Cloning And Functional Analysis Of NtFtsZ2-1 Gene From Nicotiana Tabacum

FtsZ, a functional protein existed in prokaryotes and plants controlled the division of prokaryotic cells and plastids in plants. The discovery of FtsZ protein in plants provided us a chance to study the molecular mechanism controlling the division of chloroplasts in plant cells. Studies have shown that in higher plants FtsZ protein perhaps plays a role in chloroplasts shape maintenance in addition to its function in chloroplasts division. The existence of two ftsZ gene families and moreftsZ genes in higher plants also makes the analysis of their function more complex. The investigation of the function of FtsZ protein in Nicotiana tabacum will found a good foundation for us to know the molecular mechanism of chloroplasts division and the origin and evolution of eukaryotic cells. The function offtsZl family in Nicotiana tabacum had been analyzed previously in our laboratory, hence, the study of ftsZ2 family will no doubt help us understand the roles of two ftsZ families in chloroplasts division and morphology maintenance in higher plants and also the interaction relationship between them. In this study a pair of primers was designed according to the ftsZ sequence of Nicotiana tabacum (accession number: AJ271750) published in GenBank and the Nicotiana tabacum NtFtsZ2-l cDNA was cloned after RT-PCR. With the construction of sense and antisense expression plasmids pBZS3 and pBZA3 respectively, the transgenic plants were obtained after transformation and resistance selection. Microscopic observation of the number and morphology of chloroplasts displayed that both sense and antisense transformation had changed the number and morphology of chloroplasts in transgenic plants strikingly. In most transgenic plants single, enlarged and irregular chloroplasts in morphology were observed; while in other transgenic plants there were fewer, enlarged and regular chloroplasts in shape compared with that of the wild type. These experiments indicated that in Nicotiana tabacum NtFtsZ2-l protein participated in the process of chloroplasts division. Furthermore, the analyses of the content of chlorophyll in both sense and antisense transgenic plants showed that it had no striking difference compared with that of the wild type Nicotiana tabacum. So perhaps there was no obvious change in the photosynthetic capacity of the transgenic chloroplasts. Above all, the NtFtsZ2-l protein in Nicotiana tabacum taked part in the process of chloroplast division, but in transgenic plants perhaps it had no obvious effect on the normal function of chloroplasts.