New treatments to disinfect vine cuttings with Phaeomoniella chlamydospora and the reason for the control

Petri disease is a problem for vineyard caused mainly by the fungus Phaeomoniella chlamydospora. Contaminated seedlings are source of inoculum for the disease. Treatment to disinfect vine rootstock cuttings for seedling production is hot water treatment (HWT) by 50 °C for 30 min, but the efficiency is contested. To improve its efficacy, the study aimed to assess the combination of the following methods and the reason for the control: i) exposition of the fungus to five different temperatures in HWT bath for 30 min; ii and iii) exposition of the fungus and also plants infected with P. chlamydospora to different disinfection treatments (biofumigation = soil + cabbage at 40 °C; temperatures of 40 and 23 °C, all in microcosm), in different periods (7, 14 and 21 days), with and without additional HWT (51 °C for 30 min). The results showed that HWT with high temperatures (55­70 °C) for 30 min inactivated the fungus. Biofumigation technique at 40 °C and the temperature solely of 40 °C applied for up to 21 days and combined with HWT (51 °C for 30 min) inhibited mycelial growth and inactivated the fungus in vine plant tissues without compromising the rooting.

Atividade antifúngica do extrato alcoólico de própolis, álcool de cereais e do óleo essencial de manjericão sobre Botrytis cinerea / Antifungal activity of propolis alcoholic extract, grain alcohol, and basil essential oil on Botrytis cinerea

A uva é uma fruta amplamente aceita pelos consumidores, além de ser produzida em larga escala no Brasil. Entretanto é uma cultura muito suscetível a perdas em pré-colheita ocasionadas por doenças e, entre elas, pode-se citar a podridão cinzenta do cacho, cujo agente causal é o fungo Botrytis cinerea. A busca por formas alternativas para o controle desse patógeno pode minimizar o uso de agrotóxicos, garantindo um alimento mais seguro. Objetivou-se avaliar o potencial antifúngico in vitro do extrato alcoólico de própolis, álcool de cereais e óleo essencial de manjericão (Ocimum basilicum), autoclavados ou não, sobre o crescimento micelial de Botrytis cinerea, ao longo do tempo de exposição. Os tratamentos avaliados foram: extrato alcoólico de própolis e álcool de cereais, ambos nas concentrações 0, 2,5, 6,25, 12,5%; e óleo essencial de manjericão, nas concentrações 0, 0,25, 0,50, 1%. Para a obtenção do crescimento micelial foram realizadas medidas em sentidos diametralmente opostos, com um paquímetro digital, durante 0, 24, 48, 72, 96, 120 e 144 h de exposição, para o cálculo da taxa de inibição do crescimento micelial (ICM, %). O experimento foi realizado em duplicata, sendo os tratamentos dispostos em esquema fatorial 4x7 (concentrações x tempos) e os dados foram analisados por comparação de médias (teste de Tukey, p ≤ 0,05), desdobrando a interação, quando significativa. Todos os tratamentos contendo óleo essencial de manjericão autoclavado e não autoclavado foram eficientes na inibição do crescimento micelial de B. cinerea. A autoclavagem do extrato alcoólico de própolis proporciona maior eficácia para o controle do patógeno do que a não autoclavagem. Para o álcool de cereais, a autoclavagem interfere na eficiência de controle de B. cinerea.

Grape is a fruit widely accepted by consumers, besides being produced in large scale in Brazil. However, it is a crop very susceptible to losses in pre-harvest and, among the main diseases responsible for these losses, we can mention the gray rot of the bunch, whose causal agent is the fungus Botrytis cinerea. The search for alternative ways to control this pathogen can minimize the use of agrochemicals, ensuring a safer food. The aim of this study was to evaluate the in vitro antifungal potential of propolis alcoholic extract, cereal alcohol and basil oil (Ocimum basilicum), autoclaved or not, on the mycelial growth of Botrytis cinerea, during the exposure time. The treatments evaluated were: alcoholic extract of propolis and cereal alcohol, both in concentrations 0.0, 2.5, 6.25, 12.5%; and basil oil, at concentrations 0.25, 0.50, 1.00%. In order to obtain the mycelial growth, measurements were carried out in diametrically opposite directions, with a digital caliper, during 0, 24, 48, 72, 96, 120 and 144 hours of exposure, to calculate the rate of inhibition of mycelial growth (IMG, %). The experiment was performed in duplicate, with the treatments arranged in a factorial scheme 4x7 (concentrations x times) and the data were analyzed by means comparison (Tukey's test, p ≤ 0.05), unfolding the interaction, when significant. All treatments containing autoclaved and non-autoclaved basil essential oil were efficient in inhibiting the mycelial growth of B. cinerea. The autoclaving of the propolis alcoholic extract provides greater efficacy for the control of the pathogen than non-autoclaving. For cereal alcohol, autoclaving interferes with the control efficiency of B. cinerea.

