Molecular characterization of Leucoanthocyanidin reductase and Flavonol synthase gene in Arachis hypogaea

Abstract

Arachis hypogaea (peanut) is a potential source of bioactive compounds including flavonols and proanthocyanidins, which have gained particular interest of metabolic engineering owing to their significance in the growth, development and defense responses in plants. To gain insight of proanthocyanidins and flavonols production in A. hypogaea , Leucoanthocyanidin reductase (AhLAR) and Flavonol synthase (AhFLS) enzymes responsible for their production, have been structurally, transcriptionally and functionally characterized. Structural and functional analysis of putative protein sequence of AhFLS indicated two functional motifs 2OG-FeII_Oxy and DIOX_N , while six functional motifs belonging to the families of NAD-dependent dehydratase, 3, β hydroxysteroid dehydrogenase and NmrA-like family were observed in case of AhLAR. Promoter sequence analysis unraveled several promoter elements related to the development regulation, environmental stress responses and hormonal signaling. Furthermore, the expression analysis of AhFLS and AhLAR and accumulation pattern analysis of proanthocyanidins and flavonols in three selected cultivars of A. hypogaea under saline environment confirmed their role against salinity in genotype-dependent and stress level-dependent manner. Correlation studies revealed that AhFLS and AhLAR expression is not directly dependent on the antioxidant enzymes activity, biochemical and growth parameters but higher Pearson r value depicted some level of dependency. This detailed study of AhLAR and AhFLS can assist in the metabolic engineering of flavonoid biosynthetic pathway to produce stress tolerant varieties and production of proanthocyanidins and flavonols at an industrial scale.

Multi-omics analysis reveals molecular mechanism of flavonol biosynthesis during the formation of petal color in Camellia nitidissima

“…6). FLS and DFR are key structural genes by which avonoids enter different synthetic branches [3,37,38]. Studies have also shown that DFR and FLS competed for common dihydro avonol substrates, and their expression inhibits each other's transcription [16,39].…”

Multi-omics analysis reveals the regulatory mechanism of flavonol biosynthesis during the formation of petal color inCamellia nitidissima

“…Second, the expression of anthocyanin and proanthocyanidin biosynthesis genes DFR, ANS, UGT, LAR, ANR showed a downward trend during petal development (Fig 9). FLS and DFR are key structural genes by which flavonoids enter different synthetic branches (Kubra et al ., 2021; Liu et al ., 2021; Wang et al ., 2022), and overexpression of FLS increases the biosynthesis of flavonols (Park et al ., 2020; Yu et al ., 2021). Heterologous expression of Rosa rugosa RrDFR1 and Petunia hybrida PhDFR in tobacco has been reported to inhibit the expression of the endogenous NtFLS and promote the accumulation of anthocyanins (Luo et al ., 2016).…”

Insight into the Molecular Mechanism of Flower Color Regulation in Rhododendron latoucheae Franch: A Multi-Omics Approach

“…At the same time, the expression level of the transcription factor itself can have a regulatory effect on the expression intensity of structural genes [ 55 ]. In the present study, RlMYB4 was found to be homologous to FaMYB1, a typical anthocyanin repressor transcription factor, and it has been shown that the FaMYB1 transcription factor inhibits the accumulation of anthocyanins and flavonols in tobacco [ 56 ].…”