FIGURE 3.

Activity and function determination of GspInv and GspSUT1.(A) Fold changes of w5 invertase gene (GspInv) and sucrose transporter genes (GsSUT1 and GsSUT2) after 24 h cultivation in the presence of sucrose or after co-cultivated with M. truncatula at 6 dpi and 16 dpi. The control group was w5 cultured on medium without carbon source. Values are the means ± standard (n = 9). (B) Native-PAGE of purified GspInv. (C,D) Effects of pH and temperature on activity of GspInv. (E) Analysis of sugar products using 1000 mM and 500 mM sucrose as the substrate to test transglycosidase activity. (F) Heterologous expression of GspInv in invertase-deficient yeast S. cerevisiae strain SEY2102 on synthetic medium with sucrose as the sole carbon source. (G) Complementation of the yeast hexose transport-defective strain EBY.VW4000 with GspSUT1. The yeast cells were grown on SD media containing different sugars as sole carbon source at 30°C for 3 days. In each image, the yeast strain was diluted to an OD₆₀₀ of 0.2 and then ×1, ×5, ×25, and ×125 diluted with sterile water. (H) Sucrose uptake experiment using ³H-sucrose as the substrate. (I) GspSUT1 is activated in the presence of the metabolizable carbon source glucose in SEY2102. *p < 0.05; **p < 0.01.