title: Genetics and physiology of cell wall polysaccharides in the model C4 grass, Setaria viridis spp.
abstract: BACKGROUND
  Setaria viridis has emerged as a model species for the larger C4 grasses. Here the cellulose synthase (CesA) superfamily has been defined, with an emphasis on the amounts and distribution of (1,3;1,4)-β-glucan, a cell wall polysaccharide that is characteristic of the grasses and is of considerable value for human health.
  
  
  METHODS
  Orthologous relationship of the CesA and Poales-specific cellulose synthase-like (Csl) genes among Setaria italica (Si), Sorghum bicolor (Sb), Oryza sativa (Os), Brachypodium distachyon (Bradi) and Hordeum vulgare (Hv) were compared using bioinformatics analysis. Transcription profiling of Csl gene families, which are involved in (1,3;1,4)-β-glucan synthesis, was performed using real-time quantitative PCR (Q-PCR). The amount of (1,3;1,4)-β-glucan was measured using a modified Megazyme assay. The fine structures of the (1,3;1,4)-β-glucan, as denoted by the ratio of cellotriosyl to cellotetraosyl residues (DP3:DP4 ratio) was assessed by chromatography (HPLC and HPAEC-PAD). The distribution and deposition of the MLG was examined using the specific antibody BG-1 and captured using fluorescence and transmission electron microscopy (TEM).
  
  
  RESULTS
  The cellulose synthase gene superfamily contains 13 CesA and 35 Csl genes in Setaria. Transcript profiling of CslF, CslH and CslJ gene families across a vegetative tissue series indicated that SvCslF6 transcripts were the most abundant relative to all other Csl transcripts. The amounts of (1,3;1,4)-β-glucan in Setaria vegetative tissues ranged from 0.2% to 2.9% w/w with much smaller amounts in developing grain (0.003% to 0.013% w/w). In general, the amount of (1,3;1,4)-β-glucan was greater in younger than in older tissues. The DP3:DP4 ratios varied between tissue types and across developmental stages, and ranged from 2.4 to 3.0:1. The DP3:DP4 ratios in developing grain ranged from 2.5 to 2.8:1. Micrographs revealing the distribution of (1,3;1,4)-β-glucan in walls of different cell types and the data were consistent with the quantitative (1,3;1,4)-β-glucan assays.
  
  
  CONCLUSIONS
  The characteristics of the cellulose synthase gene superfamily and the accumulation and distribution of (1,3;1,4)-β-glucans in Setaria are similar to those in other C4 grasses, including sorghum. This suggests that Setaria is a suitable model plant for cell wall polysaccharide biology in C4 grasses.
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. riksfardini.ermawar@adelaide.edu.au.
authors.forename: Riksfardini A
authors.initials: RA
authors.lastname: Ermawar
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. helen.collins@adelaide.edu.au.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Collins
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. caitlin.byrt@adelaide.edu.au.
authors.forename: Caitlin S
authors.initials: CS
authors.lastname: Byrt
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. marilynhenderson1@bigpond.com.
authors.forename: Marilyn
authors.initials: M
authors.lastname: Henderson
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. lisa.odonovan@adelaide.edu.au.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: O'Donovan
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. neil.shirley@adelaide.edu.au.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Shirley
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. julian.schwerdt@adelaide.edu.au.
authors.forename: Julian G
authors.initials: JG
authors.lastname: Schwerdt
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. jelle.lahnstein@adelaide.edu.au.
authors.forename: Jelle
authors.initials: J
authors.lastname: Lahnstein
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. geoffrey.fincher@adelaide.edu.au.
authors.forename: Geoffrey B
authors.initials: GB
authors.lastname: Fincher
authors.affiliation: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA, 5064, Australia. rachel.burton@adelaide.edu.au.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Burton
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D011134:Polysaccharides / Q000235:genetics* / Q000378:metabolism; D032983:Setaria Plant / Q000166:cytology / Q000235:genetics* / Q000378:metabolism; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D011134:Polysaccharides; D047071:beta-Glucans; C067858:beta-glucan, (1-3)(1-4)-; D005964:Glucosyltransferases; C478648:cellulose synthase