Omics-based biomarkers for the identification of six Korean cultivars of sweet potato (Ipomoea batatas L. Lam)

This study was conducted to develop biomarkers to identify 26 cultivars of Korean sweet potato (Ipomoea batatas L. Lam) using omics-based methods. Random amplification of polymorphic DNA (RAPD) markers revealed that 75 random 10-mer primers generated 50 polymorphic RAPD markers from the 28 Korean sweet potato cultivars. Six sweet potato cultivars were selected for further analysis by protemnic and metabolomic approaches based on their flesh colour (two each having cream, orange, or purple flesh) and by a dendrogram generated using the polymorphic RAPD bands. Changes in the proteomes of these six sweet potato cultivars were investigated by two-dimensional gel electrophoresis (2-DGE) coupled with matrix-assisted, laser desorption/ionisation tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) analysis. Overall, ten protein spots were expressed differentially between the six cultivars and identified by MALDI-TOF/TOF MS. Among these, an ATP-dependent zinc metalloprotease and the chaperone protein, ClpC1, accumulated specifically in the cultivars 'Singeonmi' and 'Jami', respectively. Furthermore, metabolomic analysis, using reversed-phase high performance liquid chromatography (HPLC) coupled with liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS), revealed that four polyphenolic compounds accumulated differentially in the six sweet potato cultivars. Members of the caffeoylquinic acid family were detected at the highest levels in 'Juhwangmi'. These results suggest that the proteins and metabolites that accumulate differentially may be used as biomarkers to identify Korean sweet potato cultivars.