Search

Eutypa dieback of grapevine is a trunk disease that impacts vineyard productivity worldwide. Grape germplasm is typically evaluated for resistance to Eutypa dieback through controlled inoculations in the greenhouse, although the high level of replication required of this approach (40 plants per genotype) can limit the total number of genotypes evaluated. An alternative approach is to evaluate naturally infected genotypes in the field. We rated the incidence and severity of vines with the diagnostic leaf symptoms of Eutypa dieback and the incidence of mortality among such vines of 973 Vitis vinifera accessions (planted in duplicate) at the US Department of Agriculture, National Clonal Germplasm Repository in Davis, CA, USA, which is maintained as a living collection for grape research. Across 3 years and spanning a total of 5 years (2011, 2013, and 2015), 120 accessions had leaf symptoms in one or more years ("susceptible accessions"). Courbu blanc [Davis Vitis identification tag (DVIT) 2313], Frankenthal blanc (DVIT 2115), and Pinot gris (DVIT 0907) were the only accessions with leaf symptoms each year. Accessions with the most severe leaf symptoms (a rating of 5 points) were Chasselas Napoleon (DVIT 0375) and Queen of the Vineyard (DVIT 0496). We identified susceptible accessions--namely, those related to 'Chasselas' and 'Muscat'--with a shared genetic background, based on a previous single nucleotide polymorphism genotyping effort of the collection. Especially for grapevine, a long-lived perennial that is meant to produce a crop for decades, knowledge of susceptible accessions and their pedigrees can help inform breeding programs and studies on the host response to infection. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTDs) are currently considered some of the most important challenges for viticulture, curtailing vineyard longevity and productivity in nearly every raisin, table and wine grape production region in California and worldwide. Pruning wounds provide the main entry point for fungal pathogens responsible for these diseases; pathogens enter the wounds following precipitation events. The aim of this study was to evaluate the efficacy of selected chemical and experimental biological fungicides for protection of pruning wounds against two of the most common and virulent fungal pathogens causing GTDs: Eutypa lata and Neofusicoccum parvum. This study was conducted on sauvignon blanc at the UC Davis Department of Plant Pathology Field Station. Results showed that several chemical and biological fungicides, notably the chemical fungicide Luna Sensation, the biofungicide Vintec and a combination of the biofungicides Bio-Tam and CrabLife Powder, provided significant protection against at least one of the two canker pathogens used in this study. However, the majority of products tested did not provide simultaneous control of both E. lata and N. parvum pathogens, highlighting the continuing challenge of controlling GTDs.

The species Eutypa lata is one of the most critical phytopathogenic fungi that presents a threat to vineyards by causing significant economic damage. This grapevine disease is hazardous because there is no adequate chemical protection, so after its progression, there is a decrease in yield and dieback of parts or whole infected shoots. There are also no grapevine cultivars resistant to this disease. For these reasons, in this paper, testing of the susceptibility of a pair of grapevine cultivars to this disease was carried out. The testing was performed under semicontrolled conditions and included six of the most economically essential grapevine cultivars in Serbia (Riesling italico, Cabernet Sauvignon, Cardinal, Rkaziteli, Pinot noir, and Prokupac). Testing was performed using 14 isolates of E. lata isolated in Serbia and two control isolates obtained from the INRA. For specific detection of isolates of Eutypa spp. included in the experiment, a specific pair of primers, Lata 1/ Lata 2.2, was applied, and an amplicon of the expected size of approximately 385 bp was established in all isolates. In the conditions of the set experiment, of all of the domestic and foreign-tested grapevine cultivars, the local cultivar Prokupac showed greater resistance to the isolates. In contrast, the cultivars Riesling italico, Cabernet Sauvignon and Cardinal, Pinot noir showed sensitivity to the isolates of E. lata, but not to the same extent as the cultivar Rkaziteli, which proved to be susceptible. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases cause substantial economic loss worldwide. Grapevines are susceptible to infection by the causal agents when pruning during dormancy coincides with rainfall. The ascospores of Eutypa lata, the causal agent of the trunk disease Eutypa dieback, are released by fruiting bodies following rainfall and infect fresh wounds in woody tissue. Wound-colonising microbes have the potential to compete with the pathogen but the effect on such microbes of exposure of wounds on grapevines to rainfall has not been investigated. The presence of microbes in grapevine pruning wounds, both exposed to and sheltered from rainfall, was investigated at weekly intervals for one month following pruning. Surface disinfected tissue was cultured and the predominant microbes identified by morphology and by Sanger sequencing. Epicoccum nigrum, Aureobasidium pullulans, Alternaria and Cladosporium spp. were the predominant fungi, E. lata was not isolated and bacteria were isolated only rarely. The number of microbes found in rainfall-exposed wounds was greater than in those protected from rainfall and, of the above-mentioned, Epicoccum nigrum was predominant. Three of these species competed for space with E. lata when co-cultured in vitro. [ABSTRACT FROM AUTHOR]

The species Eutypa lata is one of the most critical phytopathogenic fungi that presents a threat to vineyards by causing significant economic damage. This grapevine disease is hazardous because there is no adequate chemical protection, so after its progression, there is a decrease in yield and dieback of parts or whole infected shoots. There are also no grapevine cultivars resistant to this disease. For these reasons, in this paper, testing of the susceptibility of a pair of grapevine cultivars to this disease was carried out. The testing was performed under semicontrolled conditions and included six of the most economically essential grapevine cultivars in Serbia (Riesling italico, Cabernet Sauvignon, Cardinal, Rkaziteli, Pinot noir, and Prokupac). Testing was performed using 14 isolates of E. lata isolated in Serbia and two control isolates obtained from the INRA. For specific detection of isolates of Eutypa spp. included in the experiment, a specific pair of primers, Lata 1/Lata 2.2, was applied, and an amplicon of the expected size of approximately 385 bp was established in all isolates. In the conditions of the set experiment, of all of the domestic and foreign-tested grapevine cultivars, the local cultivar Prokupac showed greater resistance to the isolates. In contrast, the cultivars Riesling italico, Cabernet Sauvignon and Cardinal, Pinot noir showed sensitivity to the isolates of E. lata, but not to the same extent as the cultivar Rkaziteli, which proved to be susceptible.

Grapevine trunk diseases (GTDs) are currently considered some of the most important challenges for viticulture, curtailing vineyard longevity and productivity in nearly every raisin, table and wine grape production region in California and worldwide. Pruning wounds provide the main entry point for fungal pathogens responsible for these diseases; pathogens enter the wounds following precipitation events. The aim of this study was to evaluate the efficacy of selected chemical and experimental biological fungicides for protection of pruning wounds against two of the most common and virulent fungal pathogens causing GTDs: Eutypa lata and Neofusicoccum parvum. This study was conducted on sauvignon blanc at the UC Davis Department of Plant Pathology Field Station. Results showed that several chemical and biological fungicides, notably the chemical fungicide Luna Sensation, the biofungicide Vintec and a combination of the biofungicides Bio-Tam and CrabLife Powder, provided significant protection against at least one of the two canker pathogens used in this study. However, the majority of products tested did not provide simultaneous control of both E. lata and N. parvum pathogens, highlighting the continuing challenge of controlling GTDs.

