Real-time RT-PCR (TaqMan®) assays for the detection of viruses associated with Rugose wood complex of grapevine

New Host Plant Species of Grapevine Virus A Identified with Vector-Mediated Infections

Grapevine virus A (GVA) is an economically important virus and a member of the genus Vitivirus (family Betaflexiviridae) that causes a range of symptoms with qualitative and quantitative effects on grape production. Wild and domesticated species of Vitis, including hybrids used as rootstocks, are considered important natural hosts of GVA. Mechanical transmission to some herbaceous plant species, graft transmission, and vector transmission from grape to grape by various mealybugs and soft scale insects have been reported. Under laboratory and greenhouse conditions, this study demonstrates the transmission of GVA from grapes to alternative hosts by the vine mealybug (Planococcus ficus). Results of ELISA, end-point one-step RT-PCR, and real-time RT-PCR, and in some cases electron microscopy and genome sequencing, confirmed successful transmission to three new plant species commonly found in Croatian vineyards: velvetleaf (Abutilon theophrasti), redroot pigweed (Amaranthus retroflexus), and field poppy (Papaver rhoeas), along with Chenopodium murale and the previously known host Nicotiana benthamiana, with variable infection rates. Depending on the host species, symptoms in the form of leaf reddening, yellow spots, reduced growth of lateral shoots, systemic vein clearing, foliar deformation and rugosity, and dwarfism were observed in GVA-infected plants, whereas no symptoms were observed in infected plants of A. theophrasti. Reverse transmission from these new hosts to grapevines by Pl. ficus was not successful. These results confirm four new GVA host species and open new research venues.

High-Throughput Sequencing of Grapevine in Mexico Reveals a High Incidence of Viruses including a New Member of the Genus Enamovirus

This is the first viral metagenomic analysis of grapevine conducted in Mexico. During the summer of 2021, 48 plants displaying virus-like symptoms were sampled in Queretaro, an important grapevine-producing area of Mexico, and analyzed for the presence of viruses via high-throughput sequencing (HTS). The results of HTS were verified by real-time RT-PCR following a standardized testing scheme (Protocol 2010). Fourteen different viruses were identified, including grapevine asteroid mosaic-associated virus (GAMaV), grapevine Cabernet Sauvignon reovirus (GCSV), grapevine fanleaf virus (GFLV), grapevine fleck virus (GFkV), grapevine Pinot gris virus (GPGV), grapevine red globe virus (GRGV), grapevine rupestris stem pitting-associated virus (GRSPaV), grapevine rupestris vein feathering virus (GRVFV), grapevine Syrah virus 1 (GSyV-1), grapevine virus B (GVB), and grapevine leafroll-associated viruses 1, 2, 3, 4 (GLRaV1, 2, 3, 4). Additionally, divergent variants of GLRaV4 and GFkV, and a novel Enamovirus-like virus were discovered. This is the first report of GAMaV, GCSV, GLRaV4, GPGV, GRGV, GRVFV, and GSyV-1 infecting grapevines in Mexico; the impact of these pathogens on production is unknown.

Biology and Ultrastructural Characterization of Grapevine Badnavirus 1 and Grapevine Virus G

The biological characteristics of grapevine viruses, such as their transmission and host range, are important for the adoption of successful prophylaxis strategies. The aim of this study was to investigate the traits of two newly described grapevine viruses widely distributed in Croatia, grapevine badnavirus 1 (GBV-1) and grapevine virus G (GVG). The vine mealybug (Planoccocus ficus) proved to be a vector of GBV-1 and GVG capable of vine-to-vine transmission with overall experimental transmission rates of 61% and 14.6%, respectively. Transmission was also demonstrated by grafting, with an overall transmission rate of 53.8% for GBV-1 and 100% for GVG, as well as by green grafting using the T-budding technique. Symptoms of GBV-1 and GVG were not observed on the woody cylinders of the indicators LN 33, Kober 5BB, 110 Richter and cvs. Chardonnay and Cabernet Sauvignon. Seed transmission and mechanical transmission were not confirmed. Electron microscopy revealed accumulation of GBV-1 particles and viroplasms in the cytoplasm, but no alternations of the cell structure. Infection with GVG revealed the proliferation of tonoplast-associated vesicles inside phloem cells and cell wall thickening.

