title: Starch synthesis and programmed cell death during endosperm development in triticale (x Triticosecale Wittmack).
abstract: Triticale (x Triticosecale Wittmack) grains synthesize and accumulate starch as their main energy source. Starch accumulation rate and synthesis activities of ADP-glucose pyrophosphorylase, soluble starch synthases, granule-bound starch synthase and starch-branching enzyme showed similar pattern of unimodal curves during endosperm development. There was no significant difference in activity of the starch granule-bound protein isolated from total and separated starch granules at different developmental stages after anthesis in triticale. Evans Blue staining and analysis of DNA fragmentation indicated that cells of triticale endosperm undergo programmed cell death during its development. Dead cells within the endosperm were detected at 6 d post anthesis (DPA), and evidence of DNA fragmentation was first observed at 21 DPA. The period between initial detection of PCD to its rapid increase overlapped with the key stages of rapid starch accumulation during endosperm development. Cell death occurred stochastically throughout the whole endosperm, meanwhile, the activities of starch biosynthetic enzymes and the starch accumulation rate decreased in the late stages of grain filling. These results suggested that the timing and progression of PCD in triticale endosperm may interfere with starch synthesis and accumulation.
authors.affiliation: College of Agriculture, Shihezi University, Xinjiang 832003, China.
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Li
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Li
authors.forename: Cheng
authors.initials: C
authors.lastname: Li
authors.forename: Denis A
authors.initials: DA
authors.lastname: Gaudet
authors.forename: André
authors.initials: A
authors.lastname: Laroche
authors.forename: Lian-Pu
authors.initials: LP
authors.lastname: Cao
authors.forename: Zhen-Xiang
authors.initials: ZX
authors.lastname: Lu
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000235:genetics / Q000378:metabolism; D000687:Amylopectin / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D053938:DNA Fragmentation; D002523:Edible Grain / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D056625:Endosperm / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000235:genetics / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D013213:Starch / Q000096:biosynthesis* / Q000235:genetics; D013214:Starch Synthase / Q000235:genetics / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D013213:Starch; D000687:Amylopectin; D015061:1,4-alpha-Glucan Branching Enzyme; D013214:Starch Synthase; D051599:Glucose-1-Phosphate Adenylyltransferase