Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros










Base de dados
Tipo de estudo
Intervalo de ano de publicação
1.
Plant Cell Environ ; 36(2): 315-27, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22789006

RESUMO

We used tomato genotypes deficient in the jasmonic acid (JA) pathway to study the interaction between the production of herbivore-induced plant volatiles (HIPVs) that serve as information cues for herbivores as well as natural enemies of herbivores, and the production of foliar trichomes as defence barriers. We found that jasmonic acid-insensitive1 (jai1) mutant plants with both reduced HIPVs and trichome production received higher oviposition of adult leafminers, which were more likely to be parasitized by the leafminer parasitoids than JA biosynthesis spr2 mutant plants deficient in HIPVs but not trichomes. We also showed that the preference and acceptance of leafminers and parasitoids to trichome-removed plants from either spr2 or wild-type (WT) genotypes over trichome-intact genotypes can be ascribed to the reduced trichomes on treated plants, but not to altered direct and indirect defence traits such as JA, proteinase inhibitor (PI)-II and HIPVs levels. Although the HIPVs of WT plants were more attractive to adult insects, the insects preferred trichome-free jai1 plants for oviposition and also had greater reproductive success on these plants. Our results provide strong evidence that antagonism between HIPV emission and trichome production affects tritrophic interactions. The interactions among defence traits are discussed.


Assuntos
Herbivoria/fisiologia , Insetos/fisiologia , Folhas de Planta/anatomia & histologia , Folhas de Planta/fisiologia , Solanum lycopersicum/fisiologia , Solanum lycopersicum/parasitologia , Compostos Orgânicos Voláteis/metabolismo , Animais , Ciclopentanos/metabolismo , Ciclopentanos/farmacologia , Genótipo , Herbivoria/efeitos dos fármacos , Interações Hospedeiro-Parasita/efeitos dos fármacos , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/imunologia , Mutação/genética , Odorantes/análise , Oxilipinas/metabolismo , Oxilipinas/farmacologia , Folhas de Planta/efeitos dos fármacos
2.
Plant Cell Environ ; 33(5): 729-39, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20519018

RESUMO

Interactions between the root-knot nematode Meloidogyne incognita and three isogenic tomato (Lycopersicon esculentum) genotypes were examined when plants were grown under ambient (370 ppm) and elevated (750 ppm) CO2. We tested the hypothesis that, defence-recessive genotypes tend to allocate 'extra' carbon (relative to nitrogen) to growth under elevated CO2, whereas defence-dominated genotypes allocate extra carbon to defence, and thereby increases the defence against nematodes. For all three genotypes, elevated CO2 increased height, biomass, and root and leaf total non-structural carbohydrates (TNC):N ratio, and decreased amino acids and proteins in leaves. The activity of anti-oxidant enzymes (superoxide dismutase and catalase) was enhanced by nematode infection in defence-recessive genotypes. Furthermore, elevated CO2 and nematode infection did not qualitatively change the volatile organic compounds (VOC) emitted from plants. Elevated CO2 increased the VOC emission rate only for defence-dominated genotypes that were not infected with nematodes. Elevated CO2 increased the number of nematode-induced galls on defence-dominated genotypes but not on wild-types or defence-recessive genotypes roots. Our results suggest that CO2 enrichment may not only increase plant C : N ratio but can disrupt the allocation of plant resources between growth and defence in some genetically modified plants and thereby reduce their resistance to nematodes.


Assuntos
Dióxido de Carbono/metabolismo , Interações Hospedeiro-Parasita , Solanum lycopersicum/genética , Solanum lycopersicum/parasitologia , Tylenchoidea/fisiologia , Animais , Antioxidantes/metabolismo , Biomassa , Carbono/metabolismo , Ciclopentanos , Genótipo , Mutação , Nitrogênio/metabolismo , Oxilipinas , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Compostos Orgânicos Voláteis/metabolismo
3.
Nucleic Acids Res ; 28(23): 4649-56, 2000 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11095674

RESUMO

A plasmid gap repair assay was used to assess the role of three known nucleases, Exo1, Mre11 and Rad1, in the processing of DNA ends and resolution of recombination intermediates during double-strand gap repair. In this assay, alterations in end processing or branch migration are reflected by the frequency of co-conversion of a chromosomal marker 200 bp from the gap. Gap repair associated with crossing over results in integration at the homologous chromosomal locus, whereas the plasmid remains episomal for non-crossover repair events. In mre11 strains, the frequency of gap repair was reduced 3- to 10-fold and conversion tracts were shorter than in the wild-type strain, consistent with a role for this nuclease in processing double-strand breaks. However, conversion tracts were longer in a strain containing the nuclease deficient allele, mre11-H125N, suggesting increased end processing by redundant nucleases. The frequency of gap repair was reduced 2-fold in rad1 mutants and crossing over was reduced, consistent with a role for Rad1 in cleaving recombination intermediates. The frequency of gap repair was increased in exo1 mutants with a significant increase in crossing over. In exo1 mre11 double mutants gap repair was reduced to below the mre11 single mutant level.


