Seeing the big picture: novel imaging tools to study spatial coordination of signalling processes in plants and algae

细胞间的通讯对于协调光合生物的生理是必不可少的。多细胞植物必须以协调的方式对来自单个细胞的感觉输入作出反应，而单细胞藻类也必须通过交流来协调群体反应，例如防御病原体或捕食者。目前的成像工具使我们能够在单细胞或群体水平上研究信号传导，但很难将两者结合起来。该项目将利用新的令人兴奋的成像技术来解决植物和藻类细胞信号的空间协调问题。Mesolens显微镜能够在亚细胞分辨率下成像大视野，使我们能够检查单个细胞反应如何对整个细胞群体的反应做出贡献。MBA拥有世界上为数不多的中透镜显微镜之一，为利用这种新兴技术开发方法提供了独特的机会。硅藻是一种单细胞藻类，在海洋生态系统中发挥着重要作用，对全球光合作用的贡献约为20%。依赖钙的信号传导过程使硅藻能够感知环境的变化并作出反应，例如营养物质的可用性、渗透胁迫或有毒代谢物的存在。我们最近的研究表明，硅藻具有独特的钙信号传导机制，包括一种在其他真核生物中没有发现的新型钙通道。该项目将使用Mesolens成像和其他荧光成像方法来检查模型硅藻褐指藻在一系列环境刺激下的细胞信号传导。表达钙和活性氧荧光生物传感器的转基因菌株将用于监测群体内这些反应的空间协调性，例如确定单个细胞受伤后细胞信号如何传播。通过CRISPR-Cas9技术的靶向基因敲除将用于确定特定离子通道在这些信号反应中的作用。该项目还将研究中第三系成像在陆地植物信号空间协调中的适用性，重点研究控制气孔打开和关闭的钙依赖信号机制。中孔的非凡分辨率使我们能够研究单个气孔保护细胞的信号过程如何在整个叶片中协调。该项目将深入了解植物和藻类信号传导的细胞机制，并帮助开发新的成像方法。学生将接受荧光显微镜、图像处理、植物和藻类生理学以及分子遗传学方法的全面培训。

Communication between cells is essential to coordinate the physiology of photosynthetic organisms. Multicellular plants must respond in a coordinated manner to sensory inputs from individual cells, whilst unicellular algae must also communicate to coordinate population responses such as defence against pathogens or predators. Current imaging tools enable us to study signalling at the single cell or population level, but struggle to combine the two. This project will utilise new and exciting imaging technology to address the spatial coordination of cellular signalling by plants and algae. The Mesolens microscope enables imaging of a large field of view at subcellular resolution, allowing us to examine how single cell responses contribute to the response of a whole population of cells. The MBA hosts one of only a very few Mesolens microscopes in the world, offering a unique opportunity to develop methodologies with this emergent technology. Diatoms are unicellular algae that play a major role in marine ecosystems, contributing an estimated 20% to global photosynthesis. Calcium-dependent signalling processes allow diatoms to sense and respond to changes in their environment, such as nutrient availability, osmotic stress or the presence of toxic metabolites. We have recently shown that diatoms possess unique mechanisms for calcium signalling, including a novel class of calcium channels that are not found in other eukaryotes. The project will use Mesolens imaging, alongside other fluorescent imaging approaches, to examine cellular signalling in the model diatom Phaeodactylum tricornutum in response to a range of environmental stimuli. Transgenic strains expressing fluorescent biosensors for calcium and reactive oxygen species will be used to monitor the spatial coordination of these responses within a population, for example determining how cellular signals propagate following wounding of individual cells. Targeted gene knockout via CRISPR-Cas9 techniques will be used to identify the role of specific ion channels in these signalling responses. The project will also examine the applicability of Mesolens imaging to the spatial coordination of signalling in land plants, focusing on the calcium-dependent signalling mechanisms that control the opening and closing of stomata. The extraordinary resolution of the Mesolens enables us to examine how signalling processes in individual stomatal guard cells are coordinated across an entire leaf. The project will provide insight into the cellular mechanisms of signalling in plants and algae and aid the development of novel imaging methodologies. The student will receive comprehensive training in fluorescent microscopy, image processing, plant and algal physiology, and molecular genetic approaches.