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The most common bud sport trait in grapevines is the change in color of grape berry skin, and the color of grapes is mainly developed by the composition and accumulation of anthocyanins. Many studies have shown that MYBA is a key gene regulates the initiation of bud sport color and anthocyanin synthesis in grape peels. In the current study, we used berry skins of 'Italia', 'Benitaka', 'Muscat of Alexandria', 'Flame Muscat', 'Rosario Bianco', 'Rosario Rosso', and 'Red Rosario' at the véraison stage (10 weeks post-flowering and 11 weeks post-flowering) as research materials. The relative expressions of genes related to grape berry bud sport skin color were evaluated utilizing RNA-Seq technology. The results revealed that the expressions of the VvMYBA1/A2 gene in the three red grape varieties at the véraison stage were higher than in the three white grape varieties. The VvMYBA1/A2 gene is known to be associated with UFGT in the anthocyanin synthesis pathway. According to the results, VvMYBA1/A2 gene expression could also be associated with the expression of LDOX. In addition, a single gene (gene ID: Vitvi19g01871) displayed the highest expressions in all the samples at the véraison stage for the six varieties. The expression of this gene was much higher in the three green varieties compared to the three red ones. GO molecular function annotation identified it as a putative metallothionein-like protein with the ability to regulate the binding of copper ions to zinc ions and the role of maintaining the internal stable state of copper ions at the cellular level. High expression levels of this screened gene may play an important role in bud sport color of grape berry skin at the véraison stage. [ABSTRACT FROM AUTHOR]

Grapevine ( Vitis vinifera L.) is considered to be one of the most popular and widespread fruit crops in the world. Numerous value added products are prepared from grape fruit and investments are being made to establish new viticulture region (Hoff et al., 2017; Imran et al., 2017). CPPU [forchlorfenuron N-(2-chloro-4-pyridyl)-N-phenylurea] is a synthetic cytokine-like plant regulator which promotes grape berry set and development. The influence of CPPU [forchlorfenuron N-(2-chloro-4-pyridyl)-N-phenylurea] on berry development of ‘Shine Muscat’ ( Vitis labruscana Bailey × V vinifera L.) grapes was evaluated under field conditions. A concentration response was observed over a range of 0, 5, and 10 mg L −1 CPPU that was applied to fruitlets (mean diameter 6 mm) at 2 weeks after full bloom. Gas-chromatography mass-spectrometry (GC–MS) revealed that volatile compounds such as terpenoids and aromatics; especially linalool, geraniol and benzyl alcohols, were greatly reduced in CPPU-treated grapes. In contrast, aliphatics, such as hexanol, were increased in CPPU-treated berries. RNA sequencing (RNA-Seq) was conducted to identify differentially expressed genes (DEGs) that were induced by CPPU, especially those related to volatile biosynthesis. A total of 494, 1237, and 1085 DEGs were detected in CPPU0-vs-CPPU5, CPPU0-vs-CPPU10, and CPPU5-vs-CPPU10 treatments, respectively. The results were compared against two databases (Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG)) to annotate gene descriptions and assign a pathway to each gene. GO covers three domains: biological processes, molecular functions and cellular components. Pathway enrichment annotation demonstrated that highly ranked genes were associated with the fatty acid degradation and biosynthesis, phenylpropanoid metabolism and biosynthesis, carotenoid biosynthesis, and plant hormone signal transduction. Analysis with qRT-PCR of twelve selected transcripts validated the data obtained by RNA-seq. Additionally, we also found that genes such as CCDs (carotenoid cleavage dioxygenase), LOX (lipoxygenase), GGDP reductase (geranylgeranyl diphosphate reductase), PAL (phenylalanine ammonia-lyase) and some hormones related genes, were closely involved in the formation of volatiles compounds in CPPU treated berries. In summary, our results provide the first sequential transcriptomic atlas of CPPU treated grape berries which significantly increases our understanding of volatile metabolites and biosynthesis pathways in grape affected by CPPU. [ABSTRACT FROM AUTHOR]

