Peptide uptake in the ectomycorrhizal fungus Hebeloma cylindrosporum: characterization of two di- and tripeptide transporters (HcPTR2A and B).
Constraints on plant growth imposed by low availability of nitrogen are a characteristic feature of ecosystems dominated by ectomycorrhizal plants. Ectomycorrhizal fungi play a key role in the N nutrition of plants, allowing their host plants to access decomposition products of dead plant and animal materials. Ectomycorrhizal plants are thus able to compensate for the low availability of inorganic N in forest ecosystems. The capacity to take up peptides, as well as the transport mechanisms involved, were analysed in the ectomycorrhizal fungus Hebeloma cylindrosporum. The present study demonstrated that H. cylindrosporum mycelium was able to take up di- and tripeptides and use them as sole N source. Two peptide transporters (HcPTR2A and B) were isolated by yeast functional complementation using an H. cylindrosporum cDNA library, and were shown to mediate dipeptide uptake. Uptake capacities and expression regulation of both genes were analysed, indicating that HcPTR2A was involved in the high-efficiency peptide uptake under conditions of limited N availability, whereas HcPTR2B was expressed constitutively.
Benjdia
Mariam
M
ZMBP, Plant Physiology, Auf der Morgenstelle 1, 72076 Tübingen, Germany.
Rikirsch
Enno
E
Müller
Tobias
T
Morel
Mélanie
M
Corratgé
Claire
C
Zimmermann
Sabine
S
Chalot
Michel
M
Frommer
Wolf B
WB
Wipf
Daniel
D
D000363:Agaricales / Q000378:metabolism*; D003001:Cloning, Molecular; D004151:Dipeptides / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D015723:Gene Library; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D038821:Mycorrhizae / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D009842:Oligopeptides / Q000378:metabolism*; D010802:Phylogeny; D020539:Sequence Analysis, Protein; D015003:Yeasts / Q000235:genetics
D004151:Dipeptides; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D009842:Oligopeptides; C043912:peptide permease; D009584:Nitrogen