Temperature, photosynthesis, and rubisco: biochemistry and physiology of land plant productivity in response to global change

光合作用是植物、藻类和一些细菌利用太阳能将二氧化碳转化为生物质的过程。光合作用基本上是所有陆地和水生食物网的能量基础，并产生食物、燃料、住所和其他维持人类文明的材料。基本新陈代谢是众所周知的，但光合作用如何对非生物环境做出反应的关键方面尚不清楚。例如，关于为什么光合作用速率在某一最适温度以上下降，有多种假说。此外，与大多数其他酶相比，Rubisco是一种实际上催化二氧化碳吸收的酶，是一种糟糕的催化剂，但我们对其功能和结构之间的微妙关系的了解还处于初级阶段。此外，Rubisco的特征只有很少的物种，目前我们使用可能不适合这一目的的常量来模拟未来的作物和森林产量。 我的研究提出了关于光合作用的温度响应以及Rubisco的特性的问题。我和我的学生将对高温下的光合作用进行详细的机制分析，这些植物的光合作用能力发生了变化。我们使用一系列生理和生化技术，在已建立的理论模型的背景下，全面测试假设。在短期内，Rubisco的研究将集中在Rubisco编码基因的表达如何随环境变化，或在具有不同生化特征的密切相关物种之间发生变化。这些研究将评估植物针对特定生长条件优化酶的可能性。在赠款周期接近尾声时，我们将确定关键作物和北方森林RuBiscos的特征，特别是温度敏感性。 使用化石燃料释放的二氧化碳正在导致气温上升和降水模式改变。光合作用将大气层和生物圈联系在一起，我的研究扩大了我们对光合作用对全球变化的反应的理解，包括Rubisco的具体作用。

Photosynthesis is the process by which plants, algae, and some bacteria use solar energy to convert CO2 into biomass. Photosynthesis is the energetic basis of essentially all terrestrial and aquatic food webs, and produces food, fuel, shelter, and other materials that sustain human civilization. The basic metabolism is well known, but crucial aspects of how photosynthesis responds to the abiotic environment are unclear. For example, there are multiple hypotheses about why photosynthetic rates decline above a certain optimum temperature. Further, Rubisco, the enzyme that actually catalyses CO2 uptake, is a poor catalyst compared to most other enzymes, but our understanding of of the subtle relationships between its function and structure is in its infancy. Moreover, Rubisco has been characterized from very few species, and presently we model future crop and forest yields using constants that may be ill-suited to the purpose. My research asks questions about the temperature responses of photosynthesis, and the characteristics of Rubisco. My students and I will conduct detailed mechanistic analyses of photosynthesis at high temperatures, on plants with altered photosynthetic capacity. We use an array of physiological and biochemical techniques to comprehensively test hypotheses, within the context of established theoretical models. In the short-term, Rubisco studies will focus on how the expression of Rubisco-encoding genes changes with environment, or between closely related species with biochemically distinct Rubiscos. These studies will evaluate the possibility that plants optimise the enzyme for specific growth conditions. Toward the end of the grant cycle, we will determine the characteristics, particularly the temperature sensitivities, of key crop and boreal forest Rubiscos. The CO2 released by fossil fuel use is causing temperatures to rise and precipitation patterns to change. Photosynthesis links the atmosphere and biosphere, and my research expands our understanding of photosynthetic responses to global change, including the specific role of Rubisco.