This result cannot be explained by the well-known action
of CPTA as a lycopene cyclase inhibitor but indicates the
presence of a novel regulatory mechanism. In fact, RNA
subtraction between CPTA-treated and untreated tissue revealed the induction of mRNA accumulation for at least two
carotenoid biosynthetic genes, coding for deoxyxylulose phosphate
synthase and -carotene hydroxylase (unpublished
data). Utilizing the transgenic rice in hand, further work is in
progress to clarify molecularly whether this mechanism works
here as well.