Juan Pablo González

Arabidopsis thaliana: A model host plant to study plant-pathogen interaction using Chilean field isolates of Botrytis cinerea

One of the fungal pathogens that causes more agriculture damage is Botrytis cinerea. Botrytis is a constant threat to crops because the fungus infects a wide range of host species, both native and cultivated. Furthermore, Botrytis persists on plant debris in and on the soil. Some of the most serious diseases caused by Botrytis include gray mold on vegetables and fruits, such as grapes and strawberries. Botrytis also causes secondary soft rot of fruits and vegetables during storage, transit and at the market. In many plant-pathogen interactions, resistance often is associated with the deposition of callose, accumulation of autofluorescent compounds, the synthesis and accumulation of salicylic acid as well as pathogenesis-related proteins. Arabidopsis thaliana has been used as a plant model to study plant-pathogen interaction. The genome of Arabidopsis has been completely sequenced and this plant serves as a good genetic and molecular model. In this study, we demonstrate that Chilean field isolates infect Arabidopsis thaliana and that Arabidopsis subsequently activates several defense response mechanisms associated with a hypersensitive response. Furthermore, we propose that Arabidopsis may be used as a model host species to analyze the diversity associated with infectivity among populations of Botrytis cinerea field isolates.

Coccidias aviares de gallineros industriales de Chile

With the purpose of identifying the coccidia species in poultry farms of Chile, 51 fecal samples (of 50 chickens each)were collected. Through flotation coprological examination of 10% of samples, oocysts of Eimeria maxima were identified. The remaining portion of the samples, was suspended in a 2.5% potassium bichromate solution, to allow the sporulation of oocysts which were then suspended in tap water and administered to 6 chickens 21 days old free of coccidia infection through a gastroesophagic tube. The identification of Eimeria species was done through measurement of the prepatent period, size of squizonts and type and locations of the intestinal lesions produced. Seven Eimeria species were found with the next frequency: E. maxima 48 %, E. praecox 62%, E. mitis 68%, E. tenella 14%, E. necatrix 14%, E. mivati 8% and E. acervulina 48%. E. brunetti and E. hagani were not detected. Mixed infections were the most frequent finding, being very common to detect the presence of 4 species simultaneously.

Características macro y microscópicas del Guayacán

El guayacan (Porlieria chilensis Johnst.) es un arbusto o arbol pequeno endemico de Chile perteneciente a la familia Zygophyllaceae, se distribuye entre la IV y VI region del pais, esta muy adaptado a sitios secos y aridos, creciendo en los faldeos cordilleranos y en las pendientes rocosas de los cerros. Esta clasificada en la categoria de especie Vulnerable. En este estudio se describen las caracteristicas macroscopicas y microscopicas de su madera, como un aporte al conocimiento de esta especie vegetal, unica representante de su genero en Chile. Las caracteristicas macroscopicas mas importantes de su madera, son el contraste de color entre la albura amarillenta y el duramen cafe oscuro a verde olivaceo, lo que le otorga un veteado muy decorativo, que unido a su gran dureza la hacen una madera muy apreciada por los artesanos de la IV Region. Microscopicamente presenta porosidad difusa, poros solitarios, fibras de paredes muy gruesas, parenquima apotraqueal difuso en agregados, radios lenosos uniseriados y estratificados. Abstract Guayacan (Porlieria chilensis Johnst.) is a small tree or shrub endemic of Chile, belong to the Zygophyllaceae family, distributed between Region IV and VI of country, is to very adapted drier sites, growing in rocky mountain slope. This specie is classified under Vulnerable category. The study described the macroscopic and microscopic characteristics of this wood, contributing at knowledge of this plant, the only represent of its genera in Chile. The more important macroscopic characteristics of wood are the contrast of color between its yellow sapwood and dark brown to green olive heartwood, obtaining an decorative figure, that joint to its hardness are characteristics very appreciated by the handicraftsman of Region IV. Microscopically presents difuse-porous, solitary vessel, fibres very thick-walled, axial parenchyma diffuse-in-aggregates, uniseriate rays and storied.