Caracterización fisiológica y molecular de la interacción Phaseolus (vulgaris: Rhizobium etli)

En este trabajo de tesis se utilizó el sistema P. vulgaris-R. etli como modelo para investigar la afinidad entre porotos pertenecientes a los centros de diversificación de Mesoamérica y de la región Andina sureña y los rizobios de esas regiones. Teniendo en cuenta los eventos que se desarrollan desde el inicio del diálogo molecular hasta la formación del nódulo fijador de nitrógeno, el presente trabajo de tesis pretende contribuir al conocimiento de la interacción entre genotipos de poroto y rizobios que coevolucionaron en el mismo centro geográfico.Facultad de Ciencias Exacta

Teaching learning Genetics at Veterinary Science College using ICT at Universidad Nacional de Río Negro

La genética es una ciencia relativamente moderna que nace con la llegada de Mendel y sus aportes al modo de herencia de los caracteres a fines de 1800. Es una ciencia que ha crecido exponencialmente en las últimas décadas y se ha diversificado en muchas especialidades. Las nuevas tecnologías de la información y comunicación (TIC) están a nuestra disposición para utilizar tanto en el aula como fuera de ella. El objetivo del trabajo fue el de innovar en la enseñanza-aprendizaje de Genética en la carrera de Veterinaria de la Universidad Nacional de Río Negro (UNRN) mediante una herramienta diferente de evaluación, así como a través del uso de diversas herramientas tecnológicas que facilitan el proceso de enseñanza y a aprendizaje.The science of genetics is relatively new, that begun with Mendel experiments and his contribution to the explanation of inheritance of different characteristics at the end of 1800’s. The science has grown all over this paste years and has diverse in many specialties. The goal of this work was to try to innovate in teaching genetics in Basics Genetics in Veterinary College of the Universidad Nacional de Río Negro using different types of evaluation and some digital tools to improve teaching and learning experience of Genetics.Ponencias.Facultad de Ciencias Veterinaria

Teaching learning Genetics at Veterinary Science College using ICT at Universidad Nacional de Río Negro

La genética es una ciencia relativamente moderna que nace con la llegada de Mendel y sus aportes al modo de herencia de los caracteres a fines de 1800. Es una ciencia que ha crecido exponencialmente en las últimas décadas y se ha diversificado en muchas especialidades. Las nuevas tecnologías de la información y comunicación (TIC) están a nuestra disposición para utilizar tanto en el aula como fuera de ella. El objetivo del trabajo fue el de innovar en la enseñanza-aprendizaje de Genética en la carrera de Veterinaria de la Universidad Nacional de Río Negro (UNRN) mediante una herramienta diferente de evaluación, así como a través del uso de diversas herramientas tecnológicas que facilitan el proceso de enseñanza y a aprendizaje.The science of genetics is relatively new, that begun with Mendel experiments and his contribution to the explanation of inheritance of different characteristics at the end of 1800’s. The science has grown all over this paste years and has diverse in many specialties. The goal of this work was to try to innovate in teaching genetics in Basics Genetics in Veterinary College of the Universidad Nacional de Río Negro using different types of evaluation and some digital tools to improve teaching and learning experience of Genetics.Ponencias.Facultad de Ciencias Veterinaria

Teaching learning Genetics at Veterinary Science College using ICT at Universidad Nacional de Río Negro

La genética es una ciencia relativamente moderna que nace con la llegada de Mendel y sus aportes al modo de herencia de los caracteres a fines de 1800. Es una ciencia que ha crecido exponencialmente en las últimas décadas y se ha diversificado en muchas especialidades. Las nuevas tecnologías de la información y comunicación (TIC) están a nuestra disposición para utilizar tanto en el aula como fuera de ella. El objetivo del trabajo fue el de innovar en la enseñanza-aprendizaje de Genética en la carrera de Veterinaria de la Universidad Nacional de Río Negro (UNRN) mediante una herramienta diferente de evaluación, así como a través del uso de diversas herramientas tecnológicas que facilitan el proceso de enseñanza y a aprendizaje.The science of genetics is relatively new, that begun with Mendel experiments and his contribution to the explanation of inheritance of different characteristics at the end of 1800’s. The science has grown all over this paste years and has diverse in many specialties. The goal of this work was to try to innovate in teaching genetics in Basics Genetics in Veterinary College of the Universidad Nacional de Río Negro using different types of evaluation and some digital tools to improve teaching and learning experience of Genetics.Ponencias.Facultad de Ciencias Veterinaria

A C subunit of the plant nuclear factor NF-Y required for rhizobial infection and nodule development affects partner selection in the common bean-Rhizobium etli Symbiosis

Legume plants are able to interact symbiotically with soil bacteria to form nitrogen-fixing root nodules. Although specific recognition between rhizobia and legume species has been extensively characterized, plant molecular determinants that govern the preferential colonization by different strains within a single rhizobium species have received little attention. We found that the C subunit of the heterotrimeric nuclear factor NF-Y from common bean (Phaseolus vulgaris) NF-YC1 plays a key role in the improved nodulation seen by more efficient strains of rhizobia. Reduction of NF-YC1 transcript levels by RNA interference (RNAi) in Agrobacterium rhizogenes-induced hairy roots leads to the arrest of nodule development and defects in the infection process with either high or low efficiency strains. Induction of three G2/M transition cell cycle genes in response to rhizobia was impaired or attenuated in NF-YC1 RNAi roots, suggesting that this transcription factor might promote nodule development by activating cortical cell divisions. Furthermore, overexpression of this gene has a positive impact on nodulation efficiency and selection of Rhizobium etli strains that are naturally less efficient and bad competitors. Our findings suggest that this transcription factor might be part of a mechanism that links nodule organogenesis with an early molecular dialogue that selectively discriminates between high- and low-quality symbiotic partners, which holds important implications for optimizing legume performance.Facultad de Ciencias Exacta

