Interactions among grapevine disease-causing fungi. The role of reactive oxygen species

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 modifi ed medium. Under these conditions, fungal colonies are able to distinguish self from non-self. The production of reactive oxygen species (ROS) was analysed by specifi cally staining for superoxide (O2 .-) or peroxide (O2 2-) 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

Control of grapevine wood fungi in commercial nurseries

Previous surveys conducted in commercial nurseries found that different wood fungi, namely Cylindrocarpon spp., Botryosphaeriaceae, Phomopsis viticola and Phaeomoniella chlamydospora infect grapevine cuttings. Two fi eld trials were carried out to evaluate the effectiveness of cyprodinil + fl udioxonil, pyraclostrobin + metiram, fl udioxonil and cyprodinil to prevent or reduce natural infections caused by such fungi. Rootstock and scion cuttings were soaked in fungicidal suspensions for 50 min prior to grafting. After callusing, the grafted cuttings were planted in two commercial fi eld nurseries with and without a previous history of grapevine cultivation. After nine months in the nursery, the plants were uprooted and analysed for the incidence and severity of the wood fungi. Plants uprooted from the fi eld without a previous history of grapevine cultivation were generally less strongly infected by wood fungi. Under this condition, only the mixture cyprodinil + fl udioxonil simultaneously reduced the incidence of Cylindrocarpon and Botryosphaeriaceae fungi, as well as the severity of Cylindrocarpon infections. Treatments did not produce signifi cant differences in the incidence and severity of P. viticola, and Pa. chlamydospora. For plants grown in the fi eld with a grapevine history, all fungicides except cyprodinil signifi cantly reduced the incidence and severity of Cylindrocarpon fungi. Also, the incidence and severity of Botryosphaeriaceae pathogens were signifi cantly decreased both by cyprodinil + fl udioxonil and by cyprodinil. No signifi cant differences were noticed for P. viticola incidence and severity, and Pa. chlamydospora was not detected again. These results suggest that the practice of soaking grapevine cuttings in selected fungicides prior to grafting signifi cantly reduces Cylindrocarpon spp. and Botryosphaeriaceae infections, thus improving the quality of planting material

Volatile Metabolism of Wine Grape Trincadeira: Impact of Infection with Botrytis cinerea

The aroma of grapes is cultivar dependent and is influenced by terroir, vineyard practices, and abiotic and biotic stresses. Trincadeira is a non-aromatic variety associated with low phenolic content and high sugar and organic acid levels. This cultivar, widely used in Portuguese wines, presents high susceptibility to Botrytis cinerea. This work aimed to characterise the volatile profile of Trincadeira grapes and how it changes under infection with B. cinerea. Thirty-six volatile organic compounds were identified, from different functional groups, namely alcohols, ester acetates, fatty acid esters, fatty acids, aldehydes, and products of the lipoxygenase pathway. Both free and glycosidic volatile organic compounds were analysed by Gas Chromatography and Gas Chromatography coupled to Mass Spectrometry for component quantification and identification, respectively. A multivariance analysis showed a clear discrimination between healthy and infected grapes with 2-trans-hexenal and isoamyl-acetate among the compounds identified as negative and positive markers of infection, respectively. Ester acetates such as 2-phenylethyl acetate, isoamyl acetate, and 2-methylbutyl acetate were present in higher contents in infected samples, whereas the contents of several fatty acid esters, such as ethyl decanoate and ethyl dodecanoate, decreased. These data were integrated with quantitative PCR data regarding genes involved in volatile metabolism and showed up-regulation of a gene coding for Hydroperoxide Lyase 2 in infected grapes. Altogether, these changes in volatile metabolism indicate an impact on the grape quality and may be related to defence against B. cinerea. The presence/absence of specific compounds might be used as infection biomarkers in the assessment of Trincadeira grapes’ qualityinfo:eu-repo/semantics/publishedVersio

Hormone Changes in Tolerant and Susceptible Grapevine Leaves Under Powdery Mildew Infection

The biotrophic fungus Erysiphe necator causes powdery mildew (PM) in grapevine. Phytohormones are major modulators of defensive responses in plants but the analysis of the hormonome associated with grapevine tolerance and susceptibility against this pathogen has not been elucidated. In this study, changes in hormonal profiling were compared between a tolerant (Vitis rupestris × riparia cv. 101-14 Millardet et de Grasset) and a susceptible (Vitis vinifera cv. Aragonêz) species upon E. necator infection. Control and PM-infected leaves were collected at 0, 6, 24, 96 h post-infection (hpi), and analysed through LC-MS/MS. The results showed a distinct constitutive hormonome between tolerant and susceptible species. Constitutive high levels of salicylic acid (SA) and indole-3- acetic acid together with additional fast induction of SA within the first 6 hpi as well as constitutive low levels of jasmonates and abscisic acid may enable a faster and more efficient response towards the PM. The balance among the different phytohormones seems to be species-specific and fundamental in providing tolerance or susceptibility. These insights may be used to develop strategies for conventional breeding and/or editing of genes involved in hormonal metabolism aiming at providing a durable resistance in grapevine against E. necatorinfo:eu-repo/semantics/publishedVersio

