Looking through the open window of root development: understanding how plant hormones position the susceptibility zone in Medicago

豆科植物与固氮根瘤菌形成有益的联系，导致根部形成固氮根瘤。这个过程只能在根的特定区域内启动，称为敏感区。在豆科植物中，生长素和细胞分裂素的变化对于根瘤的器官发生是必要的和充分的，似乎允许根瘤发育的根区限制可能与生长素和细胞分裂素在敏感区内的状态有关。植物发育的稳健性与组织在空间和时间上紧密协调其分生组织、生长和分化活动有关。在过去的十年中，我们通过分子生物学和计算模型的结合，增加了我们对拟南芥根分生组织区建立和调控的理解。生长素和细胞分裂素的作用尤为重要。这个博士项目将剖析在豆科植物根部产生敏感性区的分子基础，在那里结瘤开始。该学生将利用对拟南芥根系的最新研究进展来阐明豆科植物易感区的激素调节。通过将拟南芥根系计算框架应用于豆科植物，将产生新的假设来解释易感区调控。这些假设的实验测试将增加对共生细菌如何重新编程豆科植物根发育的机制见解。

Legumes form beneficial associations with nitrogen-fixing rhizobial bacteria, resulting in the formation of nitrogen-fixing nodules on the roots. This process can only be initiated within a specific zone of the root, referred to as the susceptibility zone. Changes in auxin and cytokinin are necessary and sufficient for nodule organogenesis in a legume and it seems likely that the restrictions in the root zonation that allow nodule development is associated with the status of auxin and cytokinins within the susceptibility zone. Robustness in plant development is associated with tissues tightly coordinating their meristematic, growth and differentiation activities both spatially and temporally. Over the last decade, we have increased our understanding, through a combination of molecular biology and computational modelling, of the establishment and regulation of root meristem zones in Arabidopsis. Particularly important roles have emerged for the hormones auxin and cytokinin. This PhD project will dissect the molecular underpinnings that create the susceptibility zone within the legume root, where nodulation is initiated. The student will make use of the recent advances in understanding of the Arabidopsis root to elucidate the hormonal regulation of the legume susceptibility zone. By adapting the Arabidopsis root computational framework for use in legumes, new hypotheses will be generated to explain the susceptibility zone's regulation. Experimental testing of these hypotheses will add mechanistic insight into how legume root development has been reprogrammed by symbiotic bacteria.