title: Systematic Analysis of Pericarp Starch Accumulation and Degradation during Wheat Caryopsis Development.
abstract: Although wheat (Triticum aestivum L.) pericarp starch granule (PSG) has been well-studied, our knowledge of its features and mechanism of accumulation and degradation during pericarp growth is poor. In the present study, developing wheat caryopses were collected and starch granules were extracted from their pericarp to investigate the morphological and structural characteristics of PSGs using microscopy, X-ray diffraction and Fourier transform infrared spectroscopy techniques. Relative gene expression levels of ADP-glucose pyrophosphorylase (APGase), granule-bound starch synthase II (GBSS II), and α-amylase (AMY) were quantified by quantitative real-time polymerase chain reaction. PSGs presented as single or multiple starch granules and were synthesized both in the amyloplast and chloroplast in the pericarp. PSG degradation occurred in the mesocarp, beginning at 6 days after anthesis. Amylose contents in PSGs were lower and relative degrees of crystallinity were higher at later stages of development than at earlier stages. Short-range ordered structures in the external regions of PSGs showed no differences in the developing pericarp. When hydrolyzed by α-amylase, PSGs at various developmental stages showed high degrees of enzymolysis. Expression levels of AGPase, GBSS II, and AMY were closely related to starch synthesis and degradation. These results help elucidate the mechanisms of accumulation and degradation as well as the functions of PSG during wheat caryopsis development.
authors.affiliation: Jiangsu Key laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
authors.forename: Xurun
authors.initials: X
authors.lastname: Yu
authors.affiliation: Jiangsu Yanjiang Institute of Agricultural Sciences, Nantong 226541, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Jiangsu Key laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Jiangsu Key laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Chen
authors.affiliation: Jiangsu Key laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wang
authors.affiliation: Jiangsu Key laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Jiangsu Key laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Xiong
mesh_terms: D000688:Amylose / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002736:Chloroplasts / Q000378:metabolism; D005638:Fruit / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000235:genetics / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018087:Plastids / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D017550:Spectroscopy, Fourier Transform Infrared; D013213:Starch / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D013214:Starch Synthase / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D010940:Plant Proteins; D013213:Starch; D000688:Amylose; C111377:starch synthase II; D013214:Starch Synthase; D051599:Glucose-1-Phosphate Adenylyltransferase