Metagenomic Analysis of Ampelographic Collections of Dagestan Revealed the Presence of Two Novel Grapevine Viruses

In this study, we analyzed the virome of 73 grape samples from two Dagestan ampelographic collections in Russia using high-throughput sequencing of total RNAs. Fourteen viruses and four viroids were identified, with one to eleven of them detected in each plant. For the first time in Russia, we identified grapevine leafroll-associated virus 7 and grapevine Kizil Sapak virus. A total of 206 genomes of viruses and viroids were obtained, and their phylogenetic analysis was carried out. The de novo assembly and tblastx analysis allowed us to obtain contigs of a novel (+) ssRNA genome of a plant virus from the genus Umbravirus, which was tentatively named grapevine umbra-like virus (GULV), as well as contigs of a novel dsDNA pararetrovirus from the genus Caulimovirus, which was tentatively named grapevine pararetrovirus (GPRV). Complete genomes of these viruses were obtained and used for Sequence Demarcation Tool (SDT) analysis and phylogeny studies. GULV and GPRV were detected in 16 and 33 germplasm samples from the Dagestan collections, respectively.

Incidence and Genetic Diversity of Grapevine Virus G in Croatian Vineyards

Grapevine virus G (GVG) is a recently discovered vitivirus infecting grapevines. Historically, viruses in the genus Vitivirus have been associated with the grapevine rugose wood disease. Based on new and previously reported GVG isolates, primers and probes were developed for real-time RT-PCR. The developed assay successfully detected the virus in infected plants during dormancy and the growing season. A field study of 4327 grapevines from Croatian continental and coastal wine-growing regions confirmed the presence of GVG in 456 (~10.5%) grapevines from three collection plantations and 77 commercial vineyards, with infection rates ranging from 2% to 100%. Interestingly, the virus was confirmed only in vines considered to be Croatian autochthonous cultivars, but not in introduced cultivars. A 564-nucleotide long portion of the coat protein gene from previously known and newly characterized GVG isolates had nucleotide and amino acid identities ranging from 89% to 100% and from 96.8% to 100%, respectively. Phylogenetic analysis revealed five distinct groups, with isolates originating from the same site being close to each other, indicating possible local infection. The information presented in this manuscript sets the stage for future studies to better understand the ecology and epidemiology of GVG and the possible need for inclusion in certification schemes.

Development of a one-step RT-qPCR assay for the detection of Grapevine leafroll-associated virus 7

Grapevine leafroll disease (GLD) is one of the most economically important viral diseases of grapevines. GLD is caused by a complex of several ssRNA (+) viruses referred to as Grapevine leafroll-associated viruses (GLRaVs). To date, five different GLRaV species have been identified. One of those species, GLRaV-7, was first reported from a symptomless white-fruited wine grape cultivar from Albania. Since its discovery, GLRaV-7 has been reported from 14 countries. Although serological assays have been developed to detect GLRaV-7, commercially available antibodies produce high background signals making them unsuitable for regulatory testing. Furthermore, while molecular detection assays have been shown to be more sensitive when compared to the serological assays, published molecular assays, except the one Reverse Transcription-quantitaive Polymerase Chain Reaction (RT-qPCR) assay based on heat shock protein 70 homologue (HSP70h) gene, have been reported to be inadequate in detecting all reported isolates of GLRaV-7. Availability of multiple assays provides flexibility to diagnostic laboratories in cases where the chosen assay fails to detect a strain or an isolate of a pathogen due to variation in its targeted region or where additional confirmation of the results is required. In this study, we developed a sensitive and specific RT-qPCR assay, based on a region of p61 gene of GLRaV-7, which detected all available isolates.

