Vascularization and loading of amino acids into nematode-induced feeding sites

两类不同的植物寄生定居线虫，胞囊线虫和根结线虫，从高度专门化的细胞摄食结构中从宿主的根部吸收养分。在孢囊线虫的情况下，营养物质通过胞间连丝以共生方式进入所谓的合胞体。在根结线虫的情况下，摄食结构由巨大的细胞组成，这些细胞是共生隔离的，因此依赖于运输蛋白来输入营养。这两个取食部位都与一种高度专门化的卸载韧皮部相连，在根结线虫的情况下，韧皮部完全由筛子分子组成。控制摄食部位的血管化和运输蛋白在营养输入巨细胞中发挥作用的机制在很大程度上是未知的。这项建议的目的之一是阐明控制摄食部位血管形成的事件。特别是植物激素生长素的作用将被讨论。此外，还将研究筛选元件标记的作用和胞间连丝定位受体的作用。该提案的另一部分旨在描述氨基酸转运体在下沉组织中的作用，特别是在巨细胞中。将研究其定位随营养状况和线虫侵染的变化。

Two different groups of plant-parasitic sedentary nematodes, the cyst nematodes and the root-knot nematodes, withdraw nutrients from their host’s roots from highly specialized cellular feeding structures. In the case of cyst nematodes nutrients enter the so-called syncytium symplastically, via plasmodesmata. In the case of root-knot nematodes the feeding structure consist of giant cells which are symplastically isolated and, therefore, depend on transport proteins for nutrient import. Both feeding sites are connected to a highly specialized type of unloading phloem, which, in case of root-knot nematodes consist exclusively of sieve elements. The mechanisms that control vascularization of feeding sites and transport proteins that play a role in nutrient import into giant cells are largely unknown. One aim of this proposal is to elucidate the events that control vascularization of feeding sites. Particularly the role of the phytohormone auxin will be addressed. Furthermore the role of a sieve element marker and the role of plasmodesmata localized receptors will be investigated. The other part of the proposal aims to characterize the role of an amino acid transporter in sink tissues, especially in giant cells. The changes of its localization in response to nutrient status and nematode infestation will be investigated.