title: Developmental analysis of maize endosperm proteome suggests a pivotal role for pyruvate orthophosphate dikinase.
abstract: Although the morphological steps of maize (Zea mays) endosperm development are well described, very little is known concerning the coordinated accumulation of the numerous proteins involved. Here, we present a proteomic study of maize endosperm development. The accumulation pattern of 409 proteins at seven developmental stages was examined. Hierarchical clustering analysis allowed four main developmental profiles to be recognized. Comprehensive investigation of the functions associated with clusters resulted in a consistent picture of the developmental coordination of cellular processes. Early stages, devoted to cellularization, cell division, and cell wall deposition, corresponded to maximal expression of actin, tubulins, and cell organization proteins, of respiration metabolism (glycolysis and tricarboxylic acid cycle), and of protection against reactive oxygen species. An important protein turnover, which is likely associated with the switch from growth and differentiation to storage, was also suggested from the high amount of proteases. A relative increase of abundance of the glycolytic enzymes compared to tricarboxylic acid enzymes is consistent with the recent demonstration of anoxic conditions during starch accumulation in the endosperm. The specific late-stage accumulation of the pyruvate orthophosphate dikinase may suggest a critical role of this enzyme in the starch-protein balance through inorganic pyrophosphate-dependent restriction of ADP-glucose synthesis in addition to its usually reported influence on the alanine-aromatic amino acid synthesis balance.
authors.affiliation: Unité Mixte de Recherche 206, Chimie Biologique, Institut National de la Recherche Agronomique, Institut National Agronomique Paris-Grignon, F-78850 Thiverval Grignon, France. mechin@grignon.inra.fr
authors.forename: Valérie
authors.initials: V
authors.lastname: Méchin
authors.forename: Claudine
authors.initials: C
authors.lastname: Thévenot
authors.forename: Martine
authors.initials: M
authors.lastname: Le Guilloux
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Prioul
authors.forename: Catherine
authors.initials: C
authors.lastname: Damerval
mesh_terms: D002455:Cell Division; D002473:Cell Wall / Q000378:metabolism; D002952:Citric Acid Cycle; D016000:Cluster Analysis; D006019:Glycolysis; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D010940:Plant Proteins / Q000145:classification / Q000378:metabolism / Q000502:physiology*; D020033:Protein Isoforms / Q000145:classification / Q000378:metabolism / Q000502:physiology; D020543:Proteome; D011772:Pyruvate, Orthophosphate Dikinase / Q000502:physiology*; D013213:Starch / Q000378:metabolism; D003313:Zea mays / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development
chemical_list: D010940:Plant Proteins; D020033:Protein Isoforms; D020543:Proteome; D013213:Starch; D011772:Pyruvate, Orthophosphate Dikinase; D010100:Oxygen