Résumé
Seeds are an attractive model to decipher the regulation of secondary metabolite biosynthesis. Furthermore, given that seeds are a major source of food for humans and that numerous secondary metabolites play a role in the nutritional value and organoleptic quality of food products, a better understanding of seed secondary metabolic networks may be a key step for seed crop breeding. Network genomics offers outstanding opportunities to unravel the underlying regulation of metabolism in seeds. For now, only a few recent studies have coupled transcriptomics and metabolomics to investigate metabolism in developing seeds, either at the genome-wide level or at the quantitative level using pathway-guided approaches and multigenotype or multienvironment designs. Using three distinct examples, the present chapter aims to show how coupled transcript-metabolite profiling can help decipher the regulation of secondary metabolite synthesis in seeds. This chapter first summarizes the latest advances made in the model plant Arabidopsis at the genome-wide level. The second example is the metabolism of carotenoids in maize, which is a model system for provitamin A biofortification. Finally, this chapter also describes the coffee seed, whose endosperm stores spectacular amounts of alkaloids and phenylpropanoid-derived compounds. These three studies concern the biosynthesis of secondary metabolites, but similar approaches may undoubtedly be used for other seed metabolic pathways.