Gymnosperm Reproductive Mechanisms

裸子植物的繁殖机制

• 批准号: 43775-2013
• 负责人: vonAderkas, Patrick
• 金额: $ 3.64万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=630377
• 关键词: Gymnosperm; Reproductive; Mechanisms

Conifers such as Douglas-fir, spruce and pines are economically significant species in Canada. Conifers are also one of the four remaining groups of gymnosperms that, from an evolutionary standpoint, are key to the understanding of the origin of flowering plants, the angiosperms. This proposed program of research investigates the events from pollination to fertilization. Seeds often fail because of pollination failure, or because of the consequences of self-pollination; such inbred embryos abort. Gymnosperms are open-pollinated and cannot exclude whatever the wind or insects bring to the ovule. So how do they protect themselves? Can they select their own pollen over foreign pollen? What mechanisms do they have, and what is the biochemical basis for the mechanism? Pollen-ovule interactions include pollen capture by a pollination drop, followed by pollen germination and penetration through the nucellus, ending with the pollen tube's delivery of male gametes into the egg. We will be studying this from a molecular standpoint. Our lab has developed deep expertise in protein analysis of pollination drops. We have discovered that the enzymes protect the ovule during reproduction by killing microbes. We intend to investigate pollination drops in all four groups of gymnosperms (conifers, gnetophytes, cycads, Ginkgo), focusing on proteins (proteome), peptides and polypeptides, sugars, phosphate compounds, and minerals. This will be complemented by an investigation of gene expression in the nucellus. We are searching for genes involved in pollination drop secretions, as well those involved in the formation of barriers to pollen growth, such as megaspore walls. Lastly, we will be investigating the changes in proteome during fertilization. The studies are hypothesis-driven and will engage three PhD students and one Masters student. The impact of this work is practical, leading to deeper understanding of events critical for conifer seed orchard management. The impact is also theoretical, as it is likely alter our understanding of adaptations critical to evolution of the seed habit.

针叶树种，如豆杉、云杉和松树，在加拿大具有重要的经济价值。针叶植物也是现存的四类裸子植物之一，从进化的角度来看，这是了解开花植物被子植物起源的关键。这项拟议的研究计划调查了从授粉到受精的过程。种子经常因为授粉失败或自花授粉的后果而失败；这样的近亲交配的胚胎会败育。裸子植物是开放授粉的，不能排除风或昆虫给胚珠带来的任何东西。那么，他们如何保护自己呢？它们能选择自己的花粉而不是外来的花粉吗？它们有什么机制，这种机制的生化基础是什么？花粉-胚珠的相互作用包括通过授粉滴捕获花粉，随后花粉萌发并穿过珠心，最终花粉管将雄配子传递到卵子中。我们将从分子的角度来研究这个问题。我们的实验室在授粉液滴的蛋白质分析方面已经形成了深厚的专业知识。我们发现，在生殖过程中，这些酶通过杀死微生物来保护胚珠。我们打算调查所有四类裸子植物(针叶植物、裸子植物、苏铁、银杏)的授粉滴落，重点是蛋白质(蛋白质组)、多肽和多肽、糖、磷酸化合物和矿物质。此外，还将对珠心细胞中的基因表达进行研究。我们正在寻找与授粉液滴分泌物有关的基因，以及那些与花粉生长障碍的形成有关的基因，如大孢子壁。最后，我们将研究受精过程中蛋白质组的变化。这些研究是假设驱动的，将涉及三名博士生和一名硕士生。这项工作的影响是实际的，导致对针叶树种子园管理至关重要的事件有更深的理解。这一影响也是理论上的，因为它可能会改变我们对种子习性进化至关重要的适应的理解。