Characterization of the psbA Gene from Chloroplasts of Populus deltoides

A 2.9 kbp EcoRi fragment from chloroplast DNA of a tree species Populus deltoides, has been cloned. Nucleotide sequence analysis led to the identification of a 1062 bp open reading frame located at one end of the recombinant clone. This open reading frame has more than 94% nucleotide sequence homology with tobacco and cotton psbA genes. The deduced amino acid sequence from poplar psbA gene is highly homologous to tobacco and differs only by 2 amino acids located at C-terminus of the protein. An AT rich region, capable of forming a potential stem-loop structure was located down stream to the psbA gene. Our Southern hybridization data confirms the presence of IR region as well as the location of the psbA gene near one of the IR in P. deltoides.