Involvement of «Phaeoacremonium» spp. and «Cylindrocarpon destructans» with Grapevine Decline in Portugal

In an attempt to determine the aetiology of young vine decline in Portugal a study was carried out in rootstock nurseries and in young vineyards during the last few years. Rootstock nurseries located in the most important production areas of Portugal (Ribatejo-Oeste and Beira Litoral) were surveyed. The fungi most frequently isolated from discoloured wood at the base of the stem were Cylindrocarpon destructans and Phaeoacremonium spp., although Acremonium sp., Phomopsis sp., Fusarium spp., Fusicoccum sp., Gliocladium sp., Phoma sp. and Sphaeropsis sp. were also present. Young vines (2- to 8-year-old) showing decline symptoms were collected from various vinegrowing regions of Portugal. Disease incidence was variable but decline symptoms were present in several wine and table grapevine cultivars grafted onto different rootstocks (99R, 110R, 1103P, 101-14, 140Ru, 5BB and 161-49). Isolations from symptomatic internal tissues revealed that also C. destructans and P. chlamydosporum were the predominant fungi isolated from the basal end of the rootstocks and grafting tissues. In the pathogenicity tests carried out with C. destructans isolates the pathogen was reisolated from inoculated plants showing black-foot symptoms but never from the controls. Our results point out that both C. destructans and P. chlamydosporum might be involved with young grapevine decline in Portugal

Obtenção in vitro do teleomorfo de Cylindrocarpon destructans, Neonectria Radicicola

Black-foot is an important grapevine disease, caused by the fungus Cylindrocarpon destructans, which causes a darkening of the basal-end of the plant, leading to early decline and death of young grapevines. Both, C. destructans and C. obtusisporum are considered responsible for this disease, although only the former was isolated in Portugal. Neonectria radicicola (teleomorph of C. destructans) is an Ascomycota forming perithecia on host tissue, but such structures haven’t been observed yet in the country in grapevine. There is some uncertainty concerning the sexual behaviour of the fungus, some authors considering this as a homothallic species while other considered it as heterothallic. Attempting to obtain the teleomorph of C. destructans, a collection of 15 isolates was used, originated from different regions of the country. Crosses between isolates (120 pairs) were done in Petri dishes containing Carnation Leaf Agar (CLA), under Near-UV light (NUV) at 6ºC. For some crosses, perithecia formation began after three months of incubation. After five months of incubation, morphological and biometrical traits of perithecia, asci and ascospores were evaluated. The teleomorph was only obtained when crossing distinct isolates, suggesting a tendency for an heterothallic behaviour of the species. Four isolates can be pointed out as more fertile (Cy68, Cy36, Cy76, Cy111), with Cy68 forming perithecia in 60% of crossings involving it, while the remaining produced perithecia in 33% of crosses. The identification of these isolates will allow enlarging the scope of the study to all C. destructans isolates under collection, aiming to confirm the sexual behaviour of this species

The road to molecular identification and detection of fungal grapevine trunk diseases

Grapevine is regarded as a highly profitable culture, being well spread worldwide and mostly directed to the wine-producing industry. Practices to maintain the vineyard in healthy conditions are tenuous and are exacerbated due to abiotic and biotic stresses, where fungal grapevine trunk diseases (GTDs) play a major role. The abolishment of chemical treatments and the intensification of several management practices led to an uprise in GTD outbreaks. Symptomatology of GTDs is very similar among diseases, leading to underdevelopment of the vines and death in extreme scenarios. Disease progression is widely affected by biotic and abiotic factors, and the prevalence of the pathogens varies with country and region. In this review, the state-of-the-art regarding identification and detection of GTDs is vastly analyzed. Methods and protocols used for the identification of GTDs, which are currently rather limited, are highlighted. The main conclusion is the utter need for the development of new technologies to easily and precisely detect the presence of the pathogens related to GTDs, allowing to readily take phytosanitary measures and/or proceed to plant removal in order to establish better vineyard management practices. Moreover, new practices and methods of detection, identification, and quantification of infectious material would allow imposing greater control on nurseries and plant exportation, limiting the movement of infected vines and thus avoiding the propagation of fungal inoculum throughout wine regionsinfo:eu-repo/semantics/publishedVersio

Los recursos educativos digitales en educación infantil. Analizando las visiones del profesorado

