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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716452
• 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性的配偶，同时拒绝相关的伴侣，保持其产量，活力和遗传多样性。在大多数开花植物中，在授粉的最早阶段，当花粉与雌性的柱头乳头细胞相互作用时，成功的繁殖被控制。在花粉和柱头之间的有利（相容）相互作用之后，花粉管穿过花柱生长并使胚珠受精。相反，为了避免遗传上相似的配偶（自花花粉），植物利用自交不亲和（SI）系统作为遗传屏障，以防止自花花粉在柱头上发育，只允许杂交花粉的发育，从而促进杂种优势和多样性。在芸苔属植物的SI反应过程中，花粉（雄性）配体SCR/SP11和柱头（雌性）SRK（受体激酶）之间的相互作用导致ARC 1 E3连接酶募集到蛋白酶体，其中ARC 1促进各种下游相容性因子的降解。我们已经描述了至少三个下游目标及其在授粉中的作用。 我的长期目标是获得一个彻底的了解，在植物繁殖过程中调节兼容和不兼容授粉事件的信号机制。三个具体的研究目标。1)我们的初步证据表明，MAPKs（丝裂原激活蛋白激酶）是组成性激活的柱头和所需的介导兼容授粉。我们建议，以确定上游调控的MAPK参与调解兼容授粉。2）阐明Exo 70 A1在授粉过程中激活的信号传导机制。将评估MAPK通过磷酸化影响Exo 70 A1功能的作用。该目标将导致完成相容性相互作用所需的MAPK下游途径3）表征JDP 1（J结构域蛋白）作为SI的正调节剂。虽然ARC 1的许多靶点已经被确定，但在ARC 1之后还没有确定SI通路的其他正调节因子。JDP 1可以与ARC 1相互作用，抑制JDP 1可导致SI的破坏，表明JDP 1是SI的正调节剂。我们建议使用转基因，分子和生物化学的方法来阐明JDP 1如何参与SI信号。 鉴于我们大多数主食的作物产量都影响到成功的繁殖，了解驱动作物繁殖潜力的遗传网络对于我们全球走向可持续发展至关重要。我们的研究计划旨在从发现和应用的角度来解决这个问题。通过该计划培训的HQP将具有在油菜籽行业找到工作的独特优势，并将在学术界，工业界和政府中获得机会。