Functional analysis of PuSWEET15. A, Heterologous expression of PuSWEET15 in yeast strain SUSY7/ura. Yeast cells with pDR196-PuSWEET15 or pDR196 vector (as a negative control) were grown on SD/−uracil solid medium containing 2% (w/v) Glc or Suc as the sole carbon source. Numbers under the images indicate the dilution fold. B and C, PuSWEET15 was overexpressed in NG pear fruit using Agrobacterium tumefaciens-mediated infiltration. The expression of PuSWEET15 was detected by RT-qPCR (B) and the sugar content was measured by HPLC (C). D and E, PuSWEET15 was silenced in BNG pear fruit using A. tumefaciens-mediated infiltration. The expression of PuSWEET15 was detected by RT-qPCR (D) and the sugar content was measured by HPLC (E). F, PuSWEET15 was overexpressed in N. benthamiana leaves using A. tumefaciens-mediated infiltration. The expression of PuSWEET15 (left) was detected by RT-qPCR, and the sugar content (right) was measured by HPLC. Three biological replicates were analyzed, and the error bars represent the se. Asterisks indicate significant difference as determined by Student’s t test (**P < 0.01).