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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. • VvPPR1 belongs to DYW class in the PLS subfamily of the PPR gene family. • VvPPR1 is mainly expressed in leaves, especially young leaves. • VvPPR1 localized in the cytoplasm and chloroplast. • Overexpressing VvPPR1 lead to the results that leaf rolling, anthocyanin accumulation and trichome longer. [ABSTRACT FROM AUTHOR]

Background: Drought stress affects grapevine growth and development and reduces berry yield and quality. Identifying genes that are involved in the plant response to drought stress will enable the development of new grape strains that are tolerant to drought. Objective: We cloned the VvibZIP14 gene from Vitis vinifera and analyzed its role in drought resistance. Methods: Gene expression was analyzed by quantitative real-time PCR. Subcellular localization was assessed with a transient expression assay. The transactivation activity of the protein was evaluated in yeast. The physiologic role of VvibZIP14 was analyzed by overexpressing VvibZIP14 in Arabidopsis following drought stress. Hydrogen peroxide accumulation in Arabidopsis was visualized by diaminobenzidine staining. Results: Drought stress caused the accumulation of VvibZIP14, which was localized in the nucleus and had transcriptional activity. Transgenic plants showed improved resistance to drought stress and reduced electrolyte leakage compared to plants overexpressing empty vector, whereas chlorophyll content, photosystem II maximal photochemical efficiency, and net photosynthetic rate were higher. Catalase, peroxidase, and superoxide dismutase activities were also increased in VvibZIP14-overexpressing plants subjected to drought stress. Conclusions: VvibZIP14 functions as a transcription factor that confers resistance to drought stress in grape by enhancing the antioxidant response. [ABSTRACT FROM AUTHOR]

BACKGROUND: Long non-coding ribonucleic acids (lncRNAs) have been linked to many important biological processes, including fruit ripening. "Fengzao" is an early-ripening bud mutant of "Kyoho" that matures nearly 30 days earlier. However, the molecular networks controlling early ripening in Fengzao are still poorly understood in comparison to those in Kyoho. OBJECTIVE: The aim of the study was to gain a better understanding of the regulatory role of lncRNAs in the early ripening of grape berries. METHODS: The RNA-sequencing approach and quantitative real-time polymerase chain reaction validation were employed to identify lncRNAs and profile their expression patterns during berry development. RESULTS: In total, 24726 lncRNAs were identified, of which 19699 were differentially expressed (DE-lncRNAs) between developmental stages. The target genes of these lncRNAs and their regulatory relationships were predicted. The oxidoreductase activity, plant–pathogen interaction, plant hormone signal transduction, and flavanol biosynthesis pathways were enriched in the target genes of DE-lncRNAs, and six key lncRNAs (TCONS_00221683, TCONS_00684459, TCONS_00022149, TCONS_00167247, TCONS_00258125, and TCONS_00261813) were identified that may regulate the early ripening of grape berries. CONCLUSIONS: The results contribute to the understanding of the role of lncRNAs in early ripening of grape berries and will provide new insights for molecular breeding of grapes. [ABSTRACT FROM AUTHOR]

• VvbZIP60 is constitutively expressed and can be induced by pathogens, SA, JA in grapes. • VvbZIP60 is localized in the nucleus and has transcriptional activation activity. • VvbZIP60 contributes to disease resistance and activation of SA pathway in Arabidopsis. Powdery mildew is a fungus that causes major losses in grape production worldwide. Recent studies demonstrate bZIP transcription factors (TFs) play an important role in plant defense against fungal pathogens. To investigate whether one or more bZIP TFs is involved in the common grapevine's defense against powdery mildew, which could provide candidate genes for breeding powdery mildew-resistant grape plants, we isolated its VvbZIP60 gene and analyzed its functional role in plants against powdery mildew. Amino acid sequence alignment and phylogenetic analysis indicated that VvbZIP60 is a U member of the bZIP gene family and is similar to AtbZIP60 of Arabidopsis. The gene expression profile of the 'Jing Xiu' variety of grape (Vitis vinifera) showed that the VvbZIP60 transcript accumulated in various tissues (especially leaves) and could quickly accumulate when this plant was treated with exogenous pathogen (PA), 1 1 Abbreviations: DAPI, 4',6-diamidino-2-phenylindole; GFP, green fluorescent protein; HPI, hours post-inoculation; JA, jasmonic acid; MeJA, methyl jasmonate; OE, overexpressing plants; PA, pathogen; PR1, pathogenesis related 1; PDF1.2, plant defensin 1.2; SA, salicylic acid; SAR, systemic acquired resistance; TFs, transcription factors; WT, wild type. salicylic acid (SA) and jasmonic acid (JA). VvbZIP60 was found localized to the nucleus and has transcriptional activation in yeast. Crucially, overexpression of VvbZIP60 increased Arabidopsis resistance to powdery mildew. Transgenic plants accumulated SA and up-regulated their expression of the pathogenesis related 1 (PR1) gene involved in the SA-signaling pathway. Taken together, these results show that VvbZIP60 is a positive regulator of resistance to fungal disease and contributes importantly to SA signaling against powdery mildew. [ABSTRACT FROM AUTHOR]

