This transcription factor belongs to a small family of genes, and homologs have been identified in closely related species. Initial Southern blotting experiments have not revealed any genes with strong homology to the CBF family, and alternative methods of identifying transcriptional activators for cold-regulated genes are being investigated.
Transgenic studies are currently underway using both constitutive and stress inducible promoters.
Thus far, no transgenic plants that express the reporter gene have been produced, although PCR results have identified transgenic plants. 1 .For example, flavones and flavonols are emitted as signal substances from leguminous roots to induce the expression of the genes that are required for nodulation in rhizobia. As flower pigments, they attract pollen-transferring insects. Moreover, they also have health benefits for humans having antioxidant, antithrombogenic and antitumor properties 2 . In citrus, flavonoids accumulate mainly as flavanone disaccharide glucosides that may affect the taste of fruits.