Functional divergence within class B MADS-box genes TfGLO and TfDEF in Torenia fournieri Lind

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.Electronic supplementary materialThe online version of this article (doi:10.1007/s00438-010-0574-z) contains supplementary material, which is available to authorized users.

A chimeric repressor of petunia PH4 R2R3-MYB family transcription factor generates margined flowers in torenia

“…Torenia genes corresponding to the genes involved in anthocyanin synthesis above have been cloned and are the subject of an earlier report. 22 Expressions of genes involved in anthocyanin synthesis were compared between NT and PhPH4-RD lines by semi-quantitative RT-PCR analysis (Fig. 5B).…”

“…Accessions of genes involved in anthocyanin synthesis and TfACT3 have been described previously. 22 Gene expression analysis RNA was extracted from whole petals using the RNeasy Plant Mini-Kit. Flower tubes, limbs and margins of limbs (approx.…”

“…Primer sequences and PCR cycles in semi-quantitative RT-PCR analysis are presented in Table 2. The RT-PCR primers for TfANS, TfCHI, TfF3 0 H1, TfF3 0 H2, TfF3 0 5 0 H, Tf3GT and TfACT3 are from Sasaki et al 22 The other RT-PCR primers were designed in this study. TfCHS1 and TfCHS2 (cloned in Sasaki et al 22 ) shared nearly the same nucleotide sequences and seemed to be alleles.…”

“…The RT-PCR primers for TfANS, TfCHI, TfF3 0 H1, TfF3 0 H2, TfF3 0 5 0 H, Tf3GT and TfACT3 are from Sasaki et al 22 The other RT-PCR primers were designed in this study. TfCHS1 and TfCHS2 (cloned in Sasaki et al 22 ) shared nearly the same nucleotide sequences and seemed to be alleles. New primers were designed to amplify TfCHS1 and TfCHS2 simultaneously (this gene is here referred to as TfCHS).…”

Promotion of Efficient Molecular Breeding Using Chimeric Repressors in Ornamental Flowers

“…In Torenia, there are two orthologs of the class B genes DEFICIENCE (DEF) and GLOBOSA (GLO), called TfDEF and TfGLO, respectively (Sasaki et al 2010). Simultaneous suppression of these genes by chimeric repressors resulted in sepal-like petals (Sasaki et al 2014), indicating that TfDEF and TfGLO synergistically played important roles in the development of petals.…”