Cloning and expression analysis of Rubisco activase genes in Carya cathayensis

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a key enzyme involved in CO2 assimilation during photosynthesis. Rubisco activation depends on the activity of Rubisco activase (RCA). We performed 3'/5' rapid amplification of cDNA ends (RACE) and reverse transcription polymerase chain reaction (RT-PCR) to amplify the 3 and 5 end sequences of RCA genes from hickory. We obtained two full-length gene sequences, designated CcRCA and CcRCA. The two corresponding cDNAs are divergent in both the translated and 3 untranslated regions. The analysis of the genomic DNA sequences suggested that the corresponding mRNAs are transcripts of two different genes and not the products of a single alternatively spliced pre-mRNA. We examined the expression of CcRCA and CcRCA in hickory leaves at various stages of development by quantitative real-time PCR (qRT-PCR) analysis. The results suggest that RCA genes play an important role in development and environmental responses. These results provide a basis for modulating RCA gene expression to improve the photosynthetic rate and plant growth in hickory.