Project description:Grapevine line pattern virus (GLPV) was described 30 years ago from Hungary, and in the lack of its sequence until now no additional information about its presence was reported. However High-Throughput Sequencing (HTS) applied on dsRNAs extracts recovered from a grapevine plant (accession Baco22A) infected with GLPV Grapevine line pattern virus (GLPV) allowed us to sequence it with different High-Throughput Sequencing (HTS) methods andthe assembleing of the full genome sequence of this virus. The availability of the sequence allowed us to validate the presence of the virus bot with RT-PCR and with Northern blot hybridization. These methods were also used to test its graft and seed transmission. In accordance as it was originally suggested its genome was found to comprise three RNA segments.Its RNA1 (3.160 bp), RNA2 (2.493 bp) and RNA3 (2.529 bp), encode four proteins, denoted 1a (Methyltransferase, helicase), 2a (RNA-dependent RNA Polymerase), 3a (Movement protein, MP) and 3b (Coat protein, CP). GLPV showed the highest amino acid identity (92%–99%) with all domains of Hop yellow virus (HYV), which is a tentative member of the genus Anulavirus of the family Bromoviridae. The phylogenetic trees constructed based on the amino acid sequences of 2a and 3b also confirmed the belongingness of GLPV to the genus Anulavirus, allocating it in one cluster together with the anulaviruses, and close to HYV. The very high sequence identity found between GLPV and HYV leaves no doubt that both are two isolates of the same viral species.
Project description:Plants regenerated from tissue culture frequently show somaclonal variation. In this study we compared the transcriptomic and epigenetic state of embryogenic callus of grapevine with leaves from mature grapevine plants. In particular, we focussed on the expression of transposable elements and changes in siRNA abundance and genome-wide methylation in these tissues.
Project description:MicroRNAs (miRNAs) are a class of non-coding RNA molecules which have significant gene regulation roles in organisms. The advent of new high throughput sequencing technologies has enabled the revelation of novel miRNAs. Although there are two recent reports on high throughput sequencing analysis of small RNA libraries from different organs of two grapevine wine varieties, there were significant divergence in the number and kinds of miRNAs sequenced in these studies. More sequencing of small RNA libraries is still important for the discovery of novel miRNAs in grapevine. Here, we initially constructed a small RNA library of flower and fruit tissues of a table grapevine cultivar ‘Summer Black’ and performed sequencing and analysis of sRNAs using the Illumina Solexa platform, expecting to discover more miRNAs related to the development of grapevine flowers and berries and the formation of dessert quality in grapevine berries. Totally, 130 conserved grapevine miRNA (Vv-miRNA) belonging to 28 Vv-miRNA families were validated, and 92 novel potential grapevine-specific ones representing 80 unique ones were first discovered. Forty-two (48.84%) of the novel miRNAs possessed differential semi-quantitative PCR expression profiles in various grapevine tissues that could further confirm their existence in the grapevine, among which twenty were expressed only in grapevine berries, indicating some fruit-specificity. 130 target genes for 46 novel miRNAs could be predicted. The locations of these potential target genes on grapevine chromosomes and their complementary levels with the corresponding miRNAs were also analyzed.
Project description:Meristem culture and somatic embryogenesis is an effective tool for virus elimination of vegetatively propagated crops including grapevine. While they both are proved to be useful to eliminate the main grapevine viruses their efficiency differs according to the virus and the variety. In our work we investigated their efficiency using small RNA high-throughput sequencing as virus diagnostic method. Field grown mother plants of four clones representing three cultivars, infected with different viruses and viroids were selected for sanitation via somatic embryogenesis and meristem culture. Our results show that the sanitation with SE was efficient against all of the presenting viruses, including grapevine Pinot gris virus, grapevine rupestris vein feathering virus and grapevine Syrah virus 1, having no data using somatic embryogenesis for their elimination. In case of other viruses and viroids such as GFkV, GRSPaV, GYSVd-1, HSVd this study confirms the findings of earlier researches, that SE is a possible way for elimination. While the efficiency of the elimination of different viruses was high, in case of viroids this ratio was lower. Our work demonstrated that efficiency of SE is comparable to the technically difficult meristem culture technique, and show promising way for the high demand of the production of virus-free grapevine in the future.
Project description:To examine the grapevine genomic methylation landscape and assess its functional significance, we generated whole genome DNA methylome maps for grapevine fruits of developmental stages. The results showed that DNA methylation happened in the grapevine fruit ripening process, and mostly happened in the biological process from the first growth stage fruit transfer to the véraison stage fruit. It further demonstrated that DNA methylation repress the gene expression. The whole-genome methylomes of grapevine fruits obtained in this study have not only broadened our understanding of the mechanism and function of DNA methylation in plant genomes, but also provided valuable data for future studies of grapevine epigenetics and the epigenetic differentiation among different fruit developmental stages.
