RESUMEN
Various lepidopteran insects are responsible for major crop losses worldwide. Although crop plant varieties developed to express Bacillus thuringiensis (Bt) proteins are effective at controlling damage from key lepidopteran pests, some insect populations have evolved to be insensitive to certain Bt proteins. Here, we report the discovery of a family of homologous proteins, two of which we have designated IPD083Aa and IPD083Cb, which are from Adiantum spp. Both proteins share no known peptide domains, sequence motifs, or signatures with other proteins. Transgenic soybean or corn plants expressing either IPD083Aa or IPD083Cb, respectively, show protection from feeding damage by several key pests under field conditions. The results from comparative studies with major Bt proteins currently deployed in transgenic crops indicate that the IPD083 proteins function by binding to different target sites. These results indicate that IPD083Aa and IPD083Cb can serve as alternatives to traditional Bt-based insect control traits with potential to counter insect resistance to Bt proteins.
Asunto(s)
Adiantum/genética , Glycine max/genética , Insecticidas , Mariposas Nocturnas , Control Biológico de Vectores , Proteínas de Plantas/genética , Zea mays/genética , Animales , Protección de Cultivos , Plantas Modificadas Genéticamente , Proteínas Recombinantes/toxicidadRESUMEN
We have characterized a novel small heat shock protein gene, viscosity 1 (vis1) from tomato (Lycopersicon esculentum) and provide evidence that it plays a role in pectin depolymerization and juice viscosity in ripening fruits. Expression of vis1 is negatively associated with juice viscosity in diverse tomato genotypes. vis1 exhibits DNA polymorphism among tomato genotypes, and the alleles vis1-hta (high-transcript accumulator; accession no. AY128101) and vis1-lta (low transcript accumulator; accession no. AY128102) are associated with thinner and thicker juice, respectively. Segregation of tomato lines heterogeneous for vis1 alleles indicates that vis1 influences pectin depolymerization and juice viscosity in ripening fruits. vis1 is regulated by fruit ripening and high temperature and exhibits a typical heat shock protein chaperone function when expressed in bacterial cells. We propose that VIS1 contributes to physiochemical properties of juice, including pectin depolymerization, by reducing thermal denaturation of depolymerizing enzymes during daytime elevated temperatures.
Asunto(s)
Frutas/metabolismo , Proteínas de Choque Térmico/genética , Pectinas/metabolismo , Proteínas de Plantas/genética , Poligalacturonasa/metabolismo , Solanum lycopersicum/metabolismo , Aclimatación/genética , Aclimatación/fisiología , Alelos , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , ADN de Plantas/genética , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Escherichia coli/metabolismo , Frutas/genética , Frutas/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Proteínas de Choque Térmico/metabolismo , Calor , Solanum lycopersicum/genética , Solanum lycopersicum/crecimiento & desarrollo , Datos de Secuencia Molecular , Familia de Multigenes , Fenotipo , Filogenia , Proteínas de Plantas/metabolismo , Polimorfismo de Nucleótido Simple , Desnaturalización Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homología de Secuencia de Aminoácido , ViscosidadRESUMEN
Treatment of tomato (Lycopersicon esculentum L. cv. Beefstake) fruit with low concentrations of (0.01 mM) methyl jasmonate (MeJA) or methyl salicylate (MeSA) substantially enhanced their resistance to chilling temperature and decreased the incidence of decay during low-temperature storage. While studying the expression of pathogenesis-related (PR) protein genes, different accumulation patterns of PR-protein mRNAs in tomato fruit were observed. MeJA substantially increased the accumulation of PR-2b transcripts encoding intracellular beta-1,3-glucanase and enhanced the mRNA levels of PR-2a and PR-3b encoding extracellular beta-1,3-glucanase and intracellular chitinase, respectively. MeSA substantially increased accumulation of PR-2b and PR-3a mRNAs and slightly increased PR-3b mRNA accumulation. Chilling temperature did not appreciably enhance the accumulation of PR-protein mRNAs in untreated fruit. However, the accumulation of PR-3b mRNAs in MeSA-treated fruit was enhanced following low-temperature storage. Transcript abundance of catalase genes also was investigated in different pretreated tomatoes. The accumulation of cat1 mRNA was increased substantially by MeJA, while it was reduced by MeSA treatment. These results suggest that the pre-treatment of tomato fruit with MeSA or MeJA induces the synthesis of some stress proteins, such as PR proteins, which leads to increased chilling tolerance and resistance to pathogens, thereby decreasing the incidence of decay.
