Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Denmark; Key Laboratory of Biology and Genetic Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China; Lab of Food Soft Matter Structure and Advanced Manufacturing, College of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
Key Laboratory of Biology and Genetic Improvement of Maize in Arid Area of Northwest Region, Ministry of Agriculture, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China.
Carbohydr Polym. 2022 Jul 1;287:119327. doi: 10.1016/j.carbpol.2022.119327. Epub 2022 Mar 10.
This review systematically documents the major different strategies of generating high-amylose (HAS) starch mutants aiming at providing high resistant starch, by engineering the starch biosynthesis metabolic pathways. We identify three main strategies based on a new representation of the starch structure: 'the building block backbone model': i) suppression of starch synthases for reduction of amylopectin (AP) side-chains; ii) suppression of starch branching enzymes (SBEs) for production of AM-like materials; and iii) suppression of debranching enzymes to restrain the transformation from over-branched pre-AP to more ordered AP. From a biosynthetic perspective, AM generated through the second strategy can be classified into two types: i) normal AM synthesized mainly by regular expression of granule-bound starch synthases, and ii) modified linear AP chains (AM-like material) synthesized by starch synthases due to the suppression of starch branching enzymes. The application of new breeding technologies, especially CRISPR, in the breeding of HAS crops is also reviewed.
本文系统地记录了通过工程淀粉生物合成代谢途径来产生高直链淀粉（HAS）淀粉突变体的主要不同策略，旨在提供高抗性淀粉。我们根据淀粉结构的新表示方法“构建块骨干模型”确定了三种主要策略：i）抑制淀粉合酶以减少支链淀粉（AP）侧链；ii）抑制淀粉分支酶（SBEs）以生产类似 AM 的材料；iii）抑制脱支酶以抑制从过度分支的前 AP 向更有序的 AP 的转化。从生物合成的角度来看，通过第二种策略产生的 AM 可以分为两种类型：i）由颗粒结合淀粉合酶的常规表达主要合成的正常 AM，和 ii）由于淀粉分支酶的抑制，由淀粉合酶合成的修饰线性 AP 链（类似 AM 的材料）。还回顾了新的育种技术，特别是 CRISPR，在 HAS 作物育种中的应用。