The potential influence of different types of light on the growth and sporulation of Eutypa lata isolates was assessed, and detection at the molecular level was also performed. By applying in vitro observations, the influence of different types of light was monitored, (24 h exposure to UV light; alternating 12 h UV and 12 h darkness; alternating 12 h artificial fluorescent light and 12 h darkness), on the radial growth and sporulation of the anamorphic stage of three isolates of Eutypa lata fungus (EL117, EL153 and EL199) by comparison with two reference isolates of Eutypa lata, BX1.10 and 8F, obtained from the INRA, France. After the molecular detection using of the specific primer pair Lata 1/ Lata 2.2, all the studied isolates were found to belong to the species Eutypa lata (syn. Eutypa armeniacae), anamorph Libertella blepharis. It was also found that the most suitable type of light for radial growth and sporulation of the studied isolates is exposure to 24 h UV light for 30 days. [ABSTRACT FROM AUTHOR]

In a multi-year experiment set up in vitro, virulence testing was conducted on 14 isolates of Eutypa lata (EL17, EL27, EL29, EL30, EL150, EL151, EL152, EL153, EL154, EL155, EL156, EL157, EL158, EL199) and two reference isolates BX1.10 and 8F obtained from the Institute National de la Recherche Agronomique, INRA, France, previously confirmend on morphological and molecular level. Namely, inoculation of unrooted and rooted grapevine plants of the Cabernet Sauvignon cultivar was performed in two separate experiments. After reading the results in both experiments, all studied isolates showed virulence to varying degrees towards inoculated cuttings of the Cabernet Sauvignon cultivar. All tested isolates showed pathogenicity to Cabernet Sauvignon to a high degree, also different isolates in both experiments showed different degrees of aggressiveness to the tested grapevine cultivar. The analysis of the obtained results shows that the final outcome of both experiments is identical. In both experiments the isolates EL150, EL152, BX1.10, EL156, EL27, EL151 EL154 and 8F proved to be the most aggressive. Based on the obtained results, we can conclude that both methods are suitable and reliable for testing pathogenicity od different grapevine cultivars to the fungus E. lata. [ABSTRACT FROM AUTHOR]

Eutypa dieback and Esca are serious fungal grapevine trunk diseases (GTDs). Eutypa dieback is caused by Eutypa lata (Elata), and is often associated Phaeoacremonium minimum (Pmin), and Phaeomoniella chlamydospora (Pch) which are also important contributors to Esca disease. Understanding the complex pathogenesis mechanisms used by these causative fungi may potentially lead targeted treatments for GTDs in the future. Elata has been reported as a wood decay "soft rot" fungus and understanding of Elata's pathogenesis chemistries can aid in controlling GTDs. Recent work that suggests that Pmin and Pch may contribute to pathogenesis by stimulating hydroxyl radical generation via secretion of low molecular weight phenolic metabolites. Building on these findings, we tested a hypothesis that antioxidants and chelators, and biocontrol agents that have been reported to secrete antioxidants and low molecular weight chelators, may inhibit the growth and activity of these fungi. Butylated hydroxy anisole (BHA) and butylated hydroxytoluene (BHT) were tested as antioxidant/chelators. BHA was found to be a highly effective control measure for the three pathogenic fungi tested at concentrations >0.5 mM. The biocontrol species Bacillus subtilis and Hypocrea (Trichoderma) atroviride were also tested, with both H. atroviride and B. subtilis effectively inhibiting growth of the three GTD fungi. • Salicylic acid and EDTA prevent iron reduction and hydroxyl radical (•OH) production by metabolites produced by GTD fungi. • BHA, BHT, salicylic acid, and EDTA block mediated Fenton chemistry, reducing •OH generation by fungal metabolites. • BHA, EDTA, and Bacillus subtilis were effective in inhibiting fungal growth involved in Esca and Eutypa dieback disease. [ABSTRACT FROM AUTHOR]

Background and Aims: Grapevine trunk diseases, caused by fungal pathogens that infect pruning wounds, pose a major threat to the sustainability of vineyards throughout the world. Pruning wound protectants can control infection, but little is known about the optimal timing of application of protectants following pruning. In this study, the timing of fungicide application to pruning wounds was evaluated to assess curative and preventative effects. Methods and Results: To assess curative control, on the day of pruning, wounds were inoculated with ascospores of Eutypa lata or conidia of Neofusicoccum luteum followed 1, 3 or 6 days later by application of the fungicides tebuconazole, pyraclostrobin or fluazinam. To assess preventative control, fresh pruning wounds were treated with the same fungicides, then inoculated 1, 6 or 14 days later. The fungicides provided curative control of both pathogens for up to 6 days and preventative control of E. lata for up to 6 days and of N. luteum for up to 14 days. Conclusion: These results indicate that fungicides can provide control of trunk disease pathogens when applied up to 6 days after wound infection, and continue to protect wounds for up to 14 days after application. Significance of the Study: Current recommendations to protect grapevine pruning wounds from trunk disease pathogens are to apply protectants within 24 h of pruning. This study suggests that a single application of the fungicides tested 6 days after pruning may provide up to 3 weeks of wound protection, thereby offering improved flexibility in managing grapevine trunk disease. [ABSTRACT FROM AUTHOR]

Background and Aims: The trunk disease Eutypa dieback causes financial losses in grapegrowing. The influence of two pruning methods, namely cane and spur pruning, on the incidence and severity of Eutypa dieback in Shiraz grapevines was investigated as pruning wounds are a major point of entry for the causal agent Eutypa lata. Methods and Results: The surface area of pruning wounds in 11 Shiraz vineyards in the Barossa Valley was measured. The incidence of Eutypa dieback in all of those vineyards and disease severity in two vineyards were determined. The surface area of wounds exposed by cane pruning was 21–33% smaller than for spur pruning. The incidence of foliar symptoms and the severity of disease were 50 and 38% lower, respectively, in cane‐pruned than in spur‐pruned vines. For cane‐pruned vines, an increase in bud number retained was associated with a smaller increase in wound surface area than for spur‐pruned vines. Conclusions: The incidence and severity of Eutypa dieback were greatest where the total surface area was largest rather than the size of individual cuts exposed by pruning. Significance of the Study: Limiting the total surface area exposed by pruning in plantings of Shiraz vines is likely to reduce the incidence and severity of Eutypa dieback. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTDs) are progressively affecting vineyard longevity and productivity worldwide. To be able to understand and combat these diseases, we need a different concept of the signals exchanged between the grapevine and fungi than the well-studied pathogen-associated molecular pattern and effector concepts. We screened extracts from fungi associated with GTDs for their association with basal defence responses in suspension cells of grapevine. By activity-guided fractionation of the two selected extracts, O -methylmellein was identified as a candidate modulator of grapevine immunity. O -Methylmellein could not induce immune responses by itself (i.e. does not act as an elicitor), but could amplify some of the defence responses triggered by the bacterial elicitor flg22, such as the induction level of defence genes and actin remodelling. These findings show that Eutypa lata , exemplarily selected as an endophytic fungus linked with GTDs, can secrete compounds that act as amplifiers of basal immunity. Thus, in addition to elicitors that can trigger basal immunity, and effectors that down-modulate antibacterial basal immunity, once it had been activated, E. lata seems to secrete a third type of chemical signal that amplifies basal immunity and may play a role in the context of consortia of mutually competing microorganisms. [ABSTRACT FROM AUTHOR]

