‘Novel flower colours’ is a target of biotechnology. Anthocyanins are major flower pigments in higher plants.
Metabolic engineering provides a powerful tool to generate novel flower colors with out changing the other desired characteristics of a cultivar.
A major target has been the development of blue pigmented flowers in species in which the development of blue color does not naturally occur, such as rose (or) carnation.
Delphidin is the anthocyanin that normally leads to blue pigmentation.
A research group in Australia identified and cloned a gene from petunia hybrid encoding a flavanoid 3’5’–hydroxylase (F3’5’ – H), which is required for the biosynthesis of delphidin.
This provides information necessary or producing transgenic plants with blue flowers.
Transgenic violet carnations have been produced by the introduction of F 3’5’H gene and its high suspension in the petals
Modification of intensity of flower color has been achieved.
White and pink flower varieties have been obtained by introducing sense and antisense chalcone synthase (CHS) transgenes into petunia. Chrysanthemum, rose, carnation, etc.
Flower color has been changed by the introduction of pathway.
Specific transcriptional activators control the genes in anthocyanin biosynthesis.
Expression of maize transcriptional factor “R” (Lc allele) under the control of the CaMV 35S promoter elevated the amount of anthocyanin in transgenic Arabidopsis and tobacco.
Expression of Lc gene in petunia resulted in purple coloration due to accumulation of anthocyanin.
This approach may allow novel color patterns to be introduced into ornamental species by the controlled expression of anthocyanin and flavanoids.
Flower color novelty in particular the generation of unknown blue & yellow flowering cultivars, is one of the major driving force in ornamental Plant breeding.
In a combination of classical & molecular methods, metabolic engineering provides powerful tools to generate novel flower colors with out losing other desirable characteristics of a pre-existing cultivar.
With this view point, production of anthocyanins has also been manipulated in several plants this resulting in making flowers with novel phenotypes such as pink petunia commonly known as “surfinia” were obtained through antisense suppression of chalcone synthase (CHS) gene.
Similar attempts have also been made to generate yellow/cream or deep purple dianthus (commonly known as moondust or roomshadow) and magenta, pale yellow and dark pink coloured petunia.
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