Molecular cloning and functional expression of tetrahydroxychalcone 2'-glucosyltransferase genes

Abstract

We cloned 35 glucosyltransferase (GT) cDNAs from the yellow petals of carnation (Dianthus caryophyllus cv. light cream candle), and expressed them in E.coli. Four clones (T170, T128, CGT93, S12A2) of them encode the UDP-glucose: 2',4,4',6'-tetrahydroxychalcone 2'-glucosyltransferase (THC2'GT) activity that is recognized as critical to yellow flower coloration of carnation, cyclamen and periwinkle. Overexpression of T170 and T128 in transgenic petunia plants successfully generated THC 2'-glucoside (THC 2'-G) in the petals. Their flower color did not change probably due to the low levels of THC 2'-G accumulation.
We also cloned T170 homologous genes from cyclamen (Cyclamen persicum) and periwinkle (Catharanthus roseus). Their recombinant proteins synthesized in E.coli exhibited THC2'GT activity.
(A part of this study was supported by the Bio-oriented Technology Research Advancement Institution, Japan.)