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Pentatricopeptide repeat (PPR) proteins play important roles in plant growth and development. However, little is known about their functions in the leaf morphogenesis of Jingxiu grape (Vitis vinifera L.). Here, we explored the function of VvPPR1, which encodes a DYW-type PPR protein in grape. We showed that VvPPR1 is involved in the regulation of leaf rolling, anthocyanin accumulation, and trichome formation in Arabidopsis thaliana. Analysis of structural characteristics showed that VvPPR1 is a DYW-type PPR gene in the PLS subfamily consisting of 15 PPR motifs. The N-terminal had a targeted chloroplast site, and the C-terminal had a DYW domain. Quantitative PCR analysis revealed that the expression level of VvPPR1 was highest in grape leaves. Subcellular localization revealed that VvPPR1 is localized in the cytoplasm and chloroplast. VvPPR1-overexpressing plants had rolled leaves, high degrees of anthocyanin accumulation, and longer trichomes. The expression levels of genes related to these phenotypes were either significantly up-regulated or down-regulated. These results demonstrate that VvPPR1 is involved in leaf rolling, anthocyanin accumulation, and trichome formation in Arabidopsis; more generally, our findings indicate that VvPPR1 could be a target for improving the cultivation of horticultural crops.

Background RING is one of the largest E3 ubiquitin ligase families and C3H2C3 type is the largest subfamily of RING, which plays an important role in plant growth and development, and growth and responses to biotic and abiotic stresses. Results A total of 143 RING C3H2C3-type genes (RCHCs) were discovered from the grapevine genome and separated into groups (I-XI) according to their phylogenetic analysis, and these genes named according to their positions on chromosomes. Gene replication analysis showed that tandem duplications play a predominant role in the expansion of VvRCHCs family together. Structural analysis showed that most VvRCHCs (67.13 %) had no more than 2 introns, while genes clustered together based on phylogenetic trees had similar motifs and evolutionarily conserved structures. Cis-acting element analysis showed the diversity of VvRCHCs regulation. The expression profiles of eight DEGs in RNA-Seq after drought stress were like the results of qRT-PCR analysis. In vitro ubiquitin experiment showed that VyRCHC114 had E3 ubiquitin ligase activity, overexpression of VyRCHC114 in Arabidopsis improved drought tolerance. Moreover, the transgenic plant survival rate increased by 30 %, accompanied by electrolyte leakage, chlorophyll content and the activities of SOD, POD, APX and CAT were changed. The quantitative expression of AtCOR15a, AtRD29A, AtERD15 and AtP5CS1 showed that they participated in the response to drought stress may be regulated by the expression of VyRCHC114. Conclusions This study provides valuable new information for the evolution of grapevine RCHCs and its relevance for studying the functional characteristics of grapevine VyRCHC114 genes under drought stress.

Additional file 3: Figure S3. Number of introns in VvRCHCs.

Additional file 2: Figure S2. The original tree of Fig. 2.

Additional file 1: Figure S1. Schematic diagram of C3H2C3 conserved sequence alignment of VvRCHCs. Cys(C) and His(H) amino acids were added on a blue and pink background. The C3H2C3 conserved amino acid sequence length of these genes is shown later in the sequence.

Additional file 6: Figure S6. VyRCHC114 in vitro ubiquitin gel imprinting (uncut). Corresponding to the original image of gel imprinting in Fig.7A and B.

Additional file 5: Figure S5. Two model diagrams (VyRCHC114 is involved in drought resistance).

Additional file 4: Figure S4. Analysis of Cis-acting elements in the VvRCHCs. a A list of VvRCHCs to facilitate correspondence. b Color-coded numbers of cis-acting elements of the three major types of VvRCHCspromoters. c Different types of cis-actingelements are represented by different colored squares and their position on each VvRCHC gene promoter.

The plant U-box E3 ubiquitin ligase-mediated ubiquitin/26S proteasome degradation system plays a key role in plant growth and development. Previously identified as a member of the grape PUB gene family, PUB38 was shown to participate in the berry-ripening progress. Here, we demonstrate that the E3 ligase VlPUB38 mediates abscisic acid (ABA) synthesis via 26S proteasome degradation and its involvement in regulating fruit-ripening processes. Strawberry-overexpressing VlPUB38 lines displayed obvious inhibition of mature phenotype, and this was rescued by exogenous ABA treatment and MG132. Post-ABA treatment, expression levels of ABA response-related genes in VlPUB38-overexpressed Arabidopsis significantly exceeded controls. Strawberry and Arabidopsis ectopic expression assays suggest that VlPUB38 negatively regulates fruit ripening in an ABA-dependent manner. Moreover, VlPUB38 has ubiquitin ligase activity, which depends on the U-box-conserved domain. VlPUB38 interacts with abscisic-aldehyde oxidase (VlAAO), targeting VlAAO proteolysis via the 26S proteasome system. These results indicate that VlPUB38 negatively regulates grape fruit ripening by mediating the degradation of key factor VlAAO in the ABA synthesis pathway.

The energy status, the level of respiration metabolism are improtant index reflecting plant growth state, participates in many growth processes. However, their relationship to berry setting remain unclear. In this study, the grape of ‘kyoho’ of CPPU [CPPU, N-(2-coloro-4-pyridinyl)-N-phenylurea] treated were used to measurement physiological indicators. The results showed that CPPU treatment reduced respiratory rate, reduced Cytochrome C oxidase (CCO) and ascorbic acid oxidase (AAO) activity, reduced NAD kinase (NADK) activity, maintained low nicotinamide adenine denucleotie phosphate (NADP) and nicotinamide adenine denucleotie phosphate reduced form (NADPH) levels, reduced nicotinamide adenine denucleotie (NADH) levels, and slowed down the reduction of energy charge. These results provided strong evidence that CPPU treatment promoted grape berry setting due to increased energy status, increased Embden-Meyerhof pathway (EMP) and the tricarboxylic acid (TCA) cycle respiratory metabolic pathways, decreased pentose phosphate pathway (PPP), and decreased CCO and AAO activity of respiratory terminal oxidase.

The effect of Ce(3+) on the chlorophyll (chl) of spinach was studied in pot culture experiments. The results showed that Ce(3+) could obviously stimulate the growth of spinach and increase its chlorophyll contents and photosynthetic rate. It could also improve the PSII formation and enhance its electron transport rate of PSII as well. By inductively coupled plasma-mass spectroscopy and atom absorption spectroscopy methods, it was revealed that the rare-earth-element (REE) distribution pattern in the Ce(3+)-treated spinach was leaf > root > shoot in Ce(3+) contents. The spinach leaves easily absorbed REEs. The Ce(3+) contents of chloroplast and chlorophyll of the Ce(3+)-treated spinach were higher than that of any other rare earth and were much higher than that of the control; it was also suggested that Ce(3+) could enter the chloroplast and bind easily to chlorophyll and might replace magnesium to form Ce-chlorophyll. By ultraviolet-visible, Fourier transform infrared, and extended X-ray absorption fine structure (EXAFS) methods, Ce(3+)-coordinated nitrogen of porphyrin rings with eight coordination numbers and average length of the Ce-N bond of 0.251 nm.