title: Molecular Structure and Physicochemical Properties of Starches from Rice with Different Amylose Contents Resulting from Modification of OsGBSSI Activity.
abstract: OsGBSSI, encoded by the Waxy (Wx) gene, is the key enzyme in the synthesis of amylose chains. Transgenic rice lines with various GBSSI activities were previously developed via site-directed mutagenesis of the Wx gene in the glutinous cultivar Guanglingxiangnuo (GLXN). In this study, grain morphology, molecular structure, and physicochemical properties were investigated in four transgenic lines with modified OsGBSSI activity and differences in amylose content. A milky opaque appearance was observed in low- and non-amylose rice grains due to air spaces in the starch granules. Gel permeation chromatography (GPC) and high-performance anion-exchange chromatography (HPAEC) analyses showed that although OsGBSSI can synthesize intermediate and extra-long amylopectin chains, it is mainly responsible for the longer amylose chains. Amylose content was positively correlated with trough viscosity, final viscosity, setback viscosity, pasting time, pasting temperature, and gelatinization temperature and negatively with gel consistency, breakdown viscosity, gelatinization enthalpy, and crystallinity. Overall, the findings suggest that OsGBSSI may be also involved in amylopectin biosynthesis, in turn affecting grain appearance, thermal and pasting properties, and the crystalline structure of starches in the rice endosperm.
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.|Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Changquan
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Chen
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Ren
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai 200032, China.
authors.forename: Derui
authors.initials: D
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai 200032, China.|Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Xiuling
authors.initials: X
authors.lastname: Cai
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.|Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Qianfeng
authors.initials: Q
authors.lastname: Li
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences , Shanghai 200032, China.|Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Jiping
authors.initials: J
authors.lastname: Gao
authors.affiliation: Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.|Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University , Yangzhou 225009, China.
authors.forename: Qiaoquan
authors.identifier: http://orcid.org/0000-0001-5543-5798
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000688:Amylose / Q000032:analysis* / Q000378:metabolism; D012275:Oryza / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000737:chemistry* / Q000378:metabolism; D013214:Starch Synthase / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D013213:Starch; D000688:Amylose; C434607:granule-bound starch synthase I; D013214:Starch Synthase
keywords: Oryza sativa L.; OsGBSSI; amylose; crystallinity; physicochemical properties; starch fine structure