Abstract/Summary

One of the major objectives in faba bean breeding is to improve its protein quality by selecting cultivars with enhanced content of sulphur-containing amino acid and other desirable physico-chemical properties. However, since protein composition of the mature seed is determined by a series of biological processes which are modulated by prevailing environmental factors, any attempt to explain the final seed composition must consider the dynamics of the seed proteome during seed development. Here, we have investigated the proteomic profile of developing faba bean seeds across 12 growth stages, from 20 days after pollination (DAP) to full maturity. We analysed trypsin digested total protein extracts from seeds of different growth stages by LC–MS/MS which, in total, identified 1217 proteins. The functional clusters of these proteins showed that, in early growth stages, proteins related to cell growth, division and metabolism were most abundant, while seed storage proteins began to accumulate from 45 DAP. Moreover, label-free quantification of the relative abundance of seed proteins, including four convicilins, three vicilins and nine legumins, revealed several distinct temporal accumulation trends amongst the storage protein classes. These results suggested that these proteins are regulated differently and lay the foundations for further understanding of Vicia faba seed protein synthesis and accumulation and possible implications of environmental stresses occurring at different grain fill stages on protein composition and the overall nutritional quality of this important legume crop.