Ectomycorrhiza-specific gene expression: Function and regulation

白杨可以成功地在养分丰富的地区，以及在养分贫乏的森林土壤，植物生活在共生与某些土壤真菌，使足够的营养。氮素作为杨树的主要营养元素，由于其巨大的需求量，对白杨的营养具有特殊的意义。在这个项目中，我们要表征硝酸盐，铵和氨基酸转运蛋白从白杨根的差异调节作为氮营养（短缺或氮过剩）的结果，或通过植物/真菌的相互作用。所选转运蛋白的动力学参数将通过异源表达来确定。将通过北方印迹和RT-PCR以及通过利用含有启动子-GFP融合体的白杨转化体来研究某些转运蛋白基因的组织和器官特异性表达。具有截短启动子的GFP融合物也将用于鉴定负责所选转运蛋白基因的氮依赖性表达的顺式元件。此外，氮营养对白杨基因表达的全球影响将使用宏观和微阵列杂交和探针的白杨根生长在不同的氮源和浓度以及菌根。

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.