RESUMO

Sugarcane orange rust caused by Puccinia kuehnii has recently become an important disease in sugarcane crops and its spread is causing great concern to growers. In this study, we analyzed spores from symptomatic orange rust sugarcane leaves collected in multiple locations in Cuba in a 4-year-period in order to characterize morphological traits of P. kuehnii, establish an adequate molecular technique to characterize it, and determine its infection court in sugarcane. Orange rust caused by P. kuehnii was confirmed by polymerase chain reaction (PCR) and morphological characterization. AFLP markers detected high diversity in P. kuenhnii samples. Sequencing of rDNA regions, as expected, did not reveal differences and SSR markers designed for P. melanocephala could not be transferred to P. kuehnii. In addition to stomata, entry through prickles was also detected as a new infection court in sugarcane. Although the presence of pustules on the adaxial leaf surface was frequently detected, no clear correlation between this presence and density of stomata and/or prickles was found.(AU)

Assuntos

RESUMO

Sugarcane orange rust caused by Puccinia kuehnii has recently become an important disease in sugarcane crops and its spread is causing great concern to growers. In this study, we analyzed spores from symptomatic orange rust sugarcane leaves collected in multiple locations in Cuba in a 4-year-period in order to characterize morphological traits of P. kuehnii, establish an adequate molecular technique to characterize it, and determine its infection court in sugarcane. Orange rust caused by P. kuehnii was confirmed by polymerase chain reaction (PCR) and morphological characterization. AFLP markers detected high diversity in P. kuenhnii samples. Sequencing of rDNA regions, as expected, did not reveal differences and SSR markers designed for P. melanocephala could not be transferred to P. kuehnii. In addition to stomata, entry through prickles was also detected as a new infection court in sugarcane. Although the presence of pustules on the adaxial leaf surface was frequently detected, no clear correlation between this presence and density of stomata and/or prickles was found.

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RESUMO

Los microsatélites son repeticiones en bloques de motivos cortos que abarcan alrededor del 3 por ciento del genoma humano. En la actualidad se conocen más de 40 enfermedades neurológicas, neurodegenerativas y musculares, entre otras, asociadas a la inestabilidad mutacional de estas secuencias. La Ontología de Genes puede ser una herramienta muy útil para el estudio del papel funcional de las secuencias repetidas y para profundizar en la comprensión de la etiología molecular de las enfermedades vinculadas a este tipo de secuencia. En este estudio se exploran las distribuciones de frecuencias de repetidos de mononucleótidos en las regiones codificadoras y no codificadoras para la mayor parte de los genes del Genoma Humano. Además se determinan los componentes celulares, las funciones moleculares y los procesos biológicos que aparecen con mayor frecuencia en genes con repetidos de gran tamaño. En general, fueron estadísticamente significativas las categorías de la Ontología de Genes relacionadas con los ácidos nucleicos, fundamentalmente con la transcripción, la regulación del ciclo celular, los procesos musculares, los receptores vinculados a la transducción de señales y a la sinapsis, así como con los implicados en el desarrollo del Sistema Nervioso Central. Se encontraron muy pocas combinaciones significativas de 2 y 3 categorías de Ontología de Genes y éstas estaban relacionadas principalmente con los ácidos nucleicos. Este trabajo contribuirá al establecimiento de patrones de normalidad en términos de frecuencia de repetidos asociados a categorías de Ontología de Genes, información valiosa para la determinación y comprensión de los umbrales de tamaño de repetidos relacionados con el riesgo a padecer determinadas enfermedades(AU)

Microsatellites are short tandem repeats that represent the 3 percent of the human genome. At present, more than 40 neurological, neurodegenerative, muscular and other diseases associated with the mutational instability of this kind of sequences are known. Gene Ontology may be a very useful tool for studying the functional role of these repetitive sequences and to get an insight into the molecular etiology of these diseases. In this study, the frequency distributions of mononucleotide repeats in coding and non-coding sequences for nearly all genes from the human genome were examined. All the cellular components, molecular functions and biological processes associated with the genes that have the longest repeats were investigated. As a general rule, the statistically significant gene ontology categories investigated corresponded to the nucleic acids, basically those related to the transcription, the cell cycle regulation, the muscular processes, the receptors linked to signals transduction and synapses, as well as those involved in the development of the Central Nervous System. Few significant two and three gene ontology combinations were found and they were predominantly related to nucleic acids. This work will be helpful to establish the normality distributions patterns of repeats associated with the main gene ontology terms, a valuable information for determining and understanding the size threshold of short tandem repeats associated with the risk to contract certain diseases(AU)

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RESUMO

El Síndrome Frágil X (SFX) es la forma más frecuente de retraso mental en varones. El defecto molecular consiste en un aumento en el número de tripletes CGG (superiores a 50) en la región 5del locus FMR1 que codifica para la proteína FMRP. En el presente estudio se analizó mediante la técnica de Southern Blot a 39 miembros de 8 familias bajo sospecha clínica de esta entidad genética. El diagnóstico molecular posibilitó confirmar el diagnóstico clínico de Síndrome de Frágil X. El conocimiento del genotipo de las mujeres portadoras es de suma importancia para garantizar un adecuado asesoramiento genético…(AU)

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