Facing Forwards - Understanding epidermal development in cereals

作为热量的主要来源，谷物是我们粮食安全的基石物种。为了可持续地满足粮食需求，我们需要在不增加投入或使用更多土地的情况下增加谷物产量，同时面临加速和更极端的温度和干旱事件。数百万年前，当植物扩展到陆地上生活时，它们面临着严峻的气候挑战。为了生存，陆地植物进化出了一个高度适应性的外表面，表面排列着表皮细胞，分泌出富含脂质的保护性角质层，以防止水分流失并反射入射辐射，散布着可调节的气孔，称为气孔，允许植物呼吸和蒸腾。通过这种方式，外表皮平衡了保护和与地面环境的交换。微调这种平衡有助于植物应对不断变化和挑战的环境。例如，草，包括主食谷类作物，发展出非常有效的气孔复合体和厚的蜡质表皮，这是帮助草在炎热、强光的平原上节水和保持温度的关键。表皮表面还可以发育其他类型的特化细胞，包括防御结构，如毛发和二氧化硅积累细胞，这些细胞也可以影响表皮水分流失，冷却和气孔功能。我们建议，这些适应性的特点，谷物表皮可以调动工程谷物作物，需要较少的灌溉和保持产量在未来的气候。要做到这一点，我们需要了解植物如何协调角质层和专门的细胞类型的表皮和相关性的每个组成部分和它们的组合表皮功能。在这项工作的一个重大进展中，我们的研究小组最近发现，高度保守的相互作用基因控制着大麦的表皮细胞模式和角质层特性，从而确定了一个共享的上游网络，控制着与谷物性能相关的多种表皮特征。该提案利用这些发现作为一个平台，以确定表皮发育的关键步骤以及它们如何相互影响，对环境条件作出反应，并影响表皮功能和整个植物的生产力。我们将部署尖端的方法，以前所未有的分辨率在表皮中描绘角质层和细胞图案，并探索这些事件之间的相互依赖关系。我们还将利用我们的遗传知识来评估小麦的遗传决定因素，小麦是一种与大麦沿着统治温带农业的密切相关的谷物。最后，我们将使用最先进的受控环境和专业的生理方法来评估改变的表皮特征对组织和整个植物水平的生理功能以及未来气候情景的影响。总之，我们的研究将使我们设计表皮特征套件的能力发生重大变化，以适应未来的作物。

As the primary source of calories, cereals are the cornerstone species of our food security. To sustainably meet food demands, we need to increase cereal grain yields without increasing inputs or using more land, all the while facing accelerating and more extreme temperature and drought events. Plants faced severe climate challenges millions of years ago when they expanded to living on land. To survive, land plants evolved a highly adaptive outer surface lined with epidermal cells that secrete a protective lipid-rich cuticle to prevent water loss and reflect incoming radiation, interspersed with adjustable air pores called stomata allowing plants to breathe and transpire. In this way, the outer epidermis balances protection and exchange with the above-ground environment. Fine-tuning this balance helps plants respond to changing and challenging environments. For example, grasses, including staple cereal crops develop extremely efficient stomatal complexes and thick waxy cuticles, key elaborations which help grasses save water and maintain temperature on hot, high light plains. Epidermal surfaces can also develop other types of specialised cells, including defensive structures such as hairs and silica-accumulating cells which can also influence epidermal water loss, cooling and stomatal function. We propose that these adaptive features of the cereal epidermis can be mobilised to engineer cereal crops which need less irrigation and maintain yield in future climates.To do this, we need to understand how plants coordinate the cuticle and specialised cell types on the epidermis and the relevance of each component and their combinations to epidermal function. In a major advance in this effort, our research group recently revealed that deeply conserved, interacting genes control both epidermal cell patterning as well as cuticle properties in barley, thus identifying a shared upstream network controlling multiple epidermal features linked to cereal performance. This proposal exploits these findings as a platform to determine the crucial steps in epidermal development and how they influence each other, respond to environmental conditions and impact epidermal functions and whole plant productivity. We will deploy cutting edge approaches to profile cuticle and cell patterning in the epidermis at an unprecedented resolution and explore the interdepenc(ies) between these events. We will also exploit our genetic knowledge to evaluate genetic determinants in wheat, a closely related cereal which along with barley dominate temperate agriculture. Finally, we will use state-of-the-art controlled environments and specialist physiological methods to assess the impact of altered epidermal features on physiological function both at the tissue and whole plant level and future climate scenarios. Taken together, our research will deliver a step-change in our ability to design suites of epidermal features to future-proof our crops.