Peptide uptake in the ectomycorrhizal fungus Hebeloma cylindrosporum: characterization of two di‐ and tripeptide transporters (HcPTR2A and B)
2006
Benjdia, Mariam | Rikirsch, Enno | Muller, Tobias | Morel, Mélanie | Corratgé, Claire | Zimmermann, Sabine | Chalot, Michel | Frommer, Wolf B. | Wipf, Daniel
• 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.
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