Seed Development and Reserve Compound Accumulation in Common Bean (Phaseolus vulgaris L.)

Much of what we know today on the molecular aspects of seed development comes from basic studies carried out in the model species Arabidopsis. However, many differences exist between the developmental programs of the small seeds of Arabidopsis, basically without nutritional reserves, and the crop legume seeds, which are bigger and accumulate nutrients designated to germination. Since seed nutritional reserves are essential to guarantee food production, it is important to understand the genetic, biochemical and physiological mechanisms favouring a better incorporation rate of the main reserve compounds in seeds, such as proteins, carbohydrates, lipids and minerals, which will foster breeding programs towards more productive and efficient genotypes. Here, we review the current understanding of seed development of common beans as well as refer to conserved developmental mechanisms between this and other related species. The state of the art of biochemistry, genetics and physiology, including protein, hormonal and nutritional interactions, during seed development of common beans and the perspectives to further understand and control it are discussed with emphases on metabolic pathways, and nutrient transport and storage compounds. The text also alludes to crop management favouring incorporation of certain substances or altering the proportion of storage compounds and genotypes that store more efficient forms of phosphate than phytates. Additionally, we discuss the major challenges and perspectives for future investigation on controlling mechanisms of the main reserve compounds in common bean seeds. _____________________________________________________________________________________________________________