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Grapevine fanleaf virus (GFLV) strains B844 and F13 induce contrasting phenotypes on Vitis vinifera cv. Gewurztraminer (Gw) vines. (a) plants were photographed in spring 2011. (b) Gw plants and fruits photographed in June and September 2012, respectively, show the drastic effect of strain B844. (c) ‘Chardonnay’ (Ch) plants and fruits photographed in June and September 2012, respectively, show similar effects of the two GFLV strains. (d–h) Ch and Gw vines infected with GFLV strains F13 and B844 were monitored for cluster number (d), cluster weight (e), berry number (f), berry weight (g), and pruning wood weight (h), from 2012 to 2014. Virus accumulation (i) was estimated by semiquantitative DAS-ELISA from 2013 to 2015. Error bars = standard deviation. Statistically significant differences (nonparametric Mann–Whitney test) are indicated with asterisks (* p < 0.05, ** p < 0.01, *** p < 0.005).
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Virus infection of plants can result in various degrees of detrimental impacts and disparate symptom types and severities. Although great strides have been made in our understanding of the virus-host interactions in herbaceous model plants, the mechanisms underlying symptom development are poorly understood in perennial fruit crops. Grapevine fanle...
Citations
... The viral infection causing mosaic, mottling, and curling of leaves had a detrimental effect on soybean growth. Mosaics and mottling cause chloroplast deficiency in the initial stages of plant development, destruction of chlorophyll, and degeneration of chloroplasts in older leaves [35] . In addition, chloroplast deformation related to the diversion of carbon flux in leaf tissue and significant loss of chloroplast function impact the yield loss [36] . ...
Mosaic and mottling viruses threaten soybean production worldwide, including Indonesia. The aims of this study were to characterize mosaic and mottling viruses from natural and artificially infected soybeans and other hosts and investigate the response of twelve soybean cultivars to potential resistance sources that can be incorporated into soybean breeding programs. Upon mechanical inoculation, seed transmission, and Bemisia tabaci and Aphis glycine vector transmission, mosaic, mottling, and local necrotic lesions developed within 6 to 14 days on soybeans and 11 to 27 days on alternate hosts. Disease incidence and severity in the vector-transmitted experiment were the highest compared with mechanical and seed transmissions. Out of the 12 soybean cultivars, five were categorized as resistant, six as moderately resistant, and one as susceptible. In this study, we observed that resistant cultivars performed with a higher number and weight of pods and better growth parameters such as plant height, number of fertile nodes, and biomass than moderately resistant and susceptible cultivars. Correlation analysis revealed a weak to moderate negative relationship between disease severity and all growth parameters and yields. Identification of causal symptoms using RT-PCR showed negative results for cowpea mild mottle virus (CpMMV) in all tested plants except Capsicum annuum. All soybean samples, including those from mechanical inoculation, seed testing, and vectors, were positive for potyvirus. Samples from the alternate hosts of Vigna unguiculata, Chenopodium amaranticolor, and Capsicum annuum were also positive for potyvirus. The remaining samples from Cucurbitaceae, Cucumis sativus, showed negative results for both targeted viruses. This study suggested that potyvirus infected Indonesian soybeans and selected alternate hosts that showed mosaic and mottling symptoms. The existence of potyvirus vectors, particularly in the virus-endemic areas, should be considered to reduce viral transmission in soybean plantations, considering the severe symptoms and disease incidence caused by these vectors.
... The Vitis metabolites were extracted from the homogenised cells with 100% methanol and analysed by ultra high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) at INRAE Grand-Est Colmar, France (Duan et al., 2015;Khattab et al., 2021). Here, the chromatographic separation was carried out using a Nucleodur C18 Htec column (150 × 2 mm, 1.8 μm particle size; Macherey-Nagel) as described previously (Martin et al., 2021). The stilbenes were detected by comparing their mass spectra and retention times and compared to those of the corresponding commercial standards. ...
In a consequence of global warming, grapevine trunk diseases (GTDs) have become a pertinent problem to viticulture, because endophytic fungi can turn necrotrophic upon host stress killing the plant. In Neofusicoccum parvum Bt-67, plant-derived ferulic acid makes the fungus release Fusicoccin aglycone triggering plant cell death. Now, we show that the absence of ferulic acid lets the fungus secrete 4-hydroxyphenylacetic acid (4-HPA), mimicking the effect of auxins on grapevine defence and facilitating fungal spread. Using Vitis suspension cells, we dissected the mode of action of 4-HPA during defence triggered by the bacterial cell-death elicitor, harpin. Early responses (cytoskeletal remodelling and calcium influx) are inhibited, as well as the expression of Stilbene Synthase 27 and phytoalexin accumulation. In contrast to other auxins, 4-HPA quells transcripts for the auxin conjugating GRETCHEN HAGEN 3. We suggest that 4-HPA is a key component of the endophytic phase of N. parvum Bt-67 preventing host cell death. Therefore, our study paves the way to understand how GTDs regulate their latent phase for successful colonisation, before turning necrotrophic and killing the vines.
