PHOTORECEPTOR OPTIMISATION OF PLANT WATER USE

不断变化的气候加上不断增加的人口和资源使用，正在给我们养活世界社会的能力造成更大的压力。作物产量取决于水资源的供应，预计水资源的减少将严重影响我们的粮食安全。因此，我们需要开发具有更高光合性能和更少用水的作物。植物的表现是由它对环境信号的反应能力决定的。光是调控植物生长发育的重要信号之一。它不仅是光合作用的必需物质，也是种子萌发、茎伸长和叶片发育等过程的必需物质。将光信号（方向、质量和数量）转化为响应是植物光感受器的作用，而光敏色素B（一种红色/远红色光感受器）在许多这些响应中起着重要作用。这包括平衡植物的光合作用性能和用水量。phyB缺陷的植物表现出一种权衡，即以减少光合作用性能为代价，显著改善其水分利用。我们的工作表明，phyB调节叶片表面气孔的发育。气孔是在叶子表面发现的小孔隙，它们是植物气体交换的关键调节器，平衡光合作用所需的二氧化碳气体的吸收，以换取水蒸气。phyB信号决定了叶片上气孔发育的数量，这对植物的水分利用和光合作用有直接影响。该提案的一个主要成果将是通过组织特异性和组织间信号传导来确定phyB信号网络在调节这一过程中的作用。调节这个phyB信号网络提供了一种操纵水分利用和光合作用之间权衡的方法，以产生性能更好的植物。

A changing climate coupled with increasing population and resource use is placing a greater strain on our ability to feed the world community. Crop productivity is dependent on water availability and predicted reductions in this resource could seriously impact our Food Security. We therefore need to develop crops with improved photosynthetic performance and reduced water use. A plants performance is determined by its ability to respond to environmental signals. Light is one of the most important signals for regulating plant growth and development. It is required not only for photosynthesis but also various other processes including seed germination, stem elongation and leaf development. Transforming a light signal (direction, quality and quantity) into a response is the role of plant photoreceptors and phytochrome B, a red/far-red photoreceptor, plays a major role in many of these responses. This includes balancing photosynthetic performance with the amount of water a plant uses. Plants defective in phyB, show a trade-off with significant improvements in their water use at the expense of reductions in their photosynthetic performance. Our work has shown that phyB regulates the development of stomata on the leaf surface. Stomata are the small pores found on the surface of leaves and they are critical regulators of plant gas exchange, balancing the uptake of carbon dioxide gas, which is required for photosynthesis, in exchange for water vapour. phyB signalling determines the number of stomata that develop on a leaf, which has a direct impact on plant water use and photosynthesis. A major outcome of this proposal will be to establish the role of a phyB signalling network in regulating this process through both tissue specific and inter-tissue signalling. Modulating this phyB signalling network presents a means of manipulating the trade-off between water use and photosynthesis to generate plants with improved performance.