Examinando por Materia "Hemileia vastatrix"

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Capillary electrophoresis as a tool for genotyping SH3 mediated coffee leaf rust resistance
(Universidad Nacional de Trujillo, 2021-03-10) Gutiérrez Calle, Savina Alejandra; Sánchez Díaz, Rosa A.; Delgado Silva, Yolanda Bedsabé; Montenegro, Juan D.; Gutiérrez Reynoso, Dina Lida; Maicelo Quintana, Jorge Luis; Guerrero Abad, Juan Carlos
Coffee is an important agricultural commodity in the world. However, it is susceptible to Hemileia vastatrix (Hv), an obligatory biotrophic fungus that causes coffee leaf rust (CLR). Natural resistance to rust has been identified in the wild species Coffea canephora and Coffea liberica. These species have been used in breeding programs where interspecific resistant hybrids have been generated. The SH3 gene, derived from C. liberica, has been shown to confer extreme and long-lasting resistance to Hv. A total of 167 accessions of the INIA’s Coffee Germplasm Collection of Peru (INIA-CGC) were screened with 4 markers linked to the SH3 gene. As positive controls, EA67 (C. liberica) and the hybrid S.288 (C. arabica x C. liberica) were used. Separation of PCR products was done by capillary electrophoresis, which allow to discriminate the alleles of each marker. For three markers, specific alleles for either C. arabica or C. liberica species were found. In all cases, S.288 exhibited specific alleles for both species; whereas the INIA-CGC accessions had exclusively C. arabica alleles and EA67 had C. liberica alleles. The BA-48-21O-f marker did not produce PCR fragments for any of the positive controls, suggesting that this marker is not as predictive as the other three to determine the presence of SH3. This work reports the existence of multiple alleles for the Sat244 marker; however, the collection does not have the SH3 mediated-resistance gene. Finally, the utility of capillary electrophoresis as a tool to identify alleles linked to SH3 was demonstrated.
Caracterización morfológica de cinco variedades de café (Coffea arabica L.) y su resistencia a la roya (Hemileia vastatrix), en el Valle del Alto Huallaga, Tingo María
(Dirección de Desarrollo Tecnológico Agrario. Instituto Nacional de Innovación Agraria, 2020-11-13) Cosme de la Cruz, Roberto Carlos; Buendía Molina, Marilyn; Adama Rojas, Enrique; Pocomucha Poma, Vicente
El objetivo fue caracterizar morfológicamente 13 caracteres cualitativos de cinco variedades de café de la especie Coffea arábica L. (Colombia, Catimor, Limani, Catuai y Caturra) y evaluar su grado de resistencia a la roya amarilla. La investigación se realizó, en el Centro Piloto de Innovación Tecnológica de café de la EEA Santa Ana, Tingo María. Se utilizó la lista de descriptores de café del International Resources Institute y se determinó los caracteres responsables de la mayor variabilidad en las variedades mediante el análisis multivariado de agrupamiento mediante software NTSYS 2.0. También, se evaluó la incidencia de la roya (Hemileia vastatrix) en las cinco variedades. De las 13 características cualitativas evaluadas en cinco variedades, nueve características fueron similares (hábito de ramificación: con muchas ramas primarias y secundarias, ángulo de inserción: semi erecto, forma de estípula: oval, forma de la hoja: lanceolada, forma de ápice: apiculada, color del peciolo: verde, forma de fruto: oblonga, color de semilla: amarillo y forma de semilla: obovada) y en las cuatro restantes se observó diferencias (forma de planta, color de hoja madura, color de brotes y color de fruto). También, la variedad caturra se mostró como la más susceptible a la roya, mientras las variedades Colombia, Catimor y Limani se mostraron resistentes a la roya.
Characterization of the horizontal resistance of coffee (Coffea arabica) to yellow rust (Hemileia vastatrix) in the field and laboratory
(The American Phytopathological Society, 2022-03-25) Paredes Espinosa, Richard; Mansilla Córdova, P. J.; Abad Romaní, Yudi Gertrudis; Gutiérrez Reynoso, Dina Lida; Guerrero Abad, Juan Carlos; Egoávil, G.
Between 2011–2013, yellow rust unleashed one of the most important phytosanitary crises in the coffee sector in Peru, causing a negative impact on the rural family economy. One of the factors associated with the intensification of the disease was the predominance of susceptible cultivars in agricultural systems. Faced with the need to rehabilitate the coffee park with new cultivars, the National Institute for Agrarian Innovation (INIA) has managed the installation of basic coffee germplasm for the development of the yellow rust resistance program, which is made up of 169 introductions from the departments of Pasco, Junín, Huánuco, Ucayali, Cajamarca, and Amazonas and obtained from 2015. The objective of the study was to evaluate the incidence and severity of epidemic conditions in the field and characterize the components of horizontal resistance, using the method of inoculations of H. vastatrix in separated coffee leaves in the laboratory. The epidemiological results collected from the field indicate that 12.43 and 20.71% of the genotypes showed complete and incomplete resistance, respectively; 66.86% showed high susceptibility to the pathogen. Three of the outstanding genotypes gave a typical horizontal resistance reaction when artificially inoculated with uredinospores on separated coffee leaves kept in a humid chamber.
Massive production of Hemileia vastatrix uredospores for infection of Coffea arabica seedlings
(Universidad Nacional de Trujillo, 2023-07-10) Hernández Amasifuen, Angel David; Rivadeneyra Chisquipama, Lenin; Padilla Dominguez, Amner; Paredes Espinosa, Richard; Guerrero Abad, Juan Carlos; Torres Flores, Elías; Peláez Rivera, Jorge Luis; Carvajal Vallejos, Fernando Marcelo; Gutiérrez Reynoso, Dina Lida; Corazon Guivin, Mike Anderson
Coffee leaf rust (Hemileia vastatrix) is the most important disease in coffee crops around the world. Currently, there is limited knowledge about mass production methodologies and ex-situ infection of H. vastatrix that lead to the development of different health characterization studies of Coffea or disease phenotyping. In this context, the aim of this research was to develop a simple protocol for the mass production of coffee rust uredospores under controlled conditions and to determine their infection in coffee seedlings. Uredospores of H. vastatrix were collected from infected plants in the “Chontal” coffee-growing area in San Martín, Peru. The viability of uredospore germination was evaluated, and a uredospores suspension (2 x 105 uredospores/mL) was prepared to inoculate coffee seedlings. Incidence and sporulation rates were evaluated after 43 days of inoculation. During the multiplication process of H. vastatrix uredospores, using controlled conditions (23±1 °C, ≈ 80% relative humidity and photoperiod of 16 hours of light) under an innovative system, the first symptoms of chlorosis were observed on coffee leaves 20 days after inoculation. Our findings show a 100% incidence of inoculated coffee plants with an average of 54 mg of H. vastatrix uredospores per plant and a 1.38 x 10-1 mg/cm2 sporulation rate. Finally, here we report a protocol that allows mass multiplication of H. vastatrix uredospores under controlled conditions, that would be useful in any time for coffee leaf rust bioassays.