented more deeply than the outer part in a wave-like pattern—a pattern that does not exist in normal cultivars. The segregation ratio of the flower colour patterns of the offspring and Southern blot analysis demonstrated that one of the two transgene loci detected may cause the wavy phenotype; the other locus is never associated with the wavy phenotype but alone it could produce the typical antisense type pattern.
Annals of Botany - ANN BOT. 01/2001; 87(3):405-409.
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ABSTRACT: A method for Agrobacterium-mediated transformation of Cyclamen persicum Mill. is reported. Etiolated petiole segments were infected with Agrobacterium tumefaciens strain AGL0 or LBA4404. These strains have a binary vector plasmid, pIG121Hm, that includes the β-glucuronidase (GUS) gene with an intron as reporter gene, and the neomycin phosphotransferase II gene and the hygromycin phosphotransferase gene as selection markers. Explants were cultured on Murashige and Skoog medium supplemented with 1.0 mg/l thidiazuron, 1.0 mg/l 2,4-dichlorophenoxyacetic acid, 300 mg/l ticarcillin, and 5 mg/l hygromycin or 100 mg/l kanamycin (selection medium) for regeneration. Transformation was confirmed by histochemical assays of GUS activity in plant tissues, and by Southern blot analysis of the GUS gene. Through five experiments, 103 independent GUS-positive plants were obtained from 920 explants.
Plant Science.
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ABSTRACT: We generated mutated ethylene receptor genes (mDG-ERS1s) from the chrysanthemum ethylene receptor (DG-ERS1) cDNA by introducing one-nucleotide substitutions corresponding to those present in Arabidopsis etr1-1, etr1-2, etr1-3, and etr1-4 and tomato Nr. The promoter of a tobacco elongation factor 1α (EF1α) gene was fused to DG-ERS1 cDNA or one of the mDG-ERS1s. The resulting constructs were named EF1α∷mDG-ERS1(etr1-1), -ERS1(etr1-2) and so on, and introduced into chrysanthemum cv. Sei-Marine. We obtained putative transformants resistant to an antibiotic paromomycin with a yield of 2.4–6.2% depending on the construct. The mDG-ERS1(etr1-4) construct tended to be more effective in conferring reduced ethylene sensitivity in chrysanthemum than the others. PCR analysis gave amplification corresponding to a partial sequence of EF1α∷mDG-ERS1 transgenes. Southern blot analysis showed that, in the mDG-ERS1(etr1-4) transformant, not only the lines with reduced sensitivity to ethylene but also those sensitive to ethylene harbored the mDG-ERS1(etr1-4) transgene. The present results showed the usefulness of mutated ethylene receptor genes mDG-ERS1s for generation of transgenic chrysanthemums with reduced ethylene sensitivity.
Postharvest Biology and Technology 37(2):101-110. · 2.41 Impact Factor
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ABSTRACT: The function of a 1.1-kb transcript of WAG, a wheat AGAMOUS homolog, has not been clarified. To analyze its function, it was fused with the cauliflower mosaic virus 35S promoter and introduced into torenia (Torenia fournieri). Torenia transformants grew normally with regular plant height, size and shape of leaves, and development of inflorescence. However, the corolla was significantly smaller in 10 transformants out of 21. Generally, the vertical and horizontal diameters of the lip part of the corolla, as well as the length of the corolla (including the tube part), were all reduced in the smaller flowers, suggesting that the size of the corolla was reduced equally in all dimensions. Southern blot analysis showed the existence of the WAG gene in the genomes of these plants. We report that WAG reduces the size of the corolla in torenia. Summary
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ABSTRACT: We modified flower color in torenia (Torenia fournieri Lind.) by transferring the chalcone synthase (CHS) or the dihydroflavonol-4-reductase (DFR) gene in sense or antisense orientation by Agrobacterium-mediated gene transfer. The modification patterns of flower color among the transformants formed three groups: (1) same color as the wild-type plant; (2) whole corolla changed to a uniformly light color; and (3) with greater degree of lightening in the tube than in the lip. Transformants incorporating antisense transgene(s) tended to become group 2 types, with no plants becoming group 3 type. Transformants harboring sense transgene(s) tended to become group 3 types, rather than group 2 types. Sense genes and antisense genes seemed to have different potential for changing the flower color. We also produced transformants with new characters in torenia flower color; for example, lines with pastel flowers, wavy patterned flowers and parti-colored flowers. We regard this system to be useful for flower color breeding in torenia and for studying gene expression.
Plant Science.
