Tobacco plastid ribosomal protein S18 is essential for cell survival

Plastid genomes contain a conserved set of genes most of which are involved in either photosynthesis or gene expression. Among the ribosomal protein genes present in higher plant plastid genomes, rps18 is special in that it is absent from the plastid genomes of several non-green unicellular organisms, including Euglena longa and Toxoplasma gondii. Here we have tested whether the ribosomal protein S18 is required for translation by deleting the rps18 gene from the tobacco plastid genome. We report that, while deletion of the rps18 gene was readily obtained, no homoplasmic Δrps18 plants or leaf sectors could be isolated. Instead, segregation into homoplasmy led to severe defects in leaf development suggesting that the knockout of rps18 is lethal and the S18 protein is required for cell survival. Our data demonstrate that S18 is indispensable for plastid ribosome function in tobacco and support an essential role for plastid translation in plant development. Moreover, we demonstrate the occurrence of flip-flop recombination on short inverted repeat sequences which generates different isoforms of the transformed plastid genome that differ in the orientation a 70 kb segment in the large single-copy region. However, infrequent occurrence of flip-flop recombination and random segregation of plastid genomes result in the predominant presence of only one of the isoforms in many tissue samples. Implications for the interpretation of chloroplast transformation experiments and vector design are discussed

Propagação in vitro de porta-enxertos de Prunus: cultura de embriões, estabelecimento, multiplicação, enraizamento e aclimatização

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Curso de Pós-Graduação em Recursos Genéticos VegetaisEstudo da micropropagação do gênero Prunus, com ênfase à avaliar o comportamento genotípico de diferentes porta-enxertos e a otimização de tipos e concentrações de reguladores de crescimento nas fases de cultura de embriões, estabelecimento, multiplicação, enraizamento e aclimatização das plantas. Busca de um método para a propagação clonal de plantas deste gênero, visando a captura, fixação de genótipos superiores e ganho genético

Propagação in vitro de porta-enxertos de Prunus

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Curso de Pós-Graduação em Recursos Genéticos VegetaisEstudo da micropropagação do gênero Prunus, com ênfase à avaliar o comportamento genotípico de diferentes porta-enxertos e a otimização de tipos e concentrações de reguladores de crescimento nas fases de cultura de embriões, estabelecimento, multiplicação, enraizamento e aclimatização das plantas. Busca de um método para a propagação clonal de plantas deste gênero, visando a captura, fixação de genótipos superiores e ganho genético

Data from: Mating system and genetic structure across all known populations of Dyckia brevifolia: a clonal, endemic and endangered rheophyte bromeliad

Dyckia brevifolia is an endemic rheophyte bromeliad that occurs exclusively in patches on rocky banks of the Itajaí-Açu River in southern Brazil. The genetic diversity of all known populations was carried out using allozyme markers and the total numbers of rosettes, reproductive rosettes, and clumps per population were characterized. The mating system was also investigated. Most rosettes were aggregated in groups, and the populations differed significantly in number of rosettes and reproductive rosettes per population. The outcrossing rate obtained was 8.2%, with predominant selfing. The populations presented an average of 1.4 alleles per locus and 27% of polymorphisms. The mean expected genetic diversity was 0.067. Downstream populations showed the highest genetic diversity which could be attributed to hydrochory (unidirectional river flow). Most genetic diversity is distributed among populations (FˆST = 0.402). Natural habitats of D. brevifolia are not recommended for the construction of hydroelectric plants given that it would seriously complicate in situ conservation of this species. Based on the results of this study, it can be concluded that between 35 and 161 reproductive rosettes must be collected for effective ex situ conservation, depending on the targeted population, or seeds collected from 157 seed-rosettes per population

Mating system and genetic structure across all known populations of Dyckia brevifolia: A clonal, endemic, and endangered Rheophyte bromeliad

Dyckia brevifolia is an endemic rheophyte bromeliad that occurs exclusively in patches on rocky banks of the Itajaí-Açu River in southern Brazil. The genetic diversity of all known populations was carried out using allozyme markers and the total numbers of rosettes, reproductive rosettes, and clumps per population were characterized. The mating system was also investigated. Most rosettes were aggregated in groups, and the populations differed significantly in number of rosettes and reproductive rosettes per population. The outcrossing rate obtained was 8.2%, with predominant selfing. The populations presented an average of 1.4 alleles per locus and 27% of polymorphisms. The mean expected genetic diversity was 0.067. Downstream populations showed the highest genetic diversity which could be attributed to hydrochory (unidirectional river flow). Most genetic diversity is distributed among populations ( F ˆ = 0.402). Natural habitats of D. brevifolia are not recommended for the construction of hydroelectric plants given that it would seriously complicate in situ conservation of this species. Based on the results of this study, it can be concluded that between 35 and 161 reproductive rosettes must be collected for effective ex situ conservation, depending on the targeted population, or seeds collected from 157 seed-rosettes per population

Mating system and genetic structure across all known populations of Dyckia brevifolia: A clonal, endemic, and endangered Rheophyte bromeliad

Dyckia brevifolia is an endemic rheophyte bromeliad that occurs exclusively in patches on rocky banks of the Itajaí-Açu River in southern Brazil. The genetic diversity of all known populations was carried out using allozyme markers and the total numbers of rosettes, reproductive rosettes, and clumps per population were characterized. The mating system was also investigated. Most rosettes were aggregated in groups, and the populations differed significantly in number of rosettes and reproductive rosettes per population. The outcrossing rate obtained was 8.2%, with predominant selfing. The populations presented an average of 1.4 alleles per locus and 27% of polymorphisms. The mean expected genetic diversity was 0.067. Downstream populations showed the highest genetic diversity which could be attributed to hydrochory (unidirectional river flow). Most genetic diversity is distributed among populations ( F ˆ = 0.402). Natural habitats of D. brevifolia are not recommended for the construction of hydroelectric plants given that it would seriously complicate in situ conservation of this species. Based on the results of this study, it can be concluded that between 35 and 161 reproductive rosettes must be collected for effective ex situ conservation, depending on the targeted population, or seeds collected from 157 seed-rosettes per population