Phytochrome types in Picea and Pinus. Expression patterns of PHYA-related types

Knowledge of the genes in gymnosperms encoding the apoproteins of the plant photoreceptor phytochrome is currently scanty as for gymnosperm nuclear pr otein coding sequences in general. Here we report two complete cDNA-derived sequences which code for two different types of gymnosperm phytochrome. On e sequence stems from Norway spruce (Picea abies) and the other from Scots pine (Pinus sylvestris). More detailed studies have shown that both types o f phytochrome gene are present in Norway spruce. From phylogenetic analyses , these types appear to branch off from progenitors that are also the commo n ancestors of the angiosperm PHYA/PHYC and PHYB/PHYD/PHYE lineages. Partia l phytochrome sequences of other gymnosperms cluster with either the one ty pe or the other of the gymnosperm phytochrome genes characterized here. Sou thern blot analysis of Picea DNA using probes derived from the full-length Picea gene indicated a family of at least five members. Whether they code f or new types may be doubted since only two phylogenetic clusters were found . Studies using RNA-PCR of Picea RNA extracted from either light- or dark-g rown seedlings indicated that the steady-state levels of the transcripts of two PHYA/C-related genes were hardly affected by light.