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.

在芥菜科（芥菜科）中，当花粉粒（雄性）沉积在雌蕊（雌性）的顶部时，有性植物生殖开始。兼容花粉粒被雌蕊识别并提供资源，使得花粉粒可以萌发并产生花粉管以运送精子细胞用于受精。这些花粉-雌蕊相互作用是严格调节的，并且是受精启动种子生产的关键。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突细胞接触时。这些乳突可以区分不同的花粉接受、拒绝或忽略花粉粒。兼容花粉被接受，因为它被认为是密切相关的。相比之下，“自花”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，被忽略的花粉只是因为距离太远而无法识别。因此，这些最初的相互作用仔细地调节和保护了从雌蕊到雄性花粉的资源共享，以便成功受精。对于这项拨款提案，戈林研究小组将调查调节初始花粉-柱头乳突相互作用的细胞-细胞通信事件，并研究这些过程如何在不同的菊科物种中保守。具体而言，本研究提出了三个目标：*（1）鉴定和表征柱头乳突（雌蕊）中负责识别和响应相容花粉的信号蛋白（例如受体）。柱头乳突识别相容花粉的机制目前尚不清楚。(2)探讨基础亲和花粉反应途径中的调节分泌机制。这是柱头乳突中的细胞系统，被假设负责将资源分配给相容的花粉粒。(3)明确自噬在自交不亲和花粉排斥中的作用和机制。这是柱头乳突中的细胞反应，假设其在排斥“自花”花粉以防止近亲繁殖中起重要作用。* 通过这三个目标，拟议的研究预计将导致重要的新发现的机制，调节早期授粉后过程中的菊科植物。最终，成功的亲和花粉接受对受精和种子生产有积极的影响，自交不亲和的花粉排斥会阻止近亲繁殖产生更健康的后代。因此，这项研究具有重要的意义，开发新的策略，以提高油菜科油料作物，如油菜种子生产力。