Project description:In this study we functionally characterized the grapevine VviNAC33 by its transient and stable overexpression in grapevine homologous system and the creation of its chimeric repressor. Through the application of DAP-seq approach we identified putative direct targets of VviNAC33, among which the SGR1 involved in the breakdown of chlorophyll. Stable VviNAC33 overexpressing transgenic plants displayed an obvious degreening effect on leaves and an inhibition of leaf growth. Consistently, transgenic plant expressing a chimeric repressor of the VviNAC33 showed the opposite phenotypic alterations. Our results evidenced that VviNAC33 is a direct player of leaf senescence program and propose a blueprint of the complex transcriptional regulatory network that govern organ phase transition in grapevine. transcription factor VviNAC33 is directly involved in leaf degreening and organ growth.
Project description:MicroRNAs (miRNAs) play a important part in post-transcriptional gene regulation and have been shown to control many genes involved in various biological and metabolic processes. There have been extensive studies to discover miRNAs and analyze their functions in model plant species, such as Arabidopsis and rice and other plants. However, the number of miRNAs discovered in grape is relatively low and little is known about miRNAs responded gibberellin during fruit germination. In this study, a small RNA library from gibberellin grape fruits was sequenced by the high throughput sequencing technology. A total of 16,033,273 reads were obtained. 812,099 total reads representing 1726 unique sRNAs matched to known grape miRNAs. Further analysis confirmed a total of 149 conserved grapevine miRNA (Vv-miRNA) belonging to 27 Vv-miRNA families were validated, and 74 novel potential grapevine-specific miRNAs and 23 corresponding novel miRNAs* were discovered. Twenty-seven (36.5%) of the novel miRNAs exhibited differential QRT-PCR expression profiles in different development gibberellin-treated grapevine berries that could further confirm their existence in grapevine. QRT-PCR analysis on transcript abundance of 27 conserved miRNA family and the new candidate miRNAs revealed that most of them were differentially regulated by the gibberellin, with most conserved miRNA family and 26 miRNAs being specifically induced by gibberellin exposure. All novel sequences had not been earlier described in other plant species. In addition, 117 target genes for 29 novel miRNAs were successfully predicted. Our results indicated that miRNA-mediated gene expression regulation is present in gibberellin-treated grape berries. This study led to the confirmation of 101 known miRNAs and the discovery of 74 novel miRNAs in grapevine. Identification of miRNAs resulted in significant enrichment of the gibberellin of grapevine miRNAs and provided insights into miRNA regulation of genes expressed in grape berries. GSM604831 is the control for the gibberellin-treated sample.
Project description:Drought has become an increasingly important constraint on grapevine sustainability due to global climate change. Vitis riparia, the only grapevine native to the upper Midwest region of the United States, is widely used in scion and rootstock breeding; however, it is not considered drought tolerant. In this study, RNA-Seq data were generated from grapevine root/shoot under WD and well-watered (control (C)) conditions to compare root signaling and shoot responses to water deficit.
Project description:microRNAs(miRNAs) play critical regulatory roles mainly through cleaving targeted mRNAs or repressing gene translation during plant developments. Grapevine is amongst the most economically important fruit crops with whole genome available, and the study on grapevine miRNAs (Vv-miRNAs) have also been emphasized. However, the regulation mode of Vv-miRNAs on their target mRNAs during grapevine development has not been studied well, especially on a transcriptome-wide level. Here, six small RNA (sRNA) and mRNA libraries from various grapevine tissues were constructed for Illumina and Degradome sequencing. Subsequently, the spatiotemporal variation in the Vv-miRNAs’ regulation on their target genes was systematically analyzed. Totally, 242 known and 132 novel Vv-miRNAs were identified, and 193 target mRNAs including 103 for known and 90 for novel miRNAs were validated in one or more of tissues examined. The interesting finding was that over 50% of novel miRNAs were expressed exclusively in flowers or berries where they had tissue-specific cleavage roles on their target genes, especially, the breadth of their cleavage sites in flower tissues. Moreover, six novel miRNAs in berries were found to response to exogenous gibberellin (GA) and/or ethylene by real time RT-PCR (qRT-PCR) analysis, confirming their regulatory functions during berry development. Other finding was that about 93.6% of the known miRNAs possessed the high conservation in various tissues where their expression levels exhibited some dynamic variations during grapevine development. Significantly, it was found the phenomena that some Vv-miRNA families exist one key member that act as the main regulator of their target genes during grapevine development.