... 65,66 It is possible that this metabolite pathway identified in N. benthamiana is unique to wildtype GFLV-GHu, as a direct metabolite profile was documented in infected grapevines. 67 Genes related to oxidative burst were also differentially expressed in symptomatic plants, suggesting that host immune response could be involved in the development of vein clearing symptoms caused by wildtype GFLV-GHu. Future work focusing on collecting quantitative data to measure oxidative stress metabolites in infected plants (i.e., peroxide, O 3 − ) would be more informative to this end. ...
Viruses can elicit varying types and severities of symptoms during plant host infection. We investigated changes in the proteome and transcriptome of Nicotiana benthamiana plants infected by grapevine fanleaf virus (GFLV) with an emphasis on vein clearing symptom development. Comparative, time-course liquid chromatography tandem mass spectrometry and 3' ribonucleic acid sequencing analyses of plants infected by two wildtype GFLV strains, one symptomatic and one asymptomatic, and their asymptomatic mutant strains carrying a single amino acid change in the RNA-dependent RNA polymerase (RdRP) were conducted to identify host biochemical pathways involved in viral symptom development. During peak vein clearing symptom display at 7 days post-inoculation (dpi), protein and gene ontologies related to immune response, gene regulation, and secondary metabolite production were overrepresented when contrasting wildtype GFLV strain GHu and mutant GHu-1EK802GPol. Prior to the onset of symptom development at 4 dpi and when symptoms faded away at 12 dpi, protein and gene ontologies related to chitinase activity, hypersensitive response, and transcriptional regulation were identified. This systems biology approach highlighted how a single amino acid of a plant viral RdRP mediates changes to the host proteome (∼1%) and transcriptome (∼8.5%) related to transient vein clearing symptoms and the network of pathways involved in the virus-host arms race.
... Indeed, Ch. quinoa has also been used in heterografting experiments to transfer a given virus or a virus isolate to a healthy grapevine rootstock (Bass and Vuittenez 1979). This technique was successfully applied to produce a population of infected grapevines used in comparative phenotypic, transcriptomic and metabolomic studies of distinct GFLV strains on different V. vinifera cultivars (Martin et al. 2021). Producing this experimental plant population using infected herbaceous hosts was more efficient and faster than graft-inoculations of woody indicators or nematode-mediated transmissions. ...
Herbaceous plant hosts are essential to grapevine virus research. Such plants offer numerous advantages as experimental hosts of viruses over Vitis species, the natural hosts. They grow faster, have a shorter generation time, and require little maintenance in the greenhouse or growth chamber in comparison with the natural hosts for which experiments are more technically challenging and last substantially longer. Local, pseudo-local, systemic, and pseudo-systemic herbaceous plants have been identified among infected experimental hosts and used for advances in grapevine virology. The discovery pipeline made possible by alternative model hosts has had a tremendous impact on the field. Species of Chenopodium, Nicotiana, Phaseolus, Cucumis, Petunia, and Cuscuta have served to document mechanical or graft transmission of grapevine viruses, fulfill Koch’s postulates, study pathogenesis, examine movement, determine replication, purify and observe virus particles, image virions at the atomic level, develop diagnostic assays, characterize vector-mediated transmission, assess defense and counter defense mechanisms, and engineer resistance, among many other critical milestones. Alternative hosts continue to have intrinsic value for discoveries, although many technologies, including high-throughput sequencing, have largely outperformed their use for diagnostic applications. This review focuses on the critical role of herbaceous plant hosts in important discoveries on the biology of grapevine viruses.
... Qualitative phenotypic traits belonging to three kinds of symptoms (discolouration of leaves, deformation of leaves and stunting of plants) were evaluated and recorded every year in June, the best time to visualize GFLV symptoms in the northern hemisphere. The same symptom scoring as described in our recent article was used [13]: discolouration and deformations of leaves were estimated on individual vines and scored from 0 to 4 (0: absence of symptom, 1: 1 to 25%, 2: 26-50%, 3: 51-75%, and 4: 76-100% of symptomatic leaves) ( Figure S2). Similarly, vine stunting was assessed and scored from 0 to 4 (0: no stunting, 1: low, 2: medium, 3: strong, 4: very strong stunting). ...