Botryosphaeria spp. recently have been identified as important grapevine pathogens worldwide. To date, Botryosphaeria rhodina has been the only species associated with cankers on Vitis vinifera in California. A field survey of 166 vineyards in 21 counties was conducted in order to determine the occurrence of other Botryosphaeria spp. in California. In all, 1,735 samples of cankered trunks, cordons, and spurs were collected. Botryosphaeria spp. were the most common fungi isolated from grapevine cankers in California. Morphological identification along with phylogenetic analysis of the internal transcribed spacer region (ITS1-5.8S-ITS2) of the nuclear ribosomal DNA (rDNA) and a partial sequence of the beta-tubulin gene showed that at least seven Botryosphaeria spp. occur on grapevines in California: B. australis, B. dothidea, B. lutea, B. obtusa, B. parva, B. rhodina, and B. stevensii. Botryosphaeria spp. were found in grapevine cankers in all grape-growing regions surveyed in California, whereas incidence and distribution varied with location. Grapevine cankers in California have been associated mainly with Eutypa dieback. However, the frequent recovery of Botryosphaeria spp. from cankers in this study indicates that the role of these fungi in grapevine health needs to be more carefully considered.

Eutypa lata is the causal agent of eutypa dieback, one of the most destructive grapevine trunk disease that causes severe economic losses in vineyards worldwide. This fungus causes brown sectorial necrosis in wood which affect the vegetative growth. Despite intense research efforts made in the past years, no cure currently exists for this disease. Host responses to eutypa dieback are difficult to address because E. lata is a wood pathogen that causes foliar symptoms several years after infection. With the aim to classify the level of susceptibility of grapevine cultivars to the foliar symptoms caused by E. lata, artificial inoculations of Merlot, Cabernet Sauvignon, and Ugni Blanc were conducted over 3 years. Merlot was the most tolerant cultivar, whereas Ugni Blanc and Cabernet Sauvignon exhibited higher and differential levels of susceptibility. We took advantage of their contrasting phenotypes to explore their defense responses, including the activation of pathogenesis-related (PR) genes, oxylipin and phenylpropanoid pathways and the accumulation of stilbenes. These analyses were carried out using the millicell system that enables the molecular dialogue between E. lata mycelium and grapevine leaves to take place without physical contact. Merlot responded to E. lata by inducing the expression of a large number of defense-related genes. On the contrary, Ugni Blanc failed to activate such defense responses despite being able to perceive the fungus. To gain insight into the role of carbon partitioning in E. lata infected grapevine, we monitored the expression of plant genes involved in sugar transport and cleavage, and measured invertase activities. Our results evidence a coordinated up-regulation of VvHT5 and VvcwINV genes, and a stimulation of the cell wall invertase activity in leaves of Merlot elicited by E. lata, but not in Ugni Blanc. Altogether, this study indicates that the degree of cultivar susceptibility is associated with the activation of host defense responses, including extracellular sucrolytic machinery and hexose uptake during the grapevine/E. lata interaction. Given the role of these activities in governing carbon allocation through the plant, we postulate that the availability of sugar resources for either the host or the fungus is crucial for the outcome of the interaction.

During a survey from 2004 to 2016, symptoms of grapevine dieback were observed in six vineyards in Serbia. Symptoms initially appeared as small, chlorotic, and necrotic spots along the rim of the leaves, deformation of leafs, and the appearance of shortened shoots, often with the so-called zigzag internodes. Over time, partial or complete dying of the vines developed. Symptomatic samples were collected and submitted to laboratory analysis. Based on the morphological characterization, the isolated fungus was initially identified as belonging to Eutypa species. Pathogenicity tests showed that 47 selected isolates caused tissue necrosis around the site of inoculation, chlorosis, and deformation of the leaves, along with the appearance of tiny, necrotic spots on the periphery of the leaf that fall off over time. Inoculated cuttings were stunted, dwarf-like with zigzag internodes. Molecular identification was done with sequence and phylogenetic analysis of ITS, TUB, and RPB2 genomic regions. Based on the phylogenetic analysis, all isolated fungi were determined as Eutypa lata. [ABSTRACT FROM AUTHOR]

The experiment was established in the greenhouse during the two years. The grapevine cultivars used in experiment were Riesling blanc, Chardonnay, Banatski muskat and Gamay noir. The susceptibility of grapevine cultivars to the isolate of the fungi Eutypa lata, causing agent of eutyposis, was analysed. One isolate EL17 was used in the experiment. The highest susceptibility was found in Riesling blanc, Banatski muskat and Gamay noir cultivars, while Chardonnay cultivar was less susceptible to the isolates of fungus Eutypa lata. [ABSTRACT FROM AUTHOR]

Eutypa lata is the causal agent of eutypa dieback, one of the most destructive grapevine trunk disease that causes severe economic losses in vineyards worldwide. This fungus causes brown sectorial necrosis in wood which affect the vegetative growth. Despite intense research efforts made in the past years, no cure currently exists for this disease. Host responses to eutypa dieback are difficult to address because E. lata is a wood pathogen that causes foliar symptoms several years after infection. With the aim to classify the level of susceptibility of grapevine cultivars to the foliar symptoms caused by E. lata , artificial inoculations of Merlot, Cabernet Sauvignon, and Ugni Blanc were conducted over 3 years. Merlot was the most tolerant cultivar, whereas Ugni Blanc and Cabernet Sauvignon exhibited higher and differential levels of susceptibility. We took advantage of their contrasting phenotypes to explore their defense responses, including the activation of pathogenesis-related (PR) genes, oxylipin and phenylpropanoid pathways and the accumulation of stilbenes. These analyses were carried out using the millicell system that enables the molecular dialogue between E. lata mycelium and grapevine leaves to take place without physical contact. Merlot responded to E. lata by inducing the expression of a large number of defense-related genes. On the contrary, Ugni Blanc failed to activate such defense responses despite being able to perceive the fungus. To gain insight into the role of carbon partitioning in E. lata infected grapevine, we monitored the expression of plant genes involved in sugar transport and cleavage, and measured invertase activities. Our results evidence a coordinated up-regulation of VvHT5 and VvcwINV genes, and a stimulation of the cell wall invertase activity in leaves of Merlot elicited by E. lata , but not in Ugni Blanc. Altogether, this study indicates that the degree of cultivar susceptibility is associated with the activation of host defense responses, including extracellular sucrolytic machinery and hexose uptake during the grapevine/ E. lata interaction. Given the role of these activities in governing carbon allocation through the plant, we postulate that the availability of sugar resources for either the host or the fungus is crucial for the outcome of the interaction. [ABSTRACT FROM AUTHOR]

