ABA Conjugates and Their Physiological Roles in Plant Cells - Abscisic Acid: Metabolism, Transport and Signaling - page 80

Fig. 5.2 Production and hydrolysis of ABA-GE and its transport across various subcellular
membranes. ABA-GE was produced through the conjugation of ABA with glucose UGT71B6 in
the cytosol. AtABCC1/2 located at the tonoplast direct translocation of ABA-GE from the cyto-
sol to the vacuole. After translocating into the ER or vacuoles, it could be hydrolyzed to produce
ABA by AtBG1 and AtBG2, respectively. Apoplastic ABA-GE could be also by hydrolyzed to
ABA by ʲ -glucosidase homologs whose identity is not known, or loaded into the xylem for long-
distance transportation to other tissues. The processes which have been experimentally demon-
strated are depicted in solid lines whereas those unknown are shown by broken lines. Putative
ABA-GE transporters at various subcellular organelles are marked by a question mark. ER, endo-
plasmic reticulum