Detection, Transmission, and Characterization of Grapevine Virus H in Croatia

A survey of recently discovered vitiviruses was performed on 113 Croatian autochthonous grapevine cultivars from the national collection “Jazbina” using one-step RT-PCR. The presence of grapevine virus H (GVH) was confirmed in nine (7.9%) cultivars and grapevine virus G in eight (7.1%), while the presence of grapevine viruses I and J were not detected. GVH was transmitted by the vine mealybug (Planococcus ficus) from a source plant to grapevine seedlings with a 10.5% transmission rate using a combination of 10 first and second instars per plant with 48 and 72 h of acquisition and inoculation access period, respectively. Transmission correlated with the presence of grapevine leafroll-associated virus 3 (GLRaV-3) in the GVH-source plant and recipient seedlings. No alternative GVH host was identified. A comparison of 356 nt fragments of the RdRP and CP coding regions showed nucleotide identity between the Croatian GVH isolates in the range of 95.5–99.2% and 97.5–99.4% and amino acid identity between 95.8 and 100% and between 98.3 and 100%, respectively. Comparison with foreign isolates revealed nucleotide sequence similarity in the RdRP and CP between 94 and 100% and between 97.7–100%, respectively. To the best of our knowledge, this is the first report of GVH in Croatia and the first identification of the vine mealybug as a vector of GVH.

Phylogenetic analysis of viruses in Tuscan Vitis vinifera sylvestris (Gmeli) Hegi

The health status of the native grapevine Vitis vinifera subsp. sylvestris (Gmeli) Hegi in natural areas in Europe has received little attention. A survey was carried out on wild grapevines in Tuscany (Italy), where isolates of the Grapevine rupestris stem pitting virus (GRSPaV), Grapevine leafroll-associated virus 1 and 3 (GLRaV-1 and GLRaV-3) and Grapevine virus A (GVA) were detected. The complete coat protein (CP) region of these isolates was sequenced to investigate the relationship of the viral variants from Tuscan wild grapevines with isolates from different geographical origins. According to the phylogenetic analyses, GLRaV-1 and GLRaV-3 isolates from Tuscan wild grapevines clustered with isolates from cultivated grapevines with nucleotide sequence identities ranging from 66% to 87% and from 72.5% to 99% respectively, without any correlation between the distribution and geographical origin. Conversely, GRSPaV and GVA isolates clustered together with other Italian isolates from V. vinifera with nucleotide sequence identities ranging from 71.14% to 96.12% and from 73.5% to 92%, respectively. Our analysis of the whole amino acid sequences revealed a high conservation level for the studied proteins explained by a selective pressure on this genomic region, probably due to functional constraints imposed on CP, such as specific interactions with cellular receptors in the insect vectors necessary for successful transmission. In addition, analyses of genetic recombination suggest no significant point mutations that might play a significant role in genetic diversification. The dN/dS ratio also estimated a low number of non-silent mutations, highlighting the purifying selective pressure. The widespread distribution of the Rugose wood complex (GRSPaV and GVA associated disease) in comparison with the Grapevine Leafroll associated viruses (GLRaV-1 and -3) could explain the major geographical correlation found for the viral variants detected in Tuscany.

Viral Diversity in Autochthonous Croatian Grapevine Cultivars

A survey was conducted on nine autochthonous grapevine cultivars grown along the Croatian coastal region. In total, 48 vines (44 from germplasm collection, 4 from vineyards) originating from 23 sites were tested for 26 viruses using molecular methods. Results revealed high infection rates with Grapevine leafroll-associated virus 3 (GLRaV-3); Grapevine virus A (GVA, both 91.7%); Grapevine fleck virus (GFkV, 87.5%); and Grapevine rupestris stem pitting-associated virus (GRSPaV, 83.3%). Other detected viruses were: Grapevine fanleaf virus (GFLV); Grapevine leafroll-associated viruses 1, 2, and strains of 4 (GLRaV-1, GLRaV-2, GLRaV-4); Grapevine viruses B, D, F (GVB, GVD, GVF); Grapevine red globe virus (GRGV); Grapevine vein feathering virus (GVFV); Grapevine Syrah virus 1 (GSyV-1); and Grapevine Pinot gris virus (GPGV). No virus-free vine was found. Mixed infections were determined in all vines, the number of viruses in a single vine ranged from three to nine. GLRaV-3 variant typing confirmed presence of group I, II, and III. Four vines with leaf deformation and mottling were positive for GPGV. Seven viruses (GLRaV-4-like group, GVD, GVE, GVF, GRGV, GSyV-1, and GVFV) were detected for the first time in Croatia. This survey confirmed the deteriorated sanitary status of autochthonous Croatian grapevine cultivars.

