title: Functional characterization of a eukaryotic melibiose transporter.
abstract: Pathogenic fungi drastically affect plant health and cause significant losses in crop yield and quality. In spite of their impact, little is known about the carbon sources used by these fungi in planta and about the fungal transporters importing sugars from the plant-fungus interface. Here, we report on the identification and characterization of MELIBIOSE TRANSPORTER1 (MBT1) from the hemibiotrophic fungus Colletotrichum graminicola (teleomorph Glomerella graminicola), the causal agent of leaf anthracnose and stalk rot disease in maize (Zea mays). Functional characterization of the MBT1 protein in baker's yeast (Saccharomyces cerevisiae) expressing the MBT1 cDNA revealed that α-D-galactopyranosyl compounds such as melibiose, galactinol, and raffinose are substrates of MBT1, with melibiose most likely being the preferred substrate. α-D-glucopyranosyl disaccharides like trehalose, isomaltose, or maltose are also accepted by MBT1, although with lower affinities. The MBT1 gene shows low and comparable expression levels in axenically grown C. graminicola and upon infection of maize leaves both during the initial biotrophic development of the fungus and during the subsequent necrotrophic phase. Despite these low levels of MBT1 expression, the MBT1 protein allows efficient growth of C. graminicola on melibiose as sole carbon source in axenic cultures. Although Δmbt1 mutants are unable to grow on melibiose, they do not show virulence defects on maize.
authors: Molecular Plant Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany.
authors: Ulrike
authors: U
authors: Lingner
authors: Steffen
authors: S
authors: Münch
authors: Björn
authors: B
authors: Sode
authors: Holger B
authors: HB
authors: Deising
authors: Norbert
authors: N
authors: Sauer
references: New Phytol. 1993 Jun;124(2):193-213
references: 33874341
references: Biochim Biophys Acta. 1994 Jun 29;1197(2):133-66
references: 8031825
references: Plant Physiol. 2009 Oct;151(2):792-808
references: 19675155
references: Trends Plant Sci. 2004 Dec;9(12):606-13
references: 15564128
references: Nucleic Acids Res. 1992 Mar 25;20(6):1425
references: 1561104
references: Plant Physiol. 2003 Oct;133(2):901-9
references: 14500789
references: J Bacteriol. 1996 Dec;178(24):7197-205
references: 8955402
references: Plant Physiol. 1977 Jan;59(1):81-5
references: 16659793
references: Biotechniques. 1997 Jan;22(1):88-90
references: 8994655
references: J Plant Physiol. 2008 Jan;165(1):41-51
references: 17765357
references: Plant Physiol. 2010 Nov;154(3):1549-57
references: 20837701
references: J Bacteriol. 1991 Mar;173(5):1817-20
references: 1999393
references: Fungal Genet Biol. 2004 Nov;41(11):973-81
references: 15465386
references: Mol Plant Microbe Interact. 2008 Oct;21(10):1325-36
references: 18785828
references: PLoS Biol. 2010 Feb 09;8(2):e1000303
references: 20161717
references: Nature. 2006 Nov 2;444(7115):97-101
references: 17080091
references: Mol Microbiol. 1995 Sep;17(6):1093-107
references: 8594329
references: Nat Biotechnol. 2000 Nov;18(11):1157-61
references: 11062433
references: Planta. 2007 Jan;225(2):311-20
references: 16845526
references: Biochimie. 1985 Jan;67(1):59-67
references: 3888292
references: Plant J. 1994 Jul;6(1):67-77
references: 7920705
references: Mol Plant Pathol. 2011 Jan;12(1):43-55
references: 21118348
references: FEBS Lett. 2007 May 25;581(12):2309-17
references: 17434165
references: Proc Natl Acad Sci U S A. 2001 Apr 10;98(8):4540-5
references: 11274355
references: Biochim Biophys Acta. 1997 Oct 9;1354(1):7-12
references: 9375783
references: J Plant Physiol. 2011 Jan 1;168(1):51-62
references: 20674079
references: J Biol Chem. 1984 Apr 10;259(7):4320-6
references: 6323466
references: Biochim Biophys Acta. 2009 Jun;1787(6):706-13
references: 19366604
references: Mol Microbiol. 1996 Mar;19(5):911-22
references: 8830272
references: Proc Natl Acad Sci U S A. 1983 Dec;80(23):7080-4
references: 6359161
references: Plant Physiol. 1984 May;75(1):154-60
references: 16663562
references: J Exp Bot. 2001 Jun;52(359):1239-49
references: 11432942
references: Eur J Biochem. 1977 Oct 17;80(1):97-102
references: 21792
references: Trends Plant Sci. 2002 Aug;7(8):352-6
references: 12167330
references: J Biol Chem. 1992 Sep 15;267(26):18371-6
references: 1339436
references: J Biol Chem. 2011 Jun 10;286(23):20913-22
references: 21502323
references: Mol Microbiol. 2003 Aug;49(4):859-67
references: 12890013
references: J Biol Chem. 1982 May 10;257(9):5125-8
references: 7040393
references: Mol Plant Microbe Interact. 2007 Dec;20(12):1555-67
references: 17990963