Biosynthetic Pathway of Proanthocyanidins in Major Cash Crops

Abstract

Proanthocyanidins (PAs) are a group of oligomers or polymers composed of monomeric flavanols. They offer many benefits for human fitness, such as antioxidant, anticancer, and anti-inflammatory activities. To date, three types of PA have been observed in nature: procyanidins, propelargonidins, and prodelphinidins. These are synthesized as some of the end-products of the flavonoid pathway by different consecutive enzymatic activities, from the same precursor—naringenin. Although the general biosynthetic pathways of PAs have been reported in a few model plant species, little is known about the species-specific pathways in major crops containing different types of PA. In the present study, we identified the species-specific pathways in 10 major crops, based on the presence/absence of flavanol-based intermediates in the metabolic pathway, and found 202 orthologous genes in the reference genomic database of each species, which may encode for key enzymes involved in the biosynthetic pathways of PAs. Parallel enzymatic reactions in the pathway are responsible for the ratio between PAs and anthocyanins, as well as among the three types of PAs. Our study suggests a promising strategy for molecular breeding, to regulate the content of PAs and anthocyanins and improve the nutritional quality of food sources globally.

Metabolic and Developmental Changes in Germination Process of Mung Bean (Vigna radiata (L.) R. Wilczek) Sprouts under Different Water Spraying Interval and Duration

“…Catechin is a flavonoid that shares the upstream biosynthetic pathway with quercetin [54]. In the flavonoid pathway, dihydroquercetin can diverge into catechin or quercetin by dihydroflavonol (DFR) or flavonol synthase (FLS), respectively [54]. Although an abundant level of catechin was detected in present study, quercetin was barely identified, which is inconsistent with previous report that two flavonoids were both steadily detected in mung bean sprouts [2,55].…”

“…Catechin is a flavonoid that shares the upstream biosynthetic pathway with quercetin [54]. In the flavonoid pathway, dihydroquercetin can diverge into catechin or quercetin by dihydroflavonol (DFR) or flavonol synthase (FLS), respectively [54].…”

The Darker the Better: Identification of Chemotype Profile in Soroses of Local and Introduced Mulberry Varieties with Respect to the Colour Type

“…In the flavonoid biosynthetic pathway, proanthocyanidins are the precursors of a branch of the anthocyanidin biosynthetic pathway. Proanthocyanidins and anthocyanins are derived from the same precursor, anthocyanidin, and share a common biosynthetic process for the conversion of phenylalanine to anthocyanidin [92]. Thus, we can conclude that the flavonoid metabolic pathway is more active in the darker infructescences.…”

“…Similarly, Truzzi et al [32] reported a strong correlation between the expression of quercetin derivatives and cyanidin 3-O-glucoside. The strong positive correlation between anthocyanins and epicatechin (0.4-0.5 **), as well as procyanidin dimer (0.6-0.9 **), reflects that these compounds are direct precursors of anthocyanins synthesis [92]. Furthermore, we were able to determine a strong correlation between anthocyanins and naringenin hexoside 1 (0.5 ** for cyanidin-3-glucoside and cyanidin-3-rutinoside), while the correlation with kaempferol-3-rutinoside was medium (0.3 *).…”

Transcriptomic profiling analysis to identify genes associated with PA biosynthesis and insolubilization in the late stage of fruit development in C-PCNA persimmon

“…PAs are synthesized via the chorismic acid pathway, phenylpropane metabolic pathway, flavonoid synthesis and proanthocyanidin pathway 9 . The structural genes encoding the enzymes have been identified in the three pathways, including chalcone isomerase ( CHI ), chalcone synthase ( CHS ), leucoanthocyanidin reductase ( LAR ), flavonoid 3′-hydroxylase ( F3′H ), and anthocyanidin reductase ( ANR ) 10 . The “coagulation effect” refers to losing astringency by PA insolubilization by converting soluble PAs into insoluble PAs with acetaldehyde 6 .…”