Cloning of tobacco rbcS promoter and determination of its activity

Abstract

In order to promote specific expression of alien gene in leaf tissue of tobacco and improve leaf quality,sequence of ribulose-1,5-bisphosphate carboxylase small subunit (rbcS) promoter was isolated from tobacco cultivar NC89 genome by PCR with amplified segment size of 979bp. PlantCARE sequence analysis showed that the sequence contained conservative sequence of promoter,and also a dozen light-responsive elements. There was 99% sequence identity with reported corresponding sequence. A recombinant expression vector prbcS-121 was constructed with rbcS promoter and GUS gene,together with pBI121,transformed into tobacco by Agrobacterium tumefaciens-mediated transformation method. The determinations of the GUS activities in ttransgenic tabacco plants indicated that rbcS promoter can drive the expression of GUS gene in leaves of transgenic plants,and the expression level of rbcS-GUS fusion gene was significantly stronger than that of CaMV35S-GUS fusion gene. A new tool was offered for high-level expression of foreign gene in transgenic plant which can achieve tissue-special and light-regulated expression of interesting gene.