The Arabidopsis sugar transporter (AtSTP) family: an update

Abstract

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.

A Versatile Monosaccharide Transporter That Operates in the Arbuscular Mycorrhizal FungusGlomussp Is Crucial for the Symbiotic Relationship with Plants

“…This K m is in the range of the highest affinity reported for plant monosaccharide transporters (Bü ttner, 2007), including the Arabidopsis thaliana transporter STP4 (K m 15 mM) (Truernit et al, 1996;Bü ttner and Sauer, 2000). STP4, together with STP1, STP7, and STP13, are the most highly expressed monosaccharide transporters in Arabidopsis roots (Bü ttner, 2010), and with the exception of STP7, whose K m has not been determined, they are all highaffinity transporters (K m 15 to 74 mM), suggesting that the concentration of available monosaccharides at the root apoplast is very low. For MST2, a pH optimum was found at pH 5.0 ( Figure 3D), a likely apoplastic pH at the plant-fungal interface (Guttenberger 2000).…”

Down-Regulating CsHT1, a Cucumber Pollen-Specific Hexose Transporter, Inhibits Pollen Germination, Tube Growth, and Seed Development

“…By contrast, pollen tubes of petunia (Petunia hybrida) grow equally well on medium containing Glc, Fru, or Suc (Ylstra et al, 1998). Although several hexose transporter genes are highly expressed in pollen grains or pollen tubes of Arabidopsis (Büttner, 2010) and rice (Oliver et al, 2007a;Wang et al, 2007Wang et al, , 2008, single knockouts of these genes do not result in a phenotype, and in vitro experiments demonstrate that the germination of Arabidopsis pollen seems to be strictly dependent on Suc in the medium. Addition of Glc causes instant bursting of Arabidopsis pollen tubes (Schneidereit et al, 2003(Schneidereit et al, , 2005Scholz-Starke et al, 2003).…”

A Novel Arabidopsis Vacuolar Glucose Exporter Is Involved in Cellular Sugar Homeostasis and Affects the Composition of Seed Storage Compounds

“…The corresponding carriers for the uptake of Suc (Sauer, 2007) and hexoses (Bü ttner, 2010) across the plasma membrane have been identified and characterized for a variety of plants. In contrast, little is known about sugar transport proteins in the tonoplast.…”