Collaborative Research: Hormonal control of stamen filament growth

合作研究：雄蕊丝生长的激素控制

• 批准号: 2343701
• 负责人: Jason Reed
• 金额: $ 65.1万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-15 至 2027-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2343701&HistoricalAwards=false
• 关键词: Collaborative; Research; Hormonal; control; stamen

In both plants and animals, many organs undergo spurts of rapid growth as they develop. Many flower organs grow very quickly for a brief period as flowers open. For successful reproduction, such growth must be coordinated so as to place male and female organs appropriately for pollination, and pollen release needs to occur at an optimal time. This project is to study how plant hormones stimulate rapid growth in stamens, the male flower organs that produce pollen. In many self-pollinating plants, stamen filaments elongate as flowers open to place pollen-bearing anthers near the female stigma. The timing and extent of filament growth thus determines the efficiency of fertilization and seed production, and is important for crop breeding and yield. The project will examine cellular and molecular events during stamen filament elongation in a model plant, to reveal in detail how stamens grow quickly without buckling, how hormones control this growth, and how filament growth is coordinated with pollen release. Genetic tools generated in the work may enable targeted modification of growth in flower organs, for example to modulate the location and timing of pollen release in crop plants. The mechanisms discovered will also be relevant to modulating growth in other organs such as leaves or fruits. Undergraduate students will be introduced to methods of scientific inquiry through carrying out research projects both in courses and in the research labs. Public outreach through museums and campus events will include information on plant reproduction. The project is to study how hormone response pathways control very fast but transient stamen filament growth in the model plant Arabidopsis thaliana. Two auxin response transcription factors, ARF6 and ARF8, mediate growth responses to the hormone auxin, and stimulate stamen filament elongation just before flowers open. ARF6 and ARF8 also stimulate production of another hormone, jasmonate, which further amplifies filament growth rate, and also promotes differentiation needed for anther dehiscence (pollen release). Time-lapse confocal microscopy, single-nucleus RNA-Seq, and fluorescent reporter genes for selected vascular cell types will be used to reconstruct three-dimensional cellular anatomy, growth, and differentiation in rapidly growing stamen filaments. Comparisons of wild type and mutants with decreased or increased hormone responses and filament growth will provide insight into how the hormones act. Biophysical, hormonal, and genetic manipulations, together with jasmonate pathway reporter genes, will probe mechanisms that couple filament growth with the contemporaneous burst of jasmonate production needed for anther dehiscence. Yeast and plant protoplast gene expression systems will be used to identify mutant forms of ARF6 and ARF8 that can activate transcription independently of auxin regulation. Such auxin-independent mutations will then be engineered into Arabidopsis plants to reveal the role of auxin response in flower maturation and other processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在植物和动物中，许多器官在发育过程中都会经历快速生长。 许多花器官在花朵开放时会在短时间内生长得非常快。 为了成功繁殖，必须协调这种生长，以便将雄性和雌性器官放置在适当的位置进行授粉，并且花粉释放需要在最佳时间发生。 该项目旨在研究植物激素如何刺激雄蕊（产生花粉的雄花器官）的快速生长。 在许多自花授粉植物中，当花朵开放时，雄蕊花丝会伸长，将带有花粉的花药放置在雌性柱头附近。 因此，丝生长的时间和程度决定了施肥和种子生产的效率，并且对于作物育种和产量很重要。 该项目将检查模型植物雄蕊花丝伸长过程中的细胞和分子事件，详细揭示雄蕊如何快速生长而不弯曲，激素如何控制这种生长，以及花丝生长如何与花粉释放协调。 这项工作中产生的遗传工具可以有针对性地改变花器官的生长，例如调节作物花粉释放的位置和时间。 发现的机制也与调节其他器官（如叶子或果实）的生长有关。 本科生将通过在课程和研究实验室开展研究项目来了解科学探究的方法。 通过博物馆和校园活动进行的公众宣传将包括有关植物繁殖的信息。该项目旨在研究激素反应途径如何控制模式植物拟南芥中非常快速但短暂的雄蕊丝生长。 两种生长素反应转录因子 ARF6 和 ARF8 介导对生长素激素的生长反应，并在花朵开放前刺激雄蕊丝伸长。 ARF6 和 ARF8 还刺激另一种激素茉莉酸的产生，进一步提高花丝生长速度，并促进花药开裂（花粉释放）所需的分化。 延时共聚焦显微镜、单核 RNA 测序和选定血管细胞类型的荧光报告基因将用于重建快速生长的雄蕊丝的三维细胞解剖结构、生长和分化。 比较野生型和激素反应减少或增加以及丝生长的突变体将有助于深入了解激素的作用方式。 生物物理、激素和遗传操作，以及茉莉酸途径报告基因，将探索将花丝生长与花药开裂所需的茉莉酸产量同时爆发相结合的机制。 酵母和植物原生质体基因表达系统将用于鉴定 ARF6 和 ARF8 的突变形式，它们可以独立于生长素调节激活转录。 然后，这种不依赖生长素的突变将被工程化到拟南芥植物中，以揭示生长素反应在花成熟和其他过程中的作用。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。