Collaborative Research: How do plants control sperm nuclear migration for successful fertilization?

动物和植物的生命都是从配子结合开始的。融合后，来自双亲的配子核相互迁移并混合遗传物质以启动下一代。虽然大多数生物体依赖微管进行配子核迁移，但开花植物已经进化出一种独特的系统，而不是利用肌动蛋白丝（F-actin）。肯塔基州大学和田纳西大学诺克斯维尔分校之间的这项合作研究项目旨在解开拟南芥中F-肌动蛋白动力学和精子核迁移的复杂性。该项目的更广泛影响涵盖科学和教育成果。从理论上讲，了解早期施肥事件的机制可能有助于解决由于气候日益不稳定而导致的作物生育力的预测未来损失。为了培养STEM教育，本科生将参与跨越实验和计算生物学的合作研究经验。一年一度的植物生物学研讨会，具有分子和计算方法，将从事大学和社区学院的学生动手学习。该团队将通过参加县科学博览会和小学科学之夜来促进对植物科学的欣赏，并将开发交互式可视化工具，使参与者能够探索细胞特征并理解其后果。大多数动物和早期分化的陆地植物，如蕨类植物，通过微管控制配子核迁移。然而，显花植物已经进化出一种新的系统，其中精子核迁移是由F-肌动蛋白控制的。在受精之前，雌性配子产生从质膜到细胞核所在的细胞中心的F-肌动蛋白网络的恒定运动。当精核释放到雌配子中时，精核沿着F-肌动蛋白网络迁移，进行核融合。然而，在开花植物中控制F-肌动蛋白动力学和精子核迁移的机制在很大程度上仍然未知。该项目结合了实时活细胞成像和计算建模，以阐明开花植物拟南芥中控制雌性配子中F-actin网络运动的分子和细胞机制，用于精子核迁移。该项目将解决关键的科学问题，包括了解ARP 2/3独立的WAVE/SCAR通路的作用，并通过实时活细胞成像揭示Xi类肌球蛋白的功能。此外，它的目的是通过计算机模拟探索F-肌动蛋白运动的生物物理机制，确定控制精子核在卵细胞中迁移的因素，并使用反向遗传学方法发现F-肌动蛋白运动的新贡献者。跨学科的方法，包括植物生物学，实时活细胞成像和计算建模，将揭示植物受精的详细分子见解。该研究成果不仅将促进对基本生物学过程的理解，而且有助于深入了解陆地植物精子核迁移机制的演变。该项目由分子和细胞生物学部的细胞动力学和功能项目沿着刺激竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Life commences with the union of gametes in both animals and plants. After the fusion, the gametic nuclei from both parents migrate towards each other and blend the genetic materials to initiate the next generation. While most organisms rely on microtubules for gamete nuclear migration, flowering plants have evolved a distinctive system that instead utilizes actin filaments (F-actin). This collaborative research project between the University of Kentucky and the University of Tennessee, Knoxville, seeks to unravel the complexities surrounding the orchestration of F-actin dynamics and sperm nuclear migration in Arabidopsis thaliana. The Broader Impacts of the project span scientific and educational outcomes. Agriculturally, understanding the mechanisms governing early fertilization events may help address the predicted future loss of crop plant fertility due to an increasingly unstable climate. To nurture STEM education, undergraduate students will participate in collaborative research experiences spanning experimental and computational biology. An annual plant biology workshop, featuring both molecular and computational approaches, will engage university and community college students in hands-on learning. The team will promote appreciation for plant science by participating in county science fairs and elementary school science nights, and an interactive visualization tool will be developed to enable participants to explore cell features and comprehend their consequences.Most animals and early diverging land plants, such as ferns, control gamete nuclear migration by microtubules. However, flowering plants have evolved a novel system where sperm nuclear migration is instead controlled by F-actin. Prior to fertilization, female gametes generate constant movement of an F-actin meshwork from the plasma membrane towards the center of the cell, where the nucleus is located. Upon sperm nucleus release into the female gamete, the sperm nucleus migrates along with the F-actin meshwork for karyogamy. However, the mechanisms controlling F-actin dynamics and sperm nuclear migration in flowering plants remain largely unknown. This project combines real-time live-cell imaging and computational modeling to elucidate the molecular and cellular mechanisms controlling the movement of F-actin meshwork in the female gamete for sperm nuclear migration in the flowering plant, Arabidopsis thaliana. The project will address critical scientific questions, including understanding the role of the ARP2/3-independent WAVE/SCAR pathway and unraveling the functions of class XI myosin through real-time live-cell imaging, which has been established by the team. Additionally, it aims to explore the biophysical mechanisms underlying F-actin motion via computer simulations, identify factors governing sperm nuclear migration in the egg cell, and uncover new contributors to F-actin movement using reverse genetics approaches. The interdisciplinary approach, encompassing plant biology, real-time live-cell imaging, and computational modeling, will reveal detailed molecular insights into plant fertilization. The outcomes will not only advance understanding of fundamental biological processes but also contribute insights into the evolution of sperm nuclear migration mechanisms in land plants.This project is jointly funded by the Cellular Dynamics and Function program in the Division of Molecular and Cellular Biosociences along with the Established Program to Stimulate Competitive Research (EPSCoR).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.