Assuntos
Troca Genética/genética , Reparo do DNA , Proteínas de Ligação a DNA , Desoxirribonucleases/genética , Endodesoxirribonucleases , Conversão Gênica/genética , Plasmídeos/genética , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Enzimas Reparadoras do DNA , Desoxirribonucleases/deficiência , Endonucleases/deficiência , Endonucleases/genética , Exodesoxirribonucleases/deficiência , Exodesoxirribonucleases/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Mutação , Plasmídeos/metabolismo , Saccharomyces cerevisiae/enzimologia
4.
Mol Cell Biol ; 20(24): 9162-72, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11094068

RESUMO

A number of studies of Saccharomyces cerevisiae have revealed RAD51-independent recombination events. These include spontaneous and double-strand break-induced recombination between repeated sequences, and capture of a chromosome arm by break-induced replication. Although recombination between inverted repeats is considered to be a conservative intramolecular event, the lack of requirement for RAD51 suggests that repair can also occur by a nonconservative mechanism. We propose a model for RAD51-independent recombination by one-ended strand invasion coupled to DNA synthesis, followed by single-strand annealing. The Rad1/Rad10 endonuclease is required to trim intermediates formed during single-strand annealing and thus was expected to be required for RAD51-independent events by this model. Double-strand break repair between plasmid-borne inverted repeats was less efficient in rad1 rad51 double mutants than in rad1 and rad51 strains. In addition, repair events were delayed and frequently associated with plasmid loss. Furthermore, the repair products recovered from the rad1 rad51 strain were primarily in the crossover configuration, inconsistent with conservative models for mitotic double-strand break repair.


Assuntos
DNA Nucleotidiltransferases/genética , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Mutação , Recombinação Genética/genética , Saccharomyces cerevisiae/genética , Dano ao DNA , DNA Nucleotidiltransferases/metabolismo , DNA Fúngico/genética , DNA Fúngico/metabolismo , Proteínas de Ligação a DNA/genética , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Proteínas Fúngicas/genética , Conversão Gênica , Óperon Lac/genética , Modelos Genéticos , Plasmídeos/genética , Plasmídeos/metabolismo , Rad51 Recombinase , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae
5.
Mol Cell Biol ; 20(4): 1194-205, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10648605

RESUMO

DNA double-strand breaks may be induced by endonucleases, ionizing radiation, chemical agents, and mechanical forces or by replication of single-stranded nicked chromosomes. Repair of double-strand breaks can occur by homologous recombination or by nonhomologous end joining. A system was developed to measure the efficiency of plasmid gap repair by homologous recombination using either chromosomal or plasmid templates. Gap repair was biased toward gene conversion events unassociated with crossing over using either donor sequence. The dependence of recombinational gap repair on genes belonging to the RAD52 epistasis group was tested in this system. RAD51, RAD52, RAD57, and RAD59 were required for efficient gap repair using either chromosomal or plasmid donors. No homologous recombination products were recovered from rad52 mutants, whereas a low level of repair occurred in the absence of RAD51, RAD57, or RAD59. These results suggest a minor pathway of strand invasion that is dependent on RAD52 but not on RAD51. The residual repair events in rad51 mutants were more frequently associated with crossing over than was observed in the wild-type strain, suggesting that the mechanisms for RAD51-dependent and RAD51-independent events are different. Plasmid gap repair was reduced synergistically in rad51 rad59 double mutants, indicating an important role for RAD59 in RAD51-independent repair.


Assuntos
Proteínas de Ciclo Celular , Reparo do DNA , DNA Fúngico/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Sequência de Bases , Quinase do Ponto de Checagem 2 , Cromossomos Fúngicos/genética , Cromossomos Fúngicos/metabolismo , Troca Genética , Primers do DNA/genética , DNA Fúngico/genética , Proteínas de Ligação a DNA/genética , Epistasia Genética , Proteínas Fúngicas/genética , Genes Fúngicos , Modelos Biológicos , Mutação , Plasmídeos/genética , Plasmídeos/metabolismo , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Rad51 Recombinase , Proteína Rad52 de Recombinação e Reparo de DNA , Recombinação Genética , Saccharomyces cerevisiae/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...