A field based detection method for Rose rosette virus using isothermal probe-based Reverse transcription-recombinase polymerase amplification assay

Rose rosette disease, caused by Rose rosette virus (RRV; genus Emaravirus) is a major threat to the rose industry in the U.S. The only strategy currently available for disease management is early detection and eradication of the infected plants, thereby limiting its potential spread. Current RT-PCR based diagnostic methods for RRV are time consuming and are inconsistent in detecting the virus from symptomatic plants. Real-time RT-qPCR assay is highly sensitive for detection of RRV, but it is expensive and requires well-equipped laboratories. Both the RT-PCR and RT-qPCR cannot be used in a field-based testing for RRV. Hence a novel probe based, isothermal reverse transcription-recombinase polymerase amplification (RT-exoRPA) assay, using primer/probe designed based on the nucleocapsid gene of the RRV has been developed. The assay is highly specific and did not give a positive reaction to other viruses infecting roses belonging to both inclusive and exclusive genus. Dilution assays using the in vitro transcript showed that the primer/probe set is highly sensitive, with a detection limit of 1 fg/μl. In addition, a rapid technique for the extraction of viral RNA (<5min) has been standardized from RRV infected tissue sources, using PBS-T buffer (pH 7.4), which facilitates the virus adsorption onto the PCR tubes at 4°C for 2min, followed by denaturation to release the RNA. RT-exoRPA analysis of the infected plants using the primer/probe indicated that the virus could be detected from leaves, stems, petals, pollen, primary roots and secondary roots. In addition, the assay was efficiently used in the diagnosis of RRV from different rose varieties, collected from different states in the U.S. The entire process, including the extraction can be completed in 25min, with less sophisticated equipments. The developed assay can be used with high efficiency in large scale field testing for rapid detection of RRV in commercial nurseries and landscapes.

A Synoptic Analysis of the Temporal and Spatial Aspects of Grapevine Leafroll Disease in a Historic Napa Vineyard and Experimental Vine Blocks

Five Grapevine leafroll-associated virus 3 (GLRaV-3) epidemics were analyzed utilizing a standardized approach to robustly characterize the temporal and spatial parameters. Published data included in the analysis are from Spain, New Zealand, and Napa Valley, CA together with new data from a historic vineyard in Napa Valley, CA. Linear regression analyses of logit-transformed incidence data indicated a maximum average increase of 11% per year in disease incidence, with considerable variation among locations. Spatial analyses, including distribution fitting, examination of the effective sample size, and evaluation of the parameters of the binary power law fitted to variance data for disease incidence, indicated a high degree of consistency among the data sets. In all cases, except at very low disease incidence, a high degree of spatial aggregation was noted, with evidence that the degree of aggregation varied as a function of mean disease incidence. The polyetic dynamics of disease follow a logistic-like pattern over multiple seasons, consistent with limitation by inoculum availability (infected vines) at low incidence and limitation by disease-free vines at high incidence.

Comparative detection of a large population of grapevine viruses by TaqMan® RT-qPCR and ELISA

Grapevine (Vitis spp.) can be infected by numerous viruses that are often widespread and of great economic importance. Reliable detection methods are necessary for sanitary selection which is the only way to partly control grapevine virus diseases. Biological indexing and ELISA are currently the standard methods for screening propagation material, and PCR-methods are becoming increasingly popular. Due to the diversity of virus isolates, it is essential to verify that the tests allow the detection of the largest possible virus populations. We developed three quadruplex TaqMan^® RT-qPCR assays for detecting nine different viruses that cause considerable damage in many vineyards world-wide. Each assay is designed to detect three viruses and the grapevine Actin as an internal control. A large population of grapevines from diverse cultivars and geographic location was tested for the presence of nine viruses: Arabis mosaic virus (ArMV), Grapevine fleck virus (GFkV), Grapevine fanleaf virus (GFLV), Grapevine leafroll-associated viruses (GLRaV-1, -2, -3), Grapevine rupestris stem pitting-associated virus (GRSPaV), Grapevine virus A (GVA), and Grapevine virus B (GVB). In general, identical results were obtained with multiplex TaqMan^® RT-qPCR and ELISA although, in some cases, viruses could be detected by only one of the two techniques.

