When tested for complementation of the growth defect of the EBY4000
mutant strain, OsSWEET1a and OsSWEET1b showed limited growth on glucose,
while OsSWEET2a and OsSWEET2b did not show growth. When tested on the toxic
glucose analogue 2-deoxyglucose, only OsSWEET1a and OsSWEET1b failed to
grow, suggesting that they may be glucose transporters. In contrast,
OsSWEET2a and OsSWEET2b were able to grow in the presence of the
2-deoxyglucose, possibly because they are localized to the vacuole membrane
and are not able to mediate uptake of the sugar analogue.