title: Grain sorghum proteomics: integrated approach toward characterization of endosperm storage proteins in kafirin allelic variants.
abstract: Grain protein composition determines quality traits, such as value for food, feedstock, and biomaterials uses. The major storage proteins in sorghum are the prolamins, known as kafirins. Located primarily on the periphery of the protein bodies surrounding starch, cysteine-rich β- and γ-kafirins may limit enzymatic access to internally positioned α-kafirins and starch. An integrated approach was used to characterize sorghum with allelic variation at the kafirin loci to determine the effects of this genetic diversity on protein expression. Reversed-phase high performance liquid chromatography and lab-on-a-chip analysis showed reductions in alcohol-soluble protein in β-kafirin null lines. Gel-based separation and liquid chromatography-tandem mass spectrometry identified a range of redox active proteins affecting storage protein biochemistry. Thioredoxin, involved in the processing of proteins at germination, has reported impacts on grain digestibility and was differentially expressed across genotypes. Thus, redox states of endosperm proteins, of which kafirins are a subset, could affect quality traits in addition to the expression of proteins.
authors.affiliation: School of Agriculture and Food Sciences and ⊥Institute for Molecular Bioscience, The University of Queensland , St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: Julia E
authors.initials: JE
authors.lastname: Cremer
authors.forename: Scott R
authors.initials: SR
authors.lastname: Bean
authors.forename: Michael M
authors.initials: MM
authors.lastname: Tilley
authors.forename: Brian P
authors.initials: BP
authors.lastname: Ioerger
authors.forename: Jae B
authors.initials: JB
authors.lastname: Ohm
authors.forename: Rhett C
authors.initials: RC
authors.lastname: Kaufman
authors.forename: Jeff D
authors.initials: JD
authors.lastname: Wilson
authors.forename: David J
authors.initials: DJ
authors.lastname: Innes
authors.forename: Edward K
authors.initials: EK
authors.lastname: Gilding
authors.forename: Ian D
authors.initials: ID
authors.lastname: Godwin
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D056625:Endosperm / Q000737:chemistry*; D005838:Genotype; D054477:Glutaredoxins / Q000378:metabolism; D056656:Lab-On-A-Chip Devices; D009154:Mutation; D010802:Phylogeny; D010940:Plant Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D055315:Prolamins / Q000378:metabolism; D040901:Proteomics; D055314:Seed Storage Proteins / Q000378:metabolism; D045868:Sorghum / Q000737:chemistry* / Q000235:genetics; D053719:Tandem Mass Spectrometry; D013879:Thioredoxins / Q000378:metabolism
chemical_list: D054477:Glutaredoxins; D010940:Plant Proteins; D055315:Prolamins; D055314:Seed Storage Proteins; C080615:kafirin protein, Sorghum bicolor; D013879:Thioredoxins
keywords: HPLC; digestibility; kafirin; mass spectrometry; seed storage proteins; sorghum