Coordinated Photoreceptor Engineering for Improved Biomass Production

植物生物学家面临的一个关键挑战是通过改变光合生产力来提高植物产量，以确保粮食、能源和环境的可持续性。趋光蛋白受体激酶（phot1和phot2）在这方面发挥重要作用，协调多个光捕获过程。这些包括向光性、叶绿体运动、叶片定位、叶片扩张和气孔开放，所有这些都通过提高光捕获效率、减少光损伤和调节叶片与大气之间的气体交换来影响植物的光合能力。然而，几乎没有努力针对这些途径来改善生物质生产。我们最近已经表明，有针对性的工程可以成功地用于修改的光敏感性的phototropins，并增加其对光的敏感性。具有这些工程化的光感受器的植物表现出更快速和稳健的叶绿体运动响应以及改善的叶定位和扩展，导致在光限制条件下超过2倍的生物质积累增加。这些发现证明了工程化光感受器用于改善植物生长的可行性，并提供了通过增加光合能力来提高植物产量的额外机会。该提案利用了这些发现，并将使用组合蛋白质工程策略，在更广泛的光照条件下更有效地同步光致蛋白的作用，而不会引起有害的高光胁迫。更好的同步之间的趋光素受体的设计原则将首先在拟南芥中建立，并以大麦为模型扩展到作物。因此，这种相互关联的努力的一个主要成果将是建立一个结构和功能的蓝图，用于构建工程光感受器，这将提供一个非转基因的，基于基因组编辑的方法，以协调逐步增强光合性能，目的是增加作物产量。这项工作将同时产生具有定制光化学特性的新感光器组件，这些组件将用于产生基于合成蛋白质的开关，这些开关旨在通过光来调节靶细胞活动。由于我们对趋光蛋白受体信号传导的了解还远远不够，因此该提案还将利用从我们的趋光蛋白工程工作中鉴定的新型脱敏感光细胞突变体背景的可用性，通过遗传抑制剂筛选来鉴定趋光蛋白信号传导的新组分。总之，这项研究的基础和应用方面将扩大我们对光致激素受体功能的理解，并利用微调其作用的能力作为真正的手段来调节产量，以获得农学增益。

A key challenge for plant biologists has been to increase plant yield by altering photosynthetic productivity to secure food, energy and environmental sustainability. Phototropin receptor kinases (phot1 and phot2) play an important role in this regard by coordinating multiple light-capturing processes. These include phototropism, chloroplast movements, leaf positioning, leaf expansion and stomatal opening all of which influence a plant's photosynthetic competence by improving the efficiency of light capture, reducing photodamage, and regulating gas exchange between leaves and the atmosphere. However, little effort has been made to target these pathways for improving biomass production. We have recently shown that targeted engineering can be used successfully to modify the light-sensing properties of the phototropins and increase their sensitivity to light. Plants with these engineered photoreceptors exhibit more rapid and robust chloroplast movement responses and improved leaf positioning and expansion, leading to over 2-fold increases biomass accumulation under light-limiting conditions. These findings demonstrate the feasibility of engineering photoreceptors for improved plant growth and offer additional opportunities for enhancing plant yield through increases in photosynthetic competence. This proposal capitalises on these findings and will use a combinatorial protein engineering strategy to better synchronise the actions of the phototropins more effectively over a wider range of light conditions without causing detrimental high-light stress. Design principles for better synchronisation between phototropin receptors will be established first in Arabidopsis and extended to crops using barley as a model. Thus, a major outcome of this interlinked effort will be to establish a structural and functional blueprint for constructing engineered photoreceptors that will provide a non-transgenic, genome editing-based approach to coordinate stepwise enhancements in photosynthetic performance with an aim to increasing crop yield. This work will concurrently generate new photoreceptor components with tailored photochemical properties that will have utility in generating synthetic protein-based switches designed to regulate target cellular activities by light. As our knowledge of phototropin receptor signalling is still far complete, this proposal will also exploit the availability of a novel desensitised photoreceptor mutant background, identified from our phototropin engineering work, to identify new components of phototropin signalling through genetic suppressor screening. Together, the fundamental and applied aspects of this research will expand our understanding of phototropin receptor function and harness the ability to fine tune their action as a bona fide means to modulate yield for agronomic gain.