Engineering more water-use efficient crops: functional genomics of the circadian control of CO2 fixation associated with Crassulacean acid metabolism

由于气候变化，世界正变得越来越热、越来越干燥，而且人口正在迅速增长，据预测，到2050年，我们需要将粮食产量提高50%至70%，才能养活预计的90亿至100亿人口。与今天的农业用水相比，这种额外的粮食生产必须使用相同的土地和相同或更少的淡水。在作物生产力方面取得如此巨大的进步，以支撑本世纪的人类粮食安全，被广泛认为是一项关键的全球重大挑战，需要突破性的、创新的方法，“跳出框框思考”。我们的研究旨在利用一种自然发生的超强光合作用适应，称为天冬酸代谢（CAM）。这种适应可以提高植物的水分利用效率，远远超过当今任何主要粮食作物物种，如水稻、小麦或玉米。通过对CAM模型物种的基因组和转录组进行解码，并对Kalanchoë属CAM模型物种进行功能基因组学研究，建立CAM在水稻、小麦等C3作物中工程化的最小部件清单，以提高作物水分利用效率和光合作用。这个项目将利用我们最近的发现，利用萤火虫荧光素酶报告基因来探索与CAM相关的基因的调控区域，以“看到”启动子的活性。特别是，我们试图了解CAM所需基因的活性如何受到内源性生物钟的调节；生物体内的计时器，用来优化它们的生物化学相对于日常的光/暗循环。这将使学生对我们理解与CAM相关的遗传因素及其最佳时间调节做出关键贡献。学生还将完成植物转化和所需的技术详细的分子，生化和生理特性的产生转基因系。

The world is getting hotter and drier due to climate change, and the human population is growing rapidly to the extent that it has been predicted that we will need to increase crop yields by 50 - 70 % by 2050 in order to feed the predicted 9 - 10 billion people. This extra food production has to be achieved using the same land and the same or less fresh water relative to the water used by agriculture today. Achieving such dramatic advances in crop productivity to underpin human food security this century is widely regarded as a key global grand challenge that requires ground-breaking, innovative approaches that "think outside the box". Our research aims to leverage a naturally occurring super-charged adaptation of photosynthesis called Crassulacean acid metabolism (CAM). This adaptation can enhance plant water use efficiency well beyond that of any of today's major food crop species such as rice, wheat or maize. Through decoding the genomes and transcriptomes of model CAM species and undertaking functional genomics research in model CAM species in the genus Kalanchoë, our work is establishing the minimal parts list for the engineering of CAM into C3 crops such as rice or wheat in order to enhance crop water use efficiency and photosynthesis. This project will work to leverage our recent discoveries by exploring the regulatory regions of genes involved in CAM using the firefly luciferase reporter gene to "see" the activity of the promoter. In particular, we seek to understand how the activity of the genes required for CAM is regulated by the endogenous circadian clock; the internal timekeeper that organisms use to optimise their biochemistry relative to the daily light/ dark cycle. This will allow the student to make a key contribution to our understanding of the genetic elements associated with CAM and its optimal temporal regulation. The student will also become accomplished in plant transformation and the techniques required for the detailed molecular, biochemical and physiological characterisation of the generated transgenic lines.