Host genes involved in nodulation preference in common bean (Phaseolus vulgaris)-Rhizobium etli symbiosis revealed by suppressive subtractive hybridization

Common bean cultivars are nodulated preferentially by Rhizobium etli lineages from the same center of host diversification. Nodulation was found to be earlier and numerous in bean plants inoculated with the cognate strain. We predicted that analysis of transcripts at early stages of the interaction between host and rhizobium would identify plant genes that are most likely to be involved in this preferential nodulation. Therefore, we applied a suppressive subtractive hybridization approach in which cDNA from a Mesoamerican cultivar inoculated with either the more- or less-efficient strain of R. etli was used as the driver and the tester, respectively. Forty-one independent tentative consensus sequences (TCs) were obtained and classified into different functional categories. Of 11 selected TCs, 9 were confirmed by quantitative reverse-transcriptase polymerase chain reaction. Two genes show high homology to previously characterized plant receptors. Two other upregulated genes encode for Rab11, a member of the small GTP-binding protein family, and HAP5, a subunit of the heterotrimeric CCAAT-transcription factor. Interestingly, one of the TCs encodes for an isoflavone reductase, which may lead to earlier Nod factor production by specific strains of rhizobia. The transcript abundance of selected cDNAs also was found to be higher in mature nodules of the more efficient interaction. Small or no differences were observed when an Andean bean cultivar was inoculated with a cognate strain, suggesting involvement of these genes in the strain-specific response. The potential role of these genes in the early preferential symbiotic interaction is discussed.Instituto de Biotecnologia y Biologia MolecularFacultad de Ciencias Exacta

A C subunit of the plant nuclear factor NF-Y required for rhizobial infection and nodule development affects partner selection in the common bean-Rhizobium etli Symbiosis

Legume plants are able to interact symbiotically with soil bacteria to form nitrogen-fixing root nodules. Although specific recognition between rhizobia and legume species has been extensively characterized, plant molecular determinants that govern the preferential colonization by different strains within a single rhizobium species have received little attention. We found that the C subunit of the heterotrimeric nuclear factor NF-Y from common bean (Phaseolus vulgaris) NF-YC1 plays a key role in the improved nodulation seen by more efficient strains of rhizobia. Reduction of NF-YC1 transcript levels by RNA interference (RNAi) in Agrobacterium rhizogenes-induced hairy roots leads to the arrest of nodule development and defects in the infection process with either high or low efficiency strains. Induction of three G2/M transition cell cycle genes in response to rhizobia was impaired or attenuated in NF-YC1 RNAi roots, suggesting that this transcription factor might promote nodule development by activating cortical cell divisions. Furthermore, overexpression of this gene has a positive impact on nodulation efficiency and selection of Rhizobium etli strains that are naturally less efficient and bad competitors. Our findings suggest that this transcription factor might be part of a mechanism that links nodule organogenesis with an early molecular dialogue that selectively discriminates between high- and low-quality symbiotic partners, which holds important implications for optimizing legume performance.Facultad de Ciencias Exacta

Host genes involved in nodulation preference in common bean (Phaseolus vulgaris)-Rhizobium etli symbiosis revealed by suppressive subtractive hybridization

Common bean cultivars are nodulated preferentially by Rhizobium etli lineages from the same center of host diversification. Nodulation was found to be earlier and numerous in bean plants inoculated with the cognate strain. We predicted that analysis of transcripts at early stages of the interaction between host and rhizobium would identify plant genes that are most likely to be involved in this preferential nodulation. Therefore, we applied a suppressive subtractive hybridization approach in which cDNA from a Mesoamerican cultivar inoculated with either the more- or less-efficient strain of R. etli was used as the driver and the tester, respectively. Forty-one independent tentative consensus sequences (TCs) were obtained and classified into different functional categories. Of 11 selected TCs, 9 were confirmed by quantitative reverse-transcriptase polymerase chain reaction. Two genes show high homology to previously characterized plant receptors. Two other upregulated genes encode for Rab11, a member of the small GTP-binding protein family, and HAP5, a subunit of the heterotrimeric CCAAT-transcription factor. Interestingly, one of the TCs encodes for an isoflavone reductase, which may lead to earlier Nod factor production by specific strains of rhizobia. The transcript abundance of selected cDNAs also was found to be higher in mature nodules of the more efficient interaction. Small or no differences were observed when an Andean bean cultivar was inoculated with a cognate strain, suggesting involvement of these genes in the strain-specific response. The potential role of these genes in the early preferential symbiotic interaction is discussed.Instituto de Biotecnologia y Biologia MolecularFacultad de Ciencias Exacta

A C Subunit of the Plant Nuclear Factor NF-Y Required for Rhizobial Infection and Nodule Development Affects Partner Selection in the Common Bean–Rhizobium etli Symbiosis[C][W]

This study provides evidence that a plant nuclear factor plays a key role in the development of functional nitrogen-fixing nodules and demonstrates that constitutive expression of this gene is sufficient not only to improve nodulation performance of less efficient rhizobium strains but also to enhance the rate of nodule occupancy by strains that are bad competitors in the soil