Occurrence of the Redglobe strain of Grapevine leafroll-associated virus 2 in table and wine grape varieties in Italy

Research NoteThe Redglobe strain of Grapevine leafrollassociated virus 2 (GLRaV-2-RG) is a recently discovered closterovirus so far reported to infect solely cv. Redglobe. A survey for this virus 2 in about 380 accessions of table and wine grape varieties conducted during 2001-2003 proved that GLRaV-2-RG was present also in other table grape varieties, though to a smaller extent, while it was never detected in wine varieties.

Fast transmission of grapevine 'Pinot gris' virus (GPGV) in vineyard

Grapevine 'Pinot gris' virus (GPGV) is a newly emergent virus associated with the appearance of grapevine leaf mottling and deformation disease (GLMD). The worldwide spreading of this virus, and sometimes of the associated disease, that has occurred in the last years, requests further epidemiological studies to verify the progress of natural infection in the field. In the present paper, GPGV infection and spatiotemporal spreading of GLMD, investigated in two vineyards with high disease occurrence, confirmed an elevated presence of the virus in vineyards of Northeastern Italy, and revealed an increasing of symptomatic plants over the time. At the same time, the progress of natural infection was monitored after the placement of new grafted plants near the symptomatic grapevines in the infected vineyards. After three years, 76 % of the plantlets that were initially GPGV-free became GPGV-infected, giving an evidence of the fast transmission of GPGV in the field. Only 14 % of the plantlets, all collocated inside a patch with diseased plants, showed typical GLMD-symptoms. Interestingly, some plantlets, which were already GPGV-infected with the "asymptomatic" GPGV variant before planting in the field, did not become infected with the "symptomatic" viral wild variant after three years and never showed GLMD symptoms

Genetic identification, origin and sanitary status of grapevine cultivars (Vitis vinifera L.) grown in Babar, Algeria

This research focused on present grapevine biodiversity of neglected cultivars grown in 'Babar' region, Northeastern Algeria. The obtained results demonstrate the complex, rich, and even surprising inheritance of grapevine biodiversity in such a small region, with currently residual viticulture practiced only for direct consumption. Babar is one of the oldest inhabited areas in Algeria and part of the Atlas Mountains, considered very favorable for wild and cultivated vine growing since protohistoric times. Thirty-seven vines from the traditional growing area were analyzed using nuclear microsatellite (SSR) markers for cultivar identification and RT-qPCR analysis for virus detection and sanitary status evaluation. As a result, thirteen different genotypes were found, most of them showing a very good sanitary status, then constituting a valuable biological source for clonal selection. A close relatedness was evidenced with some Mediterranean varieties, resulting from previous exchanges of grapevine cultivars in the past. Furthermore, the present study highlighted the existence of three new genotypes, highly probably autochthonous of Babar region, with proposed names 'Babari', 'Babar-Algeria', and 'Amesski-Babar'. They could represent unique Algerian varieties, probably preserved over time. The conservation of these endangered genotypes is highly recommended

A successful defence strategy in grapevine cultivar ‘Tocai friulano’ provides compartmentation of grapevine Flavescence dorée phytoplasma

Background: Flavescence dorée (FD) is a grapevine disease caused by phytoplasma and it is one of the most destructive pathologies in Europe. Nowadays, the only strategies used to control the epidemics are insecticides against vector, but more sustainable techniques are required. Completely resistant Vitis vinifera varieties have not been uncovered yet, but differences in susceptibility among cultivars and spontaneous recovery from FD symptoms have been observed. The grapevine cultivar ‘Tocai friulano’ shows very low susceptibility to FD but its defence strategy to counteract the phytoplasma spread has not been deciphered yet. In this work, the mechanisms occurring within ‘Tocai friulano’ FD-infected plants were examined in depth to identify the phytoplasma distribution and the defence pathways involved. Results: In ‘Tocai friulano’ symptoms of FD-infection remained confined near the area where they appeared during all the vegetative season. Analyses of secondary phloem showed a total absence of FD phytoplasma (FDp) in the trunk and its disappearance in 2-year-old arms from July to November, which was different from ‘Pinot gris’, a highly susceptible variety. Diverse modulations of defence genes and accumulation of metabolites were revealed in 1-year-old canes of ‘Tocai friulano’ FD-infected plants, depending on the sanitary status. Symptomatic portions showed high activation of both jasmonate- and salicylate-mediated responses, together with a great accumulation of resveratrol. Whereas activation of jasmonate-mediated response and high content of ε-viniferin were identified in asymptomatic 1-year-old cane portions close to the symptomatic ones. Conclusion: Successful defence mechanisms activated near the symptomatic areas allowed the compartmentation of FD symptoms and phytoplasmas within the infected ‘Tocai friulano’ plants. These results could suggest specific agronomical practices to be adopted during FD management of this variety, and drive research of resistance genes against FD

Chitosan induces delayed grapevine defense mechanisms and protects grapevine against Botrytis cinerea

