Phytochrome control of phototropism and chlorophyll accumulation in the apical cells of protonemal filaments of wildtype and an aphototropic mutant of the moss Ceratodon purpureus [Bryophyta]
1997
Lamparter, T. (Free Univ. Berlin (Germany)) | Esch, H. | Cove, D. | Hartmann, E.
The phototropic mutant line ptr116 of the moss Ceratodon purpureus shows characteristics of a deficiency in the phytochrome chromophore. Photoreversibility measurements indicate an approximately 20 time lower concentration of spectrally active phytochrome compared to wild-type, whereas normal phytochrome apoprotein levels are found on immunoblots. Feeding with the tetrapyrroles biliverdin, the proposed precursor of the phytochrome chromophore, or phycocyanobiliun, which may replace the phytochrome chromophore, resulted in the rescue of ptr116 phototropism. The results indicate that phytochrome as well as a blue light photoreceptor regulate chlorophyll accumulation in c. purpureus protonemata. It can be assumed that in ptr116, the synthesis of the phytochrome chromophore is blocked specifically beyond the synthesis common to chlorophyll and the phytochrome chromophore and affects an enzymatic step between protoporphyrin and biliverdin
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