Isolation and identification of fungi associated with Esca in Vinho Verde region (RDVV): northwest Portugal

In the Portuguese Vinho Verde region (RDVV), during the last years the esca incidence is taking serious proportions. In this context, in the summers of 2004 and 2005 three vineyards were selected (two within the Monção subregion and one outside) in order to isolate associated Esca-fungi. Cordons were taken from 10 infected Alvarinho cultivar grapevines showing esca foliar symptomatology. Results confirm the occurrence of species P. chlamydospora and P. angustius in RDVV. They identify for the first time the species P. viticola and P. inflatipes, both is this wine region and in the Alvarinho grape variety. Results show that there are different strains within one fungus specie in the majority of the isolated species, and also that the closer the vineyards, the higher the similarity of the fungi strains.Fundação para a Ciência e a Tecnologia (FCT) - bolsa (SFRHD/BD/32159/2006

Effects of Esca disease on leaf gas exchange of cv. Alvarinho in a vineyard of the Portuguese Vinho Verde region

Esca is a very complex disease that is usually noticed when the grapevine show external symptoms. However, the grapevines can be infected for a long period of time and rarely manifest the typical leaf symptoms. Moreover, little is know about the consequences of Esca on vineyard productivity. In Portugal, in Vinho Verde region, Alvarinho sub-region, most vineyards are infected with Esca. In this work we evaluate the impact of Esca on some physiological parameters of grapevines cv. Alvarinho.This preliminary work reveal the importance that these kind of physiological measurements can have in the valuation of the infected Esca grapevine physiological conditions. These results may be used as a pattern to predict the damage magnitude of Esca disease in grapevines.Fundação para a Ciência e a Tecnologia (FCT)Fundação Luso-American

Differential phenolic production of Vitis vinifera cv. Alvarinho leaves affected with Esca disease

Esca is a destructive disease that affects Vitis vinifera around the world leading to important losses in wine production. Information on the response of Vitis vinifera plants to this disease is still scarce. To study the defence mechanisms of Vitis plants to Esca, we analysed leaves from both infected and non-affected boughs of Vitis vinifera cv. Alvarinho, of the Vinho Verde region (North of Portugal). Phenolics were analysed by HPLC-DAD-MS and by multivariate statistical analysis.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/17944/200

«Phaeoacremonium chlamydosporum» and « Phaeoacremonium angustius» Associated with Esca and Grapevine Decline in «Vinho Verde» Grapevines in Northwes Portugal

Vinho Verde is a unique wine, exclusively produced in the northwest region of Portugal. The production of this wine is an important component of portuguese agriculture. The aims of the present work were to make a preliminary assessment of the presence of esca and grapevine decline in the Vinho Verde region, and to check for the presence of Phaeoacremonium spp. in diseased plants. The results showed that esca and grapevine decline do occur in the Vinho Verde region, and can be widespread in this region. From ten diseased grapevines we isolated nine strains of P. chlamydosporum, and one strain as P. angustius. Our results agree with other reports that P. chlamydosporum is frequently isolated from the wood of grapevines showing symptoms of esca or grapevine decline. P. aleophilum and P. inflatipes were not isolated from the plants examined in the present study. Instead, P. angustius was isolated from a diseased plant

First Report of Fusarium Wilt Caused by Fusarium oxysporum f. sp. basilici on Ocimum minimum in Portugal

Ocimum minimum L. (fine-leaved basil) is cultivated along the Douro Litoral Region in Portugal. In June 2009, a disease was observed in fine-leaved basil fields in three geographically separated locations: Maia, Rio Tinto, and São Mamede Infesta. Affected plants showed wilt symptoms, chlorotic leaves, and stem necrosis. Discolored vascular tissue was observed when the stems were cut longitudinally. For isolation, crown and stem sections (10 cm long) were surface disinfected for 1 min in 1.5% NaOCl and washed twice with sterile distilled water. The sections were cut longitudinally and small pieces of discolored vascular tissue were plated onto potato dextrose agar (PDA) amended with streptomycin sulfate (0.5 g liter–1). Plates were incubated at 25°C in the dark. Fusarium colonies were consistently isolated from symptomatic plants sampled from the three different locations and transferred to PDA and Spezieller Nährstoffarmer agar (SNA) culture media for morphological species identification (2). After 10 days of incubation at 25°C, all isolates were identified as F. oxysporum. A PCR-based assay was conducted with nine single-spored isolates (F2, F3, F4, F7, F8, F9, F10, F11, and F13) using the F. oxysporum f. sp. basilici specific primer pair, Bik 1 and Bik 2 (1). A single DNA fragment of 382 bp was amplified in all isolates, which confirmed the identification of F. oxysporum f. sp. basilici. Pathogenicity of all nine isolates was determined on 2-month-old fine-leaved basil seedlings growing in sterile peat moss. Plants were inoculated by watering the roots with 20 ml of a conidial suspension (106 conidia ml–1) harvested from 3-week-old cultures grown on PDA. Thirty-six replicates (each one in individual pots) for each isolate were used, with an equal number of control plants. Plants were maintained in a greenhouse at 15 to 20°C. Within 2 weeks of inoculation, all inoculated plants wilted and exhibited severe leaf and stem necrosis. The fungus was reisolated from vascular tissues of the crown area and the stems of symptomatic seedlings, fulfilling Koch's postulates. Control plants remained healthy. To our knowledge, this is the first report of F. oxysporum f. sp. basilici infecting fine-leaved basil in Portugal.Fundação para a Ciência e a Tecnologia (FCT

Differential phenolic production in leaves of Vitis vinifera cv. Alvarinho affected with esca disease

Esca is a destructive disease of complex etiology affecting grapevines worldwide. A major constraint to the study and control of esca is that the disease is not diagnosed until external leaf and/or fruit symptoms are visible; however external symptoms usually appear several years after infection onset. We studied the phenolic content of V. vinifera cv. Alvarinho leaves using high performance liquid chromatography diode array detection-mass spectrometry (HPLC-DAD-MS)/LC-MS. Leaves from affected cordons with and without visible symptoms (diseased and apparently healthy leaves, respectively) and leaves from asymptomatic cordons (healthy leaves) were analyzed. Application of principal components analysis (PCA) to HPLC data showed a clear separation between diseased, apparently healthy, and healthy leaves, with the apparently healthy leaves clustered in a medial position. Several compounds were highly correlated with diseased leaves indicating a differential phenolic production due to esca disease in V vinifera cv. Alvarinho leaves. Total phenolic production was shown to significantly increase in diseased leaves, compared to healthy leaves, with apparently healthy leaves containing a medial amount. Transcaffeoyltartaric acid, trans-coumaroyl-tartaric acid, quercetin-3-O-glucoside, quercetin-3-O-galactoside, kaempferol-3-glucoside and myricetin were identified among the compounds associated with disease and their content shown to change similarly to total phenolic production. This study shows that it is possible to discriminate between diseased, healthy and apparently healthy leaves by applying PCA to HPLC data.We acknowledge the collaboration of Palacio da Brejoeira Viticultores, SA. (Moncao, Portugal), namely Eng. Paulo Mendo. ML and MF were supported by Fundacao para a Ciencia e a Tecnologia through the Doctorate grants SFRH/BD/17944/2004 and SFRH/BD/32159/2006, respectively.info:eu-repo/semantics/publishedVersio