From seed to shoot: the organ-specific composition of the vicine/convicine pool in faba bean

Divicine and isouramil, the aglycons of vicine (VC) and convicine (CV) pyrimidine glycosides present in faba bean ( Vicia faba L.) seeds, cause favism in individuals with glucose-6-phosphate dehydrogenase deficiency. Although breeding has resulted in low vicine and convicine (V-CV) cultivars, recent metabolomic studies described V-CV derivatives whose biological relevance and distribution across plant organs are unknown. Here, the composition of the V-CV derivative pool in seeds and vegetative organs during early seedling development is described. Metabolic profiling was performed on seeds of 10 faba bean cultivars representing genotypes having or lacking the low -VC (LVC) trait. cultivars lacking the low-VC trait, have a normal content in VC and CV and are annotated here as high-vicine convicine (HVC) cultivars. In addition, the V-CV pools of seeds, germinated seeds, roots, and shoots were compared for one variety having the LVC trait and one lacking this trait. Seed profiling revealed a seed-specific derivative pool, and although most of the derivatives showed lower signal intensities in LVC cultivars, cultivar-specific fingerprints were observed independent of the abundance of V-CV. The composition of the V-CV pool indifferent organs changed from relatively simple seed-associated compounds toward chemically complex derivatives in the roots and shoots. Principal component analysis (PCA) and hierarchical clustering showed organ identity as the primary determinant of the V-CV pool composition, with genotype as the secondary factor. Our data on the seeds indicates that genetic background influences both the precursor availability and derivatization pathways. The comparison of the V-CV profiles in the different organs suggests that V-CV metabolism involves active, organ-specific derivatization processes. Given the diversity and high MS signal intensities for some derivatives, the inclusion of these in studies on the biosynthesis, distribution, and toxicity of V-CV may result in new insights.