Vitis vinifera is affected by many diseases every year, depending on causal agents, susceptibility of cultivars, and climate region. Some are caused by a single agent, such as gray mold caused by Botrytis cinerea or powdery mildew caused by Erysiphe necator. Others result from the actions of a complex of pathogens such as grapevine trunk diseases (GTDs). GTDs are presently among the most devastating diseases in viticulture worldwide because both the economic losses and the long-term sustainability of vineyards are strongly affected. The complexity of GTDs results from the diversity of associated fungi, the undetermined period of latency within the vine (asymptomatic status), the erratic foliar symptom expression from one year to the next, and. probably correlated with all of these points, the lack of efficient strategies to control them. Distinct methods can be beneficial to improve our knowledge of GTDs. In vitro bioassays with cell suspensions, calli, foliar discs, full leaves, or plantlets, and in vivo natural bioassays with cuttings, grafted plants in the greenhouse, or artificially infected ones in the vineyard, can be applied by using progressive integrative levels of in vitro and in vivo, depending on the information searched. In this review, the methods available to understand GTDs are described in terms of experimental procedures, main obtained results, and deliverable prospects. The advantages and disadvantages of each model are also discussed. [ABSTRACT FROM AUTHOR]

Little is known about effects of salinity and flooding on plant symbionts, including baldcypress trees (Taxodium distichum), the dominant trees in many swamp ecosystems in the southeastern US. In this study, we characterize the culturable fungal and bacterial endophytes in the roots and leaves of baldcypress trees at four sites with varying levels of salinity and flooding regimes in southeastern Louisiana. Both salinity and flooding (water level) contributed to endophytic community composition of leaves and roots. We found that diversity and endophyte isolation frequency were higher in roots than in leaves, with leaf bacteria being almost negligible. Our study demonstrates a connection between environmental variables, plant symbionts, and a key restoration species. This work may help in predicting future outcomes of sea level rise for endophytes communities in baldcypress and other wetland plants. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTD) are one of the most important constraints for grapevine and wine production worldwide. Most of the published studies on these diseases in Europe relate to the major vine growing regions mainly located in southern Europe. This is the first study of GTD incidence and associated fungal pathogens in Czech vineyards, as an example of the north-eastern European grape-growing region. Annual incidence of GTD symptoms in vineyards of cvs. ‘Chardonnay’ and ‘Cabernet Sauvignon’ in three Czech locations was surveyed. On average, 3.7% of the ‘Chardonnay’ plants showed GTD symptoms and 0.7% suddenly collapsed each year. Within the ‘Cabernet Sauvignon’ vineyards, 10.1% of the plants showed GTD symptoms and 2.5% suddenly collapsed. Several fungal pathogens were associated with the suddenly collapsed grapevines, and the most frequent was Phaeomoniella chlamydospora (77% of analyzed grapevines), followed by Eutypa lata (62%), Diaporthe ampelina (31%), Botryosphaeria dothidea (15%) and Fomitiporia mediterranea (15%).

Grapevine trunk diseases (GTD) are one of the most important constraints for grapevine and wine production worldwide. Most of the published studies on these diseases in Europe relate to the major vine growing regions mainly located in southern Europe. This is the first study of GTD incidence and associated fungal pathogens in Czech vineyards, as an example of the north-eastern European grape-growing region. Annual incidence of GTD symptoms in vineyards of cvs. 'Chardonnay' and 'Cabernet Sauvignon' in three Czech locations was surveyed. On average, 3.7% of the 'Chardonnay' plants showed GTD symptoms and 0.7% suddenly collapsed each year. Within the 'Cabernet Sauvignon' vineyards, 10.1% of the plants showed GTD symptoms and 2.5% suddenly collapsed. Several fungal pathogens were associated with the suddenly collapsed grapevines, and the most frequent was Phaeomoniella chlamydospora (77% of analyzed grapevines), followed by Eutypa lata (62%), Diaporthe ampelina (31%), Botryosphaeria dothidea (15%) and Fomitiporia mediterranea (15%). [ABSTRACT FROM AUTHOR]

This study assessed the infection rates of different spore inoculum doses of the grapevine trunk pathogens Diplodia seriata, Phaeomoniella chlamydospora and Eutypa lata following artificial inoculation of pruning wounds. Potted vines of cv. Tempranillo were inoculated with doses ranging from 10 to 4000 conidia per wound of D. seriata and P. chlamydospora and led to recovery percentages of 10–100% for D. seriata and 16–94% for P. chlamydospora. Eutypa lata, when inoculated onto wounds of vines in a mature vineyard (cv. Shiraz) and on detached canes (cv. Cabernet Sauvignon) with a dose range of 10 to 1000 ascospores per wound, led to recovery percentages of 17–95%. In the field assay, there was no difference in recovery from wounds that were exposed to single or double inoculations with the same total spore dose, or between canes that were harvested 7 or 11 months after inoculation. The results obtained in this study showed significant variability in pathogen recovery between trials, comparable with that reported previously, which suggests that factors such as pathogen virulence, environmental parameters and experimental conditions may influence the infection process. According to this study, in order to obtain optimal recovery percentages of 50–70% for robust evaluation of pruning wound treatments, dose ranges of 100-1000 conidia of D. seriata, 100–2000 conidia of P. chlamydospora, and 100–500 ascospores of E. lata per wound would be required.

Cell suspension cultures of Vitis vinifera cv. Dauphine berries were used to study the response to the vascular pathogen, Eutypa lata, in comparison with a biological control agent, Trichoderma atroviride, that was previously shown to be effective in pruning wound protection. The expression of genes coding for enzymes of the phenylpropanoid pathway and pathogenesis-related (PR) proteins was profiled over a 48-h period using quantitative reverse transcriptase PCR. The cell cultures responded to elicitors of both fungi with a hypersensitive-like response that lead to a decrease in cell viability. Similar genes were triggered by both the pathogen and biocontrol agent, but the timing patterns and magnitude of expression was dependent on the specific fungal elicitor. Culture filtrates of both fungi caused upregulation of phenylalanine ammonia-lyase ( PAL), 4-coumaroyl Co-A ligase ( CCo-A) and stilbene synthase ( STS), and a downregulation of chalcone synthase ( CHS) genes. The pathogen filtrate caused a biphasic pattern in the upregulation of PAL and STS genes which was not observed in cells treated with filtrates of the biocontrol agent. Analytical assays showed significantly higher total phenolic content and chitinolytic enzyme activity in the cell cultures treated with the T. atroviride filtrate compared to the pathogen filtrate. These results corresponded well to the higher expression of PAL and chitinase class IV genes. The response of the cell cultures to T. atroviride filtrate provides support for the notion that the wound protection by the biocontrol agent at least partially relies on the induction of grapevine resistance mechanisms. [ABSTRACT FROM AUTHOR]

