The senescence process is the last stage in leaf develop ment and is characterized by dramatic ch... more The senescence process is the last stage in leaf develop ment and is characterized by dramatic changes in cellular metabolism and the degeneration of cellular structures. Several reports of senescence-associated genes (SAGs) have appeared, and an overlap in some of the genes induced during senescence and pathogen infections has been observed. For example, the en hanced expression of SAGs in response to diseases caused by fungi, bacteria, and viruses that trigger the hypersensitive response (HR) or during infections in duced by virulent fungi and bacteria that elicit necrotic symptoms has been observed. The present work broadens the search for SAGs induced during com patible viral interactions with both the model plant Arabidopsis thaliana and a commercially important grapevine cultivar. The transcript profiles of Arabidop sis ecotype Uk-4 infected with tobacco mosaic virus strain Cg (TMV-Cg) and Vitis vinifera cv. Carmenere infected with grapevine leaf roll-associated virus strain 3...
The common strain of the tobacco mosaic virus (TMV-U1), and the crucifer-infecting tobacco mosaic... more The common strain of the tobacco mosaic virus (TMV-U1), and the crucifer-infecting tobacco mosaic virus (TMV-Cg), both members of Tobamovirus genus, infect efficiently the solanaceous plants such as tomato and tobacco. The crucifer-infecting tobacco mosaic virus (TMV-Cg) also infects Arabidopsis thaliana plant, spreading systemically without causing severe symptoms. In contrast, Arabidopsis is a poor host for TMV-U1 infection. Within the past 10 years, Arabidopsis has developed into a powerful model system for studying plant-pathogen interaction. However, a detailed analysis comparing the accuracy of various viral detection methods has not been reported previously. Four detection methods were evaluated in A. thaliana (ecotype Po-1), infected with TMV-U1 or TMV-Cg. Western blots, enzyme-linked immunosorbent assay (ELISA), reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ RNA hybridization methods were used to determine viral spread at various days post inoculation (dpi) in inoculated and apical non-inoculated leaves. The detection of viral spread of TMV-U1 and TMV-Cg in Arabidopsis, using these four detection methods, supports previous studies, which demonstrate that the systemic spreads of these two viruses differ in Arabidopsis. Western blotting and ELISA detected TMV-Cg at 5dpi, and TMV-U1 at 12 dpi in systemic tissues. Viral spread was detected earlier when using RNA detection methods. Reverse transcriptase-polymerase chain reaction (RT-PCR) was very sensitive for detecting TMV-Cg in A. thaliana, but less sensitive for TMV-U1 detection. In situ RNA hybridization showed differential distribution of TMV-Cg and TMV-U1 in the inoculated leaf and systemic tissues.
Tolerancia a la salinidad en la germinacion de tres especies de Prosopis (P. alba, P. chilensis y... more Tolerancia a la salinidad en la germinacion de tres especies de Prosopis (P. alba, P. chilensis y P. tamarugo)
Seeds of Prosopis chilensis, a leguminous tree from semi-arid regions of Central Chile, were germ... more Seeds of Prosopis chilensis, a leguminous tree from semi-arid regions of Central Chile, were germinated at temperatures of 25-30-35-40-45 and 50{degree}C. Germination was 100% between 25 and 40{degree}C, being faster at 35{degree}C. The best temperature for root growth was also 35{degree}C. There was not germination at 50{degree}C. However, seedlings coming from seeds germinated at 35{degree}C were capable of growing at higher temperatures of 45 and 50{degree}C. Pattern of protein synthesis was followed in roots incubated with {sup 35}S-methionine at increasing temperatures between 35 and 50{degree}C. SDS-PAGE of the proteins followed by fluorography shows that at temperatures above 35{degree}C, new protein bands appear while others become thicker. Most of the protein bands have decreased at 50{degree}C, with the exception of the new bands. A band of 70 KD, that is present at 35{degree}C, is more prominent at 50{degree}C. These proteins may have an important role in the thermotolerance of Prosopis chilensis to stressing temperatures.
Background Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which indu... more Background Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which induces the rapid closure of stomatal pores to prevent water loss. This event is trigged by a series of signals produced inside guard cells which finally reduce their turgor. Many of these events are tightly regulated at the transcriptional level, including the control exerted by MYB proteins. In a previous study, while identifying the grapevine R2R3 MYB family, two closely related genes, VvMYB30 and VvMYB60 were found with high similarity to AtMYB60, an Arabidopsis guard cell-related drought responsive gene. Results Promoter-GUS transcriptional fusion assays showed that expression of VvMYB60 was restricted to stomatal guard cells and was attenuated in response to ABA. Unlike VvMYB30, VvMYB60 was able to complement the loss-of-function atmyb60-1 mutant, indicating that VvMYB60 is the only true ortholog of AtMYB60 in the grape genome. In addition, VvMYB60 was differentially regulated during d...
The tobamovirus TMV-Cg induces an HR-like response in Nicotiana tabacum cv. Xanthi nn sensitive p... more The tobamovirus TMV-Cg induces an HR-like response in Nicotiana tabacum cv. Xanthi nn sensitive plants lacking the N or N′ resistance genes. This response has been characterized by the appearance of necrotic lesions in the inoculated leaf and viral systemic spread, although the defence ...
