Scopoletin Involvement in Post-Harvest Physiological Deterioration of Cassava Root (Manihot esculentaCrantz)

Large-Scale Proteomics of the Cassava Storage Root and Identification of a Target Gene to Reduce Postharvest Deterioration

“…However, further biochemical analysis will be necessary to determine if this overall modulation of the phenylpropanoid pathway is directed primarily toward an increased production of scopoletin and its glucosylated derivative scopolin that accumulate during PPD (Wheatley and Schwabe, 1985;Buschmann et al, 2000b). Previous studies demonstrated the antioxidant activity of free scopoletin as well as the phenylpropanoid caffeoyl quinate (chlorogenic acid), which is produced by p-coumaroyl shikimate/quinate 39-hydroxylase (Chong et al, 1999;Niggeweg et al, 2004;Rommens et al, 2008).…”

“…The coumarin scopoletin accumulates to high levels during PPD progression (Tanaka et al, 1983;Wheatley and Schwabe, 1985;Buschmann et al, 2000b;Bayoumi et al, 2010). Enzymes involved in the final steps of scopoletin biosynthesis were significantly upregulated 6 h after harvest (Supplemental Figure 8), including 4-coumarate-CoA ligase and caffeoyl-CoA O-methyltransferase enzymes, which convert 4-coumarate into coumaroyl-CoA and caffeoyl-CoA into feruoylCoA, respectively.…”

Variation in cassava germplasm for tolerance to post-harvest physiological deterioration

“…The thickness of the cut slices was about 1 cm at 25, 50, and 75% of the total root length, referred to as proximal, medial, and distal, respectively. Next, the severity of PPD was evaluated according to two diagrammatic scales, one proposed by Wheatley and Schwabe (1985) for peripheral symptoms, and the second proposed by Venturini et al (2015) for symptoms distributed throughout the root, both with variation in scores from 0 to 100%. The PPD values for each root were calculated by averaging the scores of the three transverse slices.…”

“…Although the standard method for PPD analyses (Wheatley and Schwabe, 1985) discards the proximal and distal ends of the roots to accelerate the PPD, in this study the roots were evaluated without cutting, aiming to better simulate the cassava production system, especially by temporary storage in warehouses with or without roofing. The roots that showed rot symptoms related to deterioration by microorganisms, or were infested by insects, were not used in analyses of PPD tolerance.…”

Cassava Biotechnology

“…In most varieties the physiological deterioration of the roots commences within 24 hours, and is fIrst characterized by vasculardiscolouration (streaking), followed by general discolouration of the storage parenchyma and secondary deterioration caused by microbial pathogens, which renders the roots unacceptable for human, animal or industrial use. Although still poorly understood, many of the metabolic changes during the initial physiological deterioration resemble those observed during normal plant wound response reaction, and it has been speculated that the cause of the physiological deterioration could be a sustained wound reaction spreading systemically from the wound site into the whole root (Beechinget al, 1994(Beechinget al, , 1995 Increased levels of among others, flavonols and other secondary metabolites are produced during the primary deterioration, and this is accompanied by activation of the enzymes of the phenylpropanoid pathway and also by initiation ofde novo protein synthesis (Tanakaetal., 1983, Rickard, 1985Wheatley and Schwabe, 1985;Beeching et al, 1994Beeching et al, , 1995.…”