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Mapeamento de QTL para produção de grãos e caracters de planta em milho tropical utilizando marcadores microssatelites; Mapping QTL for grain yield and plant traits using microsatellite markers in a tropical maize population

Milena de Luna Alves Lima
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/02/2006 Português
Relevância na Pesquisa
46.06%
A maior parte dos caracteres de importância agronômica e econômica do milho estão sob o controle de diversos locos gênicos, denominados locos de caracteres quantitativos (QTL). A possibilidade do uso de marcadores moleculares e o aperfeiçoamento dos modelos estatístico-genéticos possibilitaram o mapeamento desses locos gênicos que afetam tais caracteres. Pouco enfoque no estudo de mapeamento de QTL foi dado em populações derivadas do germoplasma do milho tropical, o qual possui uma base genética ampla com maior diversidade do que o germoplasma temperado. Da mesma forma, pouco se conhece sobre as interações dos QTL nos diferentes ambientes (QTL X E). Duzentos e cinqüenta e seis progênies F2:3, derivadas do cruzamento de duas linhagens de milho tropical, foram avaliadas em cinco ambientes. O mapa genético foi desenvolvido com 139 marcadores microssatélites, utilizando o programa MAPMAKER/EXP versão 3.0b. As análises de mapeamento de QTL e a detecção da interação QTL X E foram realizadas utilizando o procedimento JZmapQTL do programa Windows QTL-Cartographer versão 2.5, que se baseia na análise de mapeamento em ambientes múltiplos (mCIM). A extensão total do mapa genético foi de 1.858,61 cM com intervalo médio entre marcadores de 13...

Eggplant (Solanum melongena L.): tissue culture, genetic transformation and use as an alternative model plant

Magioli,Claudia; Mansur,Elisabeth
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2005 Português
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45.92%
Eggplant is an agronomically important non-tuberous solanaceous crop grown primarily for its large oval fruit. In popular medicine, eggplant is indicated for the treatment of several diseases, including diabetes, arthritis, asthma and bronchitis. Eggplant is susceptible to a number of diseases and pests capable of causing serious crop losses. This problem has been addressed by hybridizing eggplant with wild resistant Solanum species, which present a wide genetic diversity and are source of useful agronomic traits. The application of in vitro methodologies to eggplant has resulted in considerable success. Eggplant tissues present a high morphogenetic potential that is useful for developmental studies as well as for establishing biotechnological approaches to produce improved varieties, such as embryo rescue, in vitro selection, somatic hybridization and genetic transformation. Taken together, these characteristics also make eggplant a complete model for studies on different areas of plant science, including control of gene expression and assessment of genetic stability of somaclones derived from different morphogenetic processes. In the present study, important factors that affect the efficiency of in vitro regeneration through organogenesis and embryogenesis as well as genetic transformation are analyzed. The potential of this species as a model plant for studying various aspects of plant genetics and physiology is also discussed.

The Maize Genetics and Genomics Database. The Community Resource for Access to Diverse Maize Data1

Lawrence, Carolyn J.; Seigfried, Trent E.; Brendel, Volker
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Publicado em /05/2005 Português
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The Maize Genetics and Genomics Database (MaizeGDB) serves the maize (Zea mays) research community by making a wealth of genetics and genomics data available through an intuitive Web-based interface. The goals of the MaizeGDB project are 3-fold: to provide a central repository for public maize information; to present the data through the MaizeGDB Web site in a way that recapitulates biological relationships; and to provide an array of computational tools that address biological questions in an easy-to-use manner at the site. In addition to these primary tasks, MaizeGDB team members also serve the community of maize geneticists by lending technical support for community activities, including the annual Maize Genetics Conference and various workshops, teaching researchers to use both the MaizeGDB Web site and Community Curation Tools, and engaging in collaboration with individual research groups to make their unique data types available through MaizeGDB.