... Hence, the overall symptoms and the fruit yields were strongly negatively correlated (Table S4). Such association between severe GFLV symptoms and poor productive performance of the vine is consistent with results obtained in an experimental vineyard [13]. However, to our knowledge, it is the first time that viral symptomatology and agronomic performances were simultaneously considered in fanleaf-diseased commercial vineyards, illustrating a statistically supported negative correlation [9]. ...
... By comparing GFLV-infected with GFLV-free vines, GFLV always had a negative impact on fruit yield, reaching a 40% reduction on average for M+ vines but as high as 65% for the S+ category. This range of crop losses due to GFLV is in accordance with those previously described [9,13]. Given the interest of M+ category vines as candidates for cross-protection, a gain in production close to 82% in comparison to the S+ vines category was noted. ...
Fanleaf degeneration is a complex viral disease of Vitis spp. that detrimentally impacts fruit yield and reduces the productive lifespan of most vineyards worldwide. In France, its main causal agent is grapevine fanleaf virus (GFLV). In the past, field experiments were conducted to explore cross-protection as a management strategy of fanleaf degeneration, but results were unsatisfactory because the mild virus strain negatively impacted fruit yield. In order to select new mild GFLV isolates, we examined two old ‘Chardonnay’ parcels harbouring vines with distinct phenotypes. Symptoms and agronomic performances were monitored over the four-year study on 21 individual vines that were classified into three categories: asymptomatic GFLV-free vines, GFLV-infected vines severely diseased and GFLV-infected vines displaying mild symptoms. The complete coding genomic sequences of GFLV isolates in infected vines was determined by high-throughput sequencing. Most grapevines were infected with multiple genetically divergent variants. While no specific molecular features were apparent for GFLV isolates from vines displaying mild symptoms, a genetic differentiation of GFLV populations depending on the vineyard parcel was observed. The mild symptomatic grapevines identified during this study were established in a greenhouse to recover GFLV variants of potential interest for cross-protection studies.
... This is particularly interesting in the case of GFLV for which the best classification rates in the PLS-DA model were calculated at the T3-T4 measurements against the backdrop of a sharp viral load reduction in the same period. Nonetheless, this result can be assessed in the light of a "load metabolic effect" induced by virus infection in this crop along the seasonal progression (Gambino et al., 2012;Chitarra et al., 2018;Martin et al., 2021). Moreover, the results here reported support previous observations of a higher metabolic impact on grapevine plants exerted by GFLV compared to GRSPaV, corroborating the concept of a co-evolution of GRSPaV with this crop (Gambino et al., 2012) possibly resulting from the long-lasting presence of a hard to eradicate pathogen in grapevine. ...
Grapevine is one of the most cultivated fruit plant among economically relevant species in the world. It is vegetatively propagated and can be attacked by more than 80 viruses with possible detrimental effects on crop yield and wine quality. Preventive measures relying on extensive and robust diagnosis are fundamental to guarantee the use of virus-free grapevine plants and to manage its diseases. New phenotyping techniques for non-invasive identification of biochemical changes occurring during virus infection can be used for rapid diagnostic purposes. Here, we have investigated the potential of Raman spectroscopy (RS) to identify the presence of two different viruses, grapevine fan leaf virus (GFLV) and grapevine rupestris stem pitting-associated virus (GRSPaV) in Vitis vinifera cv. Chardonnay. We showed that RS can discriminate healthy plants from those infected by each of the two viruses, even in the absence of visible symptoms, with accuracy up to 100% and 80% for GFLV and GRSPaV, respectively. Chemometric analyses of the Raman spectra followed by chemical measurements showed that RS could probe a decrease in the carotenoid content in infected leaves, more profoundly altered by GFLV infection. Transcriptional analysis of genes involved in the carotenoid pathway confirmed that this biosynthetic process is altered during infection. These results indicate that RS is a cutting-edge alternative for a real-time dynamic monitoring of pathogens in grapevine plants and can be useful for studying the metabolic changes ensuing from plant stresses.
