Cellular regulation of pollen compatibility and fertility in the Brassicaceae

十字花科花粉相容性和育性的细胞调节

• 批准号: RGPIN-2018-04348
• 负责人: Goring, Daphne
• 金额: $ 4.74万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=652203
• 关键词: Cellular; regulation; pollen; compatibility; fertility

In the Brassicaceae (mustard family), sexual plant reproduction is initiated when pollen grains (male) are deposited on top of the pistil (female). Compatible pollen grains are recognized by the pistil and provided resources so that the pollen grains can germinate and produce pollen tubes to deliver sperm cells for fertilization. These pollen-pistil interactions are tightly-regulated and critical as fertilization initiates seed production. The Goring research group examines the first stage of these interactions: when the pollen comes in contact with stigmatic papillar cells at the top of pistil. These papillae can differentiate between different pollen to accept, reject or ignore the pollen grains. Compatible pollen is accepted as it is recognized as being closely-related. In contrast, ‘self'-pollen is rejected in many species as this self-recognition system is used to prevent inbreeding (self-incompatibility). Finally, pollen that is ignored is simply too distantly-related to be recognized. Thus, these initial interactions carefully regulate and conserve the sharing of resources from the female pistil to the male pollen for successful fertilization.***For this grant proposal, the Goring research group will investigate the cell-cell communication events that regulate the initial pollen-stigmatic papillae interactions and examine how these processes are conserved in different Brassicaceae species. Specifically, three objectives are proposed for this research:***(1) Identify and characterize the signaling proteins in the stigmatic papillae (pistil) that are responsible for recognizing and responding to compatible pollen (e.g. receptors). The mechanism by which stigmatic papillae recognize compatible pollen is currently unknown.***(2) Investigate the mechanism of regulated secretion in the basal compatible pollen response pathway. This is the cellular system in the stigmatic papillae that is hypothesized to be responsible for allocating resources to the compatible pollen grains.***(3) Define the role and mechanism of autophagy in self-incompatible pollen rejection. This is a cellular response in the stigmatic papillae that is hypothesized to play an important role in rejecting ‘self'-pollen to prevent inbreeding. ***Through these three objectives, the proposed research is expected to lead to significant new discoveries on the mechanisms regulating early post-pollination processes in the Brassicaceae. Ultimately, successful compatible pollen acceptance has a positive impact on fertilization and seed production, and self-incompatible pollen rejection prevents inbreeding to produce healthier offspring. Hence, this research has important implications for developing new strategies to improve seed productivity in Brassicaceae oilseed crops such as canola.

在十字花科（芥菜科）中，当花粉粒（雄性）沉积在雌蕊（雌性）顶部时，有性植物繁殖开始。相容的花粉粒被雌蕊识别并提供资源，使花粉粒能够发芽并产生花粉管以输送精子细胞进行受精。当受精启动种子生产时，这些花粉-雌蕊相互作用受到严格调控且至关重要。戈林研究小组研究了这些相互作用的第一阶段：当花粉与雌蕊顶部的柱头乳头细胞接触时。这些乳突可以区分不同的花粉以接受、拒绝或忽略花粉粒。相容花粉被接受，因为它被认为是密切相关的。相比之下，“自体”花粉在许多物种中被拒绝，因为这种自我识别系统用于防止近亲繁殖（自交不亲和）。最后，被忽视的花粉只是因为亲缘关系太远而无法被识别。因此，这些最初的相互作用仔细调节和保护从雌蕊到雄性花粉的资源共享，以实现成功受精。***对于这项拨款提案，戈林研究小组将研究调节最初花粉-柱头乳头相互作用的细胞间通讯事件，并研究这些过程在不同十字花科物种中是如何保守的。具体来说，本研究提出了三个目标：***(1) 识别并表征柱头乳头（雌蕊）中负责识别和响应相容花粉（例如受体）的信号蛋白。柱头乳头识别相容花粉的机制目前尚不清楚。***(2)研究基础相容花粉反应途径中调节分泌的机制。这是柱头乳头中的细胞系统，被认为负责将资源分配给相容的花粉粒。***(3) 定义自噬在自交不亲和花粉排斥中的作用和机制。这是柱头乳头中的细胞反应，推测在拒绝“自体”花粉以防止近交中发挥重要作用。 ***通过这三个目标，拟议的研究预计将在调节十字花科早期授粉后过程的机制方面产生重大新发现。最终，成功的相容花粉接受对受精和种子生产具有积极影响，而自交不亲和的花粉排斥可防止近亲繁殖，从而产生更健康的后代。因此，这项研究对于制定提高十字花科油料作物（如油菜籽）种子生产力的新策略具有重要意义。