CONICET | Buscador de Institutos y Recursos Humanos

The main source of ochra1oxin A (OTA) in the wine production chain is due 10the iufection of grapes by black Aspergilli at pre-harvest stage. The main ochratoxigenic black Aspergillus species occurring on grapes are the biseriate Aspergillus niger aggregate and Aspergillus carbonarius. They are opportunistic fungi that may occur and forro OTA on grapes from veraison to harvest. Understanding the ecology of the black Aspergilli can provide tools for OTA management at all stages of grape production and processing. In the vineyard, the main inoculum source of OTA-producer fungi is the soil. The goal of this work was to evaluate the distribution of black Aspergilli in soil and grapes at harvest time in vineyards from the main wine- producer regions in Argentina. Soil and grapes samples were taken, during the 2007/08 harvest season, from 16 vineyards distributed in 7 agro-ecological regions (La Rioja, San Juan, Patagonia and, 4 areas from Mendoza). The black Aspergillus species were isolated and identified by morphology, and by PCR using species specific primers based on partial calmodulin gene. In grape samples, the iufection levels with black Aspergillus were dependent on the agro-eeological region evaluated, the highest levels were observed in Mendoza (North region), La Rioja and San Juan (53%, 47.5% Y 46% respectively). Species belonging to Aspergillus nigerAspergillus species occurring on grapes are the biseriate Aspergillus niger aggregate and Aspergillus carbonarius. They are opportunistic fungi that may occur and forro OTA on grapes from veraison to harvest. Understanding the ecology of the black Aspergilli can provide tools for OTA management at all stages of grape production and processing. In the vineyard, the main inoculum source of OTA-producer fungi is the soil. The goal of this work was to evaluate the distribution of black Aspergilli in soil and grapes at harvest time in vineyards from the main wine- producer regions in Argentina. Soil and grapes samples were taken, during the 2007/08 harvest season, from 16 vineyards distributed in 7 agro-ecological regions (La Rioja, San Juan, Patagonia and, 4 areas from Mendoza). The black Aspergillus species were isolated and identified by morphology, and by PCR using species specific primers based on partial calmodulin gene. In grape samples, the iufection levels with black Aspergillus were dependent on the agro-eeological region evaluated, the highest levels were observed in Mendoza (North region), La Rioja and San Juan (53%, 47.5% Y 46% respectively). Species belonging to Aspergillus nigerAspergillus niger aggregate and Aspergillus carbonarius. They are opportunistic fungi that may occur and forro OTA on grapes from veraison to harvest. Understanding the ecology of the black Aspergilli can provide tools for OTA management at all stages of grape production and processing. In the vineyard, the main inoculum source of OTA-producer fungi is the soil. The goal of this work was to evaluate the distribution of black Aspergilli in soil and grapes at harvest time in vineyards from the main wine- producer regions in Argentina. Soil and grapes samples were taken, during the 2007/08 harvest season, from 16 vineyards distributed in 7 agro-ecological regions (La Rioja, San Juan, Patagonia and, 4 areas from Mendoza). The black Aspergillus species were isolated and identified by morphology, and by PCR using species specific primers based on partial calmodulin gene. In grape samples, the iufection levels with black Aspergillus were dependent on the agro-eeological region evaluated, the highest levels were observed in Mendoza (North region), La Rioja and San Juan (53%, 47.5% Y 46% respectively). Species belonging to Aspergillus nigerAspergillus species were isolated and identified by morphology, and by PCR using species specific primers based on partial calmodulin gene. In grape samples, the iufection levels with black Aspergillus were dependent on the agro-eeological region evaluated, the highest levels were observed in Mendoza (North region), La Rioja and San Juan (53%, 47.5% Y 46% respectively). Species belonging to Aspergillus nigerAspergillus were dependent on the agro-eeological region evaluated, the highest levels were observed in Mendoza (North region), La Rioja and San Juan (53%, 47.5% Y 46% respectively). Species belonging to Aspergillus nigerAspergillus niger aggregate were isolated in 86.6 % of the samples, folIowed by A. carbonarius (7.8%) and Aspergilluscarbonarius (7.8%) and Aspergillus uniseriate (5.6%). A. carbonarius was isolated from 3 out of 7 regions evaluated, and the higher levels of infection were observed in samples obtained from San Juan and La Rioja. These later agroecological regions had semiarid climate, with low anoual rainfall and strong solar radiation, with summer temperatures that eould rise up to 40"C. In soil samples the UFC g-Iof black Aspergi llus were significantly different among the regions evaluated, the highest eount was observed in the Patagonia vineyards (18,500 UFC g-I), and the low eount Was observed in Mendoza (Valle de Veo region). There was not found eorrelation between the amount of soil inoculum and the percentage of grape iufection with black aspergilli, only was observed eorrelation between the presence of A. carbonarius in the soil samples and the grape samples from the same vineyard. AlI the A. carbonarius strains isolated were OTA producers, with a mean value of 16 ug g-I; while 9.8% ofthe strains belonging to A. nigercarbonarius was isolated from 3 out of 7 regions evaluated, and the higher levels of infection were observed in samples obtained from San Juan and La Rioja. These later agroecological regions had semiarid climate, with low anoual rainfall and strong solar radiation, with summer temperatures that eould rise up to 40"C. In soil samples the UFC g-Iof black Aspergi llus were significantly different among the regions evaluated, the highest eount was observed in the Patagonia vineyards (18,500 UFC g-I), and the low eount Was observed in Mendoza (Valle de Veo region). There was not found eorrelation between the amount of soil inoculum and the percentage of grape iufection with black aspergilli, only was observed eorrelation between the presence of A. carbonarius in the soil samples and the grape samples from the same vineyard. AlI the A. carbonarius strains isolated were OTA producers, with a mean value of 16 ug g-I; while 9.8% ofthe strains belonging to A. nigerAspergi llus were significantly different among the regions evaluated, the highest eount was observed in the Patagonia vineyards (18,500 UFC g-I), and the low eount Was observed in Mendoza (Valle de Veo region). There was not found eorrelation between the amount of soil inoculum and the percentage of grape iufection with black aspergilli, only was observed eorrelation between the presence of A. carbonarius in the soil samples and the grape samples from the same vineyard. AlI the A. carbonarius strains isolated were OTA producers, with a mean value of 16 ug g-I; while 9.8% ofthe strains belonging to A. nigerUFC g-I), and the low eount Was observed in Mendoza (Valle de Veo region). There was not found eorrelation between the amount of soil inoculum and the percentage of grape iufection with black aspergilli, only was observed eorrelation between the presence of A. carbonarius in the soil samples and the grape samples from the same vineyard. AlI the A. carbonarius strains isolated were OTA producers, with a mean value of 16 ug g-I; while 9.8% ofthe strains belonging to A. nigercarbonarius in the soil samples and the grape samples from the same vineyard. AlI the A. carbonarius strains isolated were OTA producers, with a mean value of 16 ug g-I; while 9.8% ofthe strains belonging to A. nigercarbonarius strains isolated were OTA producers, with a mean value of 16 ug g-I; while 9.8% ofthe strains belonging to A. nigerniger aggregate were positive for OTA production, with amean value ofO.98 ng g-I. Based on the results, the incidence of black aspergilli in grapes at harvest is not significantly correlated with the presence of these fungi in the soil. The incidence of A. carbonarius in soil and grape samples in Argentina is low, and it could be relevant only in some agro-eeological regions from the North ofthe eountry.carbonarius in soil and grape samples in Argentina is low, and it could be relevant only in some agro-eeological regions from the North ofthe eountry.

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