Biochemical and Functional Characterization of Anthocyanidin Reductase (ANR) from Mangifera indica L.

Abstract

Mango (Mangifera indica L.) is abundant in proanthocyanidins (PAs) that are important for human health and plant response to abiotic stresses. However, the molecular mechanisms involved in PA biosynthesis still need to be elucidated. Anthocyanidin reductase (ANR) catalyzes a key step in PA biosynthesis. In this study, three ANR cDNAs (MiANR1-1,1-2,1-3) were isolated from mango, and expressed in Escherichia coli. In vitro enzyme assay showed MiANR proteins convert cyanidin to their corresponding flavan-3-ols, such as (−)-catechin and (−)-epicatechin. Despite high amino acid similarity, the recombinant ANR proteins exhibited differences in enzyme kinetics and cosubstrate preference. MiANR1-2 and MiANR1-3 have the same optimum pH of 4.0 in citrate buffer, while the optimum pH for MiANR1-1 is pH 3.0 in phosphate buffer. MiANR1-1 does not use either NADPH or NADH as co-substrate while MiANR1-2/1-3 use only NADPH as co-substrate. MiANR1-2 has the highest Km and Vmax for cyanidin, followed by MiANR1-3 and MiANR1-1. The overexpression of MiANRs in ban mutant reconstructed the biosynthetic pathway of PAs in the seed coat. These data demonstrate MiANRs can form the ANR pathway, leading to the formation of two types of isomeric flavan-3-ols and PAs in mango.

Transcriptome and Metabolome Analyses Reveal the Involvement of Multiple Pathways in Flowering Intensity in Mango

“…For a better understanding of flowering initiation, differential gene expression analysis among divergent genotypes is expected to provide meaningful insights (Shalom et al, 2014 ). Moreover, previous studies have focused either on the transcriptome (Sharma et al, 2020 ) or the metabolome of mango for flowering or other traits (Tan et al, 2018 , 2020 ; Shivashankara et al, 2019 ).…”

Transcriptomic and metabolomic analysis reveals the difference between large and small flower taxa of Herba Epimedii during flavonoid accumulation

“…The results showed the enrichment of flavonoid biosynthesis, flavone and flavonol biosynthesis, isoflavonoid biosynthesis, and upstream phenylpropanoid biosynthesis pathways in all samples. The basic metabolic pathways of flavonoids in plants have been elucidated with genes such as CHS, CHI, CYP75A, ANR, FLS and DFR, known to play a key role in the synthesis of bioactive components in medicinal plants [31][32][33][34][35][36][37][38][39] . In this study, the expression of FLS and DFR were upregulated in the leaves and flowers of the small flower group compared to the large flower group, which led to the enhanced accumulation of maohuoside B, lcariside II, Epimedin B, maohuoside A and diphylloside B.…”

The heat shock factor GhHSFA4a positively regulates cotton resistance to Verticillium dahliae

“…In previous studies, these marker genes were identified as key genes in the above pathways and were involved in stress resistance. For example, in tobacco, the overexpression of DFR or ANR , which encode crucial regulatory enzymes for flavonoid synthesis, improves the resistance of plants to biotic or abiotic stresses ( Tan et al., 2018 ; Sun et al., 2021 ). The transcription levels of TPS family genes and jasmonate-responsive genes in cotton plants treated with plant-growth-promoting rhizobacteria were higher than those in the untreated control plants and exhibited improved resistance to Spodoptera exigua ( Zebelo et al., 2016 ).…”