title: Characterization of a carbohydrate transporter from symbiotic glomeromycotan fungi.
abstract: The symbiotic relationships between mycorrhizal fungi and plants have an enormous impact on terrestrial ecosystems. Most common are the arbuscular mycorrhizas, formed by fungi belonging to the phylum Glomeromycota. Arbuscular mycorrhizal fungi facilitate the uptake of soil nutrients by plants and in exchange obtain carbohydrates, thus representing a large sink for atmospheric plant-fixed CO(2). However, how carbohydrates are transported through the symbiotic interface is still unknown. Here we report the characterization of the first known glomeromycotan monosaccharide transporter, GpMST1, by exploiting the unique symbiosis of a glomeromycotan fungus (Geosiphon pyriformis) with cyanobacteria. The GpMST1 gene has a very low GC content and contains six introns with unusual boundaries. GpMST1 possesses twelve predicted transmembrane domains and functions as a proton co-transporter with highest affinity for glucose, then mannose, galactose and fructose. It belongs to an as yet uncharacterized phylogenetic monosaccharide transporter clade. This initial characterization of a new transporter family involved in fungal symbiosis will lead to a better understanding of carbon flows in terrestrial environments.
authors.affiliation: Darmstadt University of Technology, Institute of Botany, Schnittspahnstrasse 10, 64287 Darmstadt, Germany. arthur.schuessler@lrz.uni-muenchen.de
authors.forename: Arthur
authors.initials: A
authors.lastname: Schüssler
authors.forename: Holger
authors.initials: H
authors.lastname: Martin
authors.forename: David
authors.initials: D
authors.lastname: Cohen
authors.forename: Michael
authors.initials: M
authors.lastname: Fitz
authors.forename: Daniel
authors.initials: D
authors.lastname: Wipf
mesh_terms: D001692:Biological Transport; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D005658:Fungi / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D008969:Molecular Sequence Data; D010710:Phosphates / Q000378:metabolism; D013559:Symbiosis
chemical_list: D002352:Carrier Proteins; D005656:Fungal Proteins; D010710:Phosphates; D002244:Carbon; D005947:Glucose