Using Antarctic green algae to study photosynthesis in extreme environments

超过70%的地球生物圈永久低于5摄氏度，包括大部分海洋、极地和高山地区。包括真核藻类在内的光合微生物是寒冷环境中主要的初级生产者，但我们对极端寒冷环境下光合作用是如何运作的知之甚少。我的研究项目的首要目标是了解光合生物如何在极端条件下茁壮成长。我使用极端藻类Chlamydomonas sp. UWO241（以下简称UWO241）来解决对极端环境的驯化和进化适应问题。与像UWO241这样具有良好特征的非模型系统一起工作，为新发现提供了前所未有的机会。******南极生物的研究是一个新的领域，由于最近的气候变化趋势威胁到极地环境，因此受到了极大的关注。寒冷极端微生物也被认为是生物技术应用的新型代谢物和冷适应酶的来源，是寒冷国家（如加拿大）室外生物反应器和生物修复的优秀候选者。我将生物信息学与分子和细胞生物学结合起来，阐明极端藻类如何克服低温和不利光线的限制。******在接下来的五年里，我将专注于三个短期目标，以我的知识为基础：1)调查极端条件如何塑造UWO241基因组，重点是重复基因及其蛋白质产物。CPN60是一种叶绿体伴侣复合物，对核酮糖-1,5-二磷酸羧化酶/加氧酶（RubisCO）折叠至关重要，由UWO241基因组中一个扩展的基因家族编码；2)研究了RubisCO活性调控酶Rca的功能和结构特性。我假设Rca具有固有的高结构灵活性和低温下的高活性，使其成为寒冷条件下光合作用的重要因素；3)阐明极地藻类在极端光周期（延长的年度光/暗循环）下生长和生存的分子和生理策略，包括南极藻类叶绿素合成途径。从长远来看，我感兴趣的是确定冷适应生物共同的进化适应。为了解决这个问题，我将把北极的藻类纳入我的研究中，并将重点放在光合作用、呼吸作用和叶绿体-线粒体相互作用上。最终，我将把从极端微生物中获得的见解应用到中温藻类和作物植物中，改善低温下的生长。******我的研究项目将为年轻的HQP在一个新的和新兴的生物学领域提供机会。这里描述的项目将为HQP提供在任何科学工作场所都很有价值的技术和软技能，并将为他们未来在学术界、工业界或政府的职业生涯做好准备。**

More than 70% of the Earth's biosphere is permanently below 5C, including most of the oceans, polar and alpine regions. Photosynthetic microorganisms, including eukaryotic algae, are the dominant primary producers in cold habitats, but we know very little of how photosynthesis operates in the extreme cold. The overarching goal of my research program is to understand how photosynthetic organisms thrive under extreme conditions. I use the extremophilic green alga Chlamydomonas sp. UWO241 (hereafter UWO241) to address questions on acclimation and evolutionary adaptation to extreme environments. Working with a well-characterized non-model system such as UWO241 provides an unprecedented opportunity for novel discoveries.******The study of Antarctic organisms is a new field that has garnered significant attention due to recent climate change trends that threaten polar environments. Cold extremophiles (psychrophiles) are also recognized as a source of novel metabolites and cold-adapted enzymes for biotechnological applications and are excellent candidates for outdoor bioreactors and bioremediation in cold countries, such as Canada. I use bioinformatics together with molecular and cell biology to elucidate how extremophilic algae overcome the constraints imposed by low temperatures and unfavorable light.******Over the next five years, I will focus on three short-term objectives designed to build on my knowledge: 1) Investigating how extreme conditions shaped the UWO241 genome, with emphasis on duplicated genes and their protein products. I will focus on CPN60, a chloroplast chaperone complex essential for ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) folding and encoded by an expanded gene family in the UWO241 genome; 2) Examining the functional and structural properties of psychrophilic RubisCO activase (Rca), a regulatory enzyme necessary for proper RubisCO activity. I hypothesize that Rca has inherently high structural flexibility and high activity at low temperatures making it an important factor for photosynthesis in the cold; 3) Elucidating the molecular and physiological strategies of polar algae for growth and survival under extreme photoperiods (extended annual light/dark cycles), including the chlorophyll synthesis pathway in Antarctic algae. In the long-term, I am interested in identifying evolutionary adaptations common to cold-adapted organisms. To address this, I will include algae from the Arctic in my research and focus on photosynthesis, respiration and chloroplast-mitochondria interactions. Ultimately, I will apply the insights obtained from extremophiles to mesophilic algae and crop plants and improve growth at low temperatures.******My research program will provide opportunities for young HQP in a new and emerging area of biology. The projects described here will provide HQP with technical and soft skills that are valued in any scientific workplace, and will prepare them for future careers in academia, industry or government. **