Caracterización y control de Cylindrocarpon SPP.agente causal del pie negro de la vid

El pie negro de la vid está causado por las especies fúngicas Cylindrocarpon liriodendri y C. macrodidymum. Estos patógenos afectan a las plantas de vid en los viveros y en las plantaciones jóvenes, principalmente de menos de cinco años de edad. En esta Tesis se ha caracterizado una colección de 82 aislados de Cylindrocarpon españoles, obtenidos de plantas de vid con síntomas de pie negro procedentes de viveros y de viñedos jóvenes. Los aislados fueron identificados mediante el estudio de las secuencias de las regiones BT1 del gen de la ß-tubulina e ITS del ADN ribosómico; y el análisis estadístico multivariante de las variables fenotípicas: morfología de las colonias, producción de conidios y crecimiento miceliar a diferentes temperaturas. Así, 26 de los aislados correspondieron a la especie C. liriodendri y 56 a C. macrodidymum. Barbados enraizados del portainjerto cultivar R 110 se inocularon con aislados representativos de C. liriodendri o C. macrodidymum. Todas las plantas inoculadas desarrollaron los síntomas típicos del pie negro confirmando la patogenicidad de ambas especies a vid. La técnica de análisis "Inter-Simple Sequence Repeat" se utilizó para estudiar la diversidad genética en C. liriodendri y C. macrodidymum. Los resultados mostraron diversidad genética en ambos patógenos siendo ésta mucho mayor en la especie C. macrodidymum. A su vez, los ensayos de patogenicidad efectuados con aislados seleccionados de ambas especies en plántulas de semillas obtenidas del cultivar Tempranillo, demostraron que C. macrodidymum presenta también variabilidad en virulencia. Todos los aislados de C. liriodendri y C. macrodidymum fueron caracterizados para determinar la posible presencia de micovirus. Sin embargo, con el método de extracción utilizado, que se basa en cromatografía en celulosa, no se detectó ARN de doble cadena en ninguno de ellos. Respecto al control, los ensayos efectuados in vitro demostraron que tanto los tratamientos con fAlaniz Ferro, SM. (2008). Caracterización y control de Cylindrocarpon SPP.agente causal del pie negro de la vid [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/2422Palanci

Diversity of the Ganoderma species in Uruguay

Ganoderma is a cosmopolitan genus that includes a great diversity of species. Many of them have been historically described based only on morphological characteristics; however, due to their morphological plasticity, there is no complete understanding about their relationship and taxonomic status. Commonly applied names, particularly in the southern Neotropics, come from species of North Hemisphere distribution (e.g. G. lucidum, G. resinaceum and G. applanatum). The objective of the present work was to perform a survey of Ganoderma species thriving in Uruguay. We aimed to identify and characterize them through molecular, morphological and ecological analysis. The results confirm the presence of four reddish laccate species first registered for Uruguay (G. dorsale, G. platense, G. martinicense and G. mexicanum), and one non-laccate species (G. australe s.l.) composed of two clades. The species are morphologically differentiated mainly by its stipe, pilear surface, context, pores, basidiospores and cutis cells. Regarding the ecological data, the species present differences in substrate preferences. In addition, a taxonomic discussion regarding phylogenetic relationships and taxonomic status of Uruguayan Ganoderma species is presented

Evaluation of grapevine rootstocks against soilborne pathogens associated with trunk diseases

[EN] The susceptibility of the grapevine rootstocks most commonly used in Spain to black-foot (Ilyonectria liriodendri and Dactylonectria macrodidyma-complex) and petri disease (Cadophora luteo-olivacea, Phaeomoniella chlamydospora and five species of Phaeoacremonium) pathogens was evaluated. Rooted cuttings of rootstocks 110R, 1103P, 140Ru, 161-49C, 196-17C, Fercal and SO4 were inoculated with black-foot pathogens by dipping their roots in conidial suspensions (5×105 conidia mL-1), planted in pots containing sterilized peat moss and placed in a greenhouse. After four months of incubation, root disease severity index and dry weights of shoots and roots were recorded for each plant. Regarding petri disease pathogens, one-year-old grapevine cuttings of five rootstocks (41B, 140Ru, 161-49C, 1103P and 110R) were vacuum-inoculated with spore suspensions (106 conidia mL-1) of the fungal species and planted in two fields. After four months, the proportion of vines that sprouted in spring was visually determined. At the end of the growing season, dormant plants were uprooted, washed, and assessed for undried shoot weight. Then, the stem of each grapevine cutting was transversally split at 10 cm from the base of the plant to estimate the percentage of vascular tissue discoloured on a scale of 0 to 4. All rootstocks inoculated with Ilyonectria and Dactylonectria species were affected by the disease in some degree, the rootstock 110R being the most susceptible to black-foot. Petri disease pathogens caused a significant reduction of sprouting and shoot weight, as well as a significant increase of disease severity percentage in all grapevine rootstocks with the exception of 161-49C. Both 110R and 140Ru were the most susceptible. Grapevine rootstocks showed different levels of disease resistance, being the rootstock 110R the most susceptible to both diseases and the 161-49C rootstock the most tolerant to petri disease infection.Gramaje Pérez, D.; Alaniz Ferro, SM.; Abad Campos, MP.; García Jiménez, J.; Armengol Fortí, J. (2016). Evaluation of grapevine rootstocks against soilborne pathogens associated with trunk diseases. Acta Horticulturae. 1136:245-249. doi:10.17660/ActaHortic.2016.1136.34S245249113