SWEET11 and SWEET12 transporters function in tandem to modulate sugar flux in Arabidopsis: An account of the underlying unique structure-function relationship

Sugar will eventually be exported transporters (SWEETs) have been identified as a unique class of sugar efflux transporters in all biological kingdoms. AtSWEET11 and AtSWEET12 in Arabidopsis act synergistically to perform distinct physiological roles, particularly in apoplasmic phloem loading, seed filling, and sugar level alteration at the site of pathogen infection. Plasma membrane-localized AtSWEET11 and AtSWEET12 transporters exclusively facilitate sucrose transport along the concentration gradient. This article examines the sucrose binding pocket of AtSWEET11 and AtSWEET12 using docking studies, and how they act synergistically in various functions throughout plant development and during abiotic and biotic stresses. Further, we highlight the phylogenetic and the in-silico analyses of AtSWEET11 and AtSWEET12 orthologs from 39 economically important plant species that could provide new platforms for future studies on sugar allocation mechanisms across the different plant families. In-depth understanding of these transporters and their molecular regulatory mechanisms could be harnessed for crop improvement and crop protection.