First studies on the potential of a copper formulation for the control of leaf stripe disease within esca complex in grapevine

An experimental formulation based on copper oxychloride and gluconates, which is able to penetrate vine foliar tissue, was tested for wood treatment against some of the fungi involved in the diseases included in the esca disease complex. In vitro trials were carried out to: i) test the effect of the formulationon the mycelial growth rate of Phaeomoniella chlamydospora (Pch), Phaeoacremonium aleophilum (Pal) and Fomitiporia mediterranea (Fmed), and on the conidial germination of Pch and Pal; and ii) conduct a preliminaryinvestigation of the presence of the copper formulation on the ability of Pal to produce toxic metabolites. Trials were also conducted on potted vines to i) measure copper penetration into the trunk of potted vines using atomic absorption spectrophotometry; and ii) test the effect of the copper formulation on colonization ofthe fungus in trunks. Finally, the copper formulation was field-tested in vineyards showing leaf stripe. The implications of the tests in the control of the esca disease complex are discussed

Rainfall and temperature influence expression of foliar symptoms of grapevine leaf stripe disease (esca complex) in vineyards

Two vineyards in the Abruzzo Region, central Italy, affected by grapevine leaf stripe disease (GLSD), were monitored for incidence and severity of foliar symptoms of the disease for 21 consecutive years (1994 to 2014). Each year, rainfall and temperature were recorded. Correlations between symptom incidence or severity and rainfall or temperature of different periods of the year or single months were assessed. July rainfall and temperature were highly correlated with incidence and severity of leaf symptoms. The vineyards were characterized by high longevity, vigour and yields, and a particular dynamic of GLSD. In the period following 2005, the year of peak vine mortality, there was a decrease of the expression of foliar symptoms, which was not correlated with both of the climate parameters. Greater mortality occurred for vines showing severe symptoms at the first appearance of GLSD than for vines with low severity

Bioassays on the Activity of Resveratrol, Pterostilbene and Phosphorous Acid towards Fungi Associated with Esca of Grapevine

An examination was carried out under laboratory conditions to determine whether resveratrol, pterostilbene and mixtures of each stilbene with phosphorous acid had an inhibitory activity against some fungi involved in esca: Phaeoacremonium aleophilum, Phaeomoniella chlamydospora, Libertella blepharis (anamorph of Eutypa lata), Fomitiporia punctata and Stereum hirsutum. An inhibition of mycelial growth by resveratrol was not found but there was a clear correlation between pterostilbene concentration and reduction of radial growth confirming the antifungal activity of this phytoalexin. Although phosphorous acid proved to be generally ineffective, an increase of antifungal activity of stilbenes in the mixtures was observed with all fungi except F. punctata. The possible relation between fungal phenol oxidase activity and inhibition by mixtures of stilbenes and phosphorous acid was discussed

How Iron Could Be Involved in Esca Fungi Development

Iron reduction capability was detected by ferrozine assay in Phaeomoniella chlamydospora, Phaeacremonium aleophilum and Fomitiporia punctata. On the other hand, the Chrome Azurol S (CAS) assay demonstrated that low molecular weight chelator agents were produced by P. chlamydospora, P. aleophilum, Libertella blepharis and F. punctata. Foliar analysis carried out at harvest showed higher levels of the iron in symptomatic than in asymptomatic leaves. Conversely, levels of the other transition metals (copper, manganese and zinc), and of calcium and magnesium were basically similar in symptomatic and asymptomatic leaves. A possible relationship between iron, esca fungi and host-plant was hypothesized

Mixture of calcium, magnesium and seaweed affects leaf phytoalexin contents and grape ripening on vines with grapevine leaf stripe disease

Grapevine leaf stripe disease (GLSD) is a tracheomycosis caused by Phaeomoniella chlamydospora and Phaeoacremonium minimum. Impacts on yields of grapes were correlated with the incidence and severity of GLSD symptoms on vine canopies. In 2012 and 2013, vines in two vineyards were treated with nine applications of a mixture of leaf fertilizers containing calcium, magnesium and seaweed extracts. At different growth stages, leaves were sampled from treated and control plots of healthy, GLSD-asymptomatic, or GLSD-symptomatic vines and contents were measured of the phytoalexins trans-resveratrol, trans-ε-viniferin, trans-δ-viniferin and trans-pterostilbene. Grape ripening was also monitored from veraison to harvest during both vintages. The treatments caused significant reductions in canopy symptom expression. Increased phytoalexin contents were measured from ‘fruit set’ to ‘berries developing colour’ stages. Trans-resveratrol peak was recorded in asymptomatic diseased vines at the ‘berries pea-sized’ stage, and trans-ε-viniferin and trans-δ-viniferin increased at the ‘berries beginning to touch’ stage, compared to the contents recorded in untreated asymptomatic vines. From ‘berries developing colour’ to harvest, all treated vines had lower amounts of phytoalexins than the control ones. At harvest, treated healthy and symptomatic vines produced berries with similar amounts of total sugars compared to untreated vines. Treated asymptomatic vines produced berries with greater amounts of total sugars compared to the untreated vines. These results indicate that increased phytoalexin content recorded from ‘fruit set’ to ‘berries beginning to touch’ in asymptomatic vines treated with the mineral/seaweed mixture may reduce symptoms of GLSD

Effects of grapevine applications of fosetyl-aluminium formulations for downy mildew control on “esca” and associated fungi

