Metabolic flux from the chloroplast provides essential signals
for retrograde signalling during cold acclimation.
Abstract: Chloroplasts, the site of the primary reactions of
photosynthesis, are organelles capable of independent protein synthesis,
but which depend on the nucleus for most polypeptides. The process of
photosynthesis is especially sensitive to environmental conditions and
the composition of the photosynthetic apparatus can be modulated in
response to environmental change. This acclimation process requires
close communication between chloroplast and nucleus. Here we present
evidence that the form in which carbon is exported from the chloroplast
encodes information about the metabolic status of the photosynthetic
apparatus which in turn controls photosynthetic acclimation.
Specifically, we propose that the ratio of 3-phosphoglyceric acid to
triose phosphate exported via the triose phosphate/phosphate
translocator (TPT) may signal provide a retrograde signal driving
photosynthetic acclimation.
Keywords: acclimation, carbon metabolism, cold, fumarate,
malate, photosynthesis