[Resumen] El impacto de las tecnologías en la población infantil de 3 a 6 años es evidente tanto en el contexto familiar como el educativo, donde los docentes asumen un rol fundamental en la selección, uso y creación de recursos didácticos digitales. El objetivo de este trabajo consiste en analizar las visiones del profesorado sobre los usos didácticos y organizativos de la tecnología en general y de los Recursos Educativos Digitales en particular, y la valoración tras su introducción y puesta en práctica en la etapa de Educación Infantil. En este estudio de corte cualitativo se empleó como instrumento de recogida de la información una entrevista semiestructurada a un total de 15 docentes que desempeñan su labor en el segundo ciclo de Educación Infantil en la Comunidad de Valencia, Canarias y Galicia. Los resultados muestran desacuerdos y acuerdos entre el profesorado, independientemente de la Comunidad, en cuanto a las diferencias percibidas en el uso de tecnologías por los más pequeños en los dos contextos de socialización primaria, escuela y hogar; la identificación de los factores que limitan o impulsan la integración de las tecnologías en el aula y la valoración de los recursos educativos digitales como elemento motivador en el proceso de enseñanza/aprendizaje, pero que conviven con recursos manipulativos en entornos híbridos. En definitiva, el proceso de transformación digital de las escuelas parece ir por detrás de la realidad social y depende en gran medida de las características de cada centro, así como de la formación y las actitudes de los docentes frente al uso de tecnologías en la primera infancia.[Abstract] The impact of technology on children aged 3 to 6 is evident in both the family and educational contexts, where teachers play a fundamental role in the selection, use and creation of digital resources and teaching materials. This study aims to analyse teachers' views on the didactic and organisational uses of technology in general and Digital Educational Resources in particular, their training and assessment after their introduction and implementation in the Early Childhood Education stage. In this qualitative study, a semi-structured interview was used to collect information from 15 teachers who work in the Second Cycle of Infant Education in the Community of Valencia, the Canary Islands and Galicia. The results show agreement among the teachers, regardless of the Community, regarding the differences perceived in the use of technology by the youngest children in the two primary socialisation contexts, school and home; the identification of the factors that limit or promote the integration of technologies in the classroom and the assessment of digital educational resources as a motivating element in the teaching/learning process, but which coexist with manipulative resources in hybrid environments. In short, the digital transformation process of schools seems to lag behind social reality and depends mainly on teacher training and attitudes

Los recursos educativos digitales en educación infantil. : Analizando las visiones del profesorado.

The impact of technology on children aged 3 to 6 is evident in both the family and educational contexts, where teachers play a fundamental role in the selection, use and creation of digital resources and teaching materials. This study aims to analyse teachers' views on the didactic and organisational uses of technology in general and Digital Educational Resources in particular, their training and assessment after their introduction and implementation in the Early Childhood Education stage. In this qualitative study, a semi-structured interview was used to collect information from 15 teachers who work in the Second Cycle of Infant Education in the Community of Valencia, the Canary Islands and Galicia. The results show agreement among the teachers, regardless of the Community, regarding the differences perceived in the use of technology by the youngest children in the two primary socialisation contexts, school and home; the identification of the factors that limit or promote the integration of technologies in the classroom and the assessment of digital educational resources as a motivating element in the teaching/learning process, but which coexist with manipulative resources in hybrid environments. In short, the digital transformation process of schools seems to lag behind social reality and depends mainly on teacher training and attitudes.El impacto de las tecnologías en la población infantil de 3 a 6 años es evidente tanto en el contexto familiar como el educativo, donde los docentes asumen un rol fundamental en la selección, uso y creación de recursos didácticos digitales. El objetivo de este trabajo consiste en analizar las visiones del profesorado sobre los usos didácticos y organizativos de la tecnología en general y de los Recursos Educativos Digitales en particular, y la valoración tras su introducción y puesta en práctica en la etapa de Educación Infantil. En este estudio de corte cualitativo se empleó como instrumento de recogida de la información una entrevista semiestructurada a un total de 15 docentes que desempeñan su labor en el segundo ciclo de Educación Infantil en la Comunidad de Valencia, Canarias y Galicia. Los resultados muestran desacuerdos y acuerdos entre el profesorado, independientemente de la Comunidad, en cuanto a las diferencias percibidas en el uso de tecnologías por los más pequeños en los dos contextos de socialización primaria, escuela y hogar; la identificación de los factores que limitan o impulsan la integración de las tecnologías en el aula y la valoración de los recursos educativos digitales como elemento motivador en el proceso de enseñanza/aprendizaje, pero que conviven con recursos manipulativos  en entornos híbridos. En definitiva, el proceso de transformación digital de las escuelas parece ir por detrás de la realidad social y depende en gran medida de las características de cada centro, así como de la formación y las actitudes de los docentes frente al uso de tecnologías en la primera infancia