2.1 Materials
The sorghum wildtype and transgenic line pSbUbi:schl-qsuB #48 (variety Wheatland) used in this study have been described previously.26 The plants were grown at the University of California (UC) greenhouse Oxford facility and harvested at full maturity without the panicles.26 Each sample consisted of stem and leaf biomass from five plants, which was dried in an oven at 50 °C for five days and ground using a Model 4 Wiley Mill equipped with a 1-mm mesh (Thomas Scientific, Swedesboro, NJ). Chemicals for DES synthesis, including choline chloride and 3,4-dihydroxybenzoic acid, were purchased from JT Baker and BeanTown Chemical, respectively. The chemical used as the third constituent of the DES (ethylene glycol) was purchased from VWR. Cellulase, enzyme blend Cellic CTec2, sodium acetate trihydrate, and sodium azide were purchased from Sigma-Aldrich. The enzyme was stored at 2-8 °C.