26 research outputs found

    Effects of crop sequences on soil population dynamics of Monosporascus cannonballus ascopsores and Monosporascus root rot and vine decline incidence

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    [EN] Crop sequences effect on the soil population dynamics of Monosporascus cannonballus ascospores and the incidence of Monosporascus root rot and vine decline (MRRVD), was investigated in a field in which three different cucurbit crops: melon, watermelon, and watermelon grafted onto Cucurbita rootstock, and tomato, were grown during two consecutive growing seasons. Cultivation of melon or watermelon crops in the first growing season resulted in an increase of soil ascopore densities. But, on the contrary, the soil ascospore densities in the second growing season were lower when grafted watermelon or tomatos were cultivated in the first growing season. In the second growing season, MRRVD incidence for each cucurbit crop was significantly different depending on the previous crop, being in general higher when melon or watermelon were the previous crops, slightly lower when the previous crop was grafted watermelon and the lowest when the previous crop was tomato. Disease incidence corresponded with the percentage of isolation of M. cannonballus from the roots, being always significantly lower when the previous crop was tomato. These results demonstrate the potential of crop rotation as a management strategy to reduce infection and reproduction of M. cannonballus, ascospore densities in soil and disease incidence in cucurbits.Ben Salem, I.; M'hamdi, M.; Armengol Fortí, J.; Boughalleb-Mhamdi, N. (2015). Effects of crop sequences on soil population dynamics of Monosporascus cannonballus ascopsores and Monosporascus root rot and vine decline incidence. International Journal of Current Microbiology and Applied Sciences (Online). 4(9):482-500. http://hdl.handle.net/10251/89413S4825004

    Effect of somatic cell count on milk composition and mozzarella cheese quality

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    The aim of this study was to investigate the effect of somatic cell count (SCC) on mozzarella cheese quality. Three categories of raw milk were selected: low (SCC 987 000 cells/ml). Cheeses were produced on the same day of milk collection and were vacuum packed in plastic bags and analysed weekly for 60 days at cold storage (4 °C). As somatic cell count increases, casein content, casein as a percentage of true protein, lactose content, and titratable acidity decrease significantly in raw milk. No significant differences were observed in moisture, fat, and total protein contents among mozzarella cheese samples from the different SCC categories. However, cheese samples produced from high SCC milk had significantly higher pH (6.83) compared to samples produced with low and medium SCC milk, 5.58 and 5.46, respectively. The extension of proteolysis was not significant for cheese samples made from raw milk with low SCC during the first 30 days of cold storage. Proteolysis levels increased significantly on the 15th storage day for cheeses made with medium and high SCC, whereas significant increases were only observed on the 45th storage day for cheeses made with low SCC

    Resistencia aumentada a Rhizoctonia solani por la expresión combinada de quitinasa y proteínas inactivantes de los ribosomas en patatas transgénicas

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    Potato (Solanum tuberosum L.) is susceptible to many fungal pathogens including Rhizoctonia solani. In the present study, the potato cultivar Desirée was transformed via Agrobacterium tumefaciens strain GV3101 containing the binary plasmid pGJ132 harboring both the chitinase (chiA) and rip30 genes. The potato leaf disc was used as an explant for transformation. PCR, Southern blot and Western blot were used for characterization of the transgenic plants. In this study it was shown that not all the plants developed in selective medium were positive for the corresponding gene using the PCR technique. Southern blot analysis confirmed that transgenic plants integrated 2-3 copies of chiA and rip30 genes respectively into their genome. The expression of the CHIA and RIP30 proteins was confirmed in the leaf extracts of the transgenic clones by Western blot analysis. Transgenic potato plants expressing rip30 and chiA genes showed enhanced resistance to R. solani in a greenhouse assay.La patata (Solanum tuberosum L.) es susceptible a muchos hongos fitopatógenos, incluyendo Rhizoctonia solani. En el presente estudio, se transformó el cultivar de patata ‘Desirée’ mediante Agrobacterium tumefaciens, cepa GV3101, que contiene el plásmido binario pGJ132 que alberga los genes quitinasa (chiA) y rip30. Se utilizaron discos de hojas como explante para la transformación de plantas. Se utilizaron las técnicas de PCR, Southern y Western blot para la caracterización de las plantas transgénicas. En este estudio se demostró, mediante PCR, que no todas las plantas que se desarrollaron en medio selectivo fueron positivas para el gen correspondiente. El análisis de Southern blot confirmó que las plantas transgénicas integraron en su genoma 2-3 copias de los genes chiA y rip30. Se llevó a cabo un ensayo de invernadero para evaluar la resistencia a R. solani de los clones transgénicos que expresan los transgenes. Las plantas transgénicas que expresan los genes rip30 y chiA mostraron una resistencia completa a R. solani

