Wild Relatives of the Wheat Grain Proteome

We applied proteomics analysis to generate a map of the wild relatives of wheat grain proteins. These differentially expressed proteins are potentially involved in metabolism, stress responses, and other biological activities. Using two-dimensional electrophoresis, we detected 119, 134, and 193 reproducible spots on gels loaded with protein samples extracted from the A, B, and D genomes, respectively, of the mature grain. In all, 89, 53, and 54 distinct proteins, respectively, were found among these genomes through MALDI-TOF mass spectrometry. Of these, 26% (n = 52) proteins were considered distinct. They included 18.89% (n = 17) in the A, 28.30% (n = 15) in the B, and 37.04% (n = 20) in the D genome, all functioning in disease and defense roles. For example, the ABA-inducible protein PHVA1 can be induced by drought, cold, heat, and salinity, while the basic endochitinase confers protection against chitin-containing fungal pathogens. The diverse functional categories found here suggest different biological processes, such as disease/defense, energy metabolism, protein synthesis and storage, cellular organization, signal transduction, transcription, and the facilitation of transport. Our findings demonstrate that these functional proteins have important roles in stress tolerance and the maintenance of quality in mature grains. The interacting effects of genetics and environment on differential protein production may be partially mediated by a regulatory mechanism in those grains.