Previous study has demonstrated that the riboflavin treatment promoted the early ripening of the 'Kyoho' grape berry. However, the molecular mechanism causing this was unclear. In order to reveal the regulation mechanism of riboflavin treatment on grape berry development and ripening, the different berry developmental stages of the 'Kyoho' berry treated with 0.5 mmol/L of riboflavin was sampled for transcriptome profiling. RNA-seq revealed that 1526 and 430 genes were up-regulated and down-regulated, respectively, for the comparisons of the treatment to the control. TCseq analysis showed that the expression patterns of most of the genes were similar between the treatment and the control, except for some genes that were related to the chlorophyll metabolism, photosynthesis–antenna proteins, and photosynthesis, which were revealed by the enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The differentially expressed genes and weighted gene co-expression network analysis (WGCNA) analysis identified some significantly differentially expressed genes and some hub genes, including up-regulation of the photosynthesis-related ELIP1 and growth and development-related GDSL; and down-regulation of the oxidative stress-related ATHSP22 and berry softening-related XTH32 and GH9B15. The results suggested that the riboflavin treatment resulted in the variations of the expression levels of these genes, and then led to the early ripening of the 'Kyoho' berry. [ABSTRACT FROM AUTHOR]

Enzymes and non-enzyme elements related to the metabolism of reactive oxygen species (ROS), such as catalase (CAT), superoxide dismutase (SOD), ascorbic acid (AsA), glutathione (GSH), NADPH oxidase (NOX), hydrogen peroxide (H 2 O 2 ), superoxide anion (O 2 - ), lipoxygenase (LOX) and malondialdehyde (MDA), were measured in ‘Kyoho’ and its early ripening bud mutant ‘Fengzao’ to compare ROS level changes and investigate the potential roles of ROS in grape berry development and the ripening process. In addition, the anthocyanin and sugar contents as well as berry diameter were also investigated at different berry development stages. The results showed that the H 2 O 2 content and LOX activity exhibited obviously different trends between ‘Fengzao’ and ‘Kyoho’ during the berry development stages. Before berry softening, the SOD activity, LOX activity and H 2 O 2 content were significant lower in ‘Fengzao’ than in ‘Kyoho’, but there were no significant differences in the production rate of O 2 - , ROS scavengers (CAT, AsA, GSH) and MDA content between them, which indicated that the higher oxidation status in ‘Fengzao’. It may promote the faster development of ‘Fengzao’ berry than ‘Kyoho’ before berry softening (EL31-33). The significant higher LOX and CAT activities at EL-34, as well as significant higher LOX activity and H 2 O 2 content at EL-35 in ‘Fengzao’ than in ‘Kyoho’ indicated H 2 O 2 was acted as the appropriate oxidative stress factor and the signal molecule to further accelerate the berry ripening of ‘Fengzao’. The increasing O 2 - and H 2 O 2 after EL-35 in ‘Fengzao’ further promoted the ripening process. Furthermore, after the spraying of 300 μmol/L H 2 O 2 solution on ‘Kyoho’ at EL-31 stage, the berries matured 15 days earlier than the untreated. Evidence in this study indicated that the overall oxidation status (ROS levels) in ‘Fengzao’ is higher than in ‘Kyoho’ and H 2 O 2 could promote the early ripening of ‘Kyoho’ berry. [ABSTRACT FROM AUTHOR]