Reverse Genetics of Floral Scent: Application of Tobacco Rattle Virus-Based Gene Silencing in Petunia1[OA]

Spitzer, Ben; Zvi, Michal Moyal Ben; Ovadis, Marianna; Marhevka, Elena; Barkai, Oren; Edelbaum, Orit; Marton, Ira; Masci, Tania; Alon, Michal; Morin, Shai; Rogachev, Ilana; Aharoni, Asaph; Vainstein, Alexander
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Publicado em /12/2007 Português
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Floral fragrance is responsible for attracting pollinators as well as repelling pathogens and pests. As such, it is of immense biological importance. Molecular dissection of the mechanisms underlying scent production would benefit from the use of model plant systems with big floral organs that generate an array of volatiles and that are amenable to methods of forward and reverse genetics. One candidate is petunia (Petunia hybrida), which has emerged as a convenient model system, and both RNAi and overexpression approaches using transgenes have been harnessed for the study of floral volatiles. Virus-induced gene silencing (VIGS) is characterized by a simple inoculation procedure and rapid results relative to transgenesis. Here, we demonstrate the applicability of the tobacco rattle virus-based VIGS system to studies of floral scent. Suppression of the anthocyanin pathway via chalcone synthase silencing was used as a reporter, allowing easy visual identification of anthocyaninless silenced flowers/tissues with no effect on the level of volatile emissions. Use of tobacco rattle virus constructs containing target genes involved in phenylpropanoid volatile production, fused to the chalcone synthase reporter, allowed simple identification of flowers with suppressed activity of the target genes. The applicability of VIGS was exemplified with genes encoding S-adenosyl-l-methionine:benzoic acid/salicylic acid carboxyl methyltransferase...

Large-Scale Reverse Genetics in Arabidopsis: Case Studies from the Chloroplast 2010 Project1[C][W][OA]

Ajjawi, Imad; Lu, Yan; Savage, Linda J.; Bell, Shannon M.; Last, Robert L.
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Publicado em /02/2010 Português
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46.07%
Traditionally, phenotype-driven forward genetic plant mutant studies have been among the most successful approaches to revealing the roles of genes and their products and elucidating biochemical, developmental, and signaling pathways. A limitation is that it is time consuming, and sometimes technically challenging, to discover the gene responsible for a phenotype by map-based cloning or discovery of the insertion element. Reverse genetics is also an excellent way to associate genes with phenotypes, although an absence of detectable phenotypes often results when screening a small number of mutants with a limited range of phenotypic assays. The Arabidopsis Chloroplast 2010 Project (www.plastid.msu.edu) seeks synergy between forward and reverse genetics by screening thousands of sequence-indexed Arabidopsis (Arabidopsis thaliana) T-DNA insertion mutants for a diverse set of phenotypes. Results from this project are discussed that highlight the strengths and limitations of the approach. We describe the discovery of altered fatty acid desaturation phenotypes associated with mutants of At1g10310, previously described as a pterin aldehyde reductase in folate metabolism. Data are presented to show that growth, fatty acid, and chlorophyll fluorescence defects previously associated with antisense inhibition of synthesis of the family of acyl carrier proteins can be attributed to a single gene insertion in Acyl Carrier Protein4 (At4g25050). A variety of cautionary examples associated with the use of sequence-indexed T-DNA mutants are described...

DTH8 Suppresses Flowering in Rice, Influencing Plant Height and Yield Potential Simultaneously1[W][OA]

Wei, Xiangjin; Xu, Junfeng; Guo, Hongnian; Jiang, Ling; Chen, Saihua; Yu, Chuanyuan; Zhou, Zhenling; Hu, Peisong; Zhai, Huqu; Wan, Jianmin
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Português
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45.94%
The three most important agronomic traits of rice (Oryza sativa), yield, plant height, and flowering time, are controlled by many quantitative trait loci (QTLs). In this study, a newly identified QTL, DTH8 (QTL for days to heading on chromosome 8), was found to regulate these three traits in rice. Map-based cloning reveals that DTH8 encodes a putative HAP3 subunit of the CCAAT-box-binding transcription factor and the complementary experiment increased significantly days to heading, plant height, and number of grains per panicle in CSSL61 (a chromosome segment substitution line that carries the nonfunctional DTH8 allele) with the Asominori functional DTH8 allele under long-day conditions. DTH8 is expressed in most tissues and its protein is localized to the nucleus exclusively. The quantitative real-time PCR assay revealed that DTH8 could down-regulate the transcriptions of Ehd1 (for Early heading date1) and Hd3a (for Heading date3a; a rice ortholog of FLOWERING LOCUS T) under long-day conditions. Ehd1 and Hd3a can also be down-regulated by the photoperiodic flowering genes Ghd7 and Hd1 (a rice ortholog of CONSTANS). Meanwhile, the transcription of DTH8 has been proved to be independent of Ghd7 and Hd1, and the natural mutation of this gene caused weak photoperiod sensitivity and shorter plant height. Taken together...

