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Research paper thumbnail of Cellular target of helminthosporium sacchari Toxin in sugarcane tissue

Sugar Tech, 2005

Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeled Helminthospo... more Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeled Helminthosporium (Bipolaris) sacchari toxin to determine the general effect on different organelles and structures. Toxin labeling was characterized by biochemical and physiological behaviour ...

Research paper thumbnail of Molecular aspects of abiotic stress in plants

Drought, salinity and extreme temperature are major adverse environmental factors that limit plan... more Drought, salinity and extreme temperature are major adverse environmental factors that limit plant productivity. Sensors initiate a signaling cascade to transmit the signal and activate nuclear transcription factors to induce the expression of specific sets of genes. Ionic and osmotic stress signal transduction triggers the ionic and osmotic homeostasis signaling pathways, detoxification response pathways, and pathways for growth regulation. The ionic stress is signaled via the SOS pathway where an SOS3-SOS2 complex controls the expression and activity of ion transporters. Osmotic stress activates several protein kinases which mediate osmotic homeostasis and/or detoxification responses. Understanding the mechanisms by which plants perceive and transduce the stress signals to initiate adaptive responses is essential for engineering stress-tolerant crop plants. Genetic engineering strategies rely on the transfer of one or several genes that are either involved in signaling and regulatory pathways, or that encode enzymes present in pathways leading to the synthesis of functional and structural protectants, or that encode stresstolerance-conferring proteins. Certain techniques have been described to identify the gene whose expression is differentially regulated in response to various environmental stresses in higher plants. Such methods include differential display-polymerase chain reaction, suppression subtractive hybridization, serial analysis of gene expression, DNA microarray and cDNA-amplified fragment length polymorphism.

Research paper thumbnail of Identification of genes induced upon water-deficit stress in a drought-tolerant rice cultivar

Journal of Plant Physiology, 2006

Among the abiotic stresses, the availability of water is the most important factor that limits th... more 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.

Research paper thumbnail of NmDef02, a novel antimicrobial gene isolated from Nicotiana megalosiphon confers high-level pathogen resistance under greenhouse and field conditions

Plant Biotechnology Journal, 2010

Research paper thumbnail of Identification of genes induced upon water-deficit stress in a drought-tolerant rice cultivar

Journal of Plant Physiology, 2006

Among the abiotic stresses, the availability of water is the most important factor that limits th... more 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 transcriptderived 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.

Research paper thumbnail of NmDef02, a novel antimicrobial gene isolated from Nicotiana megalosiphon confers high-level pathogen resistance under greenhouse and field conditions: NmDef02, a novel antimicrobial protein

Plant Biotechnology Journal, 2010

Plant defensins are small cysteine-rich peptides that inhibit the growth of a broad range of micr... more Plant defensins are small cysteine-rich peptides that inhibit the growth of a broad range of microbes. In this article, we describe NmDef02, a novel cDNA encoding a putative defensin isolated from Nicotiana megalosiphon upon inoculation with the tobacco blue mould pathogen Peronospora hyoscyami f.sp. tabacina. NmDef02 was heterologously expressed in the yeast Pichia pastoris, and the purified recombinant protein was found to display antimicrobial activity in vitro against important plant pathogens. Constitutive expression of NmDef02 gene in transgenic tobacco and potato plants enhanced resistance against various plant microbial pathogens, including the oomycete Phytophthora infestans, causal agent of the economically important potato late blight disease, under greenhouse and field conditions.

Research paper thumbnail of Cellular target of helminthosporium sacchari Toxin in sugarcane tissue

Sugar Tech, 2005

Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeledHelminthospor... more Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeledHelminthosporium (Bipolaris) sacchari toxin to determine the general effect on different organelles and structures. Toxin labeling was characterized by biochemical and physiological behaviour of the fungal pathogen (dry weight, pH, refractive index, invertase and β -galactosidase activity and the biological activity of the toxin), allowing to improve the metabolic uptake of a labeled structural precursor of the toxin. A more efficient toxin labeling than previously reported was obtained. The labeled toxin was used as a tracer for determination of interactions at mitochondrial level. Binding activity reached saturation in time, confirming respiratory and ultrastructural analysis of the toxin effect.