Atividade antifúngica do extrato alcoólico de própolis, álcool de cereais e do óleo essencial de manjericão sobre Botrytis cinerea / Antifungal activity of propolis alcoholic extract, grain alcohol, and basil essential oil on Botrytis cinerea

A uva é uma fruta amplamente aceita pelos consumidores, além de ser produzida em larga escala no Brasil. Entretanto é uma cultura muito suscetível a perdas em pré-colheita ocasionadas por doenças e, entre elas, pode-se citar a podridão cinzenta do cacho, cujo agente causal é o fungo Botrytis cinerea. A busca por formas alternativas para o controle desse patógeno pode minimizar o uso de agrotóxicos, garantindo um alimento mais seguro. Objetivou-se avaliar o potencial antifúngico in vitro do extrato alcoólico de própolis, álcool de cereais e óleo essencial de manjericão (Ocimum basilicum), autoclavados ou não, sobre o crescimento micelial de Botrytis cinerea, ao longo do tempo de exposição. Os tratamentos avaliados foram: extrato alcoólico de própolis e álcool de cereais, ambos nas concentrações 0, 2,5, 6,25, 12,5%; e óleo essencial de manjericão, nas concentrações 0, 0,25, 0,50, 1%. Para a obtenção do crescimento micelial foram realizadas medidas em sentidos diametralmente opostos, com um paquímetro digital, durante 0, 24, 48, 72, 96, 120 e 144 h de exposição, para o cálculo da taxa de inibição do crescimento micelial (ICM, %). O experimento foi realizado em duplicata, sendo os tratamentos dispostos em esquema fatorial 4x7 (concentrações x tempos) e os dados foram analisados por comparação de médias (teste de Tukey, p ≤ 0,05), desdobrando a interação, quando significativa. Todos os tratamentos contendo óleo essencial de manjericão autoclavado e não autoclavado foram eficientes na inibição do crescimento micelial de B. cinerea. A autoclavagem do extrato alcoólico de própolis proporciona maior eficácia para o controle do patógeno do que a não autoclavagem. Para o álcool de cereais, a autoclavagem interfere na eficiência de controle de B. cinerea.(AU)

Grape is a fruit widely accepted by consumers, besides being produced in large scale in Brazil. However, it is a crop very susceptible to losses in pre-harvest and, among the main diseases responsible for these losses, we can mention the gray rot of the bunch, whose causal agent is the fungus Botrytis cinerea. The search for alternative ways to control this pathogen can minimize the use of agrochemicals, ensuring a safer food. The aim of this study was to evaluate the in vitro antifungal potential of propolis alcoholic extract, cereal alcohol and basil oil (Ocimum basilicum), autoclaved or not, on the mycelial growth of Botrytis cinerea, during the exposure time. The treatments evaluated were: alcoholic extract of propolis and cereal alcohol, both in concentrations 0.0, 2.5, 6.25, 12.5%; and basil oil, at concentrations 0.25, 0.50, 1.00%. In order to obtain the mycelial growth, measurements were carried out in diametrically opposite directions, with a digital caliper, during 0, 24, 48, 72, 96, 120 and 144 hours of exposure, to calculate the rate of inhibition of mycelial growth (IMG, %). The experiment was performed in duplicate, with the treatments arranged in a factorial scheme 4x7 (concentrations x times) and the data were analyzed by means comparison (Tukey's test, p ≤ 0.05), unfolding the interaction, when significant. All treatments containing autoclaved and non-autoclaved basil essential oil were efficient in inhibiting the mycelial growth of B. cinerea. The autoclaving of the propolis alcoholic extract provides greater efficacy for the control of the pathogen than non-autoclaving. For cereal alcohol, autoclaving interferes with the control efficiency of B. cinerea.(AU)

