Spatial and temporal expression of chalcone synthase and dihydroflavonol 4-reductase genes in the Asiatic hybrid lily

Abstract

cDNA clones of three chalcone synthase (CHS) genes (LhCHSA, LhCHSB and LhCHSC) and one dihydroflavonol 4-reductase (DFR) gene (LhDFR) were isolated, and spatial and temporal expression of these genes was analyzed for two Asiatic hybrid lily cultivars, ‘Montreux’ (pink tepals with spots) and ‘Connecticut King’ (yellow tepals without spots). Pink tepals and tepal spots contain the same kind of anthocyanin, and yellow tepals have no anthocyanin. In both cultivars, the expression of all four genes was not detected in unpigmented leaves, stems and white bulbscales, but was detected in anthocyanin pigmentation-induced bulbscales, indicating that these genes are transcriptionally active in both cultivars. In flower organs, three CHS genes were expressed in anthocyanin-pigmented tepals, filaments and pistils of ‘Montreux’, and in unpigmented filaments and pistils of ‘Connecticut King’. Pigmented anthers accumulated only LhCHSC mRNA in both cultivars. LhDFR was abundantly expressed in pigmented tepals, anthers, filaments and pistils of ‘Montreux’, and in pigmented anthers of ‘Connecticut King’. These results indicate that different expression of these genes, especially of the LhDFR gene, controls the distinct pigmentation pattern in flower organs in both cultivars. In three F1 plants with many spots on yellow or white tepals, derived from a cross between ‘Montreux’ and ‘Connecticut King’, anthocyanin accumulation in tepal spots was accompanied by the LhCHSA and LhDFR expression, indicating that the expression of CHS and DFR genes is independently controlled between tepals and tepal spots.