Carbon allocation in ectomycorrhizas: identification and expression analysis of an Amanita muscaria monosaccharide transporter

• Published in: Molecular plant-microbe interactions Vol. 11; no. 3; pp. 167 - 176
• Main Authors: Nehis, U, Wiese, J, Guttenberger, M, Hampp, R
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.03.1998; The American Phytopathological Society
• Subjects: ACTIVE TRANSPORT; ADN; Agronomy. Soil science and plant productions; AMANITA; Amanita - genetics; Amanita - metabolism; Amino Acid Sequence; AMINO ACID SEQUENCES; ARN MENSAJERO; ARN MESSAGER; Base Sequence; Biological and medical sciences; CELL MEMBRANES; CHEMICAL COMPOSITION; COMPLEMENTARY DNA; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; Consensus Sequence; Conserved Sequence; DNA; DNA Primers; Economic plant physiology; EXPRESION GENICA; EXPRESSION DES GENES; FRUCTOSA; FRUCTOSE; Fundamental and applied biological sciences. Psychology; Fungal Proteins - biosynthesis; Fungal Proteins - chemistry; Fungal Proteins - genetics; GENBANK/Z83828; GENE EXPRESSION; Gene Library; GENETIC TRANSFORMATION; GLUCOSA; GLUCOSE; HYPHAE; MEMBRANAS CELULARES; MEMBRANE CELLULAIRE; MESSENGER RNA; MICELIO; MOLECULAR SEQUENCE DATA; MONOSACARIDOS; MONOSACCHARIDE; Monosaccharide Transport Proteins - biosynthesis; Monosaccharide Transport Proteins - chemistry; Monosaccharide Transport Proteins - genetics; MONOSACCHARIDES; MYCELIUM; Neurospora crassa - genetics; NUCLEOTIDE SEQUENCE; Open Reading Frames; Phylogeny; PICEA ABIES; Plant physiology and development; PLASMA MEMBRANES; Polymerase Chain Reaction; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; RNA, Messenger - biosynthesis; Saccharomyces cerevisiae - genetics; SCHIZOSACCHAROMYCES POMBE; SECUENCIA NUCLEOTIDICA; Sequence Alignment; Sequence Homology, Amino Acid; SEQUENCE NUCLEOTIDIQUE; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); TRANSFORMACION GENETICA; TRANSFORMATION GENETIQUE; Trees - microbiology; Water and solutes. Absorption, translocation and permeability; Symbiosis; Nucleotide sequence; Amanita muscaria; Vegetal microorganism relation; Basidiomycetes; Homology; Gene expression; Fungi; Membrane transport; Poisonous fungi; DNA; Softwood forest tree; Gymnospermae; Mycorrhiza; Ectomycorrhiza; Coniferales; Spermatophyta; Carbohydrate; Picea abies; Carrier protein; Aminoacid sequence; Thallophyta
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi.1998.11.3.167

Ectomycorrhizas are formed between certain soil fungi and fine roots of predominantly woody plants. An important feature of this symbiosis is the supply of plant-derived carbohydrates to the fungus. As a first step toward a better understanding of the molecular basis of this process, we cloned a monosaccharide transporter from the ectomycorrhizal fungus Amanita muscaria. Degenerate oligonucleotide primers were designed to match conserved regions from known fungal sugar transporters. A cDNA fragment of the transporter was obtained from mycorrhizal mRNA by reverse transcription-polymerase chain reaction. This fragment was used to identify a clone (AmMst1) encoding the entire monosaccharide transporter in a Picea abies/A. muscaria mycorrhizal cDNA library. The cDNA codes for an open reading frame of 520 amino acids, showing best homology to a Neurospora crassa monosaccharide transporter. The function of AmMST1 as monosaccharide transporter was confirmed by heterologous expression of the cDNA in a Schizosaccharomyces pombe mutant lacking a monosaccharide uptake system. AmMst1 was constitutively expressed in fungal hyphae under all growth conditions. Nevertheless, in mycorrhizas as well as in hyphae grown at monosaccharide concentrations above 5 mM, the amount of AmMst1 transcript increased fourfold. We therefore suggest that AmMst1 is upregulated in ectomycorrhizas by a monosaccharide-controlled mechanism