Abstract
Flower color is one of the most important factors affecting the commercial value of ornamental plants. Recently, green-hued flowers have become popular for commercial purposes. However, the pigment composition of green flowers and their mechanisms of color development are totally unknown. We analyzed the pigment composition of various green flowers by HPLC. We revealed that some green flowers, for instance, lisianthus (Eustoma grandiflorum), contain chlorophyll and pheophytin a. Pheophytin a is generated by removal of the central magnesium atom from the porphyrin macrocycle of chlorophyll a. Pheophytinase (PPH) was recently found to catalyze the dephytylation of pheophytin a in the chlorophyll-degradation pathway (Schelbet et al., 2009, Morita et al., 2009). The leaves of pph mutants are reported to accumulate pheophytin a and exhibit the "stay-green" phenotype. We therefore presumed that PPH may be involved in the green coloration of the petals. Next, we isolated the PPH gene from E. grandiflorum and examined its expression levels in green and white flowers.
