The shape of sustainable crop production - re-engineering plant architecture for sustainable food production

可持续作物生产的形态——为可持续粮食生产重新设计植物结构

• 批准号: 2878037
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2878037
• 关键词: shape; sustainable; crop; production; re

This project is focused on better characterising the molecular mechanisms behind gravitropic responses in plant shoots and roots for important crop species. This is for the purpose of engineering crop architecture to improving light capture and decrease lodging occurrence (shoots) and/or nutrient acquisition and drought tolerance (roots).Previous work in this field has established that lateral roots and shoots maintain their growth angles through gravitropic set-point angles as seen in arabidopsis model organisms. The gravitropic-set point angle is the angle defined by its relationship to the gravity vector so a vertically downward shoot/root possessing a GSA of 0 and plant organs are maintained at this GSA in response to gravitropism (Digby, Fern, 1995). This gravity-dependent process is mediated by auxin phytohormones with auxin flux on the upper and lower side leading to differential elongation or elongation inhibition in the shoots and roots respectively. The gravity-sensing apparatus of the root/shoot tip, according to the startch-statolith hypothesis, the columella of dicot and monocot roots and the statocytes of dicot shoots are a collection of polarised cells containing starch-filled amyloplasts which respond to gravity through starch sedimentation to a particular pole of the cell. As a consequence of downward starch sedimentation to the nascent bottom region of the cell when the root/shoot is moved away from the vertical, there is increased downward flux of auxin to the abaxial side of the shoot/root. This acts against the anti-gravitropic offset flux of auxin to the adaxial side of the shoot and root. This disparity between adaxial and abaxial auxin concentrations across the organ leads to differential cell elongation followed by the upward bending in shoots and downwards bending in roots to return to their initial GSAs for optimal plant growth (Roychoudhry and Kepinski 2021).The molecular process behind this gravity-sensing mechanism has been well characterised in arabidopsis models with work. For example, the role of the auxin transporters PIN3, 4 and 7 and their role in establishing gravicompetence in shoots and roots (Roychoudhry et al., 2022). However, translating this understanding of root and shoot responses to gravity and how that impacts plant architecture is still necessary for numerous important crop species, with efforts aimed at improving rooting for increase nutrient/water acquisition in response to increasing drought prevalence under climate change (as well as decreasing shoot lodging where the plant stem snaps whilst maintaining crop yield).Work into cereal species such as wheat and rice has been conducted by fellow postgraduate researchers at the University of Leeds, and elsewhere, with both wheat and rice lateral roots returning to their original GSAs with wheat laterals restoring their GSAs faster than rice laterals which shows variation in the response between species as well as monocots (cereals) and dicots (arabidopsis) with rice potentially possessing a stronger auxin-dependent anti-gravitropic offset response relative to wheat lateral roots. Additionally, rice DRO1 which regulates root growth angle has shown to lead to higher rice yields in water-scarce environments when overexpressed as more vertical root systems are developed (Walsh et al., unpublished). Continuing to elucidate the molecular mechanisms of root and shoot angle development and maintenance in crop species can act as a crucial tool in improving crop yields and establishing better food security. Some crops such as Barley and Sorghum have some early research established whilst other staple crops like soybean have none. This PhD project aims to expand the knowledge of root and shoot angles in these seminal crop species to engineer crops that are resilient to the ever worsening issues of climate change with key emphasis on staple crops like rice and wheat.

该项目的重点是更好地描述重要作物品种的植物芽和根向地性反应背后的分子机制。这是为了工程作物结构的目的，以提高光捕获和减少倒伏发生（芽）和/或养分获取和耐旱性（根）。该领域先前的研究已经证实，侧根和侧芽通过向地性设定点角度来维持其生长角度，这在拟南芥模式生物中可见。向地性设定点角是由其与重力矢量的关系定义的角度，因此垂直向下的茎/根的GSA为0，植物器官保持在该GSA以响应向地性（Digby, Fern, 1995）。这一依赖重力的过程是由生长素激素介导的，生长素通量在上侧和下侧，分别导致芽和根的差异伸长或伸长抑制。根据淀粉-静石假说，根/茎尖的重力感应装置，双子叶根和单子叶根的小柱和双子叶茎的静细胞是一组极化细胞的集合，这些细胞含有淀粉填充的淀粉质体，通过淀粉沉积到细胞的特定极点来响应重力。当根/茎远离垂直方向移动时，淀粉向下沉积到细胞新生的底部区域，生长素向下通量增加到茎/根的背面。这与生长素向茎和根正面的反向地向偏移通量相反。整个器官内的正向和反向生长素浓度的差异导致细胞伸长的差异，随后是芽向上弯曲和根向下弯曲，以恢复其初始gsa以实现最佳植物生长（Roychoudhry和Kepinski 2021）。这种重力感应机制背后的分子过程已经在拟南芥模型中得到了很好的表征。例如，生长素转运体PIN3、4和7的作用及其在芽和根中建立重力能力的作用（Roychoudhry et al., 2022）。然而，对于许多重要的作物物种来说，转化对根和芽对重力的响应及其如何影响植物结构的理解仍然是必要的，努力改善根系以增加营养/水分获取，以应对气候变化下日益严重的干旱（以及在保持作物产量的同时减少茎折断处的茎倒伏）。利兹大学和其他地方的研究生研究人员对小麦和水稻等谷物物种进行了研究，小麦和水稻侧根都恢复到原来的gsa，小麦侧根恢复gsa的速度比水稻侧根快，这表明物种之间以及单子叶（谷物）和双子叶（拟南芥）之间的响应存在差异，水稻可能比小麦侧根具有更强的生长素依赖的抗地向抵消响应。此外，在缺水的环境中，随着更多垂直根系的形成，当过度表达时，调节根系生长角度的水稻DRO1会导致更高的水稻产量（Walsh等人，未发表）。继续阐明作物物种的根冠角发育和维持的分子机制，可以作为提高作物产量和建立更好的粮食安全的重要工具。一些作物如大麦和高粱有一些早期的研究，而其他主要作物如大豆没有。该博士项目旨在扩大对这些种子作物物种的根和芽角度的了解，以设计能够适应日益恶化的气候变化问题的作物，重点是水稻和小麦等主要作物。