|Grennan, A - PLANT BIOLOGY UOFI URBANA|
Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 1999
Publication Date: N/A
Technical Abstract: The decrease in photosynthetic activity in warm-climate plants during low temperature, high light exposure is a well-documented phenomenon. This decrease in photosynthesis is reversible once the plant is returned to growth conditions. Concomitant with the inhibition of photosynthesis is a decrease in net D1 de novo synthesis, as shown by [**35S]-methionine incorporation during in vivo labeling. There is no change in the steady state mRNA levels of psbA during the stress conditions, indicating translational control of D1 expression. Past work with tomato show that low temperature, high light conditions interfere with thioredoxin-dependent, reductive activation pathway of stromal bisphosphatases, implicating a change in stromal redox potential under these conditions. Work in Chlamydomonas has demonstrated that translation of psbA transcript requires the thioredoxin dependent reduction of translation factors for initiation to occur. Application of the photooxidative herbicide methylviologen to leaves prior to pulse labeling with [**35S]-methionine mimics the effect of high light, low temperature (i.e. decrease in net de novo synthesis of D1) further implicating that change in stromal redox state alters D1 expression in tomato.