18 research outputs found
Homeologous Plastid DNA Transformation in Tobacco Is Mediated by Multiple Recombination Events
Efficient plastid transformation has been achieved in Nicotiana tabacum using cloned plastid DNA of
Solanum nigrum carrying mutations conferring spectinomycin and streptomycin resistance. The use of the
incompletely homologous (homeologous) Solanum plastid DNA as donor resulted in a Nicotiana plastid
transformation frequency comparable with that of other experiments where completely homologous plastid
DNA was introduced. Physical mapping and nucleotide sequence analysis of the targeted plastid DNA
region in the transformants demonstrated efficient site-specific integration of the 7.8-kb Solanum plastid
DNA and the exclusion of the vector DNA. The integration of the cloned Solanum plastid DNA into
the Nicotiana plastid genome involved multiple recombination events as revealed by the presence of
discontinuous tracts of Solanum-specific sequences that were interspersed between Nicotiana-specific
markers. Marked position effects resulted in very frequent cointegration of the nonselected peripheral
donor markers located adjacent to the vector DNA. Data presented here on the efficiency and features
of homeologous plastid DNA recombination are consistent with the existence of an active RecA-mediated,
but a diminished mismatch, recombination/repair system in higher-plant plastids
Transplastomic tobacco plants expressing a fatty acid desaturase gene exhibit altered fatty acid profiles and improved cold tolerance
The possibility of altering the unsaturation
level of fatty acids in plant lipids by genetic transformation
has implications for the stress tolerance of
higher plants as well as for their nutritional value and
industrial utilisation. While the integration and expression
of transgenes in the plastome has several potential
advantages over nuclear transformation, very few
attempts have been made to manipulate fatty acid
biosynthesis using plastid transformation. We produced
transplastomic tobacco plants that express a Delta9
desaturase gene from either the wild potato species
Solanum commersonii or the cyanobacterium Anacystis
nidulans, using PEG-mediated DNA uptake by protoplasts. Incorporation of chloroplast antibioticinsensitive
point mutations in the transforming DNA
was used to select transformants. The presence of the
transcript and the Delta9 desaturase protein in transplastomic
plants was confirmed by northern and western
blot analyses. In comparison with control plants,
transplastomic plants showed altered fatty acid profiles
and an increase in their unsaturation level both in leaves
and seeds. The two transgenes produced comparable
results. The results obtained demonstrate the feasibility
of using plastid transformation to engineer lipid
metabolic pathways in both vegetative and reproductive
tissues and suggest an increase of cold tolerance in
transplastomic plants showing altered leaf fatty acid
profiles. This is the first example of transplastomic
plants expressing an agronomically relevant gene
produced with the ‘‘binding-type’’ vectors, which do
not contain a heterologous marker gene. In fact, the
transplastomic plants expressing the S. commersonii
gene contain only plant-derived sequences, a clear
attraction from a public acceptability perspective
Stimulation of shoot regeneration in Triticum aestivum and Nicotiana plumbaginifolia Viv. tissue cultures using the ethylene inhibitor AgNO3
Silver nitrate effectively promoted shoot regeneration in wheat (Triticum aestivum L.) callus cultures derived from immature embryos. This effect could be observed in both weakly and strongly regenerating cultivars, and in using material from both field and greenhouse grown plants. The role of silver ions as an inhibitor of ethylene action was supported by a reversal of the inhibitory effects of 2,4-D and ethylene on morphogenesis in wheat callus cultures.Enhancement of shoot regeneration by silver nitrate was also observed in callus cultures of non-regenerating or weakly regenerating mutants of Nicotiana plumbaginifolia Viv. derived from cell cultures
Societies in change. Teacher's resource book
