One of the most efficient options for the control of late blight disease in potato (Solanum tuberosum) is the development of resistant varieties to Phytophthora infestans mediated by the direct transfer of resistance (R) genes through genetic engineering. In the present work, we used Solanum bulbocastanum RB gene to confers broad spectrum resistance to P. infestans races. To that end, Agrobacterium - mediated genetic transformation was used to transform a susceptible potato variety, Desiree, with the binary vector pCIP68 harboring the RB gene. As a result, 19 transformed plants containing the RB gene were obtained. kanamycin resistance test and polymerase chain reaction (PCR) assays confirmed the integration of the T-DNA in the potato genome. The 19 transformed plants, also called transgenic events were subjected to infection under biosafety greenhouse conditions. Phytophthora infestans isolate POX067 of the EC-1 clonal lineage, commonly find in Peru, was used for the infection. Three of the 19 plants ([RB]54, [RB]56 and [RB]70) show high resistance levels to isolate POX067 of P. infestans.

Una de las opciones para el control de la enfermedad del tizón tardío de la papa es el desarrollo de variedades resistentes a Phytophthora infestans mediante la transferencia directa de genes de resistencia (R) por ingeniería genética. En el siguiente trabajo de investigación, se usó el gen RB de Solanum bulbocastanum, el cual otorga un amplio espectro de resistencia a razas de P. infestans. Para dicho fin, se transformó genéticamente vía Agrobacterium la variedad susceptible de papa Desiree (Solanum tuberosum) con el vector binario pCIP68 que contiene el gen RB. Como resultado, se obtuvieron 19 plantas transformadas con el gen RB, confirmadas por la prueba de resistencia a kanamicina y por la prueba de reacción en cadena de la polimerasa (PCR). Las 19 plantas transgénicas fueron sometidas a infección en invernadero bajo condiciones de bioseguridad con el aislamiento POX067 de P. infestans perteneciente al linaje clonal EC-1 que es dominante en el Perú. Tres de las 19 plantas ([RB]54, [RB]56 y [RB]70) presentaron un alto nivel de resistencia al aislamiento POX067 de P. infestans.

The Oomycete Phytophthora infestans (Mont.) de Bary, the causal agent of the disease known as late blight, is primarily responsible for the decreased in production performance and potato crops worldwide. The integration of the complete R genes sequences in the potato genome using Agro-transformation appears an alternative to be considered in the fight against this pathogen. The Rpi-blb2 gene (R gene) from the wild species Solanum bulbocastanum Dunal shows a broad resistance to isolates of P. infestans, making it an important candidate for plant breeding studies. This paper reports the integration of the Rpi-blb2 gene into potato var. Désirée genome by Agrobacterium tumefaciens - mediated transformation system, the molecular characterization of 29 events transformed and whole plant infection with isolate POX67 of P. infestans from Peru. Désirée events [Rpi-blb2] 4 and Désirée [Rpi-blb2] 30, showed a substantial resistance to P. infestans infection confirming complete transfer of the Rpi-blb2 gene from a wild species to a cultivated species by genetic transformation.

El Oomiceto Phytophthora infestans (Mont.) de Bary, agente causal de la enfermedad denominada tizón tardío, es el principal responsable del déficit en rendimiento y producción en el cultivo de papa a nivel mundial; una de las alternativas a considerar en la lucha contra este patógeno es la integración de secuencias completas de genes R en el genoma de la papa a través de Agrotransformación. El gen Rpi-blb2 (gen R) de la especie silvestre Solanum bulbocastanum Dunal, presenta una amplia resistencia a los aislamientos de P. infestans, haciéndolo un importante candidato en los estudios de mejoramiento genético en plantas. En el presente trabajo se describe la introducción del gen Rpi-blb2 por Agrobacterium tumefaciens en el genoma de la papa variedad Désirée, la caracterización molecular de 29 eventos transformados e infección de plantas completas con el aislamiento POX067 de P. infestans obtenido en el Perú. Los eventos Désirée [Rpi-blb2] 4 y Désirée [ Rpi-blb2] 30, presentaron una resistencia considerable frente a la infección de P. infestans, comprobando de esta manera la transferencia del gen Rpi-blb2 de una especie silvestre a una cultivada mediante transformación genética.

Late blight is an important disease of potato in Ethiopia, causing up to 100% loss in susceptible cultivars. In this study, two putatively resistant cultivars of relatively recent introduction (Jalenie and Gudenie) and a widely grown susceptible cultivar (White Flower) were evaluated for late blight severity and yield under five different contact fungicide (mancozeb) regimes and in unsprayed plots. Trials were carried out at two major potato production locations in southern Ethiopia: Awassa and Kokate, located at 1700 and 2156 meters above sea level, respectively. Greater disease pressure occurred at Awassa but the three cultivars performed consistently based on relative disease severity levels at the two locations. While White Flower was assigned a susceptibility score of 8 (highly susceptible) in both sites, Jalenie had scores between 1 and 0, and Gudenie had scores of 3 and 4, in Awassa and Kokate, respectively. With Jalenie, one application of contact fungicide was sufficient in both trials, while for Gudenie, two sprays appeared more appropriate as little or no gain was clear with three or more sprays. With the susceptible White Flower, four sprays were beneficial but little benefit was evident with the fifth spray.