Project description:We present new 238U-230Th-226Ra-210Pb and supporting data for young lavas from southwest Pacific island arcs, Eyjafjallajökull, Iceland, and Terceira, Azores. The arc lavas have significant 238U and 226Ra excesses, whereas those from the ocean islands have moderate 230Th and 226Ra excesses, reflecting mantle melting in the presence of a water-rich fluid in the former and mantle melting by decompression in the latter. Differentiation to erupted compositions in both settings appears to have taken no longer than a few millennia. Variations in the (210Pb/226Ra)0 values in all settings largely result from degassing processes rather than mineral-melt partitioning. Like most other ocean island basalts, the Terceira basalt has a 210Pb deficit, which we attribute to ~8.5 years of steady 222Rn loss to a CO2-rich volatile phase while it traversed the crust. Lavas erupted from water-laden magma systems, including those investigated here, commonly have near equilibrium (210Pb/226Ra)0 values. Maintaining these equilibrium values requires minimal persistent loss or accumulation of 222Rn in a gas phase. We infer that degassing during decompression of water-saturated magmas either causes these magmas to crystallize and stall in reservoirs where they reside under conditions of near stasis, or to quickly rise towards the surface and erupt.
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:Plant response to insect feeding appears to be highly specific with regard to the organisms in the system. Here, we report on the interaction between grapevine Vitis vinifera plants and a phloem-feeding insect pest, the vine mealybug Planococcus ficus. Plants were exposed to P. ficus for periods of 6 hours and 96 hours, after which they were analysed for gene expression levels using microarrays and quantitative real-time PCR (qPCR). Both methods showed that grapevine displayed only a minimal response to mealybug feeding at the transcript level at both time periods. Intermediate grapevine exposure times (24, 48 and 72 hours) to P. ficus feeding were investigated using qPCR analysis of ten additional genes associated with known plant defense responses. Results showed that only a single gene, pathogenesis-related protein 1, was differentially expressed after 48 hours of mealybug feeding. During the course of mealybug feeding, however, a number of other genes were significantly up- or down-regulated at certain time points. Thus, it appears as if grapevine responds minimally to feeding by P. ficus as well as within a very narrow time period. The relative lack of grapevine plant defense mechanisms may be a result of the feeding strategies of mealybugs. Eight samples were analysed. Two replicates each were included for each treatment (6 hour and 96 hour feeding), resulting in four samples. Two control replicates were included for each treatment (6 hour and 96 hour feeding controls), resulting in a further four samples.
Project description:Grapevine red blotch is a recently identified viral disease that was first recognized in the Napa Valley of California. Infected plants showed foliar symptoms similar to leafroll, another grapevine viral disease, on vines testing negative for known grapevine leafroll-associated virus. Later, the Grapevine red blotch virus (GRBV) was independently discovered in the US states of California and New York and was demonstrated to be the causal agent of red blotch disease. Due to its wide occurrence in the US, vector transmission and impacts on grape industry, this virus has the potential to cause serious economic losses. Despite numerous attempts, it was not possible to isolate or visualize viral particles from GRBV infected plants. Consequently, this has hampered the development of a serological assay that would facilitate GRBV detection in grapevine. We therefore decided to explore mass spectrometry approaches in order to quantify GRBV in infected plants and to identify potential biomarkers for viral infection. We present for the first time the physical detection on the protein level of the two GRBV genes V1 (coat protein) and V2 in grapevine tissue lysates. The GRBV coat protein load in leaf petioles was determined to be in the range of 100 to 900 million copies per milligram wet weight by using three heavy isotope labeled reference peptides as internal standards. The V1 copy number per unit wet tissue weight in leaves appeared to be about six times lower, and about 200-times lower in terms of protein concentration in the extractable protein mass than in petioles. We found a consistent upregulation of several enzymes involved in flavonoid biosynthesis in leaf and petiole extracts of GRBV-infected plants by label-free shotgun proteomics, indicating the activation of a defense mechanism against GRBV, a plant response already described for grapevine leafroll associated virus infection on the transcriptome level. Last but not least, we identified some other microorganisms belonging to the grapevine leaf microbiota, two bacterial species (Novosphingobium sp. Rr 2-17 and Methylobacterium) and one virus, Grapevine rupestris stem pitting associated virus.