Background and Aims Eutypa dieback is an economically important disease of grapevines and a major threat to vineyard longevity throughout the world. Developing effective preventative strategies offers the best means of control. In this study, pruning wound protectants and various spray applications were evaluated for their ability to prevent infection by ascospores of Eutypa lata. Methods and Results Fungicides and natural alternative treatments were applied by hand to grapevine pruning wounds in winter prior to inoculation with E. lata. In a series of greenhouse and field experiments, tebuconazole, pyraclostrobin, fluazinam, garlic extract and lactoferrin significantly reduced infection. A range of tractor-driven sprayers was used to apply tebuconazole to pruning wounds, and those which provided good coverage reduced infection by E. lata to a level similar to that when tebuconazole was applied with a paintbrush. Conclusion Eutypa dieback can be controlled with several fungicides and natural treatments. Tractor-driven sprayers, which by design or modification can efficiently deliver maximum possible coverage at high output rates, can be used for application of pruning wound treatments. Significance of the Study Results of this study contributed to registration of fungicides for use as pruning wound treatments to control E. lata in Australia. Demonstrating the ability of tractor-driven sprayers to apply treatments effectively has led to greater industry adoption of dormant treatments and may decrease the future impact of Eutypa dieback. [ABSTRACT FROM AUTHOR]

In grapevine, eutypa dieback is a disease induced by ascomyceta fungus, Eutypa lata. At present, eutypa dieback is considered as the most serious deterioration disease of grapevine. The external symptoms of this disease are most conspicuous during the first months of the annual growth cycle and include dwarfed shoots with smaller and necrotic leaves and unfavourable development of grapes. All these symptoms were still suggested an hormonal perturbation in grapevine organs. The aim of this work was to determine the effects of eutypa dieback on abscisic acid contents in flower buds, flowers, young berries, leaves and internodes of grapevine. This study was also performed to determine the relationship between this growth regulator and disease development. The study was performed using organs (1) from healthy vines, (2) healthy appearing organs from vines with one symptomless arm and one diseased arm, and (3) moderately and (4) strongly diseased organs. From flowers buds separated to bunch of grapes closed stages, free abscisic acid (ABA) and the glucose esters of this acid (ABA-GE) were analysed in Vitis vinifera L. cv. Cabernet Sauvignon which is sensitive to E. lata. In the healthy appearing organs, growth and development as well as water and ABA contents were not changed by eutypa dieback fungi. Whereas eutypa dieback induced a decrease of water content and the rate of growth increase in diseased organs. During all the period studied in leaves and since fruit set stage in the internodes, the ABA and ABA-GE contents were increased by eutypa dieback proportionally to symptoms. The ABA levels increase in leaves and internodes were not seem to be produced by ABA-GE hydrolysis since increase in ABA-GE levels were also observed in response to eutypa dieback. The maximum of ABA characterising grapevine flowers was delayed by eutypa dieback and their level was reduced with increasing symptoms severity. In flower buds, flowers and young berries, this disease induced a decrease of ABA-GE contents during all period studied proportionally to symptoms severity. The mycelium of two E. lata isolates cultured in Errikson and Petersson medium culture can synthesize ABA. A part of this growth regulator was diffused in medium culture. It was suggested that increase of ABA levels in diseased organs must have many origins: perturbation of (1) ABA-GE translation, (2) synthesis of ABA by grapevine caused by water stress and (3) synthesis of ABA by the fungi. The possible relationship between increased ABA content in the diseased organs and expression of eutypa dieback symptoms is discussed.

The phytopathogenic fungus Eutypa lata (Pers.: Fr.) Tul. and C. Tul., the causing agent of eutypa dieback, has been increasingly often identified in recent times as a cause of grapevine disease. It was first discovered and identified in Australian vineyards (Carter,1973), where it represented one of the most dangerous fungus pathogens of this plant. A few years later it was discovered in European vineyards as well. This polyfagous fungus,known originally as E. armeniaca (Honsf. & Carter), was first discovered on apricot, on which it caused the “gummosis disease”.In Serbia, Eutypa lata has not been determined officially. However, bearing in mind the form of its spreading (anemochory), as well as the fact that our country is a major producer of grape and fruit, we need to pay special attention to this dangerous pathogen since thereare indications that it is already present in our vineyards.During the period between 2003 and 2005, an inspection of a great number of vineyards in the areas of Vršac, Fruška Gora and Kruševac, was conducted. Many of them had grapevines with typical eutypa dieback symptoms. The aim of the inspection was to find grapevines with this disease, to mark them and take samples for laboratory analysis. Marking suspicious grapevines enabled us to monitor the volume of symptoms, as well as other changes on grapevines. Different colours were used for markings, according to the principle “same colour – same year” The procedure revealed that the average periodbetween early and mild disease symptoms and extreme changes, including withering of entire vines, was 2 to 3 years.The signs of eutypa dieback on diseased grapevines are manifested: on leaves in the form of chlorosis, twisting, necrosis of the edges, drying out and falling off; on shoots,where the shortening of internodia is noticable, as well as colour change and “zig-zag” distribution of internodes; on blossoms and clusters, where absence of flowering, partial bareness and irregular berry size are observed; and on trunks, where necrosis appears on the cross section in a typical “V” form.These studies also established that there is not a single grapevine plant with symptoms indicating eutypa dieback or a similar disease that is older than 8-10 years.The research results, based on examination and monitoring of disease development in the studied vineyards in previous years, indicate that the fungus Eutypa lata, the inducer of grapevine eutyposis, is most probably present in Serbia, and that our viticulture is facingyet another serious threat.In most European and other viticultural centers, highly specialized research teams are being organised to deal with the phenomenon of eutypa dieback, and its inducer Eutypa lata, which is more and more frequently classified as a top priority disease of wooden tissue,especially considering that the economic losses are very significant and occur in all vineyards,regardless of their location. Therefore, in order to prevent infection and fight the disease successfully, we need to take immediate measures of integral protection of grapevinewithout any delay.

Development of polyamines levels [Putrescine (Put), Spermidine (Spd), and Spermine (Spm)] was investigated in internodes of grapevine infected by eutypiosis fungus, Eutypa lata. The study was performed using (1) internodes from healthy vines, (2) apparently healthy internodes from vines with one arm symptomless and one diseased arm and (3) diseased internodes. Free polyamines (PAs: hydrochloric acid soluble fraction), conjugated polyamines (PAs-fpm: PAs covalently linked to molecules with low molecular weight like hydroxycinnamic acids) and bound polyamines (PAs-mm: covalently linked to macromolecules) were analysed in Vitis vinifera L. cv. Cabernet sauvignon, which is sensitive to eutypiosis. The internodes stunting induced by eutypiosis was accompanied by a decrease of free Put and free Spm contents between flower buds separated and fruit set stages. The same results were observed for PAs-mm but more slightly than free PAs. The Put-fpm and Spd-fpm levels increased in the apparently healthy internodes and decreased in diseased organs by Eutypa lata effect. The relationship between free PAs contents in the diseased internodes and their growth reduction, as well as the involvement of PAs-fpm on the grapevine response to Eutypa lata infection are discussed.

