Cellular signalling mechanisms during pollen-pistil interactions in Brassicaceae

十字花科花粉-雌蕊相互作用过程中的细胞信号机制

• 批准号: RGPIN-2020-05301
• 负责人: Samuel, Marcus
• 金额: $ 3.42万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744827
• 关键词: Cellular; signalling; mechanisms; during; pollen

Plants maintain their yield, vigour and genetic diversity through appropriate selection of genetically diverse mates while rejecting related partners. In most flowering plants, successful reproduction is controlled at the earliest stages of pollination when the pollen interacts with the stigmatic papillary cell of the female. Following a favourable (compatible) interaction between the pollen and the stigma, the pollen tube grows through the style and fertilizes the ovule. In contrast, to avoid genetically similar mates (self-pollen), plants utilize self-incompatibility (SI) system as a genetic barrier to prevent self-pollen from developing on the stigma, allowing development of only cross-pollen, thereby promoting hybrid vigour and diversity. During SI response in Brassica, interaction between the pollen (male) ligand SCR/SP11 and the stigma (female) SRK (receptor kinase), leads to recruitment of ARC1 E3 ligase to the proteasome, where ARC1 facilitates degradation of various downstream compatibility factors. We have characterized at least three of these downstream targets and their role in pollination. My long-term goal is to gain a thorough understanding of the signaling mechanisms that regulate compatible and incompatible pollination events during plant reproduction. Three specific research objectives are described. 1) Our preliminary evidence suggests that MAPKs (mitogen-activate protein kinases) are constitutively activated in the stigmas and are required for mediating compatible pollination. We propose to identify the upstream regulators of MAPKs that are involved in mediating compatible pollination. Identification of the activator(s) of these MAPKs would allow us to build the compatible signaling pathway 2) Elucidate the signaling mechanism behind activation of Exo70A1 during pollination. The role of MAPKs in influencing the function of Exo70A1 through phosphorylation will be assessed. This objective will lead to completion of the pathway downstream of MAPKs that is required for compatible interactions 3) Characterizing JDP1 (J-domain protein) as a positive regulator of SI. Although a number of targets of ARC1 have been identified, no other positive regulator of SI pathway has been identified after ARC1. JDP1 can interact with ARC1 and suppression of JDP1 leads to breakdown of SI, suggesting JDP1 is a positive regulator of SI. We propose to use transgenic, molecular and biochemical approaches to elucidate how JDP1 participates in SI signaling. Given that crop-yield in most of our staple foods impinge on successful reproduction, understanding the genetic networks that drive the reproductive potential of a crop plant is crucial for our global move toward sustainability. Our research program aims to address this from both a discovery and an applied perspective. The HQPs trained through this program will have a unique advantage of finding jobs in the canola industry and will have opportunities in academia, industry and the government.

植物通过适当选择遗传多样的伴侣在拒绝相关伴侣的同时，保持其产量，活力和遗传多样性。在大多数开花植物中，当花粉与雌性的污名化乳头细胞相互作用时，成功的繁殖是在最早的授粉阶段控制的。在花粉和污名之间存在良好的（兼容）相互作用之后，花粉管通过样式生长并施肥。相比之下，为避免遗传相似的伴侣（自主），植物利用自我兼容性（SI）系统作为遗传障碍，以防止在污名上产生自我，从而仅开发跨生物，从而促进杂交的活力和多样性。在Brassica的Si反应过程中，花粉（雄性）配体SCR/SP11与柱头（雌性）SRK（受体激酶）之间的相互作用会导致ARC1 E3连接酶募集到蛋白酶体，其中ARC1促进了各种下游兼容性因素的降解。我们已经表征了其中至少三个下游目标及其在授粉中的作用。 我的长期目标是对调节植物繁殖过程中调节兼容和不兼容的授粉事件的信号传导机制有透彻的了解。描述了三个特定的研究目标。 1）我们的初步证据表明，MAPK（有丝分裂原激活蛋白激酶）在污名中被组成式激活，并且是介导兼容授粉所必需的。我们建议确定参与介导兼容授粉的MAPK的上游调节器。这些MAPK的激活因子的识别将使我们能够构建兼容的信号通路2）在授粉过程中阐明Exo70A1激活背后的信号传导机制。将评估MAPK在影响EXO70A1通过磷酸化功能的功能中的作用。该目标将导致兼容相互作用所需的MAPK下游的途径3）将JDP1（J-domain蛋白）表征为SI的正调节剂。尽管已经确定了许多ARC1的靶标，但是在ARC1之后未鉴定出SI途径的其他正调节剂。 JDP1可以与ARC1相互作用，而JDP1的抑制会导致SI的崩溃，这表明JDP1是SI的积极调节剂。我们建议使用转基因，分子和生化方法来阐明JDP1如何参与SI信号。 鉴于我们的大多数主食中的农作物收益促进了成功的繁殖，因此了解驱动农作物植物生殖潜力的遗传网络对于我们全球朝着可持续性转移至关重要。我们的研究计划旨在从发现和应用的角度来解决这一问题。经过该计划培训的HQP将具有在低芥酸菜籽行业找到工作的独特优势，并将在学术界，工业和政府中有机会。