Sang Shifei, Sun Xiaohan, Ma Tengyun, Zhang Yijing, Yao Guoqin, Wang Xinyu, Tan Xiaoyu, Feng Liuchun, Li Junhua, Ji Shengdong, Cheng Hongtao
College of Life Sciences, Henan Normal University/Engineering Research Center of Crop Genetic Improvement and Germplasm Innovation in Henan Province, College of Life Sciences, Henan Normal University, Xinxiang, Henan 453007, China.
School of Agronomy and Horticulture, Jiangsu Vocational College of Agriculture and Forestry, No. 19, Wenchang East Road, Jurong City, Jiangsu Province 212400, China.
Int J Biol Macromol. 2025 Feb;290:138904. doi: 10.1016/j.ijbiomac.2024.138904. Epub 2024 Dec 18.
Rice, a staple in diets, undergoes digestion post-consumption, often triggering a swift surge in blood sugar among diabetics, intensifying their health burden. Notably, resistant starch (RS) emerges as a potent ally in fostering satiety and mitigating metabolic syndrome in diabetes. The SBEIIb gene, a key orchestrator of starch branching enzymes, plays a pivotal role in starch synthesis, and its genetic alteration can dramatically boost RS content in rice. Cultivating RS-rich functional germplasms is of great significance for improving human nutrition and health. In this study, the application of CRISPR/Cas9 technology was investigated for precise multi-target editing within the SBEIIb promoter, aiming to generate valuable germplasm resources enriched with RS. The results revealed extensive mutations in the SBEIIb promoter region, resulting in a varied reduction in SBEIIb expression levels. Remarkably, the grains from the homozygous T1 mutant lines displayed a substantial elevation in RS content, ranging from 3 to 12 times greater than that of the wild-type, accompanied by notable alterations in the starch granule morphology of these grains. This study presents an effective breeding strategy for the precise enhancement of RS content and establishes a foundation for further insights into the molecular mechanisms governing cis-element regulation of RS synthesis.
大米是日常饮食中的主食，食用后会被消化，这常常会使糖尿病患者的血糖迅速飙升，加重他们的健康负担。值得注意的是，抗性淀粉（RS）在促进饱腹感和减轻糖尿病患者的代谢综合征方面成为了有力的帮手。淀粉分支酶的关键调控基因SBEIIb在淀粉合成中起关键作用，其基因改变可显著提高大米中的RS含量。培育富含RS的功能性种质资源对改善人类营养和健康具有重要意义。在本研究中，研究了CRISPR/Cas9技术在SBEIIb启动子内进行精确多靶点编辑的应用，旨在生成富含RS的宝贵种质资源。结果显示，SBEIIb启动子区域发生了广泛的突变，导致SBEIIb表达水平不同程度降低。值得注意的是，纯合T1突变体系的谷粒RS含量大幅提高，比野生型高3至12倍，同时这些谷粒的淀粉颗粒形态也有显著变化。本研究提出了一种精确提高RS含量的有效育种策略，并为进一步深入了解RS合成顺式元件调控的分子机制奠定了基础。
