Estudio de la sarna común de la papa en Uruguay: avances y desafíos. [Resumen]

La sarna común de la papa es una enfermedad de distribución mundial causada por bacterias del género Streptomyces. Se caracteriza por la presencia de lesiones necróticas con una textura corchosa en la superficie de los tubérculos que varían en severidad y apariencia dependiendo de la interacción entre la planta, las condiciones ambientales y el patógeno

Evaluación de fuentes de resistencia contra bacterias vasculares de importancia en el cultivo de tomate. [Resumen]

El tomate (Solanum lycopersicum L.) es una de las cuatro hortalizas principales del Uruguay considerando la superficie que ocupa, el número de productores y el valor bruto de producción. Los problemas sanitarios en los cultivos repercuten negativamente en la rentabilidad y, por consiguiente, en el ingreso económico de los productores. Los objetivos generales de este trabajo son la identificación de nuevas fuentes de resistencia a las enfermedades bacterianas de tomate producidas por Cmm y Rs, con potencialidad de ser utilizadas en el mejoramiento genético de tomate, y analizar la base genética de la resistencia

Comparación de metodologías de detección de Clavibacter michiganensis subsp. michiganensis en semillas de tomate. [p4*].

El cancro bacteriano del tomate causado por Clavibacter michiganensis subsp. michiganensis (Cmm) es considerada la enfermedad más importante de este cultivo a nivel mundial. En Uruguay, ha habido epidemias severas de esta enfermedad en los últimos años, causando importantes pérdidas económicas

Bacteriosis en cultivos de cebolla en Uruguay: identificación y análisis filogenético de las especies involucradas. [Resumen]

El suministro de cebolla muestra variaciones interanuales en Uruguay, asociadas a grandes pérdidas durante la conservación poscosecha. Las pudriciones bacterianas son la principal causa de tales pérdidas. El objetivo de este trabajo es por tanto identificar a nivel de especie los agentes causales de pudriciones de bulbos y lesiones foliares en cultivos de cebolla en Uruguay

Molecular Detection of Ralstonia solanacearum to Facilitate Breeding for Resistance to Bacterial Wilt in Potato

Potato bacterial wilt is caused by the devastating bacterial pathogen Ralstonia solanacearum. Quantitative resistance to this disease has been and is currently introgressed from a number of wild relatives into cultivated varieties through laborious breeding programs. Here, we present two methods that we have developed to facilitate the screening for resistance to bacterial wilt in potato. The first one uses R. solanacearum reporter strains constitutively expressing the luxCDABE operon or the green fluorescent protein (gfp) to follow pathogen colonization in potato germplasm. Luminescent strains are used for nondestructive live imaging, while fluorescent ones enable precise pathogen visualization inside the plant tissues through confocal microscopy. The second method is a BIO-multiplex-PCR assay that is useful for sensitive and specific detection of viable R. solanacearum (IIB-1) cells in latently infected potato plants. This BIO-multiplex-PCR assay can specifically detect IIB-1 sequevar strains as well as strains belonging to all four R. solanacearum phylotypes and is sensitive enough to detect without DNA extraction ten bacterial cells per mL in complex samples.The described methods allow the detection of latent infections in roots and stems of asymptomatic plants and were shown to be efficient tools to assist potato breeding programs

Specific Genes from the Potato Brown Rot Strains of Ralstonia solanacearum and Their Potential Use for Strain Detection

International audienceRalstonia solanacearum is the agent of bacterial wilt infecting >200 different plant species covering >50 botanical families. The genus R. solanacearum can be classified into four phylotypes and each phylotype can be further subdivided into sequevars. The potato brown rot strains of R. solanacearum from phylotype IIB, sequevar 1 (IIB1), historically known as race 3, biovar 2 strains, are responsible for important economic losses to the potato industry and threaten ornamental crop production worldwide. Sensitive and specific detection methods are required to control this pathogen. This article provides a list of 70 genes and 15 intergenes specific to the potato brown rot strains of R. solanacearum from phylotype IIB1. This list was identified by comparative genomic hybridization on microarray and subsequent polymerase chain reaction validation with 14 IIB1 strains against 45 non-IIB1 strains that covered the known genetic diversity in R. solanacearum. The microarray used consisted of the previously described microarray representative of the phylotype I strain GMI1000, to which were added 660 70-mer oligonucleotides representative of new genomic islands detected in the phylotype IIB1 strain IPO1609. The brown rot strain-specific genes thus identified were organized in nine clusters covering 2 to 29 genes within the IPO1609 genome and 6 genes isolated along the genome. Of these specific genes, 29 were parts of mobile genetic elements. Considering the known instability of the R. solanacearum genome, we believe that multiple probes are required to consistently detect all IIB1 strains and we recommend the use of probes which are not part of genetic mobile elements