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, 712100, China; 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; 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, 712100, China.
Carbohydr Polym. 2020 Nov 1;247:116681. doi: 10.1016/j.carbpol.2020.116681. Epub 2020 Jun 24.
Two high amylose (HAM) inbred lines with apparent amylose contents of 55 % and 62 %, respectively, were selected to explore the relationship between molecular structure and gene expression of starch-synthase involved enzymes. GPC analysis of debranched starches showed that the HAM starches (HAMSs) had shorter amylose chains and longer amylopectin chains than normal maize starch (NMS). FACE analysis showed that these HAMSs had a higher content of amylopectin chains of DP > 21. Quantitative Real-Time PCR analysis showed that the HAM lines had specifically low expression of the starch branching enzyme IIb (SBEIIb), and the starch synthase IIIa (SSIIIa) homologue, and high expression of the isoamylase 2 (ISA2), potentially suppressing the generation of amylopectin molecules through deficient branching and excessive debranching process, thereby increasing the relative amylose content. A high expression of GBSS1 was potentially associated with increased short amylose chain lengths in HAMSs.
选取了两个高直链淀粉（HAM）近交系，其直链淀粉含量分别为 55%和 62%，旨在探讨参与淀粉合成酶的分子结构与基因表达之间的关系。对脱支淀粉的 GPC 分析表明，HAM 淀粉（HAMS）的直链淀粉链较短，支链淀粉链较长，而普通玉米淀粉（NMS）则较长。FACE 分析表明，这些 HAMS 具有更高含量的 DP > 21 的支链淀粉链。实时定量 PCR 分析表明，HAM 系的淀粉分支酶 IIb（SBEIIb）和淀粉合成酶 IIIa（SSIIIa）同源物表达水平较低，异淀粉酶 2（ISA2）表达水平较高，可能通过分支不足和过度去分支过程抑制支链淀粉分子的生成，从而增加相对直链淀粉含量。GBSS1 的高表达可能与 HAMS 中短直链淀粉链长度的增加有关。