    Evaluation de la durabilité des exploitations laitières tunisiennes par la méthode IDEA

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    Assessment of Tunisian dairy farms durability using IDEA method. The sustainability of 30 dairy farms was evaluated using IDEA method “Indicators of durability of farms”. Based on statistical methods (PCA, ACH), the three scales of sustainability (agro-ecologic, socio-territorial, and economic) have been characterized for the surveyed farms and has allowed to build groups. “Production system” typology is relevant for describing farms by agro-ecological and economical scales. The socio-territorial scale gives the limiting sustainability value for most farms. Inside this scale, the main way of progress relies on employment and services improvement (services, contribution to employment and collective work). Economically, sustainability is determined by the level of efficiency and depends on financial independence. Socio-territorial scale is the only one which is not linked to production system and is based on farmer’s way of life. On the other end, global sustainability evaluation of farm as well as creating collective references mean to be able to analyze links between the three scales of sustainability

    Ribosome Inactivating Protein of barley enhanced resistance to Rhizoctonia solani in transgenic potato cultivar 'Desirée' in greenhouse conditions

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    In the present study, the potato cultivar 'Desirée' was transformed via Agrobacterium tumefaciens strain LBA4404 containing the plasmid pBIN19 which harbors the Ribosome Inactivating Protein (rip30). The potato leaf discs were used as an explant for transformation. The in vitro regeneration parameters (percentage of callus regenerated, number of shoots per callus, percentage of regenerated roots and percentage of the transgenic plants) were evaluated. The PCR technique was used for identification of transformed plants. Southern and Western blot analyses were applied for molecular characterization of the transgenic clones. A greenhouse assay was carried out to evaluate the resistance to Rhizoctonia solani pathogen of transgenic clones expressing the rip30 gene. The results revealed that not all the plants developed in selective medium were positive for the corresponding gene using the PCR technique. Southern blot analysis demonstrated that the tested transgenic plants integrated three copies of rip30 gene into their genome. The expression of the RIP30 protein was confirmed in the leaf extracts of the transgenic clones by Western blot analysis. Resistance evaluation of the transgenic plants in greenhouse conditions showed that disease incidence and severity were reduced for R. solani

    Phytochemicals, antioxidant and antifungal activities of Allium roseum var. grandiflorum subvar. typicum Regel

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    The chemical composition of essential oil hydrodistillized from Allium roseum var. grandiflorum subvar. typicum Regel. leaves was analyzed by GC and GC/MS. Nine extracts obtained from flowers, stems and leaves and bulbs and bulblets of A. roseum var. grandiflorum were tested for their total phenol, total flavonoid and total flavonol content. All these extracts and the essential oils from fresh stems, leaves and flowers were screened for their possible antioxidant and antifungal properties. The results showed that the hexadecanoic acid was detected as the major component of the leaf essential oil (75.9%). The ethyl acetate extract of stems and leaves had the highest antioxidant activity with a 50% inhibition concentration (IC50) of 0.35 ± 0.01 mg/mL of DPPH• and 0.71 ± 0.01 mg/mL of ABTS•+. All the extracts appeared to be able to inhibit most of the tested fungi. The essential oil of the leaves had an antifungal growth effect on Fusarium solani f. sp. cucurbitae and Botrytis cinerea (39.13 and 52.50%, respectively). This could be attributed to the presence of hexadecanoic acid, known for its strong antifungal activity. In conclusion, in addition to the health benefits of A. roseum, it can be used as an alternative pesticide in the control of plant disease and in the protection of agriculture product
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