Redirection of photoassimilate partitioning by biotrophic, hemibiotrophic and mutualistic fungi through altered transporter gene expression

高等植物体内碳水化合物、氨基酸、离子、水和许多其他化合物的分配和分布受到严格的调节。至关重要的是，要向多个汇充分和及时地供应这些化合物，因为这些汇在开发过程中并根据环境因素不断变化其强度和数量。在植物与病原菌相互作用过程中，病原菌通过参与宿主光合同化物库的形成来触发新库组织的形成。这些转运蛋白基因表达变化的信号转导机制在很大程度上是未知的。该项目的目的是鉴定和表征宿主靶基因，这些基因负责改变同化物分配和宿主/真菌相互作用期间调节的真菌转运蛋白。为此，将来自三个不同物种（大麦、拟南芥、玉米）的植物用病原性真菌（Blumeria -大麦[B2];白粉菌属-拟南芥;黑粉菌属[A2]和炭疽菌属[Al] -玉米）和互利共生真菌（所有三个物种的梨形孢属[B2]）以及可用的无病原性真菌突变体（黑粉菌属，A2）感染。将鉴定转运蛋白基因转录物的改变水平（微阵列分析），并将其分为独特的（植物和/或植物病原体特异性）和普遍存在的变化。将分析这些基因的过表达或减少表达（RNAi）对野生型和突变体植物（拟南芥）中真菌感染的影响。将从相互作用的不同阶段鉴定真菌转运蛋白基因（炭疽菌属）[A1]，并分析其对真菌生长的作用。

Allocation and distribution of carbohydrates, amino acids, ions, water and numerous other compounds is tightly regulated in higher plants. It is essential for sufficient and timely supply of these compounds to multiple sinks that continuously change in strength and number during development and in response to environmental factors. During plant-pathogen interactions the formation of new sink tissues is triggered by the pathogen that aims to participate in the host s pool of photoassimilates. The signal transduction mechanisms underlying these changes in transporter gene expression are largely unknown. The aim of this project is the identification and characterization of host target genes responsible for altered assimilate partitioning and of fungal transport proteins regulated during host/fungus interaction. To this end, plants from three different species (barley, Arabidopsis, maize) will be infected with a pathogenic (Blumeria - barley [B2]; Erysiphe - Arabidopsis; Ustilago [A2] and Colletotrichum [A1] - maize) and a mutualistic fungus (Piriformospora [B2] for all three species) and with apathogenic fungal mutants, where available (Ustilago, A2). Altered levels of transporter gene transcripts will be identified (microarray analyses) and will be separated into unique (plant and/or plant-pathogen specific) and ubiquitous changes. The effect of overexpression or of reduced expression (RNAi) of these genes on fungal infection in wild type and mutant plants (Arabidopsis) will be analyzed. Fungal transporter genes (Colletotrichum) will be identified from different stages of the interaction [A1] and their role for fungal growth will be analyzed.