DkPK Genes Promote Natural Deastringency in C-PCNA Persimmon by Up-regulating DkPDC and DkADH Expression.
DkPK Genes Promote Natural Deastringency in C-PCNA Persimmon by Up-regulating DkPDC and DkADH Expression.
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DkPK 基因通过上调 DkPDC 和 DkADH 表达促进 C-PCNA 柿子的天然脱涩性
DOI：
10.3389/fpls.2017.00149
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发表时间：
2017
影响因子：
5.6
通讯作者：
Yang Y
中科院分区：
文献类型：
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作者：
Guan C;Du X;Zhang Q;Ma F;Luo Z;Yang Y
中国授粉恒定非涩性（C-PCNA）柿子（Diospyros kaki Thunb.）的涩味可以在树上自然去除。该过程由单一基因座控制，相对于其他类型的柿子具有优势；因此，该变体是商业化种植和 PCNA 品种育种的重要候选者。在我们前期的研究中，分离出了丙酮酸激酶基因（DkPK1-6）的6个全长编码序列（CDS），DkPK1被认为参与了C-PCNA柿子果实的天然脱涩作用。在这里，我们根据转录组数据表征了 C-PCNA 柿子果实中的其他 8 个 DkPK 基因 (DkPK7-14)。研究了C-PCNA、J-PCNA和非PCNA柿子在不同果实发育阶段DkPK7-14基因的转录变化及其与原花青素（PA）含量的相关性； DkPK7 和 DkPK8 在 C-PCNA 柿子的最后发育阶段表现出上调模式，与可溶性 PA 的减少呈负相关。系统发育分析和亚细胞定位分析表明DkPK7和DkPK8是胞浆蛋白。值得注意的是，DkPK7 和 DkPK8 在各种柿子器官中普遍表达，并且在种子中大量上调。此外，柿叶中DkPK7和DkPK8的瞬时过表达导致可溶性PA含量显着降低，但与乙醛代谢密切相关的丙酮酸脱羧酶（DkPDC）和乙醇脱氢酶基因（DkADH）的表达水平显着增加。 DkPDC和DkADH基因上调导致积累的乙醛可以与可溶性PA结合形成不溶性PA，从而去除柿子果实中的涩味。因此，我们认为 DkPK7 和 DkPK8 可能通过在 C-PCNA 柿子的最后发育阶段上调 DkPDC 和 DkADH 表达来参与自然脱涩。
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.