Esca of grapevine is a fungal disease with a complex aetiology that is common in almost all regions of the world where grapes are cultivated. Despite much research, no effective control of the disease has been found. We investigated possible activity of fosetyl-aluminium (fosetyl-Al), an active ingredient in many fungicides against downy mildew, to inhibit development of esca in grapevine and the main pathogens linked to the disease, Phaeomoniella chlamydospora (Pch) and Phaeoacremonium aleophilum (Pal). In greenhouse experiments conducted on vines artificially inoculated with Pch or Pal, we found a reduction in necrosis in the woody tissue. In field experiments conducted over several years statistically significant reductions in the annual and cumulative incidence of the disease symptoms, and in cumulative vine mortality, were seen. The effect of fosetyl-Al treatments on leaf gas exchange, levels of resveratrol and å-viniferin in the wood, and enzymatic activities were also studied. Hypotheses regarding the mechanism of action of fosetyl-Al against esca are outlined, and the possible use of products containing the chemical, applied on foliage to control downy mildew, is discussed as a strategy for control of esca

Patterns of phytoalexins in the grapevine leaf stripe disease (esca complex)/grapevine pathosystem

Vineyards containing vines affected with grapevine leaf stripe disease (GLSD), one of the diseases of the esca complex, suffer losses in grape yield and quality every growing season. To examine the relation between GLSD foliar symptoms and levels of phytoalexins in grapevine, phytoalexin levels were monitored in the leaves of symptomatic, asymptomatic/diseased, and healthy grapevine leaves, at various growth stages, in two vineyards in Italy, over four growing seasons. At the same time, the leaf symptoms of the vines at some of those growth stages were recorded in each vineyard and in each growing season. The compounds extracted and identified were: trans-resveratrol, trans-pterostilbene, trans-ε-viniferin and trans-δ-viniferin. The most common phytoalexin found was resveratrol. Amounts of all the phytoalexins were generally greater in symptomatic leaves than in asymptomatic/diseased or healthy leaves. In symptomatic leaves, resveratrol levels were greatest at pre-bunch closure, and peaks in pterostilbene occurred at the same time. Leaves of each category (symptomatic, asymptomatic/diseased, healthy) had lower amounts of these compounds at veraison and generally higher amounts at the stages of harvesting and/or the softening of berries. It seems therefore that the formation and pattern over time of the phytoalexins was linked to the growth stage of the vines. Leaf symptoms never occurred before pre-bunch closure, but became much more common from veraison to harvest. This study provides evidence of a relationship between the levels of phytoalexins, grapevine growth stage, and the seasonal pattern of development of GLSD symptoms

Patterns of phytoalexins in the grapevine leaf stripe disease (esca complex)/grapevine pathosystem

Vineyards containing vines affected with grapevine leaf stripe disease (GLSD), one of the diseases of the esca complex, suffer losses in grape yield and quality every growing season. To examine the relation between GLSD foliar symptoms and levels of phytoalexins in grapevine, phytoalexin levels were monitored in the leaves of symptomatic, asymptomatic/diseased, and healthy grapevine leaves, at various growth stages, in two vineyards in Italy, over four growing seasons. At the same time, the leaf symptoms of the vines at some of those growth stages were recorded in each vineyard and in each growing season. The compounds extracted and identified were: trans-resveratrol, trans-pterostilbene, trans-ε-viniferin and trans-δ-viniferin. The most common phytoalexin found was resveratrol. Amounts of all the phytoalexins were generally greater in symptomatic leaves than in asymptomatic/diseased or healthy leaves. In symptomatic leaves, resveratrol levels were greatest at pre-bunch closure, and peaks in pterostilbene occurred at the same time. Leaves of each category (symptomatic, asymptomatic/diseased, healthy) had lower amounts of these compounds at veraison and generally higher amounts at the stages of harvesting and/or the softening of berries. It seems therefore that the formation and pattern over time of the phytoalexins was linked to the growth stage of the vines. Leaf symptoms never occurred before pre-bunch closure, but became much more common from veraison to harvest. This study provides evidence of a relationship between the levels of phytoalexins, grapevine growth stage, and the seasonal pattern of development of GLSD symptoms

Beyond BRCA1 and BRCA2: deleterious variants in DNA repair pathway genes in italian families with breast/ovarian and pancreatic cancers

The 5-10% of breast/ovarian cancers (BC and OC) are inherited, and germline pathogenic (P) variants in DNA damage repair (DDR) genes BRCA1 and BRCA2 explain only 10-20% of these cases. Currently, new DDR genes have been related to BC/OC and to pancreatic (PC) cancers, but the prevalence of P variants remains to be explored. The purpose of this study was to investigate the spectrum and the prevalence of pathogenic variants in DDR pathway genes other than BRCA1/2 and to correlate the genotype with the clinical phenotype. A cohort of 113 non-BRCA patients was analyzed by next-generation sequencing using a multigene panel of the 25 DDR pathways genes related to BC, OC, and PC. We found 43 unique variants in 18 of 25 analyzed genes, 14 classified as P/likely pathogenic (LP) and 28 as variants of uncertain significance (VUS). Deleterious variants were identified in 14% of index cases, whereas a VUS was identified in 20% of the probands. We observed a high incidence of deleterious variants in the CHEK2 gene, and a new pathogenic variant was detected in the RECQL gene. These results supported the clinical utility of multigene panel to increase the detection of P/LP carriers and to identify new actionable pathogenic gene variants useful for preventive and therapeutic approaches