Project description:Plant response to insect feeding appears to be highly specific with regard to the organisms in the system. Here, we report on the interaction between grapevine Vitis vinifera plants and a phloem-feeding insect pest, the vine mealybug Planococcus ficus. Plants were exposed to P. ficus for periods of 6 hours and 96 hours, after which they were analysed for gene expression levels using microarrays and quantitative real-time PCR (qPCR). Both methods showed that grapevine displayed only a minimal response to mealybug feeding at the transcript level at both time periods. Intermediate grapevine exposure times (24, 48 and 72 hours) to P. ficus feeding were investigated using qPCR analysis of ten additional genes associated with known plant defense responses. Results showed that only a single gene, pathogenesis-related protein 1, was differentially expressed after 48 hours of mealybug feeding. During the course of mealybug feeding, however, a number of other genes were significantly up- or down-regulated at certain time points. Thus, it appears as if grapevine responds minimally to feeding by P. ficus as well as within a very narrow time period. The relative lack of grapevine plant defense mechanisms may be a result of the feeding strategies of mealybugs.
Project description:As virus diseases cannot be controlled by traditional plant protection methods the risk of their spread have to be minimized on vegetatively propagated plants, such as grapevine. Metagenomics approaches used for virus diagnostics, offer a unique opportunity to reveal the presence of all viral pathogens in the investigated plant, why their usage can reduce the risk of using infected material for a new plantation. Here we used a special field, deep sequencing of virus derived small RNAs, of this high throughput method for virus diagnostics and determined viromes of vineyards in Hungary. With NGS of virus derived small RNAs we could detect not only the viruses tested routinely, but also new ones, which have never been described in Hungary before. Virus presence didn’t correlated with the age of the plantation, moreover phylogenetic analysis of the identified virus isolates suggests that infections mostly caused by the usage of infected propagating material. Our results, validated by other molecular methods, highlighted further questions to be answered before these method can be introduced as a routine, reliable test for grapevine virus diagnostics.
Project description:To understand the fruit changes and mechanisms involved in the compatible grapevine-virus interaction, we analyzed the berry transcriptome in two stages of development (veraison and ripening) in the red wine cultivar Cabernet Sauvignon infected with Grapevine leaf-roll-associated virus-3 (GLRaV-3). Analysis of global gene expression patterns indicate incomplete berry maturation in infected berries as compared to uninfected fruit suggesting viral infection interrupts the normal berry maturation process. PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Andrea Vega. The equivalent experiment is VV28 at PLEXdb. GLRaV-3 virus-infected, developmental stage: Veraison(3-replications); GLRaV-3 virus-infected, developmental stage: Ripening(3-replications); Virus-free, developmental stage: Veraison(4-replications); Virus-free, developmental stage: Ripening(4-replications)
Project description:Purpose and strategy: Grapevine fanleaf virus (GFLV) causes variable symptoms in most vineyards worldwide. To better understand GFLV-grapevine interactions in relation to symptom development, field and greenhouse trials were conducted with a grapevine genotype that exhibits distinct symptoms in response to a severe and a mild strain of GFLV. Results: After validation of the infection status of the experimental vines by high throughput sequencing, the transcriptomic and metabolomic profiles in plants infected with the two viral strains were tested and compared by RNA-Seq and LC-MS, respectively, in the differentiating grapevine genotype. In vines infected with the severe GFLV strain, 1,023 genes, among which some are implicated in the regulation of the hypersensitive-type response, were specifically de-regulated, and a higher accumulation of resveratrol and phytohormones was observed. Interestingly, some experimental vines restricted the virus to the rootstock and remained symptom-less. Our results suggest that GFLV induces a strain- and cultivar-specific defense reaction similar to a hypersensitive reaction. This type of defense leads to a severe stunting phenotype in some grapevines whereas others are resistant. This work is the first evidence of a hypersensitive-like reaction in grapevine during virus infection. Conclusion: Our results suggest that GFLV induces a strain- and cultivar-specific defense reaction similar to a hypersensitive reaction. This type of defense leads to a severe stunting phenotype in some grapevines whereas others are resistant. This work is the first evidence of a hypersensitive-like reaction in grapevine during virus infection.
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.