In the present study, a commercial chitosan soluble in acid solution and obtained from shrimp shell waste, with a molecular weight of 173 kDa and a degree of acetylation of 17%, named as chitosan (173/17), was investigated. Chitosan is a well-known biopolymer whose antimicrobial properties are highly influenced by the molecular weight, degree of acetylation as well as the preparation and derivatization methods used. Chitosan (173/17) was applied on grapevine leaves before Botrytis cinerea inoculation to verify its effectiveness as a preventive treatment against the fungal infection. The expression of a set of defense marker genes, as well as accumulation of stilbene phytoalexins, was investigated. Thanks to its fungistatic and filmogenic properties, chitosan (173/17) protected grapevine leaves against B. cinerea. Moreover, it induced grapevine defense response: three days after the treatment an induction of the jasmonic acid and ethylene-mediated response, a repression of the salicylic acid-mediated signaling, and a transient accumulation of trans-resveratrol were registered. Our data indicate that chitosan (173/17), when used in preventive application, is able to protect grapevine against B. cinerea infection. The effectiveness of chitosan (173/17) as a natural ecofriendly product for the control of B. cinerea on grapevine was demonstrated

Comparison of distance measures in spatial analytical modeling for health service planning

<p>Abstract</p> <p>Background</p> <p>Several methodological approaches have been used to estimate distance in health service research. In this study, focusing on cardiac catheterization services, Euclidean, Manhattan, and the less widely known Minkowski distance metrics are used to estimate distances from patient residence to hospital. Distance metrics typically produce less accurate estimates than actual measurements, but each metric provides a single model of travel over a given network. Therefore, distance metrics, unlike actual measurements, can be directly used in spatial analytical modeling. Euclidean distance is most often used, but unlikely the most appropriate metric. Minkowski distance is a more promising method. Distances estimated with each metric are contrasted with road distance and travel time measurements, and an optimized Minkowski distance is implemented in spatial analytical modeling.</p> <p>Methods</p> <p>Road distance and travel time are calculated from the postal code of residence of each patient undergoing cardiac catheterization to the pertinent hospital. The Minkowski metric is optimized, to approximate travel time and road distance, respectively. Distance estimates and distance measurements are then compared using descriptive statistics and visual mapping methods. The optimized Minkowski metric is implemented, via the spatial weight matrix, in a spatial regression model identifying socio-economic factors significantly associated with cardiac catheterization.</p> <p>Results</p> <p>The Minkowski coefficient that best approximates road distance is 1.54; 1.31 best approximates travel time. The latter is also a good predictor of road distance, thus providing the best single model of travel from patient's residence to hospital. The Euclidean metric and the optimal Minkowski metric are alternatively implemented in the regression model, and the results compared. The Minkowski method produces more reliable results than the traditional Euclidean metric.</p> <p>Conclusion</p> <p>Road distance and travel time measurements are the most accurate estimates, but cannot be directly implemented in spatial analytical modeling. Euclidean distance tends to underestimate road distance and travel time; Manhattan distance tends to overestimate both. The optimized Minkowski distance partially overcomes their shortcomings; it provides a single model of travel over the network. The method is flexible, suitable for analytical modeling, and more accurate than the traditional metrics; its use ultimately increases the reliability of spatial analytical models.</p

Symbolic approach and induction in the Heisenberg group

We associate a homomorphism in the Heisenberg group to each hyperbolic unimodular automorphism of the free group on two generators. We show that the first return-time of some flows in "good" sections, are conjugate to niltranslations, which have the property of being self-induced.Comment: 18 page

Explorando el potencial bioestimulante del alga invasora Rugulopterix okamurae en vid

Trabajo presentado en las IV Jornadas del Grupo de Viticultura de la Sociedad Española de Ciencias Hortícolas, celebradas en Pamplona (España), del 26 al 28 de octubre de 202

Transient silencing of the grapevine gene VvPGIP1 by agroinfiltration with a construct for RNA interference

Grapevine is an economically important crop, and the recent completion of its genome makes it possible to study the function of specific genes through reverse genetics. However, the analysis of gene function by RNA interference (RNAi) in grapevine is difficult, because the generation of stable transgenic plants has low efficiency and is time consuming. Recently, transient expression of genes in grapevine leaves has been obtained by Agrobacterium tumefaciens infiltration (agroinfiltration). We therefore tested the possibility to silence grapevine genes by agroinfiltration of RNAi constructs. A construct to express a double strand RNA (dsRNA) corresponding to the defense-related gene VvPGIP1, encoding a polygalacturonase-inhibiting protein (PGIP), was obtained and transiently expressed by agroinfiltration in leaves of grapevine plants grown in vitro. Expression of VvPGIP1 and accumulation of PGIP activity were strongly induced by infiltration with control bacteria, but not with bacteria carrying the dsRNA construct, indicating that the gene was efficiently silenced. In contrast, expression of another defense-related gene, VST1, encoding a stilbene synthase, was unaffected by the dsRNA construct. We have therefore demonstrated the possibility of transient down-regulation of grapevine genes by agroinfiltration of constructs for the expression of dsRNA. This system can be employed to evaluate the effectiveness of constructs that can be subsequently used to generate stable RNAi transgenic plants