Facing Forwards - Understanding epidermal development in cereals

作为卡路里的主要来源，谷物是我们粮食安全的基石。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提高谷物产量，同时面临加速和更极端的温度和干旱事件。数百万年前，当植物扩张到陆地上生活时，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种高度适应的外表面，表皮细胞分泌富含脂质的保护层，防止水分流失，反射入射的辐射，点缀着可调节的气孔，称为气孔，使植物能够呼吸和蒸发。通过这种方式，外表皮平衡了与地上环境的保护和交换。微调这种平衡有助于植物对变化和具有挑战性的环境做出反应。例如，包括主要谷类作物在内的禾本科植物发育出极其高效的气孔复体和厚厚的蜡质角质层，这是帮助禾本科植物在炎热、高光平原上节水和保持温度的关键精细结构。表皮表面还可以发育其他类型的特化细胞，包括防御结构，如毛发和硅积聚细胞，它们也可以影响表皮的失水、冷却和气孔功能。我们提出，可以利用谷物表皮的这些适应性特征来设计需要较少灌溉的谷物作物，并在未来的气候条件下保持产量。要做到这一点，我们需要了解植物如何协调表皮上的角质层和特化细胞类型，以及每种成分及其组合与表皮功能的相关性。在这项工作的重大进展中，我们的研究小组最近发现，大麦中深度保守的、相互作用的基因控制着表皮细胞模式和角质层特性，从而确定了一个共同的上游网络，控制着与谷物性能相关的多种表皮特征。本研究利用这些发现作为平台来确定表皮发育的关键步骤，以及它们如何相互影响，如何响应环境条件，如何影响表皮功能和整个植物的生产力。我们将采用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模式，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，小麦是一种密切相关的谷物，与大麦一起主导温带农业。最后，我们将使用最先进的受控环境和专业的生理学方法来评估表皮特征的改变对组织和整个植物水平以及未来气候情景的生理功能的影响。综上所述，我们的研究将为我们设计表皮特征套件的能力带来一个阶段性的变化，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.