DkPK Genes Promote Natural Deastringency in C-PCNA Persimmon by Up-regulating DkPDC and DkADH Expression

Abstract

The astringency of Chinese pollination-constant non-astringent (C-PCNA) persimmon (Diospyros kaki Thunb.) can be naturally removed on the tree. This process is controlled by a single locus and is dominant against other types of persimmons; therefore, this variant is an important candidate for commercial cultivation and the breeding of PCNA cultivars. In our previous study, six full-length coding sequences (CDS) for pyruvate kinase genes (DkPK1-6) were isolated, and DkPK1 is thought to be involved in the natural deastringency of C-PCNA persimmon fruit. Here, we characterize the eight other DkPK genes (DkPK7-14) from C-PCNA persimmon fruit based on transcriptome data. The transcript changes in DkPK7-14 genes and correlations with the proanthocyanidin (PA) content were investigated during different fruit development stages in C-PCNA, J-PCNA, and non-PCNA persimmon; DkPK7 and DkPK8 exhibited up-regulation patterns during the last developmental stage in C-PCNA persimmon that was negatively correlated with the decrease in soluble PAs. Phylogenetic analysis and subcellular localization analysis revealed that DkPK7 and DkPK8 are cytosolic proteins. Notably, DkPK7 and DkPK8 were ubiquitously expressed in various persimmon organs and abundantly up-regulated in seeds. Furthermore, transient over-expression of DkPK7 and DkPK8 in persimmon leaves led to a significant decrease in the content of soluble PAs but a significant increase in the expression levels of the pyruvate decarboxylase (DkPDC) and alcohol dehydrogenase genes (DkADH), which are closely related to acetaldehyde metabolism. The accumulated acetaldehyde that results from the up-regulation of the DkPDC and DkADH genes can combine with soluble PAs to form insoluble PAs, resulting in the removal of astringency from persimmon fruit. Thus, we suggest that both DkPK7 and DkPK8 are likely to be involved in natural deastringency via the up-regulation of DkPDC and DkADH expression during the last developmental stage in C-PCNA persimmon.

Comparative transcriptomic analysis reveals genetic divergence and domestication genes in Diospyros

“…2). This finding is consistent with the previous reports that the high expression of the genes PDC , PK, ERF , and LAR promote the deastringency of persimmon fruits [35, 36]. It should be noted that these genes exhibited a similar pattern (Fig.…”

MiR858b Inhibits Proanthocyanidin Accumulation by the Repression of DkMYB19 and DkMYB20 in Persimmon

“…We found that DkMYB19 could interact with the DkPK2 protein, which is a pyruvate kinase that may be involved in the natural loss of astringency in C-PCNA persimmon mediated by the upregulation of DkPDC (pyruvate decarboxylase) and alcohol dehydrogenase ( DkADH ) expression during the last developmental stage ( Guan et al, 2016 , 2017 ). The pGBDT7–DkMYB19 and pGADT7–DkPK2 fusion proteins were co-transformed, and the Y2H assay verified the interactions ( Supplementary Figure S3 ).…”

miRNA858b Inhibits Proanthocyanidin Accumulation by Repression ofDkMYB19andDkMYB20in Persimmon

“…We found DkMYB19 could interact with a DkPK2 protein, that is a pyruvate kinase gene maybe a potential roles in the natural loss of astringency in C-PCNA persimmon via the up-regulation of DkPDC and DkADH expression during the last developmental stage (Guan et al ., 2016, 2017). The pGBDT7-DkMYB19 and pGADT7-DkPK2 fusion protein were co-transformed to the Y2H furthermore verified the interactions (Fig.…”

“…DkMYB6 was identificated as a putative transcriptional activator, induced by high CO2, which is involved in persimmon fruit deastringency, by operating on both DkPDC structural genes and DkERF transcription factors (Fang et al ., 2016). Meanwhile, pyruvate kinase genes ( DkPK ) are involved in the natural loss of astringency in Chinese PCNA persimmon via enhancement of the transcript levels of the DkPDC and DkADH genes (Guan et al ., 2016; 2017). Furthermore, Xu et al .…”