Abstract：Fructose-6-phosphate,2-kinase/fructose-2,6-bisphosphatase(F2KP), which is comfirmed to be a bifunctional enzyme, is a key regulatory enzyme involved in carbon accumulation and partitioning processes. In the previous study, F2KP with both kinase and phosphatase domain named SoF2KP-L was obtained from the leaf of sugarcane. In this research, different sizes of F2KP homologous fragments from the stem of sugarcane(Saccharum officinarum L.) were amplified and named SoF2KP-S1, SoF2KP-S2 and SoF2KP-S3, respectively. Based on the bioinfomatical analysis, the putative protein SoF2KP-S1, SoF2KP-S2 and SoF2KP-S3 were incomplete respectively with part of kinase domain, phosphatase domain and only several amino acid. Therefore, SoF2KP-L with complete kinase/phosphatase catalytic domains was inserted into plant expression plasmid under the Cauliflower mosaic virus 35S promoter, then transferred into tobacco(Nicotiana tabacum) plants by Agrobacterium-mediated transformation. RT-PCR (Reverse transcription PCR) analysis confirmed that SoF2KP-L was successfully transcripted in mature leaf. The changing rates of soluble sugar/starch, reducing sugar/starch and sucrose/starch indicated that carbohydrate level and carbohydrate partitioning of the transgenic plants had been changed. These results indicate that there may be different transcripts existing in sugarcane and SoF2KP-L regulates the carbon portioning in sugarcane as F2KP in other plants. This stuty will provide theory basis for further study on the biological function of F2KP from sugarcane and for its potential application in sugarcane molecular breeding.