Alterations in primary and secondary metabolism in Vitis vinifera 'Malvasía de Banyalbufar' upon infection with Grapevine leafroll-associated virus 3

Plant defense mechanisms against pathogens result in differential regulation of various processes of primary and secondary metabolism. Imaging techniques, such as fluorescence imaging and thermography, are very valuable tools providing spatial and temporal information about these processes. In this study, effects of Grapevine leafroll-associated virus 3 (GLRaV-3) on grapevine physiology were analyzed in pot-grown asymptomatic plants of the white cultivar Malvasía de Banyalbufar. The virus triggered changes in the activity of photosynthesis and secondary metabolism. There was a decrease in the photorespiratory intermediates glycine and serine in infected plants, possibly as a defense response against the infection. The content of malate, which plays an important role in plant metabolism, also decreased. These results correlate with the increased non-photochemical quenching found in infected plants. On the other hand, the concentration of flavonols (represented by myricetin, kaempferol and quercetin derivatives) and hydroxycinnamic acids (which include derivatives of caffeic acid) increased following infection by the virus. These compounds could be responsible for the increase in multicolor fluorescence F440 (blue fluorescence) and F520 (green fluorescence) on the leaves, and changes in the fluorescence parameters F440/F680, F440/F740, F520/F680, F520/F740 and F680/F740. The combined analysis of chlorophyll fluorescence kinetics and blue-green fluorescence emitted by phenolics could constitute disease signatures allowing the discrimination between GLRaV-3 infected and non-infected plants at very early stage of infection, prior to the development of symptoms.

Interactive effects of grapevine leafroll-associated virus 3 (GLRaV-3) and water stress on the physiology of Vitis vinifera L. cv. Malvasia de Banyalbufar and Giro-Ros

Among several biotic and abiotic stress combinations, interaction between drought and pathogen is one of the most studied combinations in some crops but still not in grapevine. In the present work, we focused on the interaction effects of biotic (GLRaV-3) and abiotic (drought) stresses on grapevine photosynthetic metabolism on two cultivars (cvs. 'Malvasia de Banyalbufar and Giro-Ros'). Non-infected and GLRaV-3 infected potted plants were compared under water stress conditions (WS) and well-watered (WW) conditions. Under WW condition, the results showed that photosynthesis (AN) in both cultivars was decreased by the presence of GLRaV-3. The stomatal conductance (gs) was the main factor for decreasing AN in Malvasia, meanwhile reductions in Giro-Ros were closely related to decreases in gm. The observed differences in gm between both cultivars might result from variation in their leaf anatomical, Giro-Ros having higher values of gm and leaf porosity (in all treatments). Moderate water deficit resulted in a closure of stomata and a decrease in gm accompanied by a decrease in AN in both cultivars. The maximum velocity of carboxylation (Vcmax) and electron transport rate (Jmax) were also reduced under water stress. Moreover, the combined stress resulted in a reduction of most physiological parameters compared to healthy irrigated plants. However, no considerable differences were found between non-infected and virus infected (GLRaV-3) plants under water stress. Most of the results could be explained by the difference of virus concentration between cultivars and treatments.

Reverse transcription-PCR for phytoplasma detection utilizing crude sap extractions

Phytoplasmas are routinely detected by nucleic acid-based techniques. These approaches rely on enriched phytoplasma DNA extracts of good quality, following labor intensive and time-consuming purification protocols. Here we describe a very rapid, specific, sensitive, and reliable method for flavescence dorée phytoplasma detection, based on real-time Taqman(®) reverse transcription-PCR of the 16S rRNA. The protocol is particularly useful for large-scale screening of vineyards and nurseries, pathogen surveys, and field epidemiological studies.

