中国生物工程杂志

Banana bunchy top disease is one of major diseases in banana, the pathogen of the disease is banana bunchy top virus. The virus genome consists of at least 6 components of circular ssDNA about 1.0~1.1kb. Each DNA component contains encoding region and non-coding one. On the basis of previous research, we want to understand further the promoter function of BBTV DNA components. According as the genomic sequence of BBTV Hainan isolate, a 540bp fragment（BV3.1） generated by PCR amplification, which is the promoter sequence of BBTV DNA3 component; and a 646bp splicing sequence（BV23）is consisted of non-coding regions of DNA2 and DNA3 components generated by overlapping PCR amplification. This two promoter sequences substituted the 35S promoter sequence in pBI121 vector and fuse with gus gene respectively, and then got the plant expression vector named for pBIBV3.1(540bp)、pBIVBV23(646bp) are constructed. By GUS histochemical staining, the very weak GUS activity was limited in the leave veins of pBIBV3.1 transgenic tobacco, it confirmed the promoter activity is associated with phloem specific expression. Whereas the faint GUS activities were detected in the mesophyll, the leaf margin of pBIVBV23 transgenic tobacco and in some leaf veins as well. It indicates that the transcriptional method of DNA2 component is different with one of DNA3 component.