Grape (Vitis vinifera L.) berries are susceptible to quality deterioration after harvest. This study aimed to investigate the effect of folic acid (FA) treatment on the postharvest quality of table grape berries. Harvested 'Kyoho' (V. vinifera × V. labrusca L.) bunches were immersed in 1 mg L−1 FA solution for 15 min, then stored for sample collection and phenotype observation. Treatment with FA decreased the rates of berry abscission, water loss, and berry softening, reduced the accumulation of reactive oxygen species (ROS), and altered ROS metabolism-associated enzyme activities and gene expression levels. Transcriptome analysis revealed 507, 684, and 250 differentially expressed genes (DEGs) between FA-treated and non-treated berries at 3, 6, and 9 d after treatment, respectively. The DEGs were grouped into six modules according to a weighted correlation network analysis. A hub transcription factor, annotated as a WRKY transcription factor, was screened from the module associated with cell wall metabolism and identified as VvWRKY31. Transient transformation of grape berry slices revealed that overexpression of VvWRKY31 enhanced the relative expression level of VvRboh. The dual-luciferase assay showed that VvWRKY31 was capable of binding to VvRboh promoter. The present results provide insights into the potential molecular mechanism underlying FA-induced delay postharvest quality deterioration of grape berries. Specifically, FA inhibits expression of genes associated with ROS generation by reducing VvWRKY31 expression, thereby delaying quality deterioration induced by excessive accumulation of ROS. These results will be helpful in table grape breeding programs focused on delaying deterioration in postharvest quality. • Folic acid affects ROS metabolism in postharvest grape. • VvWRKY31 is a hub transcription factor in cell wall metabolism. • VvWRKY31 promotes VvRboh expression by binding its promoter. [ABSTRACT FROM AUTHOR]

• Hydrogen peroxide (H 2 O 2) treatment improves K+ uptake in grapes. • H 2 O 2 treatment activates flavonoid biosynthesis pathway. • H 2 O 2 changes ethylene signaling to promote K+ uptake by regulating K+ transporters. Potassium ion (K+) is an essential nutrient for plants. Grapes are an important industrial crop with an extremely high demand for potassium. However, potassium deficiency occurs frequently in viticulture and greatly restricts the grape industry. Developing a technique to improve potassium uptake efficiency is of vital importance for grapes. In this study, we found that hydrogen peroxide (H 2 O 2) treatment could improve K+ uptake in grapes. To determine the mechanisms underlying H 2 O 2 -induced K+ uptake, transcriptome sequencing (RNA-seq) was conducted and the differentially expressed genes were further analyzed. Gene Ontology (GO) enrichment indicated that ion transport-related pathways and genes changed after H 2 O 2 treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and weighted gene co-expression network analysis (WGCNA) showed that the flavonoid biosynthesis pathway was closely related to H 2 O 2 -induced K+ uptake, and H 2 O 2 treatment could activate the flavonoid biosynthesis pathway. Further analysis demonstrated that H 2 O 2 treatment could activate ethylene synthesis and the ethylene signaling pathway, which promoted K+ uptake by regulating K+ transporter genes. Overall, this study demonstrates a new technique, H 2 O 2 treatment, for enhancing potassium uptake efficiency in grapes and reveals the molecular mechanisms underlying H 2 O 2 -induced K+ uptake. [ABSTRACT FROM AUTHOR]

• Berries firmness/propectin-associated genes in grape were elucidated. • Cell wall metabolism pathways fluctuated during Hypotaurine (HT)-mediated delayed postharvest softening in grape. • VvMYB-like and VvNAC22 function by binding to VvPEI and VvCESA promoters. The rapid softening of postharvest fruit has a serious detrimental effect on quality and market value. In this study, postharvest grape berries treated with hypotaurine (HT) or H 2 O 2 were employed to explore the dynamic physical and transcriptional changes after the treatment. The berry firmness and the content of propectin were higher in the berries with HT treatment compared to the control (CK) and H 2 O 2 treatment. A total of 1774 differentially expressed genes (DEGs) were identified from comparisons of CK_vs_HT (1,020) and CK_vs_H 2 O 2 (1,072). Weighted gene coexpression network analysis (WGCNA) showed that genes assigned to 'MEgreen' were predicted to be highly correlated to fruit firmness and propectin content. Based on transcriptome and quantitative real-time polymerase chain reaction (RT-qPCR), expression levels of VvMYB-like , VvNAC22 , VvPEI and VvCESA-like were upregulated whereas VvMADS-box and VvPG were downregulated in HT-treated berries compared to H 2 O 2 treatment. Dual luciferase reporter assay confirmed that VvMYB-like and VvNAC22 upregulate the expression of VvPEI and VvCESA respectively by binding to the corresponding sites of their promoters. Meanwhile, HT treatment triggered the differential expression of Accelerated Cell Death 6 (VvACD6), VvXyloglucan galactosyltransferase (VvXyG galactosyltransferase) and Cell wall/Vacuolar Inhibitor of Fructosidase 1-like (VvC/VIF1-like). Finally, a possible regulatory model that HT delays berry softening by regulating pectin and cell metabolism pathway through VvMYB-like and VvNAC22 was proposed. This study laid a foundation for understanding the molecular mechanisms of delaying berry softening which HT mediated. [ABSTRACT FROM AUTHOR]

