PLANT PHYSIOLOGY , Vol 113, Issue 4 1023-1031, Copyright © 1997 by American Society of Plant Biologists
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DEVELOPMENT AND GROWTH REGULATION |
hcf5, a Nuclear Photosynthetic Electron Transport Mutant of Arabidopsis thaliana with a Pleiotropic Effect on Chloroplast Gene Expression
R. D. Dinkins, H. Bandaranayake, L. Baeza, AJF. Griffiths and B. R. Green
Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
A photosynthetic mutant of Arabidopsis thaliana, hcf5, was isolated by
screening M2 seedlings for high chlorophyll fluorescence. Thylakoid
morphology was strikingly abnormal, with large grana stacks and almost no
stroma lamellae. Fluorescence induction kinetics, activity assays, and
immunoblotting showed that photosystem II was absent. Polypeptides of the
photosystem I complex, the Cyt b6/f complex, coupling factor, and the large
subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase were also
severely depleted. However, the nuclear-encoded chlorophyll a/b
light-harvesting complex polypeptides were unaffected. The rbcL transcript
was present at very low levels, the pattern of transcripts from the
polycistronic psbB-psbH-petB-petD operon was abnormal, and the mature psbH
message was almost completely lacking. This suggests that the hcf5 locus
may encode a product required for the correct expression of several
chloroplast genes.