Wogonin and related natural flavones overcome tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) protein resistance of tumors by down-regulation of c-FLIP protein and up-regulation of TRAIL receptor 2 expression

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent that kills various tumor cells without damaging normal tissues. However, many cancers remain resistant to TRAIL. To overcome TRAIL resistance, combination therapies using sensitizers of the TRAIL pathway would be an efficacious approach. To investigate potential sensitizers of TRAIL-induced apoptosis, we used TRAIL-resistant human T cell leukemia virus type 1 (HTLV-1)-associated adult T cell leukemia/lymphoma (ATL) cells as a model system. So far, HTLV-1-associated ATL is incurable by presently known therapies. Here, we show that wogonin and the structurally related natural flavones apigenin and chrysin break TRAIL resistance in HTLV-1-associated ATL by transcriptional down-regulation of c-FLIP, a key inhibitor of death receptor signaling, and by up-regulation of TRAIL receptor 2 (TRAIL-R2). This effect is mediated through transcriptional inhibition of the p53 antagonist murine double minute 2 (Mdm2), leading to an increase in p53 levels and, consequently, to up-regulation of the p53 target gene TRAIL-R2. We also show that these flavones can sensitize to TNFα- and CD95-mediated cell death. Furthermore, we show that wogonin, apigenin, and chrysin also enhance TRAIL-mediated apoptosis in other human cancer cell lines including breast cancer cell line MDA-MB-231, colon cancer cell line HT-29, hepatocellular carcinoma cell line HepG2, melanoma cell line SK-MEL-37, and pancreatic carcinoma cell line Capan-1 by the same mechanism. Thus, our study suggests the potential use of these flavones as an adjuvant for TRAIL-mediated anticancer therapy.

A novel synthetic quantification standard including virus and internal report targets: application for the detection and quantification of emerging begomoviruses on tomato

BACKGROUND

Begomovirus is a genus of phytopathogenic single-stranded DNA viruses, transmitted by the whitefly Bemisia tabaci. This genus includes emerging and economically significant viruses such as those associated with Tomato Yellow Leaf Curl Disease, for which diagnostic tools are needed to prevent dispersion and new introductions. Five real-time PCRs with an internal tomato reporter gene were developed for accurate detection and quantification of monopartite begomoviruses, including two strains of the Tomato yellow leaf curl virus (TYLCV; Mld and IL strains), the Tomato leaf curl Comoros virus-like viruses (ToLCKMV-like viruses) and the two molecules of the bipartite Potato yellow mosaic virus. These diagnostic tools have a unique standard quantification, comprising the targeted viral and internal report amplicons. These duplex real-time PCRs were applied to artificially inoculated plants to monitor and compare their viral development.

RESULTS

Real-time PCRs were optimized for accurate detection and quantification over a range of 2 × 10(9) to 2 × 10(3) copies of genomic viral DNA/μL for TYLCV-Mld, TYLCV-IL and PYMV-B and 2 × 10(8) to 2 × 10(3) copies of genomic viral DNA/μL for PYMV-A and ToLCKMV-like viruses. These real-time PCRs were applied to artificially inoculated plants and viral loads were compared at 10, 20 and 30 days post-inoculation. Different patterns of viral accumulation were observed between the bipartite and the monopartite begomoviruses. Interestingly, PYMV accumulated more viral DNA at each date for both genomic components compared to all the monopartite viruses. Also, PYMV reached its highest viral load at 10 dpi contrary to the other viruses (20 dpi). The accumulation kinetics of the two strains of emergent TYLCV differed from the ToLCKMV-like viruses in the higher quantities of viral DNA produced in the early phase of the infection and in the shorter time to reach this peak viral load.

CONCLUSIONS

To detect and quantify a wide range of begomoviruses, five duplex real-time PCRs were developed in association with a novel strategy for the quantification standard. These assays should be of a great interest for breeding programs and epidemiological surveys to monitor viral populations.

