title: Effects of grain development on formation of resistant starch in rice.
abstract: Three rice mutants with different contents of resistant starch (RS) were selected to investigate the effects of grain filling process on the formation of resistant starch. During grain development, the content of RS was increased with grain maturation and showed negative correlations with the grain weight and the starch molecular weight (Mn, Mw) and a positive correlation with the distribution of molecular mass (polydispersity, Pd). The morphologies of starch granules in high-RS rice were almost uniform in single starch granules and exhibited different proliferation modes from common rice. The lower activities of ADP-glucose pyrophosphorylase and starch branching enzyme and the higher activity of starch synthase and starch de-branching enzyme observed in high-RS rice might be responsible for the formation of small irregular starch granules with large spaces between them. In addition, the lower molecular weight and the broad distribution of molecular weights lead to differences in the physiochemical properties of starch.
authors.affiliation: State Key Lab of Rice Biology and Key Lab of the Ministry of Agriculture for Nuclear Agricultural Sciences, Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, PR China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shu
authors.affiliation: State Key Lab of Rice Biology and Key Lab of the Ministry of Agriculture for Nuclear Agricultural Sciences, Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Lab of Rice Biology and Key Lab of the Ministry of Agriculture for Nuclear Agricultural Sciences, Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, PR China. Electronic address: dxwu@zju.edu.cn.
authors.forename: Dianxing
authors.initials: D
authors.lastname: Wu
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000378:metabolism; D055598:Chemical Phenomena; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D012275:Oryza / Q000737:chemistry* / Q000235:genetics / Q000254:growth & development*; D012639:Seeds / Q000737:chemistry* / Q000254:growth & development*; D013213:Starch / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D013214:Starch Synthase / Q000378:metabolism
chemical_list: D013213:Starch; D015061:1,4-alpha-Glucan Branching Enzyme; D013214:Starch Synthase; D051599:Glucose-1-Phosphate Adenylyltransferase
keywords: Resistant starch; Rice development; Starch granules; Starch synthesis