Evolution and Function of the Plant Cell Wall Synthesis-Related Glycosyltransferase Family 81[W][OA]

Yin, Yanbin; Chen, Huiling; Hahn, Michael G.; Mohnen, Debra; Xu, Ying
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Português
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45.97%
Carbohydrate-active enzyme glycosyltransferase family 8 (GT8) includes the plant galacturonosyltransferase1-related gene family of proven and putative α-galacturonosyltransferase (GAUT) and GAUT-like (GATL) genes. We computationally identified and investigated this family in 15 fully sequenced plant and green algal genomes and in the National Center for Biotechnology Information nonredundant protein database to determine the phylogenetic relatedness of the GAUTs and GATLs to other GT8 family members. The GT8 proteins fall into three well-delineated major classes. In addition to GAUTs and GATLs, known or predicted to be involved in plant cell wall biosynthesis, class I also includes a lower plant-specific GAUT and GATL-related (GATR) subfamily, two metazoan subfamilies, and proteins from other eukaryotes and cyanobacteria. Class II includes galactinol synthases and plant glycogenin-like starch initiation proteins that are not known to be directly involved in cell wall synthesis, as well as proteins from fungi, metazoans, viruses, and bacteria. Class III consists almost entirely of bacterial proteins that are lipooligo/polysaccharide α-galactosyltransferases and α-glucosyltransferases. Sequence motifs conserved across all GT8 subfamilies and those specific to plant cell wall-related GT8 subfamilies were identified and mapped onto a predicted GAUT1 protein structure. The tertiary structure prediction identified sequence motifs likely to represent key amino acids involved in catalysis...

Molecular Evolution and Selection Patterns of Plant F-Box Proteins with C-Terminal Kelch Repeats1[W][OA]

Schumann, Nadine; Navarro-Quezada, Aura; Ullrich, Kristian; Kuhl, Carsten; Quint, Marcel
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.94%
The F-box protein superfamily represents one of the largest families in the plant kingdom. F-box proteins phylogenetically organize into numerous subfamilies characterized by their carboxyl (C)-terminal protein-protein interaction domain. Among the largest F-box protein subfamilies in plant genomes are those with C-terminal kelch repeats. In this study, we analyzed the phylogeny and evolution of F-box kelch proteins/genes (FBKs) in seven completely sequenced land plant genomes including a bryophyte, a lycophyte, monocots, and eudicots. While absent in prokaryotes, F-box kelch proteins are widespread in eukaryotes. Nonplant eukaryotes usually contain only a single FBK gene. In land plant genomes, however, FBKs expanded dramatically. Arabidopsis thaliana, for example, contains at least 103 F-box genes with well-conserved C-terminal kelch repeats. The construction of a phylogenetic tree based on the full-length amino acid sequences of the FBKs that we identified in the seven species enabled us to classify FBK genes into unstable/stable/superstable categories. In contrast to superstable genes, which are conserved across all seven species, kelch domains of unstable genes, which are defined as lineage specific, showed strong signatures of positive selection...

