Wheat is the second most produced cereal in the world, important for food, feed and many industrial uses. Understanding of the mechanisms involved in grain development is fundamental for developing high quality wheat. In particular, detailed knowledge of the wheat grain physiology and molecular mechanisms involved in its development would help in breeding not only of wheat but also many other cereals. A proteomic approach has been used in this context but, up to now, there had been no work on developing tissues at very short temporal distances. This thesis presents, firstly, a proteomic study to characterize protein expression changes in peripheral layers and in starchy endosperm of wheat, during kernel development. We used grains of Triticum aestivum cv Récital, cultivated at INRA, Clermont-Ferrand. Grains were harvested at each 50°Cd from fertilization to maturity at fifteen stages for peripheral layers and at twenty-one stages for starchy endosperm. After grain dissection, protein extraction and 2DE- MALDI-TOF MS and data mining, we identified 207 differentially expressed proteins at fifteen stages (0°Cd-700°Cd) of peripheral layers during kernel development. These proteins were then classed in sixteen different functional classes. HCA revealed five different expression profiles during development. Similarly after obtaining starchy endosperm from dissected grains, we performed protein extraction specific to metabolic proteins. After 2DE, 487 proteins were identified from fertilization to grain maturity (0°Cd-1006°Cd), using LC-MS and data mining. Proteins were grouped in nine different expression profiles and were classed in seventeen biochemical functions. We have constructed proteome maps of these two important grain tissues during kernel development. Further, the comparison of peripheral layers and starchy endosperm proteomic data was made, with an objective to understand whether the changes in different biochemical processes differ between these tissues.Finally, we performed an integration of our proteomic data (focusing our approach on proteins involved in carbohydrate metabolism) with that of transcriptomics. Only 32% of proteome/transcriptome expression profiles showed a significant correlation during development (from 152°Cd-700°Cd). Comparison of enzyme expression profiles with those of proteome and transcriptome would help to distinguish the processes regulated at transcriptome level and those controlled at the proteome level. This comprehensive grain development data could further help in construction of a Récital databank, which may be used as reference for studies of diseased and stressed grain tissues during development.
Proteomic analysis of endosperm and peripheral layers during kernel development of wheat (Triticum aestivum L.) and a preliminary approach of data integration with transcriptome