• Four hydrogen peroxide sensors VvHPCA1-4 in grape are identified. • H 2 O 2 and ROS inhibitor change ROS scavenge system and VvHPCAs ' expression levels. • VvHPCA is cytomembrane protein with stress-responsive cis-acting elements in promoter. • VvHPCAs respond to ROS stress. Hydrogen peroxide is an important factor involved in the senescence and quality deterioration of postharvest fruit. However, few studies have examined hydrogen peroxide sensors and their expression patterns in grape. Here, postharvest grape berries were treated with H 2 O 2 and the ROS inhibitor hypotaurine (HT). HT reduced the H 2 O 2 content by increasing ROS-scavenging enzyme activity, whereas H 2 O 2 accelerated senescence. Four hydrogen peroxide sensors (VvHPCA1 , 2 , 3 , and 4) were identified and isolated from the grape genome. Sequence analysis indicated that VvHPCAs shared a conserved structure, including the LRR-RK and hydrogen peroxide (HP) domains, with other homologous hydrogen peroxide sensor genes. Furthermore, the expression patterns of the four VvHPCAs were investigated under H 2 O 2 and HT treatment in grape. The expression levels of the four VvHPCA s were lower in grape berries treated with HT than in grape berries treated with H 2 O 2 or water treatment (Control) in at least one of the sampling points during storage. VvHPCAs are cytomembrane proteins with stress-responsive cis-acting elements in their promoters, indicating that these four identified VvHPCAs might function as hydrogen peroxide sensors in grape and regulate hydrogen peroxide signaling and metabolism. Thus, VvHPCAs are capable of responding to postharvest ROS stress. These findings provided new insight into the function of these four VvHPCAs, which are potential candidate genes involved in regulating ROS stress in grape. [ABSTRACT FROM AUTHOR]

• The intersection of the variants detected by 'Kyoho' vs 'Fengzao' and 'Zana' vs '90–1′ with Genome Analysis Tool Kit (GATK) and samtools were taken. • The candidate genes located in the QTL regions were screened. • Five of the SNPs were verified. Single nucleotide polymorphisms (SNPs), insertion-deletion mutations (InDels) and structural variation (SV) play an important role in the generation of mutant genotypes. In this study, we conducted whole genome resequencing analysis of 'Kyoho', 'Zana' and their early-ripening bud sports, 'Fengzao' and '90–1′, respectively, to identify variants related to the early ripening trait. First, we determined the variants between 'Kyoho' vs. 'Fengzao' and 'Zana' vs. '90–1′ comparison groups using Genome Analysis Tool Kit (GATK) and samtools. Then, 324 genes harboring 1,135 SNPs and InDels were identified, based on sequencing depth and variant allele frequency. We also detected 39,112 and 35,825 SVs specific to 'Fengzao' and '90–1′, based on their comparison with 'Kyoho' and 'Zana' sequence data, respectively. Among these SVs, 89 were common to both 'Fengzao' and '90–1′. Then, variants were found in the coding sequences (CDSs) or upstream regions of 204 genes, of which 96 mapped to early ripening-related quantitative trait loci (QTLs). Subsequently, transcriptome analysis of 'Kyoho' and 'Fengzao' genotypes at four development stages revealed that 69 genes affected by variants were differentially expressed at one or more time points. Finally, five SNPs were validated in 'Kyoho' and 'Fengzao' by Sanger sequencing. Overall, abundant genetic variation was detected in 'Kyoho' and 'Fengzao' genomes, which may play a role in their early ripening phenotype. [ABSTRACT FROM AUTHOR]