Tandem repeat distribution of gene transcripts in three plant families

da Maia, Luciano Carlos; de Souza, Velci Queiróz; Kopp, Mauricio Marini; de Carvalho, Fernando Irajá Félix; de Oliveira, Antonio Costa
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.92%
Tandem repeats (microsatellites or SSRs) are molecular markers with great potential for plant genetic studies. Modern strategies include the transfer of these markers among widely studied and orphan species. In silico analyses allow for studying distribution patterns of microsatellites and predicting which motifs would be more amenable to interspecies transfer. Transcribed sequences (Unigene) from ten species of three plant families were surveyed for the occurrence of micro and minisatellites. Transcripts from different species displayed different rates of tandem repeat occurrence, ranging from 1.47% to 11.28%. Both similar and different patterns were found within and among plant families. The results also indicate a lack of association between genome size and tandem repeat fractions in expressed regions. The conservation of motifs among species and its implication on genome evolution and dynamics are discussed.

Plant Genetics, Sustainable Agriculture and Global Food Security

Ronald, Pamela
Fonte: Genetics Society of America Publicador: Genetics Society of America
Tipo: Artigo de Revista Científica
Publicado em /05/2011 Português
Relevância na Pesquisa
56.17%
The United States and the world face serious societal challenges in the areas of food, environment, energy, and health. Historically, advances in plant genetics have provided new knowledge and technologies needed to address these challenges. Plant genetics remains a key component of global food security, peace, and prosperity for the foreseeable future. Millions of lives depend upon the extent to which crop genetic improvement can keep pace with the growing global population, changing climate, and shrinking environmental resources. While there is still much to be learned about the biology of plant–environment interactions, the fundamental technologies of plant genetic improvement, including crop genetic engineering, are in place, and are expected to play crucial roles in meeting the chronic demands of global food security. However, genetically improved seed is only part of the solution. Such seed must be integrated into ecologically based farming systems and evaluated in light of their environmental, economic, and social impacts—the three pillars of sustainable agriculture. In this review, I describe some lessons learned, over the last decade, of how genetically engineered crops have been integrated into agricultural practices around the world and discuss their current and future contribution to sustainable agricultural systems.

The use of weighted multiple linear regression to estimate QTL-by-QTL epistatic effects

Bocianowski, Jan
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.93%
Knowledge of the nature and magnitude of gene effects, as well as their contribution to the control of metric traits, is important in formulating efficient breeding programs for the improvement of plant genetics. Information concerning a genetic parameter such as the additive-by-additive epistatic effect can be useful in traditional breeding. This report describes the results obtained by applying weighted multiple linear regression to estimate the parameter connected with an additive-by-additive epistatic interaction. Three weight variants were used: (1) standard weights based on estimated variances, (2) different weights for minimal, maximal and other lines, and (3) different weights for extreme and other lines. The approach described here combines two methods of estimation, one based on phenotypic observations and the other using molecular marker data. The comparison was done using Monte Carlo simulations. The results show that the application of weighted regression to the marker data yielded estimates similar to those obtained by phenotypic methods.

Genetic and Physiological Characterization of Two Clusters of Quantitative Trait Loci Associated With Seed Dormancy and Plant Height in Rice

Ye, Heng; Beighley, Donn H.; Feng, Jiuhuan; Gu, Xing-You
Fonte: Genetics Society of America Publicador: Genetics Society of America
Tipo: Artigo de Revista Científica
Publicado em 01/02/2013 Português
Relevância na Pesquisa
46.09%
Seed dormancy and plant height have been well-studied in plant genetics, but their relatedness and shared regulatory mechanisms in natural variants remain unclear. The introgression of chromosomal segments from weedy into cultivated rice (Oryza sativa) prompted the detection of two clusters (qSD1-2/qPH1 and qSD7-2/qPH7) of quantitative trait loci both associated with seed dormancy and plant height. Together, these two clusters accounted for >96% of the variances for plant height and ~71% of the variances for germination rate in an isogenic background across two environments. On the initial introgression segments, qSD1-2/qPH1 was dissected genetically from OsVp1 for vivipary and qSD7-2/qPH7 separated from Sdr4 for seed dormancy. The narrowed qSD1-2/qPH1 region encompasses the semidwarf1 (sd1) locus for gibberellin (GA) biosynthesis. The qSD1-2/qPH1 allele from the cultivar reduced germination and stem elongation and the mutant effects were recovered by exogenous GA, suggesting that sd1 is a candidate gene of the cluster. In contrast, the effect-reducing allele at qSD7-2/qPH7 was derived from the weedy line; this allele was GA-insensitive and blocked GA responses of qSD1-2/qPH1, including the transcription of a GA-inducible α-amylase gene in imbibed endosperm...