Using an RNA sequencing (RNA-seq) approach, we analyzed the differentially expressed genes (DEGs) and physiological behaviors of "Manicure Finger" grape plantlets grown in vitro under white, blue, green, and red light. A total of 670, 1601, and 746 DEGs were identified in plants exposed to blue, green, and red light, respectively, compared to the control (white light). By comparing the gene expression patterns with the growth and physiological responses of the grape plantlets, we were able to link the responses of the plants to light of different spectral wavelengths and the expression of particular sets of genes. Exposure to red and green light primarily triggered responses associated with the shade-avoidance syndrome (SAS), such as enhanced elongation of stems, reduced investment in leaf growth, and decreased chlorophyll levels accompanied by the expression of genes encoding histone H3, auxin repressed protein, xyloglucan endotransglycosylase/hydrolase, the ELIP protein, and microtubule proteins. Furthermore, specific light treatments were associated with the expression of a large number of genes, including those involved in the glucan metabolic pathway and the starch and sucrose metabolic pathways; these genes were up/down-regulated in ways that may explain the increase in the starch, sucrose, and total sugar contents in the plants. Moreover, the enhanced root growth and up-regulation of the expression of defense genes accompanied with SAS after exposure to red and green light may be related to the addition of 30 g/L sucrose to the culture medium of plantlets grown in vitro. In contrast, blue light induced the up-regulation of genes related to microtubules, serine carboxypeptidase, chlorophyll synthesis, and sugar degradation and the down-regulation of auxin-repressed protein as well as a large number of resistance-related genes that may promote leaf growth, improve chlorophyll synthesis and chloroplast development, increase the ratio of chlorophyll a (chla)/chlorophyll b (chlb), and decrease the ratio of carbohydrates to proteins in plants. Although exposure to red and green light seems to impose "shade stress" on the plantlets, growth under blue light is comparable to growth observed under white or broad-spectrum light. [ABSTRACT FROM AUTHOR]

Background: Bud dormancy is an important biological phenomenon of perennial plants that enables them to survive under harsh environmental circumstances. Grape (Vitis vinifera) is one of the most grown fruit crop worldwide; however, underlying mechanisms involved in grape bud dormancy are not yet clear. This work was aimed to explore the underlying molecular mechanism regulating bud dormancy in grape. Results: We have performed transcriptome and differential transcript expression analyses of "Shine Muscat" grape buds using the Illumina RNA-seq system. Comparisons of transcript expression levels among three stages of dormancy, paradormancy (PD) vs endodormancy (ED), summer buds (SB) vs ED and SB vs PD, resulted in the detection of 8949, 9780 and 3938 differentially expressed transcripts, respectively. Out of approximately 78 million high-quality generated reads, 6096 transcripts were differentially expressed (log2 ratio ⩾ 1, FDR ⩽ 0.001). Grape reference genome was used for alignment of sequence reads and to measure the expression level of transcripts. Furthermore, findings obtained were then compared using two different databases; Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), to annotate the transcript descriptions and to assign a pathway to each transcript. KEGG analysis revealed that secondary metabolites biosynthesis and plant hormone signaling was found most enriched out of the 127 total pathways. In the comparisons of the PD vs ED and SB vs ED stages of grape buds, the gibberellin (GA) and abscisic acid (ABA) pathways were found to be the most enriched. The ABA and GA pathways were further analyzed to observe the expression pattern of differentially expressed transcripts. Transcripts related to the PP2C family (ABA pathway) were found to be up-regulated in the PD vs ED comparison and down-regulated in the SB vs ED and SB vs PD comparisons. GID1 family transcripts (GA pathway) were up-regulated while DELLA family transcripts were down-regulated during the three dormancy stages. Differentially expressed transcripts (DEGs) related to redox activity were abundant in the GO biological process category. RT-qPCR assay results for 12 selected transcripts validated the data obtained by RNA-seq. Conclusion: At this stage, taking into account the results obtained so far, it is possible to put forward a hypothesis for the molecular mechanism underlying grape bud dormancy, which may pave the way for ultimate improvements in the grape industry. [ABSTRACT FROM AUTHOR]