Sugar and polymer intermediates are shown in black, whereas the proteins (enzymes) involved in each step are shown in blue. Detailed protein names, annotation and RNA-Seq expression data are provided in S12 File. * indicates the DEGs. Yellow-blue scale and white-red scale indicate relative and absolute expression profiles, respectively. A, apical stem segment; M, middle stem segment; B, basal stem segment. Absolute expression level (RPKM) is only shown for basal stem segment. CESA, cellulose synthase; CSLA, cellulose synthase like A; FRK, fructokinase; GMP, GDP-D-mannose pyrophosphorylase; HEX, hexokinase; INV, invertase; PGI, phosphoglucose isomerase; PGM, phosphoglucomutase; PMI, phosphomannose isomerase; PMM, phosphomannomutase; SUSY, sucrose synthase; UGP, UDP-glucosepyrophosphorylase.