The monograph "Virus, phytoplasma and bacterial diseases of the grapevine" presents the phytoplasmas, viruses and bacteria that cause diseases of the grapevine and reveals the approaches and methods for their diagnosis. Damage to the buds, leaves, shoots, roots, fronds and bunches caused the death of the plants and sometimes the destruction of entire vineyards. Maintaining the vines in good health and obtaining high and quality grape yields is impossible only by applying high agricultural techniques. It is necessary to carry out plant protection, which, in addition to protecting the vine from diseases and enemies, also observes the protection of nature from pollution with pesticides. Its implementation is possible only with a good knowledge of viral, bacterial and phytoplasma diseases and their vectors, as well as modern directions and future strategy in plant protection. Tactics in the fight against enemies should be aimed at regulating them below a certain level, since their complete destruction is practically impossible. This approach makes it possible for beneficial species of insects and mites to multiply in vineyards, which, together with climatic factors, are often able to keep enemies below the thresholds of economic harm without human intervention.
The measures against grapevine diseases is extremely prophylactic. For the implementation of the new diagnostic methods in plant protection, it is necessary that the vine plantations are under constant surveillance. Knowing the signs of diseased plants is an important condition for performing differential diagnostics, and the new methods for detecting and confirming viral, bacterial and phytoplasma diseases for improving the phytosanitary condition of the grapevine.
The monographic work is based on the author's theoretical statements and empirical research in wine-growing regions of Bulgaria and on vine planting material from wine-growing regions in France, Italy, Serbia, Germany and Austria.
The monograph "Virus, Phytoplasma and Bacterial Diseases of the Grapevine" is aimed at specialists in the study of grapevine infections, grape growers, students and a wide range of readers who are interested in the cultivation of grapevines.
The European Green Deal aims to reduce the pesticide use, notably by developing biocontrol products to protect crops from diseases. Indeed, the use of significant amounts of chemicals negatively impact the environment such as soil microbial biodiversity or groundwater quality, and human health. Grapevine (Vitis vinifera) was selected as one of the first targeted crop due to its economic importance and its dependence on fungicides to control the main damaging diseases worldwide: grey mold, downy and powdery mildews. Chitosan, a biopolymer extracted from crustacean exoskeletons, has been used as a biocontrol agent in many plant species, including grapevine, against a variety of cryptogamic diseases such as downy mildew (Plasmopara viticola), powdery mildew (Erysiphe necator) and grey mold (Botrytis cinerea). However, the precise molecular mechanisms underlying its mode of action remain unclear: is it a direct biopesticide effect or an indirect elicitation activity, or both? In this study, we investigated six chitosans with diverse degrees of polymerization (DP) ranging from low to high DP (12, 25, 33, 44, 100, and 470). We scrutinized their biological activities by evaluating both their antifungal properties and their abilities to induce grapevine immune responses. To investigate their elicitor activity, we analyzed their ability to induce MAPKs phosphorylation, the activation of defense genes and metabolite changes in grapevine. Our results indicate that the chitosans with a low DP are more effective in inducing grapevine defenses and possess the strongest biopesticide effect against B. cinerea and P. viticola. We identified chitosan with DP12 as the most efficient resistance inducer. Then, chitosan DP12 has been tested against downy and powdery mildews in the vineyard trials performed during the last three years. Results obtained indicated that a chitosan-based biocontrol product could be sufficiently efficient when the amount of pathogen inoculum is quite low and could be combined with only two fungicide treatments during whole season programs to obtain a good protection efficiency. On the whole, a chitosan-based biocontrol product could become an interesting alternative to meet the chemicals reduction targeted in sustainable viticulture.
Grapevine downy mildew, caused by the oomycete Plasmopara viticola, is an important disease present in grapevine-growing areas worldwide. Current strategies of control rely on the use of fungicides, which is harmful for the environment and human health. Using resistant varieties is an environmentally friendly alternative to fungicides. Modification of plant susceptibility genes may lead to recessive resistance and CRISPR/Cas9 editing offers an opportunity to modify plant genes. Downy mildew resistant 6 (DMR6) from Arabidopsis thaliana is a negative regulator of plant immunity whose loss of function confers resistance to downy mildew. In grapevine, DMR6 is present in two copies, named VvDMR6-1 and VvDMR6-2. Here we describe the editing of VvDMR6-1 using CRISPR/Cas9 and show that edited plants are less susceptible to P. viticola and exhibit increased levels of salicylic acid.
Plant proteins with domains rich in leucine repeats play important roles in detecting pathogens and triggering defense reactions, both at the cellular surface for pattern-triggered immunity and in the cell to ensure effector-triggered immunity. As intracellular parasites, viruses are mostly detected intracellularly by proteins with a nucleotide binding site and leucine-rich repeats but receptor-like kinases with leucine-rich repeats, known to localize at the cell surface, have also been involved in response to viruses. In the present review we report on the progress that has been achieved in the last decade on the role of these leucine-rich proteins in antiviral immunity, with a special focus on our current understanding of the hypersensitive response.
