title: DkPKGenes Promote Natural Deastringency in C-PCNA Persimmon by Up-regulatingDkPDCandDkADHExpression.
abstract: The astringency of Chinese pollination-constant non-astringent (C-PCNA) persimmon (Diospyros kakiThunb.) 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, andDkPK1is thought to be involved in the natural deastringency of C-PCNA persimmon fruit. Here, we characterize the eight otherDkPKgenes (DkPK7-14) from C-PCNA persimmon fruit based on transcriptome data. The transcript changes inDkPK7-14genes and correlations with the proanthocyanidin (PA) content were investigated during different fruit development stages in C-PCNA, J-PCNA, and non-PCNA persimmon;DkPK7andDkPK8exhibited 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,DkPK7andDkPK8were ubiquitously expressed in various persimmon organs and abundantly up-regulated in seeds. Furthermore, transient over-expression ofDkPK7andDkPK8in 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 theDkPDCandDkADHgenes can combine with soluble PAs to form insoluble PAs, resulting in the removal of astringency from persimmon fruit. Thus, we suggest that bothDkPK7andDkPK8are likely to be involved in natural deastringency via the up-regulation ofDkPDCandDkADHexpression during the last developmental stage in C-PCNA persimmon.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F UniversityYangling, China; Key Laboratory of Horticultural Plant Biology - Ministry of Education, Huazhong Agricultural UniversityWuhan, China.
authors.forename: Changfei
authors.initials: C
authors.lastname: Guan
authors.affiliation: Institute of Pomology, Yantai Academy of Agricultural Sciences Yantai, China.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Du
authors.affiliation: Key Laboratory of Horticultural Plant Biology - Ministry of Education, Huazhong Agricultural University Wuhan, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University Yangling, China.
authors.forename: Fengwang
authors.initials: F
authors.lastname: Ma
authors.affiliation: Key Laboratory of Horticultural Plant Biology - Ministry of Education, Huazhong Agricultural University Wuhan, China.
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University Yangling, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
keywords: DkADH; DkPDC; DkPK; PAs; deastringency; persimmon; qRT-PCR; transient over-expression