Cloning and expression analysis of sugarcane photosystem I psaD gene

In the present study,rapid amplification of cDNA ends(RACE PCR)was used to clone gene for PS Ⅰ reaction center subunitⅡfrom the sugarcane leaf roll,which was named as SopsaDgene,with the GenBank accession number of JX866950.The full-length cDNA of SopsaD was 904bp.It possessed the open reading frame of 603bp encoding 200amino acids with predicted molecular weight of 21.85ku and an isoelectric point of 10.5.At the N-end of SoPsaD protein,1~44aa was the chloroplast transit peptide sequence and 62~199aa was the conserved Pfam:PasD domain.The similarity comparison revealed that the gene nucleotide sequence shared 85%,85%,84% and 81% homology with those of the psaD genes from Zea mays(EU953246),Oryza sativa(AY224449),Hordeum vulgare(M98254)and Brachypodium distachyon(XM003564060),while the similarity at the amino acid sequences with those species was 92%,88%,87% and 85%respectively.The results of real-time fluorescent quantitative PCR(qRT-PCR) showed expression of SopsaDcould be detected in the leaves,flowers,buds,stalks and roots,among which the highest was found in leaves,followed by flowers,and the lowest in roots.Overall performance of SopsaDexpression was high in the function leaves,but low at the old leaves during the periods of technical maturing and physiological maturing.