Esterase isozymes patterns of grape vine (Vitis vinifera L) are altered in response to fungicide exposure / Padrões de isozimas Esterases de videira (Vitis vinifera L) alterados em resposta à exposição a fungicidas

Current analysis characterizes the effect of different fungicides often applied for pest control on a-and b-esterase patterns of four economically important table-wine grape cultivars (Italia, Rubi, Benitaka and Brasil) of Vitis vinifera. The a- and b-esterase patterns in bud leaves of the cultivars were assessed by native PAGE analysis. Cabrio Top® compound inhibited Est-2, Est-5, Est-6, Est-7, Est-8, Est-9 and Est-10 carboxylesterases, whereas Est-4, Est-11, Est-12, Est-13, Est-14 acetylesterases and Est-16 carboxylesterase were detected as weakly stained bands. Carboxylesterases and acetylesterases were also detected as weakly stained bands when exposed to fungicides Orthocide 500®, Positron Duo® and Folicur PM®. No changes in a- and b-esterase patterns were reported when the vines were exposed to the fungicides Rovral SC®, Kumulus DF®, Curzate M®, Score® or Cuprogarb 500®. The evidence of functional changes in carboxylesterase and acetylesterase levels in current study is a warning to grape producers on the dangers inherent in the indiscriminate use of potent and modern fungicides extensively used in agriculture. The inhibition effect of fungicides on esterase isozyme molecules seems to be independent of the fungicide chemical.(AU)

O presente estudo caracterizou o efeito de diferentes fungicidas comumente aplicados como medidas de controle de pragas sobre padrões de - e -esterases de quatro importantes cultivares de uva de mesa (Itália, Rubi, Benitaka e Brasil) de Vitis vinifera. Os padrões de - e -esterases de brotos foliares das cultivares foram avaliados por PAGE. O composto Cabrio Top® inibiu as carboxilesterases EST-2, EST-5, EST-6, EST-7, EST-8, EST-9 e EST-10, enquanto as acetilesterases EST-4, EST-11, EST-12, EST-13, EST-14 e a carboxilesterase EST-16 foram detectadas como bandas fracamente coradas. As carboxilesterases e acetilesterases também foram detectadas como bandas fracamente coradas quando expostas aos fungicidas Orthocide 500®, Positron Duo® e Folicur PM®. Não foram observadas alterações nos padrões de - e -esterases quando as videiras foram expostas aos fungicidas Rovral SC®, Kumulus DF®, Curzate M®, Score® ou Cuprogarb 500®. A evidência de alterações em nível funcional em carboxilesterases e acetilesterases, apresentada neste estudo, pode servir como um alerta aos produtores de uva dos perigos inerentes ao uso indiscriminado de fungicidas potentes e modernos amplamente utilizados hoje na agricultura. O efeito dos fungicidas sobre as enzimas esterases parece ser independente do grupo químico ao qual pertence o fungicida.(AU)

Characterization of pectinase activity for enology from yeasts occurring in Argentine Bonarda grape

Pectinolytic enzymes are greatly important in winemaking due to their ability to degrade pectic polymers from grape, contributing to enhance process efficiency and wine quality. This study aimed to analyze the occurrence of pectinolytic yeasts during spontaneous fermentation of Argentine Bonarda grape, to select yeasts that produce extracellular pectinases and to characterize their pectinolytic activity under wine-like conditions. Isolated yeasts were grouped using PCR-DGGE and identified by partial sequencing of 26S rRNA gene. Isolates comprised 7 genera, with Aureobasidium pullulans as the most predominant pectinolytic species, followed by Rhodotorula dairenensis and Cryptococcus saitoi. No pectinolytic activity was detected among ascomycetous yeasts isolated on grapes and during fermentation, suggesting a low occurrence of pectinolytic yeast species in wine fermentation ecosystem. This is the first study reporting R. dairenensis and Cr. saitoi species with pectinolytic activity. R. dairenensis GM-15 produced pectinases that proved to be highly active at grape pH, at 12 °C, and under ethanol and SO2 concentrations usually found in vinifications (pectinase activity around 1.1 U/mL). This strain also produced cellulase activity at 12 °C and pH 3.5, but did not produce β-glucosidase activity under these conditions. The strain showed encouraging enological properties for its potential use in low-temperature winemaking. (AU)

