Multi-omic analyses unveil contrasting composition and spatial distribution of specialized metabolites in seeds of Camelina sativa and other Brassicaceae

Abstract

Seeds of Brassicaceae produce a large diversity of beneficial and antinutritional specialized metabolites (SMs) that influence their quality and provide resistance to stresses. While SM distribution has been described in leaves and root tissues, limited information is available about their spatiotemporal accumulation in seeds. Camelina sativa (camelina) is an oilseed Brassicaceae cultivated for human and animal nutrition and for industrial uses. While we previously explored SM diversity and plasticity, no information is available about SM distribution and expression of related proteins and genes in camelina seeds. In this study, we used a multi-omic approach, integrating untargeted metabolomics, proteomics, and transcriptomics to investigate the synthesis, modification, and degradation of SMs accumulated in camelina seed tissues (seed coat, endosperm, embryo) at six developmental and two germination stages. Metabolomic results showed distinct patterns of SMs and their related pathways, highlighting significant contrasts in seed composition and spatial distribution for the defense-related and antinutritional glucosinolate (GSL) compounds among camelina, Arabidopsis thaliana, and Brassica napus, three closely related Brassicaceae species. Notably, thanks to metabolomic and proteomic/transcriptomic techniques the variation in GSL spatial distributions was primarily driven by differences in their structure (metabolomics data) and transport (transcriptomic and proteomic data) mechanisms. Long-chain C8–C11 methylsulfinylalkyl GSLs were predominantly accumulated in the seed coat and endosperm, while mid- and short-chain C3–C7 methylsulfinylalkyl GSLs were accumulated in the embryo. Characterizing the spatial dynamics of seed SMs provides valuable insights that can guide the development of crops with optimized distribution of beneficial and toxic metabolites, improving seed nutritional profiles.