This study assessed the infection rates of different spore inoculum doses of the grapevine trunk pathogens Diplodia seriata, Phaeomoniella chlamydospora and Eutypa lata following artificial inoculation of pruning wounds. Potted vines of cv. Tempranillo were inoculated with doses ranging from 10 to 4000 conidia per wound of D. seriata and P. chlamydospora and led to recovery percentages of 10-100% for D. seriata and 16-94% for P. chlamydospora. Eutypa lata, when inoculated onto wounds of vines in a mature vineyard (cv. Shiraz) and on detached canes (cv. Cabernet Sauvignon) with a dose range of 10 to 1000 ascospores per wound, led to recovery percentages of 17-95%. In the field assay, there was no difference in recovery from wounds that were exposed to single or double inoculations with the same total spore dose, or between canes that were harvested 7 or 11 months after inoculation. The results obtained in this study showed significant variability in pathogen recovery between trials, comparable with that reported previously, which suggests that factors such as pathogen virulence, environmental parameters and experimental conditions may influence the infection process. According to this study, in order to obtain optimal recovery percentages of 50-70% for robust evaluation of pruning wound treatments, dose ranges of 100-1000 conidia of D. seriata, 100-2000 conidia of P. chlamydospora, and 100-500 ascospores of E. lata per wound would be required. [ABSTRACT FROM AUTHOR]

By HPLC analysis, we showed that myceliums of two Eutypa lata isolates cultivated in Enikson and Petersson medium culture synthesized polyamines (Putrescine, Spermidine and Spermine) and abscisic acid (ABA). ln this medium, myceliums of high virulent isolate (BXI-IO) produced fewer polyamines than less virulent isolate (BX 1-5) while inverse phenomenon was observed for ABA content. The two growth regulators were diffused in medium culture in which their levels increase with age of mycelium. In the end, variations of PA and ABA in myceliums show antagonist effect of the two growth regulators in Eutypa lata fungi.

A series of long-term trials was established to monitor the effect of remedial surgery for the control of Eutypa dieback in commercial vineyards of South Australia. Removing infected cordons and trunks has been used as a strategy for managing Eutypa dieback in grapevines for many years and this study is the first to provide evidence of its effect in controlling the disease. Between 42 and 100% of vines produced watershoots after removal of infected wood, depending on time after surgery and height of the trunk remaining. Remedial surgery reduced the incidence of vines with foliar symptoms of Eutypa dieback in vineyards, and the severity of those symptoms, but the efficacy varied with the presumed extent of pre-existing infection and the origin of the watershoot. It is recommended that all stained wood and a further 10 cm of healthy tissue be removed to reduce the likelihood that symptoms of Eutypa dieback will recur.

Abstract: The present study aimed to determine the most efficient experimental conditions of iron sulfate use leading to optimal inhibition in the development of fungal pathogens. Assays have been focused on fungal species inducing severe grapevine diseases. FeSO4 directly inhibited the in vitro mycelial growth of Botrytis cinerea, Eutypa lata, Phaeomoniella chlamydospora, Phaeoacremonium aleophilum, Diplodia seriata, and Neofusicoccum parvum with variable efficiency in the range of 0.5–10mM. The development was always completely inhibited at 20mM. This inhibitory effect was greatly increased at acidic pH values. The anionic moiety of the molecule was of importance since bromide, chloride and sulfate were highly active, whereas acetate and oxalate showed a small effect. Electron microscope observations on E. lata and B. cinerea showed that a treatment with FeSO4 induced dramatic changes in the hyphal organization leading to cell death. No toxicity was observed on grapevine leaves following repeated FeSO4 sprays in the antifungal concentration range. Therefore, FeSO4 may be proposed to effectively replace the long-term pollutant use of CuSO4 as an antifungal agent, with the additional advantage of iron being an important plant micronutrient. [Copyright &y& Elsevier]

A series of long-term trials was established to monitor the effect of remedial surgery for the control of Eutypa dieback in commercial vineyards of South Australia. Removing infected cordons and trunks has been used as a strategy for managing Eutypa dieback in grapevines for many years and this study is the first to provide evidence of its effect in controlling the disease. Between 42 and 100% of vines produced watershoots after removal of infected wood, depending on time after surgery and height of the trunk remaining. Remedial surgery reduced the incidence of vines with foliar symptoms of Eutypa dieback in vineyards, and the severity of those symptoms, but the efficacy varied with the presumed extent of pre-existing infection and the origin of the watershoot. It is recommended that all stained wood and a further 10 cm of healthy tissue be removed to reduce the likelihood that symptoms of Eutypa dieback will recur. [ABSTRACT FROM AUTHOR]

Trunk disease pathogens of grapevines, viz. Phaeomoniella chlamydospora, Eutypa lata and several species in Botryosphaeriaceae, Phaeoacremonium and Phomopsis are known to infect fresh pruning wounds by means of air-borne inoculum released after rainfall or prolonged periods of high relative humidity. Recent surveys have demonstrated that most or all of these pathogens are present in climatically diverse grape growing regions of South Africa. However, the factors controlling spore dispersal of these pathogens in vineyards were largely unknown. To address this question, spore trapping was done in a Chenin Blanc vineyard in the Stellenbosch area, South Africa, for 14 weeks during the grapevine pruning period from June to mid-September of 2004 and 2005. Hourly recordings of weather data were done by a weather station in the row adjacent to the spore trap. Spores of E. lata and Phomopsis and species in Botryosphaeriaceae were trapped throughout the trapping periods of 2004 and 2005, with higher levels of trapped spores recorded in 2005. The spores of all three pathogens were trapped during or after periods of rainfall and/or high relative humidity. In neither of the 2 years were spores of Pa. chlamydospora or Phaeoacremonium spp. trapped. Results indicated that spore event incidence, as well as the amount of spores released during a spore event of above-mentioned pathogens, were governed by rainfall, relative humidity, temperature and wind speed prior to and during the spore events. [ABSTRACT FROM AUTHOR]

