Dissecting C4 leaf biogenesis and C3 and C4 pollen development during exposure to high temperature to enable global food security

全球农业正面临危机。人口增长、耕地持续减少、肉类消费增加以及全球气候变化共同威胁着全球粮食生产。为了维持全球粮食安全，到2050年，谷物产量必须增加70%。水稻、小麦和玉米等主要粮食作物的产量随着气温升高而下降；例如，在最佳生长温度之上，温度每升高1°C，水稻和小麦的产量分别下降10%和3%至4%。维持粮食安全的努力导致了重大的国际倡议，以提高光合效率和提高作物的抗逆性。我的研究通过对生物圈中最有效的初级生产形式C4光合作用的功能发育和植物繁殖的耐热性有了基本的了解，为这些努力做出了贡献。为了维持我的捐款，本提案要求为两个项目提供资金。首先，为了支持将C4光合途径引入小麦和水稻等主要作物的持续努力，我们将研究C4叶片结构的进化发展，目的是确定C4光合叶片中碳浓缩机制所在细胞中细胞器富集起源的核心基因。我们的研究将有助于克服目前阻碍C4工程的主要瓶颈之一，本研究将着重于C3和C4物种Atriplex pair及其杂交种和草亚族Neurachninae叶片发育的分子和细胞评价。神经achninae是已知的唯一包含C3， C2和C4物种的草系，因此被认为是草光合途径进化研究的模型系统。其次，我们将利用我们实验室在了解作物热不育控制机制方面的最新进展。暴露在32°-36°C下严重降低花粉活力，从而降低种子结实率，特别是在油菜、玉米、小麦和水稻中。随着气候持续变暖，加拿大的主要作物，如小麦和油菜，也可能面临花粉不育的增加。我们发现高温通过活性氧的产生降低花粉的存活率，并确定了一种通过解毒氧化化合物赋予耐热性的基因。在本研究中，我们打算研究高温诱导的蛋白质氧化在主要作物物种繁殖过程中的作用，以便为研究人员提供在植物生命周期的这一关键阶段增强耐热性所需的信息。＊＊＊＊＊

Global agriculture is facing a time of crisis. Increasing population growth, persistent loss of arable land, increasing meat consumption and global climate change collectively threaten global food production. To maintain global food security, cereal production will have to increase 70% by 2050. Yields of major food crops - rice, wheat and corn - decline with increasing temperatures; for example, rice and wheat yields decline 10% and 3 to 4%, respectively, for every 1 °C increase in temperature above the optimal growth temperature. Efforts to maintain food security have led to major international initiatives to enhance the photosynthetic efficiency and improve crop stress tolerance. My research contributes to these efforts by developing a basic understanding of the functional development of C4 photosynthesis, the most efficient form of primary production in the biosphere, and heat stress tolerance of plant reproduction. To sustain my contribution, this proposal request funds for two projects. First, to support ongoing efforts to engineer the C4 photosynthetic pathway into our major crops such as wheat and rice, we will examine the evolutionary development of the C4 leaf structure, with the aim of identifying the genes central to the origin of organelle enrichment in cells where the carbon concentrating mechanisms resides in a C4 photosynthetic leaf. Our research should help overcome one of the main bottlenecks currently hindering C4 engineering, This effort will emphasize molecular and cellular assessment of leaf development in C3 and C4 species Atriplex pair and their hybrids and the grass subtribe Neurachninae. The Neurachninae is the only grass lineage known to contain C3, C2, and C4 species, and as such has been suggested as a model system for studies of photosynthetic pathway evolution in the grasses. Second, we will exploit recent advances in our lab in understanding the mechanisms controlling heat sterility in crops. Exposure to 32°-36 °C severely reduces pollen viability and thus seed set, particularly in canola, maize, wheat and rice. With continued climate warming, Canada's major crops such as wheat and canola may also encounter increased incidences of pollen sterility. We have found that heat reduces pollen survival via production of reactive oxygen species and have identified a gene that confers heat tolerance by detoxifying oxidative compounds. In the proposed research, we intend to examine the role of high temperature induced protein oxidation during reproduction in major crop species in order to provide researchers with information needed to enhance heat tolerance during this critical stage of the plant life cycle. *****