Figure 2.

Involvement of SWEET transporters during plant–pathogen and symbiotic interactions. Xanthomonas spp. secretes TAL effectors that induce the expression of SWEET (e.g. OsSWEET11, 13, and 14) to increase sugar leakage (Chen et al., 2010). SWEETs can be also involved in defense mechanisms like in infected Arabidopsis roots in which AtSWEET2 increases the accumulation of cytosolic sugars in the vacuole, impeding its transport to the extracellular space (Chen et al., 2015a). During interactions with beneficial microorganisms, such as in M. truncatula with the symbiotic AM (R. irregularis), MtSWEET1b transports glucose across the peri-arbuscular membrane (An et al., 2019). SW, SWEET; MST2, AM fungus Monosaccharide Transporter 2.