Plants are energy storage factories. Photosynthetic cells convert energy from sunlight to sugars that are transported to growing tissues via both extracellular and intercellular trafficking pathways. Many pathogens have evolved mechanisms to infect the nutrient-rich niche of plant tissues and exploit these sugar pipelines. Some pathogens manipulate sugar transport to enhance their access to carbohydrate. For example, Xanthomonas bacteria deliver transcriptionactivator–like effector proteins into leaf cells. These proteins induce expression of SWEET family sugar transporters to release sucrose into the apoplastic (extracellular) space where the bacteria grow (1). On page 1427 of this issue, Yamada et al. (2) show that, in return, plants can also regulate sugar transporters, to redistribute the sugars away from the infection niche, removing the pathogens' energy source and limiting their proliferation.
Authors: Peter N. Dodds, Evans S. Lagudah