Yu Shiyao, Du Dengxiang, Wu Alex C, Bai Yeming, Wu Peng, Li Cheng, Gilbert Robert G
Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, Jiangsu Province, China.
The University of Queensland, Centre for Nutrition and Food Science, Queensland Alliance for Agriculture and Food Innovation, Brisbane, QLD 4072, Australia.
Foods. 2020 Feb 20;9(2):222. doi: 10.3390/foods9020222.
This paper examines if, in maize, starch structure and starch-dependent properties might be altered by pleiotropic effects arising from genetic modifications that are not directly related to starch synthesis. The molecular structure, specifically the starch chain-length distributions (CLDs), of two maize lines transformed with () and genes (an artificial gene, encoding proteinaceous insecticidal δ-endotoxins) were compared to those of their control lines. The two transgenes are responsible for herbicidal resistance and insect tolerance, respectively. The starch CLDs were measured by enzymatic debranching and measuring the molecular weight distributions of the resulting linear chains. It was found that although all the lines had similar amylose contents, the CLDs of both amylopectin and amylose for were noticeably different from the others, having more short amylopectin and long amylose chains. These CLDs are known to affect functional properties, and indeed it was found that the transgenic lines showed a lower gelatinization temperature and faster digestion rate than the control or lines. However, a slower digestion rate is nutritionally desirable. Thus, pleiotropic effects from genetic modifications can indirectly but significantly affect the starch synthesis pathway and thus change functional properties of significance for human health.
本文研究了在玉米中，淀粉结构和淀粉相关特性是否会因与淀粉合成无直接关系的基因改造所产生的多效性效应而发生改变。将转（）基因和基因（一种人工基因，编码蛋白质类杀虫δ-内毒素）的两个玉米品系的分子结构，特别是淀粉链长分布（CLD），与其对照品系进行了比较。这两个转基因分别负责除草剂抗性和昆虫耐受性。通过酶法脱支并测量所得线性链的分子量分布来测定淀粉CLD。结果发现，尽管所有品系的直链淀粉含量相似，但品系的支链淀粉和直链淀粉的CLD与其他品系明显不同，具有更多的短支链淀粉和长直链淀粉链。已知这些CLD会影响功能特性，实际上发现转基因品系的糊化温度低于对照品系或品系，消化速率更快。然而，较慢的消化速率在营养方面是可取的。因此，基因改造产生的多效性效应可间接但显著地影响淀粉合成途径，从而改变对人类健康具有重要意义的功能特性。
