Submitted to: Federation of European Biochemical Societies Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2000
Publication Date: N/A
Interpretive Summary: High temperature is a significant stress factor that can decrease the yield of crops by decreasing photosynthesis. Heat stress inhibits photosynthesis by having a negative effect on a key photosynthtic enzyme called Rubisco activase. In this paper we investigated how heat stress influenced the genetic regulation of Rubisco activase in a model system. Heat stress led to an accumulation of Rubisco activase, including the appearance of a new form of the enzyme not found in non-stressed plants. This accumulation of Rubisco activase was not caused by increases in gene expression, but by alterations in the biochemistry of genes that were already expressed. The effect of heat stress on Rubisco activase indicated that the enzyme is part of the mechanism that allows plants to acclimate to heat stress. Improving this process could lead to plants that have increased tolerance to environmental stress. This research is applicable to public and private scientists conducting research on crop improvement and environmental stress.
Technical Abstract: Interaction of Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) activase with Rubisco is necessary for CO2 fixation in plants but is disrupted by heat stress. We examined high temperature effects on expression of activase in wheat leaves. Heat stress reduced total activase message levels but increased the amount of de novo synthesized 42-kDa activase protein and induced the synthesis of a putative novel 41-kDa isoform. Comparison of in vitro translation products with de novo protein synthesis and accumulation indicated post-transcriptional regulation of activase expression. Heat-induced alterations in patterns of activase synthesis may be necessary for the maintenance and acclimation of CO2 fixation in wheat.