Genetic and chemical diversity among yacon [Smallanthus sonchifolius (Poepp. et Endl.) H. Robinson] accessions based on iPBS markers and metabolomic fingerprinting

Metabolomic and Gene Expression Studies Reveal the Diversity, Distribution and Spatial Regulation of the Specialized Metabolism of Yacón (Smallanthus sonchifolius, Asteraceae)

“…Some STLs, such as enhydrin, polymatin A and polymatin B, were accumulated in relatively higher amounts in the leaves of the white cultivar, while others, such as fluctuadin and polymatin B aldehyde, were relatively higher in the leaves of the red cultivar ( Figure 3). While no qualitative variability was found in STLs contents between different cultivars, our results suggest semi-quantitative variations, which are in line with previous reports [26,35]. The same tendency was observed in the accumulation of smaditerpenic acids.…”

“…Interestingly, although this metabolite has been previously reported in yacón roots, our dereplication approach suggested the presence of two additional tricaffeoylaltraric acid isomers that require further studies to characterize their structure (Table S1). The independent clustering of the bract seen in the PCA scores plot (Figure 1) can be related to the presence of hexenyl-O-arabinoglucoside, a compound previously reported in yacón leaves [35,44], and other structurally related molecules accumulated in high quantities in this organ (Table 1). Significant differences between the leaves and bracts in terms of trichomes, metabolite patterns and gene expression have also been observed in sunflower (Helianthus annus L.) [45].…”

“…Among the glycosylated metabolites, detailed analyses of MS/MS data and spectral comparisons with literature information allowed the annotation of henexyl- O -araboniglucoside and two structural analogues (benzyl- O -araboniglucoside and phenylethyl- O -araboniglucoside, Table S1 ), representing potentially new reports for the genus. Henexyl-3- O -araboniglucoside has been recently reported as a minor constituent of yacón leaves [ 35 , 44 ], and previous studies suggest it possess ecological implications as an anti-herbivory agent [ 49 ]. Therefore, the accumulation of henexyl- O -arabinoglucoside in high quantities in the bracts of yacón ( Figure 3 ) could be related to a specialized mechanism to protect the reproductive organs from herbivory.…”

“…Among the caffeoylaltraric acids and analogues, four mono-, three di-and three tricaffeoylaltraric acid isomers were detected mainly in the leaves of yacón (Table S1). In addition to the mono-, di-and tricaffeoylaltraric acids previously reported in this species [24,35], molecular networking and manual inspection of MS/MS data allowed proposing the tentative identity of five structural analogues (compounds 15-17, 28 and 29, Figures 2 and 3), including one coumaroyl, one feruloyl and two trihydroxycinnamoyl derivatives with different accumulation patterns. Compound 16, accumulated only in the leaves (Figure 3), was proposed as dicaffeoylaltraric acid monoethyl ester based on the interpretation of its fragmentation pattern ( Figure S3).…”

“…Furthermore, due to their inherent limitations in terms of coverage and time, classic approaches are not suitable for large-scale studies aiming to explore the specialized metabolite diversity of an organism or tissue. Thus, global comparisons of chemical compositions present in different tissues, organs and cultivars of yacón can only be achieved through metabolomics [28,[33][34][35]. Despite recent advances, the annotation, classification and identification of the plant metabolome is still a major bottleneck in all metabolomics studies.…”