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POLITÉCNICA DE MADRID (2008)

BIOGEOGRAFÍA Y PATOLOGÍA DEL GÉNERO FUSARIUM EN AMBIENTES SALINOS Y SEMIÁRIDOS DEL LITORAL MEDITERRÁNEO DE ESPAÑA

PALMERO LLAMAS DANIEL

Titre : BIOGEOGRAFÍA Y PATOLOGÍA DEL GÉNERO FUSARIUM EN AMBIENTES SALINOS Y SEMIÁRIDOS DEL LITORAL MEDITERRÁNEO DE ESPAÑA

Auteur : PALMERO LLAMAS DANIEL

Université de soutenance : POLITÉCNICA DE MADRID

Grade : Tesis Doctorales 2008

Résumé
This PhD thesis presents the analytical results of the presence of the Fusarium genus in coastal water samples of the Mediterranean Sea in the provinces of Granada and Almeria and water from the Andarax River bed in the province of Almeria (South-eastern of Spain). A total of 18 water samples were analyzed from the Andarax River, from which 10 species of Fusarium were isolated : F. anthophilum, F. acuminatum, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. oxysporum, F. proliferatum, F. solani and F. sambucinum. Five species were isolated from 23 water samples from the Mediterranean Sea : F. equiseti, F. verticillioides, F. oxysporum, F. proliferatum and F. solani. Of the total samples analyzed, 27.45% of the river water samples and 29.41% of the marine water samples presented a minimum of one Fusarium species during almost 12 months of sampling. This research shows also the analytical results of the pathogenicity of those isolated Fusarium species on barley, kohlrabi, melon and tomato seedlings. Pathogenicity was evaluated in 41 isolates from 8 Fusarium species taken from sea and river water : F. acuminatum, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. oxysporum, F. proliferatum, F. sambucinum and F. solani. All these species and their various isolates showed pathogenicity in pre- and post-seedling emergence. Myceliar growth of 90 strains of 9 different Fusarium species was tested on potato-dextrose-agar adjusted to different osmotic potentials with either KCl or NaCl (-1.50 ; -13,79 ; -41,79 ; -70,37 ; -99,56 and -144.54 bars). Fungal growth was maximal at 25ºC. Quantity and frequency pattern of myceliar development show an increasing average growth between -1,50 and -13,79 bars, with a notorious declining growth at potentials below -41.79 bars. Germination and viability of macroconidia and/or microconidia of 21 strains of F. solani, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. oxysporum and F. proliferatum and three control strains (F. oxysporum f.sp. lycopersici Race 0, F. oxysporum f.sp. radicis-cucumerinum and F. oxysporum f.sp. melonis Race 1) was studied in three time periods (0, 24 and 48 hours), in distilled water in response to a range of water potentials adjusted with NaCl. (0 ; -13,79 ; -41,79 ; -70,37 ; -99,56 and -144,54 bars). Conidia always germinated in distilled water. The pattern of conidia germination observed in F. verticilloides, F. oxysporum, F. proliferatum, F. chlamydosporum and F. culmorum was similar : a great diminution of spore germination was found in -13.79 bars solutions. Spore germination for F. solani was maximal at 48 h. and -13.79 bars with 21.33% of germination, 16% higher than germination in distilled water. F. equiseti shows the maximum germination percentage in -144.54 bars solution in 24 h time with 12.36% of germination. The viability analysis showed the great capacity of F. verticilloides strains to form viable colonies, even in such extreme conditions as -144.54 bars after 24 h. F. proliferatum colony formation was prevented from -70.37 bars on.

Descriptores : LIMNOLOGIA, PROTECCION DE CULTIVOS, HONGOS

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Page publiée le 25 avril 2009, mise à jour le 5 février 2019