Eutypa dieback is a vascular disease that may severely affect vineyards throughout the world. In the present work, microarrays were made in order (i) to improve our knowledge of grapevine (Vitis vinifera cv. Cabernet-Sauvignon) responses to Eutypa lata, the causal agent of Eutypa dieback; and (ii) to identify genes that may prevent symptom development. Qiagen/Operon grapevine microarrays comprising 14 500 probes were used to compare, under three experimental conditions (in vitro, in the greenhouse, and in the vineyard), foliar material of infected symptomatic plants (S+R+), infected asymptomatic plants (S–R+), and healthy plants (S–R–). These plants were characterized by symptom notation after natural (vineyard) or experimental (in vitro and greenhouse) infection, re-isolation of the fungus located in the lignified parts, and the formal identification of E. lata mycelium by PCR. Semi-quantitative real-time PCR experiments were run to confirm the expression of some genes of interest in response to E. lata. Their expression profiles were also studied in response to other grapevine pathogens (Erysiphe necator, Plasmopara viticola, and Botrytis cinerea). (i) Five functional categories of genes, that is those involved in metabolism, defence reactions, interaction with the environment, transport, and transcription, were up-regulated in S+R+ plants compared with S–R– plants. These genes, which cannot prevent infection and symptom development, are not specific since they were also up-regulated after infection by powdery mildew, downy mildew, and black rot. (ii) Most of the genes that may prevent symptom development are associated with the light phase of photosynthesis. This finding is discussed in the context of previous data on the mode of action of eutypin and the polypeptide fraction secreted by Eutypa. [ABSTRACT FROM PUBLISHER]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The sampling of wood from diseased grapevine trunks is usually a destructive process that involves cutting the arms or even total uprooting. As an alternative, an increment borer (Pressler borer) could allow the study of disease evolution over time for individual vines. A borer was evaluated on vines with and without Eutypa dieback, and covariance analyses conducted to determine the correlation between foliar symptoms and the relative incidence of Eutypa lata and Diplodia seriata. The variation of isolation frequencies was similar within and between vines. D. seriata was more frequently isolated than E. lata, but the two fungi followed different patterns in relation to foliar symptom intensity. E. lata was rare in asymptomatic material and was more frequently isolated as the foliar symptoms increased, stabilizing at the highest symptom intensities. For D. seriata, the isolation frequency was highest from asymptomatic and highly symptomatic vines, which could agree with the endophytic character of this fungus. The experimental error was high, probably due to the blind nature of the sampling. [ABSTRACT FROM AUTHOR]

Botryosphaeria parva, Eutypa lata and Phomopsis viticola are ascomyceteous fungi responsible for severe canker and dieback in numerous woody plants. In grapevine, these pathogens colonise the wood mainly through pruning wounds, and the diseases gradually develop, leading to partial or total vine death. In the present study, the three fungal species were grown in Czapek Dox modified medium. Under these conditions, fungal colonies are able to distinguish self from non-self. The production of reactive oxygen species (ROS) was analysed by specifically staining for superoxide (O2.-) or peroxide (O22-) radicals. The presence of ROS in both isolated cultures and fungal interactions was confi rmed. All fungi produced both radicals, in every interaction. However, the patterns of ROS production depend on the fungus itself and on the fungal species with which it is interacting, being also dependent on the presence of antioxidant compounds in the surrounding medium. It is as though a fungal species hierarchy could be established for every interaction under each set of conditions (i.e. habitat). The results obtained suggest that fungi display more complex behaviours than generally acknowledged. They are able to recognize potential contestants and built up defence reactions, as well as weaken plant defences and structures to induce infection. [ABSTRACT FROM AUTHOR]

Perennial cankers and consequent grapevine dieback are a major problem in vineyards of Sonora and Baja California, the most important grape-production areas of Mexico. In order to identify the canker-causing agents, symptomatic arms, cordons, and trunks were collected from 13 and 6 vineyards in Sonora and Baja California, respectively. Two Botryosphaeriaceae spp., Lasiodiplodia theobromae and Diplodia seriata, were isolated frequently from infected wood and identified based on morphological and cultural characters as well as analyses of nucleotide sequences of three genes, the internal transcribed spacer region (ITS1-5.85-lTS2), a partial sequence of the 3-tubulin gene, and part of the translation elongation factor 1-α gene (EF1-α). Although both L. theobrornae and D. seriata were isolated from grapevine cankers in Baja California, only L. theobrornae was found in vines in the Sonora region. Pathogenicity of both species was verified by inoculation of rooted cuttings and green shoots of Thompson Seedless and Chardonnay cultivars. Isolates of L. theobrornae were more virulent, based on the extent of spread in the secondary wood and green tissue, than those of D. seriata. These findings confirm L. theobroinae and D. seriata as the causal agents of dieback and canker formation of grapevines in northern Mexico. [ABSTRACT FROM AUTHOR]

Abstract: The biotransformations of a series of substituted sulfides were carried out with the filamentous fungi Botrytis cinerea, Eutypa lata and Trichoderma viride. Several products underwent microbial oxidation of sulfide to sulfoxide with medium to high enantiomeric purity. With regard to sulfoxide enantioselectivity, the (R)-enantiomer was favoured in biotransformations by T. viride and E. lata while the (S)-enantiomer was favoured in those by B. cinerea. A minor amount of sulfone product was also obtained. [Copyright &y& Elsevier]

Abstract: Cysteine inhibited mycelial growth of the pathogenic fungus affecting grapevines Eutypa lata Pers. Fr. Tul. and C. Tul. in a concentration-dependent manner. The threshold value (defined by the concentration inducing a growth inhibition higher than 5%) was 0.5 mM. A 10 mM concentration induced a complete inhibition of growth and triggered necrotic processes as evidenced by an increasing number of nuclei stained by propidium iodide. In conditions mimicking the plant environment (in particular, a pH near the apoplastic value, i.e. 5.5), 6 mM cysteine induced dramatic modifications in the structural organization of the mycelium (wall, mitochondria, vacuoles and nucleus) leading to death of the hyphae. The antifungal effect of the molecule increased at the acidic experimental pH (pH 4.1). The effect was highly specific to cysteine since modifying the molecular arrangement or masking the SH-function hindered the antifungal efficiency. Cysteine spectrum of action was broad among the various strains of E. lata tested. However, a lower efficiency was observed against fungal species intervening in other grapevine diseases (esca, black dead arm). Besides its direct antifungal effect, the role of cysteine presents particular interest in the fight against fungal pathogens since it triggered an excretion of ergosterol, a compound with elicitor properties. Therefore, cysteine may indirectly increase plant defense reactions. [Copyright &y& Elsevier]

Abstract: Eutypa lata is a significant grapevine pathogen with limited means of prevention and control. The biological control agent Fusarium lateritium can prevent E. lata infection if applied directly onto a vine pruning wound. F. lateritium was suspended and stored in an invert emulsion formulation. A commercially available pruning shear was modified to dispense the formulated F. lateritium onto the cutting blade for direct application onto the pruning wound simultaneously with grapevine cutting. The modified pruner was tested for its ability to cover grapevine pruning wounds using the emulsion formulation. Efficacy of formulated F. lateritium on pruned grapevine canes was also studied using the pruner for application. Addition of grooves in the pruning blade significantly improved wound coverage. Biological efficacy testing determined that applying formulated F. lateritium with the modified pruner was as effective as pipetting formulation directly onto the pruning wound. [Copyright &y& Elsevier]

