title: A comparative glycoproteome study of developing endosperm in the hexose-deficient miniature1 (mn1) seed mutant and its wild type Mn1 in maize.
abstract: In maize developing seeds, transfer cells are prominently located at the basal endosperm transfer layer (BETL). As the first filial cell layer, BETL is a gateway to sugars, nutrients and water from mother plant; and anchor of numerous functions such as sucrose turnover, auxin and cytokinin biosynthesis/accumulation, energy metabolism, defense response, and signaling between maternal and filial generations. Previous studies showed that basal developing endosperms of miniature1 (mn1) mutant seeds lacking the Mn1-encoded cell wall invertase II, are also deficient for hexose. Given the role of glucose as one of the key sugars in protein glycosylation and proper protein folding; we performed a comparative large scale glycoproteome profiling of total proteins of these two genotypes (mn1 mutant vs. Mn1 wild type) using 2D gel electrophoresis and glycosylation/total protein staining, followed by image analysis. Protein identification was done by LC-MS/MS. A total of 413 spots were detected; from which, 113 spots matched between the two genotypes. Of these, 45 showed >20% decrease/increase in glycosylation level and were selected for protein identification. A large number of identified proteins showed decreased glycosylation levels in mn1 developing endosperms as compared to the Mn1. Functional classification of proteins, showed mainly of post-translational modification, protein turnover, chaperone activities, carbohydrate and amino acid biosynthesis/transport, and cell wall biosynthesis. These proteins and activities were related to endoplasmic reticulum (ER) stress and unfolded protein response (UPR) as a result of the low glycolsylation levels of the mutant proteins. Overall, these results provide for the first time a global glycoproteome profile of maize BETL-enriched basal endosperm to better understand their role in seed development in maize.
authors.affiliation: Proteomics, Interdisciplinary Center for Biotechnology Research, University of Florida Gainesville, FL, USA.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Silva-Sanchez
authors.affiliation: Proteomics, Interdisciplinary Center for Biotechnology Research, University of Florida Gainesville, FL, USA ; Department of Biology, UF Genetics Institute, University of Florida Gainesville, FL, USA.
authors.forename: Sixue
authors.initials: S
authors.lastname: Chen
authors.affiliation: Proteomics, Interdisciplinary Center for Biotechnology Research, University of Florida Gainesville, FL, USA.
authors.forename: Jinxi
authors.initials: J
authors.lastname: Li
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology Gainesville, FL, USA ; Department of Agronomy, University of Florida Gainesville, FL, USA.
authors.forename: Prem S
authors.initials: PS
authors.lastname: Chourey
keywords: gene expression; maize; seed development; sugar methabolism; transfer cells