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

生命始于动植物配子的结合。融合后，来自双亲的配子核向对方迁移，并将遗传物质混合以启动下一代。虽然大多数生物依靠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，转而利用肌动蛋白细丝(F-肌动蛋白)。肯塔基大学和田纳西大学诺克斯维尔分校的这项合作研究项目试图揭开围绕着拟南芥F-肌动蛋白动态协调和精子核迁移的复杂性。该项目的影响范围更广，涉及科学和教育成果。在农业上，了解控制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预计未来农作物肥力下降的问题。为了培养STEM教育，本科生将参与跨越实验和计算生物学的协作研究体验。一年一度的植物生物学研讨会，以分子和计算方法为特色，将吸引大学和社区学院的学生进行动手学习。该小组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，并将开发一个互动可视化工具，使参与者能够探索细胞特征并理解其结果。大多数动物和早期分叉的陆地植物，如蕨类植物，通过微管控制配子核迁移。然而，开花植物已经进化出一种新的系统，其中精子核迁移由F-肌动蛋白控制。在受精之前，雌配子产生F-肌动蛋白网络从质膜向细胞核所在的细胞中心不断移动。当精子核释放到雌配子中时，精子核随F-肌动蛋白网络迁移进行核配子。然而，在开花植物中控制F-肌动蛋白动态和精子核迁移的机制仍然很大程度上是未知的。该项目结合实时活细胞成像和计算建模来阐明在开花植物拟南芥中控制F-肌动蛋白网络运动的分子和细胞机制，以促进精子核迁移。该项目将解决关键的科学问题，包括了解Arp2/3非依赖的Wave/SCAR途径的作用，以及通过该团队建立的实时活细胞成像来解开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，识别控制卵细胞中精子核迁移的因素，并利用反向遗传学方法发现F-肌动蛋白运动的新贡献者。这种跨学科的方法，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。这些成果不仅将促进对基本生物学过程的理解，还将有助于深入了解陆地植物中精子核迁移机制的演变。该项目由分子和细胞生物科学部的细胞动力学和功能计划以及既定的激励竞争研究计划(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智力优势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.