Molecular cloning and characterization of BnPPT1 gene from Brassica napus

Phosphoenolpyruvate(PEP)/phosphate translocator 1(PPT1) gene is best known for its role as the translocator in importing the PEP into plastids as substrates for fatty acid biosynthesis and more important for the shikimate pathway.In order to investigate the function of PPT1 from Brassica napus,we genetically isolated a full-length cDNA encoding PPT1 with total RNA of developing seeds from Brassica napus,and the corresponding genomic DNA region from DNA of young leaves with specific primers designed according to sequences of AtPPT1 and ESTs from Brassica napus by searching the BBSRC BrassicaDB.This gene,designated BnPPT1,is 2 075 bp in length of the genomic DNA with eight introns and is 1 224 bp in length of the complete coding sequences encoding 407 amino acids.Multiple sequence alignment of protein sequences showed BnPPT1 shared high homology with AtPPT1 of Arabidopsis thaliana.Furthermore,semi-quantitative RT-PCR analysis carried out with RNA isolated from tissues and various stages of developmental seeds from Brassica napus demonstrated that BnPPT1 was preferentially expressed in seeds at middle developmental stages,which indicated that BnPPT1 gene might play an important role in carbohydrate metabolism of developing seeds in Brassica napus.