Proteomic analysis of mature kernel aleurone layer of Triticum spelta and three wheat related species

Background : A proteomics approach was used to reveal major protein differences in the aleurone layer (AL) of mature grain between four wheat species: T. aestivum and T. spelta (6X), T. durum (4X), and T. monococum (2X). Materiel and methods: In each species, one representative cultivar was used for total AL protein extraction. Two-dimensional electrophoresis of AL proteins revealed 1380, 1355, 1120 and 973 Coomassie stained spots, respectively. Result: A total of 334 spots showed quantitative or qualitative (presence/absence) differences between the four cultivars. T. aestivum and T. spelta had 90.9% and 92.6% of their AL proteome respectively, identical to the other species. Only 25 spots were significantly different between the two hexaploid cultivars. AL proteins encoded by the A genome were mainly expressed in polyploid species. Percentages of proteins encoded by A genome was 85%, in tetraploid species and 70% in the hexaploid spelt. Eighty for proteins are identified by mass spectrometry and data mining and were classified in five bbiological processes and (12) functional categories. Conclusion: The major differences between species were particularly due to storage globulins (22, 11 and 1 of Glo-3, Glo-3B, Glo-3C, respectively), stress related proteins including antioxidant proteins like 1-Cys peroxiredoxin and manganese superoxide dismutase, defence proteins like xylanase, serpin3 and heat shock proteins.