Memoria para optar al Título Profesional de: Ingeniero Agrónomo / Se evaluó la capacidad bioantagónica in vitro de diferentes bacterias (Bacillus sp. cepa 1; Paenibacillus sp. cepas 1 y 2) y hongos (cepas 24-A y 24-B de Clonostachys rosea; cepas Th 650, Th 12A 10.1 y ThF 2-1 de Trichoderma harzianum) y los productos comerciales Actinovate® (Streptomyces lydicus WYEC 108) y Trichonativa® (Trichoderma virens, Trichoderma harzianum y Trichoderma parceramosum) en el control de 13 cepas de basidiomycotas recuperadas desde plantas de vid con síntomas de enrollamiento clorótico y degradación de la madera, provenientes de 3 regiones de Chile (IV Región de Coquimbo, V Región de Valparaíso y RM de Chile). Se caracterizaron las diferentes cepas de hongos aislados respecto a temperatura (19, 22, 25 y 28ºC) y pH (5, 6, 7 y 8). La capacidad bioantagónica se determinó a través de pruebas de antagonismo directo realizado mediante cultivos duales y antagonismo por metabolitos difusibles. En los resultados de caracterización de las cepas recuperadas, se observó que el mayor crecimiento miceliar se obtuvo a 28ºC a un pH 6 del medio, determinándose ambos valores como los óptimos para el desarrollo de los aislados investigados. Acorde con los resultados obtenidos en antagonismo directo, todos los bioantagonistas demostraron tener un cierto grado de capacidad antagónica sobre las cepas. Mediante la inhibición del crecimiento miceliar, la bacteria que presentó un mayor efecto fue la cepa 1 de Paenibacillus sp., con un máximo de 63,5% de inhibición. En el caso de los hongos fueron todas las cepas de T. harzianum utilizadas, oscilando el máximo porcentaje de control entre un 82,7% para la cepa Th 650, un 84,6% para Th 12A 10.1 y 87,7% para la cepa ThF 2-1. En relación a los productos comerciales, Trichonativa® logró un 61,5% de inhibición miceliar, mientras que Actinovate® logró un 100% de inhibición, siendo por lo tanto S. lydicus WYEC108 el antagonista que ejerció el mayor efecto. Los resultados obtenidos en el ensayo de antagonismo mediante metabolitos difusibles ayudaron a corroborar el tipo de mecanismo de biocontrol que ejercieron los antagonistas. Las bacterias utilizadas para este ensayo reflejaron que básicamente son los metabolitos difusibles que producen, los que ejercen la inhibición de crecimiento miceliar de las cepas de basidiomycotas, obteniéndose con ambas cepas 1, de Bacillus sp. y Paenibacillus sp., valores en promedio superiores a 70%; en relación al producto comercial Actinovate®, se obtuvo una completa inhibición miceliar. Con respecto a los hongos C. rosea 24-B y T. harzianum ThF 2-1, estos mostraron una baja inhibición mediante la producción de metabolitos difusibles, obteniéndose valores en promedio que no superaron el 14% de inhibición de crecimiento miceliar, lo que indica que poseen otro tipo de mecanismos como en el caso de las cepas de T. harzianum. Para el producto comercial Trichonativa®, se obtuvo en promedio un 16,7% de inhibición miceliar, siendo éste el mayor dentro de los hongos. Los resultados obtenidos señalan a S. lydicus WYEC108 (Actinovate®) como al bioantagonista de mayor efecto. / The in vitro bioantagonistic capacity of different bacteria (Bacillus sp. strain 1, Paenibacillus sp. strains 1 and 2) and fungi (24-A and 24-B strains of Clonostachys rosea, and Th 650, Th 12A 10.1 and ThF 2-1 strains of Thrichoderma harzianum) and of the biofungicides Actinovate ® (Streptomyces lydicus WYEC 108) and Trichonativa ® (Trichoderma virens, Trichoderma harzianum and Trichoderma parceramosum) was evaluated in the control of 13 basidiomycota strains recovered from grapevines grown in three regions of Chile (IV Region of Coquimbo, V Region of Valparaiso and Metropolitan Region). The vines showed wood degradation and chlorotic leafroll symptoms. Different isolated fungus strains were characterized with respect to temperature (19, 22, 25, and 28ºC) and pH (5, 6, 7, and 8). The bioantagonistic capacity was determined by tests of direct antagonism with dual cultures and by diffusible metabolite antagonism. The results of recovered strain characterization showed that mycelial growth was highest with the culture medium at 28ºC and pH 6, indicating both values as optimum for the development of the investigated isolates. According to the direct antagonism results, all bioantagonists demonstrated to have some degree of antagonistic capacity over recovered strains. Through mycelial growth inhibition, the bacterium that showed a better effect was Paenibacillus sp. strain 1, with a maximum of 63.5% of inhibition. In the case of fungi, all the used T. harzianum strains had excellent results with the highest control percentages being 82.7% for the Th 650 strain, 84.6% for the Th 12A 10.1 strain and 87.7% for ThF 2-1 strain. In relation to the biofungicides tested, Trichonativa ® achieved a maximum of 61.5% of mycelial inhibition, while Actinovate ® showed 100% of inhibition of the 13 basidomycota strains. The results obtained in the antagonism trial by diffusible metabolite helped to corroborate the type of biocontrol mechanism exerted by the antagonists. The bacteria used for this trial basically showed that the diffusible metabolites that they produce are the ones which exert mycelial growth inhibition of basidiomycota strains, with both Bacillus sp. and Paenibacillus sp. strains 1 showing average values over 70%. With respect to Actinovate ®, complete mycelial growth inhibition was obtained with this biofungicide. Regarding fungi C. rosea 24-B and T. harzianum ThF 2-1, these showed low inhibition by diffusible metabolite production with average values not exceeding 14% of mycelial growth inhibition, which indicates that they have other types of mechanisms as in the case of T. harzianum strains. With Trichonativa ®, an average of 16.7% of mycelial growth inhibition was obtained, this biofungicide being the higher within the fungi used. The obtained results showed S. lydicus WYEC108 (Actinovate®) as the bioantagonist with higher effect.

