THE PHYTOCHROME GENE FAMILY IN TOMATO (SOLANUM-LYCOPERSICON L)

Phytochrome apoproteins in angiosperms are encoded by a small gene fam ily, Tomato (Solanum lycopersicum L,) serves wed as a dicotyledonous m odel system for elucidating the extent of this gene family, its expres sion patterns, and the roles of individual members of the family, five phytochrome genes (PHYA, PHYB1, PHYB2, PHYE and PHYF) have been chara cterized in tomato, Quantitative measurements of transcript abundances from each tomato PHY throughout the life cycle indicate that transcri pt levels generally range from 10 to 100 mu mol mol(-1) total mRNA, in the following order of decreasing abundance: PHYA, PHYB1, PHYE, PHYB2 and PHYF. PHYA transcripts were found to be most abundant in seedling roots, while PHYB2 and PHYF transcripts were expressed preferentially in fruit, PHYA mutants (fri) have been found to be the consequence of a single nucleotide substitution adjacent to the 3' terminus of an in tron, What are almost certainly PHYB1 mutants have also been described , although the molecular nature of these mutants remains to be reveale d, Efforts to obtain PHYB2, PHYE and PHYF mutants are currently underw ay.