Effect of arbuscular mycorrhizal fungi on young vines in copper-contaminated soil

Abstract High copper (Cu) levels in uprooted old vineyard soils may cause toxicity in transplanted young vines, although such toxicity may be reduced by inoculating plants with arbuscular mycorrhizal fungi (AMF). The objective of this study was to evaluate the effects of AMF on the plant growth, chlorophyll contents, mycorrhizal colonization, and Cu and phosphorus (P) absorption in young vines cultivated in a vineyard soil contaminated by Cu. Commercial vineyard soil with high Cu levels was placed in plastic tubes and transplanted with young vines, which were inoculated with six AMF species (Dentiscutata heterogama, Gigaspora gigantea, Acaulospora morrowiae, A. colombiana, Rhizophagus clarus, R. irregularis) and a control treatment on randomized blocks with 12 replicates. After 130 days, the mycorrhizal colonization, root and shoot dry matter (DM), height increment, P and Cu absorption, and chlorophyll contents were evaluated. The height increment, shoot DM and chlorophyll contents were not promoted by AMF, although the root DM was increased by R. clarus and R. irregularis, which had the greatest mycorrhizal colonization and P uptake. AMF increased Cu absorption but decreased its transport to shoots. Thus, AMF species, particularly R. clarus and R. irregularis, contribute to the establishment of young vines exposed to high Cu levels.(AU)

Simultaneous and successive inoculations of yeasts and lactic acid bacteria on the fermentation of an unsulfited Tannat grape must

Interactions between yeasts and lactic acid bacteria are strain specific, and their outcome is expected to change in simultaneous alcoholic -malolactic fermentations from the pattern observed in successive fermentations. One Oenococcus oeni strain Lalvin VP41TM was inoculated with two Saccharomyces cerevisiae strains either simultaneously, three days after the yeast inoculation, or when alcoholic fermentation was close to finish. Early bacterial inoculations with each yeast strain allowed for the growth of the bacterial populations, and the length of malolactic fermentation was reduced to six days. Alcoholic fermentation by Lalvin ICV D80® yeast strain left the highest residual sugar, suggesting a negative effect of the bacterial growth and malolactic activity on its performance. In sequential inoculations the bacterial populations did not show actual growth with either yeast strain. In this strategy, both yeast strains finished the alcoholic fermentations, and malolactic fermentations took longer to finish. Lalvin ICV D80® allowed for higher viability and activity of the bacterial strain than Fermicru UY4® under the three inoculation strategies. This was beneficial for the sequential completion of both fermentations, but negatively affected the completion of alcoholic fermentation by Lalvin ICV D80® in the early bacteria additions. Conversely, Fermicru UY4®, which was rather inhibitory towards the bacteria, favored the timely completion of both fermentations simultaneously. As bacteria in early inoculations with low or no SO2 addition can be expected to multiply and interact with fermenting yeasts, not only are the yeast-bacterium strains combination and time point of the inoculation to be considered, but also the amount of bacteria inoculated.(AU)

Saccharomyces cerevisiae and non-Saccharomyces yeasts in grape varieties of the São Francisco Valley

The aims of this work was to characterise indigenous Saccharomyces cerevisiae strains in the naturally fermented juice of grape varieties Cabernet Sauvignon, Grenache, Tempranillo, Sauvignon Blanc and Verdejo used in the São Francisco River Valley, northeastern Brazil. In this study, 155 S. cerevisiae and 60 non-Saccharomyces yeasts were isolated and identified using physiological tests and sequencing of the D1/D2 domains of the large subunit of the rRNA gene. Among the non-Saccharomyces species, Rhodotorula mucilaginosa was the most common species, followed by Pichia kudriavzevii, Candida parapsilosis, Meyerozyma guilliermondii, Wickerhamomyces anomalus, Kloeckera apis, P. manshurica, C. orthopsilosis and C. zemplinina. The population counts of these yeasts ranged among 1.0 to 19 x 10(5) cfu/mL. A total of 155 isolates of S. cerevisiae were compared by mitochondrial DNA restriction analysis, and five molecular mitochondrial DNA restriction profiles were detected. Indigenous strains of S. cerevisiae isolated from grapes of the São Francisco Valley can be further tested as potential starters for wine production.