Wogonin and related natural flavones are inhibitors of CDK9 that induce apoptosis in cancer cells by transcriptional suppression of Mcl-1

The wogonin-containing herb Scutellaria baicalensis has successfully been used for curing various diseases in traditional Chinese medicine. Wogonin has been shown to induce apoptosis in different cancer cells and to suppress growth of human cancer xenografts in vivo. However, its direct targets remain unknown. In this study, we demonstrate for the first time that wogonin and structurally related natural flavones, for example, apigenin, chrysin and luteolin, are inhibitors of cyclin-dependent kinase 9 (CDK9) and block phosphorylation of the carboxy-terminal domain of RNA polymerase II at Ser². This effect leads to reduced RNA synthesis and subsequently rapid downregulation of the short-lived anti-apoptotic protein myeloid cell leukemia 1 (Mcl-1) resulting in apoptosis induction in cancer cells. We show that genetic inhibition of Mcl-1 or CDK9 expression by siRNA is sufficient to mimic flavone-induced apoptosis. Pull-down and in silico docking studies demonstrate that wogonin directly binds to CDK9, presumably to the ATP-binding pocket. In contrast, wogonin does not inhibit CDK2, CDK4 and CDK6 at doses that inhibit CDK9 activity. Furthermore, we show that wogonin preferentially inhibits CDK9 in malignant compared with normal lymphocytes. Thus, our study reveals a new mechanism of anti-cancer action of natural flavones and supports CDK9 as a therapeutic target in oncology.

Vitis californica and Vitis californica × Vitis vinifera Hybrids are Hosts for Grapevine leafroll-associated virus-2 and -3 and Grapevine virus A and B

Vitis and non-Vitis spp. surrounding nine Napa Valley vineyards were surveyed for Grapevine leafroll-associated virus (GLRaV)-1 to -5 and -9, Grapevine virus A (GVA), Grapevine virus B (GVB), and Grapevine virus D (GVD). Vitis spp. from three riparian areas not adjacent to vineyards were also included. DNA fingerprinting and probability analyses indicated that the Vitis samples consisted primarily of Vitis californica followed by V. californica × V. vinifera hybrids. Single and mixed infections of GLRaV-2, -3, GVA, or GVB were detected by conventional or quantitative reverse-transcription polymerase chain reaction in 6 of the 66 V. californica and 11 of the 19 V. californica × V. vinifera hybrids. GLRaV-1, -4, -5, -9, and GVD were not detected. Phylogenetic analysis of GLRaV-2 and -3 partial coat protein gene nucleotide sequences indicated that the isolates from V. californica and V. californica × V. vinifera hybrids were closely related to isolates from V. vinifera.

Fast preparation of fungal DNA for PCR screening

Rapid DNA preparation for the quick screening is highly demanded in diverse research fields. Here, we combined an extraction buffer and heat treatment to generate DNA templates from yeast and filamentous fungal materials for PCR. This method may be widely applicable to diverse fungal species in clinical and basic studies.

Response of the Vitis vinifera L. cv. 'Nebbiolo' proteome to Flavescence dorée phytoplasma infection

Flavescence dorée is a serious phytoplasma disease affecting grapevine in several European countries. We studied the interaction of Flavescence dorée phytoplasma with its natural plant host by monitoring the effects of infection on the protein expression profile. Among the 576 analyzed spots, 33 proteins were differentially regulated in infected grapevines. Grouping into MIPS functional categories showed proteins involved in metabolism (21%), energy processes (9%), protein synthesis (3%), protein fate (18%), cellular transport and transport routes (6%), cell defense and virulence (42%). Among the differentially regulated proteins, we selected six targets (thaumatin I, thaumatin II, osmotin-like protein, plant basic secretory protein, AAA(+) Rubisco activase and proteasome α5 subunit) and we analyzed their expression by quantitative RT-PCR on samples collected in 2008 and 2009 in several vineyards in Piedmont region, Italy. There was a positive correlation between mRNA and protein expression for most of the genes in both the years. We discuss the involvement of these proteins in the specific response to phytoplasma infection. To our knowledge, this work is the first to investigate the response of the grapevine proteome to Flavescence dorée phytoplasma infection, and provides reference protein profiles for future comparative proteomic and genomic studies.