Comet-FISH for the evaluation of plant DNA damage after mutagenic treatments

Kwasniewska, Jolanta; Kwasniewski, Miroslaw
Fonte: Springer Berlin Heidelberg Publicador: Springer Berlin Heidelberg
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
45.94%
The aim of this study was to perform a comparative investigation of the actions of three mutagens that are widely used in plant mutagenesis using the comet-FISH technique. The comet-FISH technique was used for the analysis of DNA damage and the kinetics of repair within specific DNA sequences. FISH with rDNA and telomeric/centromeric DNA probes was applied to comets that were obtained from an alkaline/neutral comet assay. Migration within specific DNA sequences was analysed after treatment with two chemical mutagens-maleic hydrazide (MH) and N-nitroso-N-methylurea (MNU), and γ-rays. Barley was used as a model plant in this study. The possible utility of specific DNA sequences in a comparative assessment of the distribution of DNA damage within a plant genome was evaluated. This study proved that the comet-FISH technique is suitable for a detailed quantification of DNA damage and repair within specific DNA sequences in plant mutagenesis. The analysis of FISH signals demonstrated that the involvement of specific DNA sequences in DNA damage was different and was dependent on the mutagen used. We showed that 5S rDNA and telomeric DNA sequences are more sensitive to mutagenic treatment, which was expressed by a stronger fragmentation and migration in comparison to the other probes used in the study. We found that 5S rDNA and telomeric DNA probes are more suitable for testing the genotoxicity of environmental factors. A comparison of the involvement of specific chromosome domains in direct DNA breakage/repair and in chromosome aberration formation after mutagen treatment indicates the compatibility of the results.

Genetic control of the number of leaves above the ear in maize.

FREIRE, A. I.; DIAS, K. O. G.; OLIVEIRA, L. B. V.; NALIN, R. S.; GUEDES, F. L.; SOUZA, J. C.
Fonte: Genetics and Molecular Research, Ribeirao Preto, v. 14, n. 1, p. 1318-1323, Mar. 2015. Publicador: Genetics and Molecular Research, Ribeirao Preto, v. 14, n. 1, p. 1318-1323, Mar. 2015.
Tipo: Artigo em periódico indexado (ALICE)
Português
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46.03%
Abstract: Among the many implications of climatic change on agriculture, drought is expected to continue to have a major impact on agribusinesses. Leaf curling is an anatomical characteristic that might be potentially used to enhance plant tolerance to water deficit. Hence, we aimed to study the genetic control of leaf curl in maize. From 2 contrasting inbred lines for the trait, generations F1, F2, and the backcrosses were obtained. All of these generations were evaluated in a randomized block design with 2 replicates. Leaf curl samples were collected from 3 leaves above the first ear at the tasseling stage, and quantified by dividing the width of the leaf blade with natural curling against its extended width. The mean and variance components were estimated by the weighted least square method. It was found that the trait studied has predominance of the additive effects, with genetic control being attributed to few genes that favor selection and exhibit minimal influence from the environment.; 2015

Plastid DNA sequence homologies within the nuclear genomes of higher plant species / by Michael A. Ayliffe.

Ayliffe, Michael Anthony
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 178399 bytes; application/pdf
Publicado em //1992 Português
Relevância na Pesquisa
46.1%
The aim of this study is to characterize plastid DNA sequence homologies within higher plant nuclear genomes. It is concluded that integrated within the tobacco nuclear genome are multiple copies of large (ie. in excess of 18 kbp), contigous fracts of plastid DNA. The presence of large tracts of plastid DNA in the tobacco nuclear genome contrasts the arrangement of such sequences in the nuclear genomes of other studied plant species.; Thesis (Ph.D.)--University of Adelaide, Dept. of Genetics, 1993; Bibliography: leaves 94-108.; xi, 108, [88] leaves, [28] leaves of plates : ill. (some col.) ; 30 cm.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

Genetics of boron tolerance in barley / by Mandy Jane Jenkin.

