DkmiR397 Regulates Proanthocyanidin Biosynthesis via Negative Modulating DkLAC2 in Chinese PCNA Persimmon

Abstract

Persimmon fruits accumulate a large amount of proanthocyanidins (PAs), which makes an astringent sensation. Proanthocyanidins (PAs) are the polymers of flavan-3-ols stored in plant vacuoles under laccase activation. A laccase gene, DkLAC2, is putatively involved in PAs biosynthesis and regulated by microRNA (DkmiR397) in persimmon. However, the polymerization of PAs in association with miRNA397 still needs to be explored in persimmon. Here, we identified pre-DkmiR397 and its target gene DkLAC2 in ‘Eshi 1’ persimmon. Histochemical staining with GUS and dual luciferase assay both confirmed DkmiR397-DkLAC2 binding after co-transformation in tobacco leaves. Diverse expression patterns of DkLAC2 and DkmiR397 were exhibited during persimmon fruit development stages. Moreover, a contrasting expression pattern was also observed after the combined DkLAC2-miR397 transformation in persimmon leaves, suggesting that DkmiR397 might be a negative regulator of DkLAC2. Similarly, the transient transformation of DkmiR397 in persimmon fruit discs in vitro also reduced PA accumulation by repressing DkLAC2, whereas the up-regulation of DkLAC2 increased the accumulation of PAs by short tandem target mimic STTM-miR397. A similar expression pattern was observed when overexpressing of DkLAC2 in Arabidopsis wild type (WT) and overexpression of DkLAC2, DkmiR397 in persimmon leaf callus. Our results revealed that the role of DkmiR397 repressed the expression of DkLAC2 concerning PA biosynthesis, providing a potential target for the manipulation of PAs metabolism in persimmon.

The Citrus Laccase Gene CsLAC18 Contributes to Cold Tolerance

“…In the present study, it is possible that the CsLAC18–laccase–lignin module prevents plants from cellular damages caused by cold stress via the modulation of cell wall rigidity [ 28 ]. Secondly, the previous studies found that laccases were involved in the regulation of secondary metabolite biosynthesis in plants and some of the secondary metabolites were implicated in the responses to various environmental stresses [ 6 , 12 , 37 ]. For example, Hu et al reported that the inhibition of GhLac1 expression resulted in a redirection of metabolic flux in the phenylpropanoid pathway and the accumulation of secondary metabolites that conferred resistance of cotton plants to various biotic stresses [ 12 ].…”

“…LACs are broadly found in insects, bacteria, fungi, and plants since Yoshida first described them in 1883 [ 5 ]. Previous studies have suggested that plant LACs play a pivotal role in monolignol polymerization, anthocyanin biosynthesis, seed development, and biotic/abiotic stress responses [ 6 , 7 , 8 ]. Among them, the role of LACs in environmental stress responses has attracted the most attention.…”

Overview of Repressive miRNA Regulation by Short Tandem Target Mimic (STTM): Applications and Impact on Plant Biology

“…DkmiR397 targets the laccase gene DkLAC2 , which is a key enzyme in the biosynthesis of PA. The presence of higher levels of DkLAC2 in persimmon plants transformed with STTM397 resulted in an increased PA accumulation [ 126 ]. In tomatoes, STTM858 showed an increased anthocyanin under normal conditions, whereas SlMYB7 -like transcripts considerably increased when miR858 was downregulated.…”

Regulatory mechanisms and metabolic changes of miRNA during leaf color change in the bud mutation branches of Acer pictum subsp. mono

“…In Chinese Rosa chinensis, the miR156-RcSPL9 regulatory module was also found to affect anthocyanin synthesis in the petals ( Raymond et al., 2018 ). In Diospyros kaki, the miR397-DkLAC2 regulatory module was found to influence the biosynthesis of proanthocyanidins ( Zaman et al., 2022 ). Metabolites are the end products of the response of plants to genetic or environmental ( Fiehn, 2002 ).…”