Dg. Durnford et Pg. Falkowski, CHLOROPLAST REDOX REGULATION OF NUCLEAR GENE-TRANSCRIPTION DURING PHOTOACCLIMATION, Photosynthesis research, 53(2-3), 1997, pp. 229-241
The role of the redox state of ferredoxin/thioredoxin within the chlor
oplast is well established for the feedback regulation of enzyme activ
ity in the Calvin cycle. However, evidence has emerged also suggesting
that chloroplast electron transport components regulate plastid and n
uclear gene expression. Using the unicellular green alga, Dunaliella t
ertiolecta, as a model organism, we have shown that the cell acclimate
s to changes in growth irradiance by altering the abundance and activi
ties of photosynthetic components, in particular the light harvesting
complexes (LHC). Pharmacological data suggests that light intensity is
sensed through the redox status of the plastoquinone pool leading to
the regulation of nuclear encoded genes, such as Lhcb. This signal may
be transduced through a redox regulated protein kinase that (in)direc
tly interacts with the nuclear transcription apparatus. The redox stat
e of the plastoquinone pool seems to play a pivotal role in sensing ce
llular energy status and in regulating photosynthetic capacity. Other
cellular pathways, including carbon fixation, carbohydrate metabolism
and nutrient assimilation have been shown to have feedback influences
on photosynthesis, that may be sensed by the redox state of the plasto
quinone pool.