Ocs elements are a group of promoter sequences required for the expression of both pathogen genes in infected plants and plant defense genes. Genes for ocs element binding factors (OBFs), belonging to a specific class of basic-region leucine zipper (

SUMMARYThe vacuolar membrane is involved in solute uptake into and release from the vacuole, which is the largest plant organelle. In addition to inorganic ions and metabolites, large quantities of protons and sugars are shuttled across this membrane. Current models suggest that the proton gradient across the membrane drives the accumulation and/or release of sugars. Recent studies have associated AtSUC4 with the vacuolar membrane. Some members of the SUC family are plasma membrane proton/sucrose symporters. In addition, the sugar transporters TMT1 and TMT2, which are localized to the vacuolar membrane, have been suggested to function in proton-driven glucose antiport. Here we used the patch-clamp technique to monitor carriermediated sucrose transport by AtSUC4 and AtTMTs in intact Arabidopsis thaliana mesophyll vacuoles. In the whole-vacuole configuration with wild-type material, cytosolic sucrose-induced proton currents were associated with a proton/sucrose antiport mechanism. To identify the related transporter on one hand, and to enable the recording of symporter-mediated currents on the other hand, we electrophysiologically characterized vacuolar proteins recognized by Arabidopsis mutants of partially impaired sugar compartmentation. To our surprise, the intrinsic sucrose/proton antiporter activity was greatly reduced when vacuoles were isolated from plants lacking the monosaccharide transporter AtTMT1/TMT2. Transient expression of AtSUC4 in this mutant background resulted in proton/sucrose symport activity. From these studies, we conclude that, in the natural environment within the Arabidopsis cell, AtSUC4 most likely catalyses protoncoupled sucrose export from the vacuole. However, TMT1/2 probably represents a proton-coupled antiporter capable of high-capacity loading of glucose and sucrose into the vacuole.

The availability of complete plant genomes has greatly influenced the identification and analysis of phylogenetically related gene clusters. In Arabidopsis, this has revealed the existence of a monosaccharide transporter(-like) gene family with 53 members, which play a role in long-distance sugar partitioning or sub-cellular sugar distribution and catalyze the transport of hexoses, but also polyols and in one case also pentoses and tetroses. An update on the currently available information on these Arabidopsis monosaccharide transporters, on their sub-cellular localization and physiological function will be given.

The Arabidopsis sugar transporter (AtSTP) family is one of the best characterised families within the monosaccharide transporter (MST)-like genes. However, several aspects are still poorly investigated or not yet addressed experimentally, such as post-translational modifications and other factors affecting transport activity. This mini-review summarises recent advances in the AtSTP family as well as objectives for future studies.

Depositing metal layers onto a self‐assembled monolayer (SAM) is achieved using a new technique. Au(111) bearing a 4,4′‐dithiodipyridine SAM is immersed into a PdII solution without potential control, causing PdII to adsorb on the surface by forming a complex with the pyridine species. The PdII ions are then electrochemically reduced to Pd0 (see Figure). Angle‐resolved X‐ray photoelectron spectroscopy measurements unequivocally show that the reduced Pd resides on top of the SAM.