Cumple con los requisitos del currículo nacional inglés para la etapa de 3 de secundaria (key stage 3). Este recurso proporciona al profesor distinto tipo de material didáctico sobre estrategias de enseñanza, organización del curso, formas de evaluación y, orientación sobre actividades y preguntas basadas en el libro del alumno. Este texto esta preparado para el Schools History Project creado en 1972 para mejorar el estudio de la historia entre estudiantes de trece a dieciséis años. Reconsidera las formas en que la historia contribuye a las necesidades educativas de los jóvenes, y por ello idea nuevos objetivos, nuevos criterios para la planificación y desarrollo del curso, así como de sus materiales de apoyo. Requiere nuevos criterios de evaluación y, por tanto nuevos exámenes y, adquirió mayor expansión con la introducción del General Certificate of Secondary Education (GCSE) en 1987.SCBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 planta; 28014 Madrid; Tel. +34917748000; [email protected]
Homeologous Plastid DNA Transformation in Tobacco Is Mediated by Multiple Recombination Events
Efficient plastid transformation has been achieved in Nicotiana tabacum using cloned plastid DNA of
Solanum nigrum carrying mutations conferring spectinomycin and streptomycin resistance. The use of the
incompletely homologous (homeologous) Solanum plastid DNA as donor resulted in a Nicotiana plastid
transformation frequency comparable with that of other experiments where completely homologous plastid
DNA was introduced. Physical mapping and nucleotide sequence analysis of the targeted plastid DNA
region in the transformants demonstrated efficient site-specific integration of the 7.8-kb Solanum plastid
DNA and the exclusion of the vector DNA. The integration of the cloned Solanum plastid DNA into
the Nicotiana plastid genome involved multiple recombination events as revealed by the presence of
discontinuous tracts of Solanum-specific sequences that were interspersed between Nicotiana-specific
markers. Marked position effects resulted in very frequent cointegration of the nonselected peripheral
donor markers located adjacent to the vector DNA. Data presented here on the efficiency and features
of homeologous plastid DNA recombination are consistent with the existence of an active RecA-mediated,
but a diminished mismatch, recombination/repair system in higher-plant plastids
Homeologous Plastid DNA Transformation in Tobacco Is Mediated by Multiple Recombination Events
Efficient plastid transformation has been achieved in Nicotiana tabacum using cloned plastid DNA of
Solanum nigrum carrying mutations conferring spectinomycin and streptomycin resistance. The use of the
incompletely homologous (homeologous) Solanum plastid DNA as donor resulted in a Nicotiana plastid
transformation frequency comparable with that of other experiments where completely homologous plastid
DNA was introduced. Physical mapping and nucleotide sequence analysis of the targeted plastid DNA
region in the transformants demonstrated efficient site-specific integration of the 7.8-kb Solanum plastid
DNA and the exclusion of the vector DNA. The integration of the cloned Solanum plastid DNA into
the Nicotiana plastid genome involved multiple recombination events as revealed by the presence of
discontinuous tracts of Solanum-specific sequences that were interspersed between Nicotiana-specific
markers. Marked position effects resulted in very frequent cointegration of the nonselected peripheral
donor markers located adjacent to the vector DNA. Data presented here on the efficiency and features
of homeologous plastid DNA recombination are consistent with the existence of an active RecA-mediated,
but a diminished mismatch, recombination/repair system in higher-plant plastids
Homeologous Plastid DNA Transformation in Tobacco Is Mediated by Multiple Recombination Events
Efficient plastid transformation has been achieved in Nicotiana tabacum using cloned plastid DNA of
Solanum nigrum carrying mutations conferring spectinomycin and streptomycin resistance. The use of the
incompletely homologous (homeologous) Solanum plastid DNA as donor resulted in a Nicotiana plastid
transformation frequency comparable with that of other experiments where completely homologous plastid
DNA was introduced. Physical mapping and nucleotide sequence analysis of the targeted plastid DNA
region in the transformants demonstrated efficient site-specific integration of the 7.8-kb Solanum plastid
DNA and the exclusion of the vector DNA. The integration of the cloned Solanum plastid DNA into
the Nicotiana plastid genome involved multiple recombination events as revealed by the presence of
discontinuous tracts of Solanum-specific sequences that were interspersed between Nicotiana-specific
markers. Marked position effects resulted in very frequent cointegration of the nonselected peripheral
donor markers located adjacent to the vector DNA. Data presented here on the efficiency and features
of homeologous plastid DNA recombination are consistent with the existence of an active RecA-mediated,
but a diminished mismatch, recombination/repair system in higher-plant plastids