Jenkin, Mandy Jane
Fonte: Adelaide Thesis (Ph.D.) -- University of Adelaide, Department of Plant Science Publicador: Adelaide Thesis (Ph.D.) -- University of Adelaide, Department of Plant Science
Tipo: Tese de Doutorado Formato: 68101 bytes; application/pdf
Publicado em //1993 Português
Relevância na Pesquisa
46.07%
Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, Waite Agricultural Research Institute, 1993; 1 v.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

Extreme population-dependent linkage disequilibrium detected in an inbreeding plant species, Hordeum vulgare

Caldwell, K.; Russell, J.; Langridge, P.; Powell, W.
Fonte: Genetics Publicador: Genetics
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
Relevância na Pesquisa
56.07%
In human genetics a detailed knowledge of linkage disequilibrium (LD) is considered a prerequisite for effective population-based, high-resolution gene mapping and cloning. Similar opportunities exist for plants; however, differences in breeding system and population history need to be considered. Here we report a detailed study of localized LD in different populations of an inbreeding crop species. We measured LD between and within four gene loci within the region surrounding the hardness locus in three different gene pools of barley (Hordeum vulgare). We demonstrate that LD extends to at least 212 kb in elite barley cultivars but is rapidly eroded in related inbreeding ancestral populations. Our results indicate that haplotype-based sequence analysis in multiple populations will provide new opportunities to adjust the resolution of association studies in inbreeding crop species.; Katherine S. Caldwell, Joanne Russell, Peter Langridge, and Wayne Powell

Estudo em um fitofago especialista, Tomoplagia reticulata (Diptera:Tephritidae), e sua planta hospedeira, Eremanthus glomerulatus (Asteraceae); A study in an specialist phytophagous, Tomoplagia reticulata (Diptera:Tephritidae), and its host plant, Eremanthus glomerulatus (Asteraceae)

Aluana Gonçalves de Abreu
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/02/2009 Português
Relevância na Pesquisa
46.13%
Tomoplagia reticulata (Diptera: Tephritidae) é um fitófago especialista em Eremanthus glomerulatus (Asteraceae). Os adultos ovipõem nas inflorescências da planta hospedeira, onde as larvas se desenvolvem. O histórico de coletas de T. reticulata mostra uma grande variação na quantidade de insetos infestando cada indivíduo de E. glomerulatus. A fim de verificar se a variação no número de herbívoros nas populações do hospedeiro é associada a alguma característica química e/ou genética deste, comparamos as variabilidades genética e química entre indivíduos de E. glomerulatus com diferentes níveis de infestação por T. reticulata (cap. 1). Eremanthus glomerulatus tem baixa variabilidade genética, provavelmente associada à distribuição restrita desta espécie. Apesar da distribuição fragmentada, há pouca estruturação entre as populações desta planta, explicada pelo maior fluxo gênico entre ambientes fragmentados em espécies anemocóricas. As características genéticas e químicas de E. glomerulatus não explicam a variação no nível de herbivoria das populações do hospedeiro. No capítulo 2, testamos a hipótese de que fitófagos especialistas apresentam maior diferenciação genética e menor diversidade do que generalistas...

BioAcu2 implementación de un sistema de biominería para la extracción de cobre utilizando levaduras genéticamente mejoradas