Research paper thumbnail of Cellular target of helminthosporium sacchari Toxin in sugarcane tissue

Sugar Tech, 2005

Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeled Helminthospo... more Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeled Helminthosporium (Bipolaris) sacchari toxin to determine the general effect on different organelles and structures. Toxin labeling was characterized by biochemical and physiological behaviour ...

Research paper thumbnail of Molecular aspects of abiotic stress in plants

Drought, salinity and extreme temperature are major adverse environmental factors that limit plan... more Drought, salinity and extreme temperature are major adverse environmental factors that limit plant productivity. Sensors initiate a signaling cascade to transmit the signal and activate nuclear transcription factors to induce the expression of specific sets of genes. Ionic and osmotic stress signal transduction triggers the ionic and osmotic homeostasis signaling pathways, detoxification response pathways, and pathways for growth regulation. The ionic stress is signaled via the SOS pathway where an SOS3-SOS2 complex controls the expression and activity of ion transporters. Osmotic stress activates several protein kinases which mediate osmotic homeostasis and/or detoxification responses. Understanding the mechanisms by which plants perceive and transduce the stress signals to initiate adaptive responses is essential for engineering stress-tolerant crop plants. Genetic engineering strategies rely on the transfer of one or several genes that are either involved in signaling and regulatory pathways, or that encode enzymes present in pathways leading to the synthesis of functional and structural protectants, or that encode stresstolerance-conferring proteins. Certain techniques have been described to identify the gene whose expression is differentially regulated in response to various environmental stresses in higher plants. Such methods include differential display-polymerase chain reaction, suppression subtractive hybridization, serial analysis of gene expression, DNA microarray and cDNA-amplified fragment length polymorphism.

Research paper thumbnail of Identification of genes induced upon water-deficit stress in a drought-tolerant rice cultivar

Journal of Plant Physiology, 2006

Among the abiotic stresses, the availability of water is the most important factor that limits th... more 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.

Research paper thumbnail of NmDef02, a novel antimicrobial gene isolated from Nicotiana megalosiphon confers high-level pathogen resistance under greenhouse and field conditions

Plant Biotechnology Journal, 2010

Research paper thumbnail of Identification of genes induced upon water-deficit stress in a drought-tolerant rice cultivar

Journal of Plant Physiology, 2006

Among the abiotic stresses, the availability of water is the most important factor that limits th... more 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 transcriptderived 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.

Research paper thumbnail of NmDef02, a novel antimicrobial gene isolated from Nicotiana megalosiphon confers high-level pathogen resistance under greenhouse and field conditions: NmDef02, a novel antimicrobial protein

Plant Biotechnology Journal, 2010

Plant defensins are small cysteine-rich peptides that inhibit the growth of a broad range of micr... more Plant defensins are small cysteine-rich peptides that inhibit the growth of a broad range of microbes. In this article, we describe NmDef02, a novel cDNA encoding a putative defensin isolated from Nicotiana megalosiphon upon inoculation with the tobacco blue mould pathogen Peronospora hyoscyami f.sp. tabacina. NmDef02 was heterologously expressed in the yeast Pichia pastoris, and the purified recombinant protein was found to display antimicrobial activity in vitro against important plant pathogens. Constitutive expression of NmDef02 gene in transgenic tobacco and potato plants enhanced resistance against various plant microbial pathogens, including the oomycete Phytophthora infestans, causal agent of the economically important potato late blight disease, under greenhouse and field conditions.

Research paper thumbnail of Cellular target of helminthosporium sacchari Toxin in sugarcane tissue

Sugar Tech, 2005

Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeledHelminthospor... more Spindles from sugarcane (Saccharum spp. hybrid) tissue were challenged using labeledHelminthosporium (Bipolaris) sacchari toxin to determine the general effect on different organelles and structures. Toxin labeling was characterized by biochemical and physiological behaviour of the fungal pathogen (dry weight, pH, refractive index, invertase and β -galactosidase activity and the biological activity of the toxin), allowing to improve the metabolic uptake of a labeled structural precursor of the toxin. A more efficient toxin labeling than previously reported was obtained. The labeled toxin was used as a tracer for determination of interactions at mitochondrial level. Binding activity reached saturation in time, confirming respiratory and ultrastructural analysis of the toxin effect.