Genetic Engineering of Novel Bluer-Colored Chrysanthemums Produced by Accumulation of Delphinidin-Based Anthocyanins

Abstract

Chrysanthemums (Chrysanthemum morifolium Ramat.) have no purple-, violet- or blue-flowered cultivars because they lack delphinidin-based anthocyanins. This deficiency is due to the absence of the flavonoid 3',5'-hydroxylase gene (F3'5'H), which encodes the key enzyme for delphinidin biosynthesis. In F3'5'H-transformed chrysanthemums, unpredictable and unstable expression levels have hampered successful production of delphinidin and reduced desired changes in flower color. With the aim of achieving delphinidin production in chrysanthemum petals, we found that anthocyanin biosynthetic gene promoters combined with a translational enhancer increased expression of some F3'5'H genes and accompanying delphinidin-based anthocyanin accumulation in transgenic chrysanthemums. Dramatic accumulation of delphinidin (up to 95%) was achieved by simple overexpression of Campanula F3'5'H controlled by a petal-specific flavanone 3-hydroxylase promoter from chrysanthemum combined with the 5'-untranslated region of the alcohol dehydrogenase gene as a translational enhancer. The flower colors of transgenic lines producing delphinidin-based anthocyanins changed from a red-purple to a purple-violet hue in the Royal Horticultural Society Colour Charts. This result represents a promising step toward molecular breeding of blue chrysanthemums.

Transgenics in Ornamental Crops:Creating Novelties in Economically Important Cut Flowers

“…Increased delphinidin levels (up to 80%) were further achieved by hairpin RNA interference-mediated silencing of the endogenous F3H gene and the resulting petal colours were novel bluish hues. Blue pigmentation in petals of chrysanthemum has also been reported by Noda et al 61 through generation of delphinidin-based anthocyanins by expression of the flavonoid 3,5-hydroxylase gene. Huang et al 62 also used RNAi technology to induce red and blue flowers in C. morifolium by downregulating CmF3H (flavanone 3-hydroxylase gene hydroxylated at the 3-position) and overexpressing the Senecio cruentus F35H (PCFH) (flavanone 3-hydroxylase gene hydroxylated at the 3-and 5-positions) gene in chrysanthemum.…”

Inheritance and InDel markers closely linked to petal color gene (cpc-1) in Brassica oleracea

“…According to previous studies, flower color is an important factor in pollination and plant reproduction by attracting pollinators (Brown and Clegg 1984;Jones and Reithel 2001;Noda et al 2013) and affecting the behavior of herbivores, which discriminate against or prefer certain color morphs (Simms and Bucher 1996;Irwin et al 2003;Caruso et al 2010). Flower pigments are also related to disease defense and UV protection (Koes et al 1994;Treutter 2005).…”

Completion of Tricin Biosynthesis Pathway in Rice: Cytochrome P450 75B4 Is a Unique Chrysoeriol 5′-Hydroxylase

“…F3959H activities enable plants to synthesize delphinidin-based anthocyanins, which confer violet/ blue color in flowers and fruits, potentially a selective advantage in angiosperms for attraction of pollinators and seed dispersers (Harborne, 2014). A number of dicot F3959H genes have been isolated for engineering flower colors in plants without violet/blue pigmentation, such as roses (Rosa hybrida; Katsumoto et al, 2007), chrysanthemums (Chrysanthemum morifolium; Brugliera et al, 2013;Noda et al, 2013), and carnations (Dianthus caryophyllus; Tanaka and Brugliera, 2013). On the other hand, suppression of F3959H expression in torenia (Torenia hybrida; Suzuki et al, 2000) and cyclamen (Cyclamen persicum; Boase et al, 2010) was shown to shift the petal colors from violet/blue to red.…”