ISHS Acta Horticulturae 760: XXVII International Horticultural Congress - IHC2006: II International Symposium on Plant Genetic Resources of Horticultural Crops
DIFFERENTIAL EXPRESSION OF ANTHOCYANIN BIOSYNTHETIC GENES IN 'CHARLESTON' ROSES |
| Authors: | C.K. Hennayake, M. Kanechi, Y. Uno, N. Inagaki |
| Keywords: | chrysanthemin, cyanin, UVB, UVA, ultraviolet radiation, Rosa hybrida, flavonol |
| Abstract:
Anthocyanins are responsible for many of the vivid colors in higher plants. The natural floral color in the petals of Rosa hybrida ‘Charleston’ undergoes a striking change from yellow to red over a period of 10-12 days. This color change is due to the accumulation of two anthocyanins, cyanidin 3-glucoside (chrysanthemin) and cyanidin 3,5-diglucoside (cyanin). The production of anthocyanins is determined by expression of at least four genes, namely dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), flavonoid 3-O-glucosyltransferase (UF3GT), and flavonoid 5-O-glucosyltransferase (UF5GT). The cDNA fragments of these genes were cloned from rose and the deduced amino acid sequences of these genes shared 51~97% identities with the corresponding sequences from other plant species. Rose flowers were exposed to different light conditions such as white light (FL, cool-white fluorescent lamp) or ultraviolet radiation (UVB, 290-320 nm; UVA, 320-380 nm) to promote the accumulation of the anthocyanins in petals during flower unfolding. Anthocyanin contents were measured by HPLC and the gene expression was investigated by RNA gel-blot analysis and RT-PCR. The expression of these genes increased dramatically as flowers unfolded and also correlated positively with the production of anthocyanins. The expression of DFR was detectable in early stages of flower unfolding and the highest expression of ANS, UF3GT and UF5GT was detected during the latter half of flower unfolding. The expression levels of these genes and the temporal buildup of anthocyanins in petals were stimulated by exposing them to UVB or FL+UVB radiation. These results show the relationship between the expression of anthocyanin biosynthetic genes and the light-signaling stimuli within the narrow range of UV wavelengths. UVB radiation is increasing gradually due to the rapid destruction of ozone layer. | |
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