High temperature stress increases the expression of wheat leaf ribulose-1,5-bisphosphate carboxylase/oxygenase activase protein

Arch Biochem Biophys. 2001 Feb 15;386(2):261-7. doi: 10.1006/abbi.2000.2225.


The effect of high temperature stress on the expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase was examined in wheat (Triticum aestivum L.) leaves, which normally possess 46- and 42-kDa activase forms. Heat stress at 38 degrees C significantly reduced total activase mRNA levels compared to controls, and recovery of activase transcription was only marginal 24 h after alleviating heat stress. In contrast to transcript abundance, immunoblot analysis indicated that heat stress increased the accumulation of the 42-kDa activase and induced a putative 41-kDa form. Heat stress did not affect the amounts of the 46- and 42-kDa activase forms (present as 51- and 45-kDa preproteins) recovered after their immunoprecipitation from in vitro translation products. De novo protein synthesis in vivo in the presence of [35S]Met/Cys showed an increase in the amount of newly synthesized 42-kDa subunit after 4 h of heat stress, and synthesis of the putative 41-kDa activase was apparent. In contrast to activase, heat stress led to a rapid and large reduction in the de novo synthesis of the large and small subunits of Rubisco. Long-term (48-h) heat stress further increased the amounts of de novo synthesized 42- and 41-kDa activase forms. After 24 h of recovery from heat stress, de novo synthesis of the 42-kDa activase returned to control levels, while a small amount of 41-kDa protein was still expressed. Southern analysis suggested the presence of a single activase gene. These results indicate that heat stress alters activase expression, most likely posttranscriptionally, and suggest that the heat-induced expression of the 42- and 41-kDa subunits of wheat leaf Rubisco activase may be related to the maintenance and acclimation of photosynthetic CO2 fixation during high temperature stress in wheat.

MeSH terms

  • Blotting, Southern
  • Blotting, Western
  • Enzyme Induction
  • Gene Expression Regulation, Plant*
  • Isoenzymes / biosynthesis
  • Isoenzymes / chemistry
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Molecular Weight
  • Plant Diseases
  • Plant Leaves / enzymology*
  • Plant Leaves / genetics
  • Plant Proteins / biosynthesis*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Protein Subunits
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • Ribulose-Bisphosphate Carboxylase / biosynthesis
  • Ribulose-Bisphosphate Carboxylase / chemistry
  • Ribulose-Bisphosphate Carboxylase / genetics
  • Temperature
  • Time Factors
  • Triticum / enzymology*
  • Triticum / genetics


  • Isoenzymes
  • Plant Proteins
  • Protein Subunits
  • RNA, Messenger
  • RNA, Plant
  • rca protein, plant
  • Ribulose-Bisphosphate Carboxylase