Database Product Description
- Host Organism
- Dianthus caryophyllus (Carnation)
- Modified flower colour; Sulfonylurea herbicide tolerance, specifically triasulfuron and metsulfuron-methyl.
- Trait Introduction
- Agrobacterium tumefaciens-mediated plant transformation.
- Proposed Use
Production for the cut-flower industry.
- Product Developer
- Florigene Pty Ltd.
Summary of Regulatory Approvals
Summary of Introduced Genetic Elements Expand
Characteristics of Dianthus caryophyllus (Carnation) Expand
Modification Method Expand
Characteristics of the Modification Expand
Environmental Safety Considerations Expand
Carnations (Dianthus carophyllus L.) are among the most extensively grown cut flowers with more than 10 billion carnations produced around the world each year. Carnations are cultivated by growers, flower auctions, flower wholesalers, retailers and plant breeders worldwide and are sold as cut flowers, cuttings or plants.
Plant breeders are always in search of developing a new flower variety with a novel colour. However, for some flower varieties, no amount of traditional breeding will achieve blue, violet, or mauve flowers, due to the inability of the plant to form certain pigments. There are two major types of flower pigments: the flavonoids, which contribute to a range of colours from yellow to red to blue, and; the carotenoids, which are common pigments in flowers with colours ranging from yellow to orange. The flavonoids include the anthocyanin pigments, cyanidin (red), pelargonidin (brick red), and delphinidin (blue). Carnations, roses, lilies, chrysanthemums and gerberas, which represent 75 percent of worldwide flower sales, do not produce the blue pigment called delphinidin.
Transgenic lines 959A, 988A, 1226A, 1351A, 1363A, and 1400A were developed using recombinant DNA techniques to produce flowers with a unique deep purple colour by introducing two genes that function together in the biosynthesis of the anthocyanin pigment delphinidin. The transgenic lines were derived from the parent cultivar ‘White Unesco’, which is a white coloured carnation that was selected for a mutation in the dihydroflavonol reductase (DFR) encoding gene that did not allow for expression of a functional enzyme, and thus did not produce the anthocyanin type pigments that give rise to blue and red coloured flowers. The two genes introduced into the transgenic carnation lines included a functional dihydroflavonol reductase encoding gene isolated from petunia (Petunia hybrida) and a gene encoding the enzyme flavonoid 3’, 5’-hydroxylase (F3’, 5’H), a member of the NADPH-Cytochrome P450 reductase family, isolated from Viola. Expression of the F3’, 5’H encoding gene (bp40) allows for the production of blue coloured delphinidin anthocyanin pigments, which are not normally found in carnations.
The biology of carnation is such that there are no reasonable means for the genetically modified plants to escape from cultivation and become established as populations in the wild, or for gene dispersal from the genetically modified carnation to occur. The commercial standard carnation varieties are generally male sterile and rarely produce anthers; and if they do, little pollen is produced and this can only be transferred by insects. In commercial carnation production, outcrossing is unlikely as flowers are cut before opening. Should flowers open, only certain insects are easily able to access nectaries in flowers and there are very few opportunities for this to occur during transit and sale. Furthermore, carnations plants require 6 weeks for seed development. A genetically modified cut carnation flower lasts only 3-4 weeks, which is not enough time for seed set.
Many Dianthus species occur as common wildflowers. There has never been any evidence of hybridization between carnation and these species, nor after decades of cultivation have carnations been found in the wild. Carnation has no weedy characteristics and is not closely related to known weeds. The risk of transferring genetic traits from transgenic carnation lines to species in unmanaged environments was not judged to be significant.
Links to Further Information Expand
This record was last modified on Wednesday, February 25, 2015