Regulation of signal transduction during myorrhizal symbiosis

丛枝菌根（AM）是植物界最古老、分布最广的共生体之一。与大多数致病性相互作用形成鲜明对比的是，植物允许丛枝菌根真菌进入宿主细胞并在细胞内形成其共生活性器官-丛枝。共生体仍然被植物来源的质膜包围，该质膜表现出不同的生理特性，并含有一系列在AM共生过程中特异性诱导的蛋白质。在AM真菌感染宿主根的过程中，MYCREM蛋白仅在含有丛枝的细胞中表达，并定位于丛枝周膜。该蛋白与蛋白质家族的另一个成员（SYMREM 1）密切相关，该蛋白质家族已被证明可调节根瘤菌感染并与关键受体蛋白相互作用。在本提案中，我们旨在通过三种方法更详细地了解MYCREM的生物学作用。我们将产生和分析双突变体（symrem 1/mycrem），以评估这些蛋白质之间可能的功能冗余。其次，将使用超分辨率显微镜观察丛枝周围膜上膜筏的存在。在第三组实验中，已经确定的假定相互作用伙伴将被进一步表征。该分析包括对AM共生过程中特异性诱导的新型受体样激酶的研究。

Arbuscular mycorrhiza (AM) is one of the oldest symbiotic and most widespread interactions in the plant kingdom. In sharp contrast to most pathogenic interactions the plant allows the arbuscular mycorrhizal fungus to enter the host cells and to intracellularly form its symbiotically active organs, the arbuscules. The symbiont remains surrounded by a plant-derived plasma membrane that exhibits different physiological properties and hosts a series of proteins that are specifically induced during AM sybiosis. During infection of the host root by AM fungi a remorin protein (MYCREM) is exclusively expressed in arbuscule containing cells and localizes to the periarbuscular membrane. This remorin is closely related to another member of the protein family (SYMREM1) that has been shown to regulate rhizobial infection and to interact with key receptor proteins. In this proposal we aim to understand the biological role of MYCREM in more detail taking three approaches. We will generate and analyze double mutants (symrem1/mycrem) to assess possible functional redundancy between these proteins. Secondly, super-resolution microscopy will be used to visualize the presence of membrane rafts on the periarbuscular membrane. In a third set of experiments putative interaction partners that have already been identified will be characterized further. This analysis includes studies on a novel receptor-like kinase that is specifically induced during AM symbiosis.