Ectomycorrhiza-specific gene expression: Function and regulation

• Applicant: Professor Dr. Uwe Nehls
• Subject Area: Forestry
• Term: from 2003 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5469979

Poplar could succeed in nutrient rich areas as well as in nutrient poor forests soils where plants live in symbiosis with certain soil fungi to enable sufficient nutrition. Due to its huge demand, nitrogen, as major nutrient, is of special interest for poplar nutrition. In this project we want to characterize nitrate, ammonium and amino acid transporters from poplar roots that are differentially regulated as result of nitrogen nutrition (shortage or nitrogen excess), or by plant/fungus interaction. The kinetic parameters of selected transporters will be determined by heterologous expression. Tissue and organ specific expression of certain transporter genes will be investigated by Northern blot and RT-PCR and by the utilization of poplar transformants containing promoter-GFP fusions. GFP fusions with truncated promoters will also be used for the identification of cis-elements responsible for the nitrogen-dependent expression of selected transporter genes. In addition, the global impact of nitrogen nutrition on poplar gene expression will be investigated using macro and micro arrays hybridization and probes of poplar roots grown at different nitrogen sources and concentrations as well as mycorrhizas.

• DFG Programme: Research Units
• Subproject of: FOR 496: Poplar - a model to address tree-specific questions