Production of picotee-type flowers in Japanese gentian by CRES-T

Abstract

Chimeric repressor gene-silencing technology (CRES-T) is an efficient gene suppression system in a wide variety of dicots and monocots. In this study, we demonstrated that the CRES-T system functions in Japanese gentian. A chimeric repressor of the anthocyanin biosynthetic regulator gene GtMYB3, under the control of the Arabidopsis actin2 promoter, was introduced into blue-flowered gentian. Of 12 transgenic lines, 2 exhibited a picotee flower phenotype with a lack of pigmentation in the lower part of the petal. HPLC analysis showed that the petals of these lines contained less anthocyanin and more flavone than the wild-type, suggesting competitive accumulation of these two types of compounds. The expressions of 'late' flavonoid biosynthetic genes, including F3H, F3Ј5ЈH, DFR and ANS, were strongly suppressed in petals of these transgenic plants. In contrast, the 'early' flavonoid biosynthetic genes, such as CHS and FNSII, were not affected. Since FNSII is expressed more strongly in the lower part of petals than in the upper part, the absence of pigmentation in the lower parts might be induced by flavone synthesis. These results demonstrated that the suppression of anthocyanin biosynthetic genes by CRES-T was successfully applied to Japanese gentian to change petal color; therefore, this system could be useful for generating novel flower colors and patterns. Transgenic plants produced in this study might be utilized as elite materials in the breeding of Japanese gentian in the near future.

Morphological changes of Rosa×hybrida by a chimeric repressor of Arabidopsis TCP3

“…Chimeric repressor gene-silencing technology (CRES-T) has provided unique transgenic ornamental flowers (Nakatsuka et al 2011;Shikata et al 2011;Tanaka et al 2011). CRES-T is a type of dominant-negative strategy for transcription factors in which a transcription factor fused to a modified ERF-associated amphiphilic repression (EAR)-motif repression domain functions as a dominant chimeric repressor in transgenic plants, which leads to a loss-of-function phenotype even in the presence of redundant transcription factors (Hiratsu et al 2003).…”

Environmental risk assessment and field performance of rose (Rosa×hybrida) genetically modified for delphinidin production

“…For example, colour modified petunia, torenia and gentian (reviewed by Nishihara and Nakatuska 2010 and morphologically modified torenia (Narumi et al 2008), cyclamen , gentian (Nakatsuka et al 2011), morning glory (Ono et al 2011Sage-Ono et al 2011) and rose (Gion et al 2011) have been developed. Insect resistant chrysanthemum (Shinoyama et al 2008) has also been reported.…”

Development of DNA markers that discriminate between white- and blue-flowers in Japanese gentian plants

“…The gtmyb3-1 to gtmyb3-4 alleles were characterized as inactive in transient expression and yeast twohybrid assays , data not shown). When a chimeric repressor of GtMYB3 was transformed into blue-flowered gentian, a white-centered picotee petal-color phenotype was observed, indicating that this gene was responsible for flower pigmentation in Japanese gentians (Nakatsuka et al 2011). First, we developed a co-dominant SCAR marker to distinguish gtmyb3-1 and gtmyb3-3 alleles, which have insertions of independent transposable elements in the second exon, from other GtMYB3 alleles (Figs.…”