Temporal and spatial expression of flavonoid biosynthetic genes in flowers of Anthurium andraeanum

The expression of anthocyanin biosynthesis genes during flower colour development in Anthurium andraeanum (anthurium) was studied. A cDNA library was constructed from mRNA from the anthurium spathe, and full‐length cDNA clones identified for the flavonoid biosynthetic enzymes chalcone synthase (CHS), flavanone 3‐hydroxylase (F3H), dihydroflavonol 4‐reductase (DFR) and anthocyanidin synthase (ANS). These were used to measure transcript levels in the spathe during flower development, in cultivars with different flower colours, over the diurnal cycle, and in the spadix. CHS, F3H and ANS were expressed at all stages of spathe and spadix development. However, DFR transcript levels varied significantly between stages, and DFR may represent a key point of regulation. A diurnal rhythm of DFR transcript abundance in the spathe was also observed, with transcript levels high at dawn and dusk and low at noon. Control of anthocyanin biosynthesis in anthurium spathe differs from that described for flowers of other species, with DFR a key regulatory point and a complex mix of developmental and environmental control signals.