Brotar Limitada; Cia. Minera San Geronimo; Lebniz Institute Of Planet Genetics And Crop Plant Research; ROBERTO ACUÑA GALLEGUILLOS
Fonte: Corporação de Fomento da Produção Publicador: Corporação de Fomento da Produção
Tipo: Proyecto
Publicado em 15/07/2011 Português
Relevância na Pesquisa
46.1%
El grupo de investigación BioaCu2+ desarrolló un nuevo sistema de bio-concentración de cobre desde soluciones provenientes de la lixiviación (proceso hidrometalúrgico) como alternativa al proceso de extracción por solvente o SX. Este sistema fue elaborado en base al mejoramiento genético de levaduras capaces de acumular cobre. Se logró incrementar la capacidad de la cepa de S. cerevisiae para acumular cobre hasta 28 % p/p bioconcentrando cobre desde soluciones sintéticas bajo condiciones de laboratorio. Durante el desarrollo de esta herramienta biotecnológica se estableció un férreo vínculo de colaboración científica con The Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Alemania centro de investigación dedicado al desarrollo de soluciones biotecnológicas. La obtención de tan buenos resultados y la posibilidad de aplicar esta tecnología a la minería del cobre promovió el nacimiento de la empresa Brotar Ltda. Esta empresa se encargaría de continuar con la innovación descrita y buscar posibles socios en el sector productivo minero para la implementación y comercialización de la tecnología. Brotar encontró un socio potencial: Compañía Minera San Gerónimo (CMSG) la que dentro de sus divisiones cuenta con una que es muy innovadora en Chile la cual produce sólo sulfato de cobre pentahidratado tipo Feed-grade el cual es utilizado como aditivo para la alimentación animal y sulfato agrícola para control de hongos y bacterias. Este know-how ha permitido que CMSG visualice en la matriz actualmente existente de la levadura rica en cobre bioacumulado un producto capaz de reemplazar y potenciar el uso del cobre en las aplicaciones Feed-grade a nivel mundial debido a que su producción será ambientalmente amigable se eliminará la base de sulfuros y las concentraciones de cobre aumentaran y su base al ser de origen biológico será biodisponible y no tendrá residuos debido a que la levadura en cuestión es comestible. La alianza entre estos socios especialistas con alto know-how tanto del sector productivo minero/comercial y científico-tecnológico nacional e internacional llevará al establecimiento de un joint venture internacional (JVI). Este modelo ofrecerá la posibilidad de entrar en un mercado o en nuevos mercados a través de triangulaciones asociativas que en este caso estarán conformadas por Brotar Ltda IPK y CMSG. Este modelo permitirá a Brotar Ltda. y a su socio técnico-inversionista-comercial nacional CMSG adquirir instalaciones gerencias de know how tecnológico y poder usar la red de distribución tanto de CMSG como del inversionista extranjero con las que cuenta IPK. La base del éxito de este JVI es la combinación de esfuerzos entre los socios locales CMSG y Brotar Ltda y el socio extranjero IPK para potenciar ventajas comparativas y competitivas que catapulten el emprendimiento una empresa conjunta de riesgo compartido.; Evaluar la capacidad de las cepas recombinantes de levadura S. cerevisiae Mac1up-MT y Mac1up-HMA1 para extraer cobre desde los siguientes sustratos: sulfuros de cobre óxidos de cobre y desde soluciones de lixiviación cargada (PLS).; Corporación de Fomento de la Producción

Directed mutation of the Rubisco large subunit of Tobacco influences photorespiration and growth

Whitney, Spencer; von Caemmerer, Susanne; Hudson, G; Andrews, Thomas
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Português
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The gene for the large subunit of Rubisco was specifically mutated by transforming the chloroplast genome of tobacco (Nicotiana tabacum). Codon 335 was altered to encode valine instead of leucine. The resulting mutant plants could not grow without atmospheric CO2 enrichment, in 0.3% (v/v) CO2, the mutant and wildtype plants produced similar amounts of Rubisco but the extent of carbamylation was nearly twice as great in the mutants. The mutant enzyme's substrate-saturated CO2-fixing rate and its ability to distinguish between CO2 and O2 as substrates were both reduced to 25% of the wild type's values. Estimates of these parameters obtained from kinetic assays with the purified mutant enzyme were the same as those inferred from measurements of photosynthetic gas exchange with leaves of mutant plants. The Michaelis constants for CO2, O2, and ribulose-1,5-bisphosphate were reduced and the mutation enhanced oxygenase activity at limiting O2 concentrations. Consistent with the reduced CO2 fixation rate at saturating CO2, the mutant plants grew slower than the wild type but they eventually flowered and reproduced apparently normally. The mutation and its associated phenotype were inherited maternally. The chloroplast-transformation strategy surmounts previous obstacles to mutagenesis of higher-plant Rubisco and allows the consequences for leaf photosynthesis to be assessed.