Ectomycorrhiza-specific gene expression: Function and regulation

杨树可以在营养丰富的地区以及营养贫瘠的森林土壤中获得成功，在这些土壤中，植物与某些土壤真菌共生，从而获得足够的营养。由于杨树对氮素的需求量巨大，氮素作为杨树的主要营养元素，对杨树的营养具有特殊的意义。在这个项目中，我们想要描述杨树根部的硝酸盐、铵和氨基酸转运体的特征，这些转运体是由于氮素营养(氮素缺乏或氮素过剩)或植物/真菌相互作用而受到差异调节的。所选转运蛋白的动力学参数将由异源表达决定。某些转运蛋白基因的组织和器官特异性表达将通过Northern印迹和RT-PCR以及利用含有启动子-GFP融合的杨树转化体来研究。GFP与截短启动子的融合也将用于鉴定与选定转运蛋白基因的氮依赖表达有关的顺式元件。此外，还将利用不同氮源和浓度下生长的杨树根部以及菌根的宏微阵列杂交和探针来研究氮素营养对杨树基因表达的全球影响。

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.