El virus del enrollamiento de la papa (PLRV) es responsable de pérdidas severas en el rendimiento y calidad del cultivo de la papa en todo el mundo. Existen papas nativas y especies silvestres que presentan altos niveles de resistencia a PLRV (Solanum brevidens, S. tuberosum, S. chacoencse y S. raphanifolium). El desarrollo de nuevas variedades utilizando estas fuentes de resistencia es uno de los retos actuales del mejoramiento genético, sin embargo la naturaleza genética del cultivo de la papa que se desea mejorar es en la mayoría de los casos incompatible entre cultivos, sumándose a ello que la obtención de estos cultivos mejorados es cerca de 20 años. Por lo tanto la inserción directa de un gen que confiere resistencia a una variedad de importancia comercial tiene una ventaja muy significativa. En la presente tesis se evaluaron diez eventos (variedad Desiree) transformados con un constructo tipo hairpin que contenía el sistema de ARN de interferencia (ARNi), el cual mantiene activo y constante la formación del ARNdc entre las secuencias homólogas del transgen y el virus de PLRV. Los eventos fueron caracterizados por PCR y Southern blot, evidenciándose que tenían en su genoma entre una a dos copias del transgen. Los ensayos serológicos de DASELISA seleccionaron cuatro eventos con alta resistencia (bajas o nulas concentraciones del virus PLRV) durante su infección primaria, secundaria y terciaria. Finalmente, se determinó por Northern Blot que la resistencia a PLRV está relacionada con la presencia de los fragmentos pequeños de ARN (ARNsi) formados a partir del mecanismo de ARNi. -- PALABRAS CLAVE: Papa, transformación, PLRV, ARNi, ARNsi. / -- Potato Leafroll Virus (PLRV) is responsible for severe losses in yield and quality of potato worldwide. There are native and wild potatoes with high levels of resistance to PLRV (Solanum brevidens, S. etuberosum, and S. chacoencse raphanifolium).The development of new varieties using these sources of resistance is one of the current challenges of genetic improvement crop, however the genetic nature of the potato in most cases is incompatible between varieties, moreover to obtain the desired resistance takes over 20 years. Therefore the direct insertion of a gene that confers resistance to a variety of commercial importance have a significant advantage. The present thesis evaluated ten events (Desiree variety) transformed with a hairpin-type construct, containing the RNA interference system (RNAi), it will keep active and constant the formation of dsRNA between the homology sequence of transgene and PLRV. The events were characterized by PCR and Southern blot; they had in their genome from one to two copies of the transgene. Serological tests of DAS-ELISA selected four events with high resistance (low or zero concentrations of PLRV) during primary, secondary and tertiary infection. Finally, it was determined by Northern Blot that the resistance to PLRV is related to the presence of fragments of small interference RNA (siRNA) formed from the mechanism of RNAi. -- KEY WORDS: Potato, transformation, PLRV, RNAi, siRNA. / Tesis

Trilobites were a successful group of marine arthropods that thrived for much of the Palaeozoic Era. Akey innovation of trilobites involved the capacity to enrol their biomineralized exoskeletons for protection; a trait that appeared early in their evolutionary history during the Cambrian Period. However, even though there has been much interest in the description of enrolment-related anatomical adaptations, and different styles of enrolment, the kinematic aspect has just begun to be explored—not just as means of understanding trilobite movements, but also as a potential driver of evolution. In this study, with the use of the open-source software Blender, four models of three different species of Ordovician trilobites(two phacopines and two illaenines) were constructed and later submitted to enrolling simulations. Different angle metrics were measured and then compared between simulations to analyse the performance of the developed methodology, and between the different models to reveal potential evolutionary or developmental trends. Results suggest a clear relationship between the kind of higher-level taxonomic groups analysed and the angle arrangement of the trunk elements in an enrolled position. In contrast, the same was not as evident when comparing the measured angle metrics against the total number of segments. Illaenina models consistently resulted in lower angles between segments required to enrol, suggesting a more efficient enclosure of the body favoured by bigger and more spherical proportions of cephalon and pygidium. This study contributes to a growing field in palaeontology and provides new, detailed enrolment data for several trilobite species. In future, such data should be synthesized with those from previous and future studies to analyse the evolutionary and developmental history of trilobites from this novel perspective.