REGULATION OF PHYTOCHROME-A MESSENGER-RNA ABUNDANCE IN PARSLEY SEEDLINGS AND CELL-SUSPENSION CULTURES

A cDNA clone encoding the apoprotein of a parsley phytochrome was isol ated and classified as parsley PHYA phytochrome, on the basis of a seq uence homology comparison with all available phytochrome sequences. Re d light pulses led to a phytochrome-dependent down-regulation of PHYA mRNA abundance in etiolated parsley seedlings to a level of 10-20% com pared with the dark control. The PHYA mRNA abundance in a parsley cell suspension culture was also down-regulated by light pulses. Transient expression assays in parsley protoplasts showed light regulation of a chimeric pea PHYA promoter uidA-gene construct.