A new acidic derivative of the fungicide fenpiclonil was synthesized containing a methyl group on the alpha-position of the carboxyl function of N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole. The phloem mobility of the resulting N-(1-carboxyethyl)-3-cyano-4-(2,3-dichlorophenyl)pyrrole was comparable with that of the former compound, but was higher at external pH 5.0. Unlike the derivatives previously synthesized, it was comparable with fenpiclonil in its fungicidal activity against the pathogenic fungus Eutypa lata. [ABSTRACT FROM AUTHOR]

Abstract: Eutypa dieback (dying arm disease, eutypiosis) is a very devastating disease in many grape-producing areas around the world. This vascular disease is induced by the ascomycete Eutypa lata Pers. Fr. Tul & C. Tul. invading the trunk by pruning wounds. The environmental factors and the nutritional requirements regulating fungus development are yet poorly known. This work shows that the isolated strain of E. lata was able to grow in a large temperature range (2–30 °C). However, a higher temperature (35 °C) presented inhibitory effects on mycelial growth. E. lata was able to use various osidic molecules (C5, C6, C12, C18, C24, and starch), showing thus a large adaptation to the carbon source supplied. As nitrogen source, it used salts and numerous natural amino acids. A significant result was obtained with cysteine presenting obvious antifungal properties. This effect can further be used with the aim of setting up a curative treatment of the disease. To cite this article: B.-E. Amborabé et al., C. R. Biologies 328 (2005). [Copyright &y& Elsevier]

Effects of Eutypa lata, the fungal agent of eutypiosis, on polyamine (putrescine (Put), spermidine (Spd), spermine (Spm), diaminopropane (Dap)) and tyramine (Tyr) contents in grapevine leaves were studied to determine the relationship between these components and disease development. The external symptoms of eutypiosis are small and necrotic leaves, which could be observed on only one arm or on two arms of the vine stock. This study was carried out on healthy leaves (S, borne by healthy vine stock), apparently healthy leaves (Aps, borne by one arm without symptoms, whereas the other arm was diseased), and moderately (M. mal.) and strongly (F. mal.) diseased leaves. We analysed free polyamines (free PAs, chlorhydric acid soluble fraction), conjugated polyamines (PAs-fpm, PAs covalently linked to molecules with low molecular mass like hydroxycinnamic acids), and bound polyamines (PAs-mm, covalently linked to macromolecules) in Vitis vinifera L. 'Cabernet sauvignon', a variety sensitive to eutypiosis. In diseased leaves, we noted a decrease of free PAs, PAs-fpm, free Tyr, and Tyr-fpm levels. By contrast, the Dap-fpm level was increased by the disease. Eutypiosis also induced an increase of Spm-mm and Dap-mm levels, whereas the Put-mm and Spd-mm levels were decreased. Free Put, free Spd, PAs-fpm, free Tyr, and Tyr-fpm levels were higher in apparently healthy leaves than in healthy leaves. The PAs-mm levels were slightly affected by eutypiosis in apparently healthy leaves. The specific role of each type of polyamines and tyramine is discussed with regard to the host-parasite relationship. [ABSTRACT FROM AUTHOR]

A series of derivatives of the phenylpyrrole fungicide fenpiclonil was synthesized in which a carboxyl group was present at various sites of this non-phloem-mobile molecule. Using the Kleier model, all these acidic analogues were predicted to be moderately phloem-mobile, especially the N-substituted derivatives. One of these latter molecules, N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole, exhibited some fungicidal activity on the pathogenic fungus Eutypa lata, and was then tested as a phloem-mobile pesticide in the Ricinus system. The compound was indeed mobile in the sieve tubes and was not degraded to fenpiclonil in the phloem sap under our experimental conditions. Its concentration in the sap was closely correlated to the percentage of the undissociated form of the molecule in the external medium, and was similar under acidic conditions (external pH 4.6-5.0) to that of the herbicide glyphosate. [ABSTRACT FROM AUTHOR]

Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzaldehyde, is a toxin produced by Eutypa lata, the causal agent of eutypa dieback of grapevine. The tolerance of some grapevine cultivars to the disease has been ascribed to the potential reduction of eutypine into its corresponding non-toxic alcohol, eutypinol. In the present study, eutypine biotransformation in different tissues of grapevine was investigated by HPLC and LC–MS. Grape callus tissues were able to biotransform eutypine into eutypinol within the first 3 h of culture. The grape plantlets cultured in vitro can also transform eutypine into eutypinol. Grape plantlet leaves do not have any effect on the uptake of eutypine, which goes through the tissues following a concentration gradient. Results revealed that the toxicity of eutypine in grape tissues is an active process showing that eutypinol is rapidly metabolised into other compounds. The use of micro-cuttings and in vitro plants showed that eutypine strongly accumulates in the bottom part of the diseased plant stems. [Copyright &y& Elsevier]

The ascomycete Eutypa lata is the causative agent of eutypa dieback in grapevines, a serious economic problem in major wine grape producing areas. In order to develop a predictive, non-destructive assay for early detection of fungal infection, the phenolic metabolite profiles of 11 strains of E. lata grown on four different artificial growth media were analyzed by HPLC and their variability compared with growth on Cabernet Sauvignon grapevine wood and wood extracts. Six compounds were generally produced in significant amounts, namely eutypinol, eulatachromene, and eutypine and its benzofuran cyclization product, together with siccayne and eulatinol. The two most widely distributed and abundant metabolites were eutypinol and eulatachromene, which were present in 8 of the strains grown on grapewood aqueous extract fortified with sucrose. Metabolite production on grapevine extract was greatly enhanced relative to the artificial media, indicating that this native substrate provides optimal conditions and a more representative profile of the metabolites produced in the natural disease state. The primary metabolites were tested in a grapeleaf disc bioassay to establish their relative toxicity. Neither eutypinol nor siccayne were phytotoxic; eulatachromene, eulatinol, eutypine, and the benzofuran exhibited necrotic effects in the bioassay. The results indicate that eutypa dieback may be caused by several E. lata metabolites rather than a single compound. [Copyright &y& Elsevier]

Summary: Eutypine, 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzaldehyde, is a toxin produced by Eutypa lata, the causal agent of Eutypa dieback in grapevine. The effect of the toxin on anthocyanin synthesis has been investigated in Vitis vinifera cv. Gamay cell cultures. At concentrations higher than 200 μmol/L, eutypine reduced anthocyanin accumulation in cells. The reduction in anthocyanin accumulation was proportional to the eutypine concentrations and HPLC analysis showed that eutypine affected the levels of all anthocyanins. The effect of eutypine application on the expression of five genes of the anthocyanin biosynthesis pathway, including chalcone synthase (CHS), flavonone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX), and UDP glucose-flavonoid 3-O-glucosyl transferase (UFGT) was determined. Expression of CHS, F3H, DFR and LDOX was not affected by the addition of eutypine to grapevine cell cultures. In contrast, expression of the UFGT gene was dramatically inhibited by the toxin. These results suggest that in grapevine cell cultures, eutypine strongly affects anthocyanin accumulation by inhibiting UFGT gene expression. The mechanism of action of eutypine is discussed. [Copyright &y& Elsevier]