Studies Of Glycometabolismm And Transcriptomics In Sugarcane

The sugarcane stem is constructed with a series of internodes. The growth and development of sugarcane stem is companied with the whole process of sugar metabolism. Sugar metabolism is regulated by various genes while sugarcane is an allopolyploid charactered as complex genetic behavior of chromosome, which makes genetic research of the sugar metabolism very difficult in sugarcane. In this study, we studied:the first is the determination of sugar content in each internode in sugarcane; the second is the gene expression profiling among the internodes in sugarcane; the third is the identification of gene expression in different sections in sugarcane.In the study of sugar content in sugarcane internode,17 internodes, from the 1st internode to the 17th were selected as the materials. HPLC (High performance liquid chromatography) was applied to determinate the content of glucose, fructose and sucrose in different internodes in sugarcane, then combined with water content, the dry weight of the three kinds of sugar had been easily calculated. The result showed that there was no sucrose accumulation in the first and second internodes because these internodes were main meristematic tissue. Almost all of the photosynthesis products are used for cell morphogenesis. In the forth and fifth internodes, the stem cells stop from cell division basically to cells stretching, but the width of cell basically no longer increases, while the sucrose begins to accumulate. The cells in the seventh and eighth internode completely stop from growth to a full stop. The cell wall started thickening and lignifying and sucrose increased rapidly. The thirteenth and fourteenth internode matured completely, sucrose accumulation reached the highest level and no longer changed with time.Based on the results of sugar content of different internoeds, we have chosen the fist and second internodes, the forth internonde, the seventh internode and the fourteenth internonde in the sugarcane stem as a material for the transcriptomics research with the gene chip. By analyzing sugarcane gene expression profile, genes associated with growth, development and sugar metabolism were screened, also the differentially expressed genes and upregulated and downregulated genes. Then the real-time quantitative PCR was used to verify the transcription result with sucrose synthase gene and glycine-rich protein gene.