Untargeted Metabolomics Profiling of High Beta Carotene Cassava with respect to Postharvest Physiological Deterioration

Abstract

Cassava roots undergo postharvest physiological deterioration (PPD), and for most varieties it sets in within 72 hours of harvest. An untargeted metabolomics approach combined with a data-driven approach for statistical analysis was used to characterize and profile high beta-carotene cassava varieties with the aim of identifying any relevant metabolite changes that occur during PPD. Sixteen cassava root samples from four cassava lines were planted in a greenhouse and harvested after four months. The samples included four of 2 conventionally bred beta carotene cassava varieties – UMUCASS 38, UMUCASS 45 and four of 2 transgenic high beta carotene cultivars - EC20-7 and EC20-8 cassava lines. Extracts of fresh cassava roots from 20-100 mg tissues were used for the analyses and data were processed using Elements for Metabolomics software. Starch and lipid metabolites were the major constituents which may help explain the observed differences in starch and dry matter content among the varieties. The results provide further insight in the understanding of PPD and suggestions on controlling this deterioration in cassava are made.