RESUMO
In order to identify tobacco (Nicotiana megalosiphon) genes involved in broad-spectrum resistance to tobacco blue mold (Peronospora hyoscyami f. sp. tabacina), suppression subtractive hybridization was used to generate cDNA from transcripts that are differentially expressed during an incompatible interaction. After differential screening by membrane-based hybridization, clones corresponding to 182 differentially expressed genes were selected, sequenced, and analyzed. The cDNA collection comprised a broad repertoire of genes associated with various processes. Northern blot analysis of a subset of these genes confirmed the differential expression patterns between the compatible and incompatible interaction. Subsequent virus-induced gene silencing (VIGS) of four genes that were found to be differentially induced was pursued. While VIGS of a lipid transfer protein gene or a glutamate decarboxylase gene in Nicotiana megalosiphon did not affect blue mold resistance, silencing of an EIL2 transcription factor gene and a glutathione synthetase gene was found to compromise the resistance of Nicotiana megalosiphon to P. hyoscyami f. sp. tabacina. Potentially, these genes can be used to engineer resistance in blue mold-susceptible tobacco cultivars.
Assuntos
Glutationa Sintase/metabolismo , Nicotiana/metabolismo , Nicotiana/microbiologia , Peronospora/fisiologia , Doenças das Plantas/microbiologia , Fatores de Transcrição/metabolismo , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Glutationa Sintase/genética , Dados de Sequência Molecular , Mutação , Folhas de Planta/microbiologia , Nicotiana/enzimologia , Nicotiana/genética , Fatores de Transcrição/genéticaRESUMO
Among the abiotic stresses, the availability of water is the most important factor that limits the productive potential of higher plants. The identification of novel genes, determination of their expression patterns, and the understanding of their functions in stress adaptation is essential to improve stress tolerance. Amplified fragment length polymorphism analysis of cDNA was used to identify rice genes differentially expressed in a tolerant rice variety upon water-deficit stress. In total, 103 transcript-derived fragments corresponding to differentially induced genes were identified. The results of the sequence comparison in BLAST database revealed that several differentially expressed TDFs were significantly homologous to stress regulated genes/proteins isolated from rice or other plant species. Most of the transcripts identified here were genes related to metabolism, energy, protein biosynthesis, cell defence, signal transduction, and transport. New genes involved in the response to water-deficit stress in a tolerant rice variety are reported here.
Assuntos
Genes de Plantas , Oryza/genética , Proteínas de Plantas/genética , DNA Complementar/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Oryza/anatomia & histologia , Oryza/metabolismo , Polimorfismo Genético , Homologia de Sequência de Aminoácidos , Água/metabolismoRESUMO
To understand the molecular basis of a specific plant-pathogen interaction, it is important to identify plant genes that respond to the pathogen attack. Amplified fragment length polymorphism (AFLP) analysis of cDNA was used to identify sugarcane genes differentially expressed in disease-resistant but not in susceptible sugarcane somaclones in response to inoculation with either Ustilago scitaminea or Bipolaris sacchari (also known as Helminthosporium sacchari or Drechslera sacchari), causal agents of smut and eyespot respectively. In total 62 differentially regulated genes were identified, of which 10 were down-regulated and 52 were induced. Of these 52, 19 transcript derived fragments showed homology to known plant gene sequences, most of them related to defense or signaling. The total set of differentially expressed sugarcane genes can be an important resource for further studies aimed at understanding sugarcane pathogen defense.