Unravelling novel mechanisms of starch granule biogenesis in potato

揭示马铃薯淀粉颗粒生物发生的新机制

• 批准号: BB/X001520/1
• 负责人: David Seung
• 金额: $ 49.21万
• 依托单位: John Innes Centre
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX001520%2F1
• 关键词: Unravelling; novel; mechanisms; starch; granule

This project will develop a mechanistic understanding of starch granule formation in developing potato tubers. Starch is the major form in which plants store carbohydrates, and is vitally important to humankind as a major source of calories in our diet. Despite its importance, we still do not fully understand how plants produce starch. In its native form, starch forms insoluble granules that are composed of glucose polymers. The size of the granules is highly variable between species, and influence the physical and chemical behaviour of starch during cooking, as well as on the texture of the final food products. Recently, we have made breakthroughs in understanding the mechanism by which starch granules are initiated (or primed) in leaves of the model plant, Arabidopsis thaliana, and in cereal grains. In these plants, granule size is influenced by the number of granules initiated per plastid. However, granule initiation has not been investigated in potato, which contains the largest granule sizes among starch crops. The knowledge gained from other species make it particularly timely to discover the control of granule size and number in potato. Further, potato starch granules have a distinct ellipsoid shape, but the processes that determine the morphology of the granules are not understood in any species.This project aims to discover molecular mechanisms of starch granule initiation and morphogenesis. Firstly, we will investigate which of the granule initiation proteins establish correct granule number and size in developing tubers, by creating and studying a series of mutants defective in each initiation protein. We will then test the hypothesis that there is active granule morphogenesis in potato, based on preliminary data that this process requires a specific initiation protein isoform. State-of-the-art 3D electron microscopy and fluorescence microscopy will be used to study the structure of amyloplasts (the plastid organelle in which starch is synthesised and stored) in detail through tuber development - showing how many granules are typically initiated per amyloplast, the number of amyloplasts per cell, and how new granule formations are coordinated with new amyloplast formation.As a final objective to facilitate further impact, we will use the unique materials generated through the course of this project to assess the effects of granule size and morphology on the physical and chemical behaviour of starch during cooking, starch digestibility, as well as textural and sensory qualities in a variety of prepared potato food products. Overall, this project will greatly advance our understanding of fundamental mechanisms of starch granule biogenesis in potato.

该项目将从机理上理解马铃薯块茎发育过程中淀粉颗粒的形成。淀粉是植物储存碳水化合物的主要形式，是人类饮食中卡路里的主要来源，对人类至关重要。尽管它很重要，但我们仍然不完全了解植物是如何产生淀粉的。在其天然形态中，淀粉形成由葡萄糖聚合物组成的不溶颗粒。颗粒的大小在不同物种之间差异很大，并影响淀粉在烹饪过程中的物理和化学行为，以及最终食品的质地。最近，我们在理解模式植物拟南芥叶片和谷粒中淀粉粒启动(或启动)的机制方面取得了突破性进展。在这些植物中，颗粒大小受每个叶绿体启动的颗粒数量的影响。然而，马铃薯是淀粉作物中颗粒大小最大的作物，其颗粒起始还没有被研究过。从其他物种获得的知识使其特别及时地发现了马铃薯颗粒大小和数量的控制。此外，马铃薯淀粉颗粒具有明显的椭圆形，但决定颗粒形态的过程在任何物种中都不清楚。本项目旨在揭示淀粉颗粒起始和形态发生的分子机制。首先，我们将通过创建和研究一系列在每个启动蛋白中存在缺陷的突变体，来研究哪些颗粒启动蛋白在块茎发育中建立了正确的颗粒数量和大小。然后，我们将根据初步数据验证马铃薯中存在活跃的颗粒形态发生的假设，这一过程需要特定的起始蛋白亚型。最先进的3D电子显微镜和荧光显微镜将在块茎发育过程中详细研究淀粉体(合成和储存淀粉的质体细胞器)的结构-显示每个淀粉体通常启动的颗粒数量，每个细胞的淀粉体数量，以及新颗粒的形成如何与新的淀粉体形成相协调。作为进一步影响的最终目标，我们将使用在该项目过程中产生的独特材料来评估颗粒大小和形态对烹饪过程中淀粉的物理和化学行为、淀粉的消化率以及质地和感官质量的影响。总体而言，该项目将极大地促进我们对马铃薯淀粉粒生物发生的基本机制的理解。

项目成果

SAGA1 and SAGA2 promote starch formation around proto-pyrenoids in Arabidopsis chloroplasts.

• DOI: 10.1073/pnas.2311013121
• 发表时间: 2024-01-23
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Atkinson, Nicky;Stringer, Rhea;Mitchell, Stephen R.;Seung, David;McCormick, Alistair J.
• 通讯作者: McCormick, Alistair J.