Viral diseases affect grapevine cultures without inducing any resistance response. Thus, these pl... more Viral diseases affect grapevine cultures without inducing any resistance response. Thus, these plants develop systemic diseases and are chronically infected. Molecular events associated with viral compatible infections responsible for disease establishment and symptoms development are poorly understood. In this study, we surveyed viral infection in grapevines at a transcriptional level. Gene expression in the Vitis vinifera red wine cultivars Carménère and Cabernet-Sauvignon naturally infected with GLRaV-3 were evaluated using a genome-wide expression profiling with the Vitis vinifera GeneChip from Affymetrix. We describe numerous genes that are induced or repressed in viral infected grapevines leaves. Changes in gene expression involved a wide spectrum of biological functions, including processes of translation and protein targeting, metabolism, transport, and cell defense. Considering cellular localization, the membrane and endomembrane systems appeared with the highest number of induced genes, while chloroplastic genes were mostly repressed. As most induced genes associated with the membranous system are involved in transport, the possible effect of virus in this process is discussed. Responses of both cultivars are analyzed and the results are compared with published data from other species. This is the first study of global gene profiling in grapevine in response to viral infections using DNA microarray.
A novel Otubain-like cysteine protease gene is preferentially expressed during somatic embryogene... more A novel Otubain-like cysteine protease gene is preferentially expressed during somatic embryogenesis in Pinus radiata Felipe Aquea Æ Florencia Gutiérrez Æ Consuelo Medina Æ Patricio Arce-Johnson ... Felipe Aquea and Florencia Gutiérrez contributed equally to this work ...
Pinus radiata is one of the most important forestry species in the southern hemisphere. This work... more Pinus radiata is one of the most important forestry species in the southern hemisphere. This work describes the regeneration of this plant via somatic embryogenesis from immature zygotic embryos. To improve this process, somatic embryogenic cell suspensions were established in liquid media for the generation of material for embryo maturation. Each developmental stage of these suspensions was characterized by microscopy and their growth phases quantified. An alginate-containing medium was used as an encapsulation method for the somatic embryos that were then germinated as artificial seeds in vitro. The protocols described in this work are both useful and reliable for industrial purposes.
When inoculated into sensitive tobacco Xanthi-nn plants, the crucifer and garlic-infecting Tobacc... more When inoculated into sensitive tobacco Xanthi-nn plants, the crucifer and garlic-infecting Tobacco mosaic virus (TMV-Cg) induces local necrotic lesions that resemble those seen in the hypersensitive response (HR) of resistant tobacco plants. However, unlike these, tobacco Xanthi-nn ...
The senescence process is the last stage in leaf develop ment and is characterized by dramatic ch... more The senescence process is the last stage in leaf develop ment and is characterized by dramatic changes in cellular metabolism and the degeneration of cellular structures. Several reports of senescence-associated genes (SAGs) have appeared, and an overlap in some of the genes induced during senescence and pathogen infections has been observed. For example, the en hanced expression of SAGs in response to diseases caused by fungi, bacteria, and viruses that trigger the hypersensitive response (HR) or during infections in duced by virulent fungi and bacteria that elicit necrotic symptoms has been observed. The present work broadens the search for SAGs induced during com patible viral interactions with both the model plant Arabidopsis thaliana and a commercially important grapevine cultivar. The transcript profiles of Arabidop sis ecotype Uk-4 infected with tobacco mosaic virus strain Cg (TMV-Cg) and Vitis vinifera cv. Carmenere infected with grapevine leaf roll-associated virus strain 3...
The common strain of the tobacco mosaic virus (TMV-U1), and the crucifer-infecting tobacco mosaic... more The common strain of the tobacco mosaic virus (TMV-U1), and the crucifer-infecting tobacco mosaic virus (TMV-Cg), both members of Tobamovirus genus, infect efficiently the solanaceous plants such as tomato and tobacco. The crucifer-infecting tobacco mosaic virus (TMV-Cg) also infects Arabidopsis thaliana plant, spreading systemically without causing severe symptoms. In contrast, Arabidopsis is a poor host for TMV-U1 infection. Within the past 10 years, Arabidopsis has developed into a powerful model system for studying plant-pathogen interaction. However, a detailed analysis comparing the accuracy of various viral detection methods has not been reported previously. Four detection methods were evaluated in A. thaliana (ecotype Po-1), infected with TMV-U1 or TMV-Cg. Western blots, enzyme-linked immunosorbent assay (ELISA), reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ RNA hybridization methods were used to determine viral spread at various days post inoculation (dpi) in inoculated and apical non-inoculated leaves. The detection of viral spread of TMV-U1 and TMV-Cg in Arabidopsis, using these four detection methods, supports previous studies, which demonstrate that the systemic spreads of these two viruses differ in Arabidopsis. Western blotting and ELISA detected TMV-Cg at 5dpi, and TMV-U1 at 12 dpi in systemic tissues. Viral spread was detected earlier when using RNA detection methods. Reverse transcriptase-polymerase chain reaction (RT-PCR) was very sensitive for detecting TMV-Cg in A. thaliana, but less sensitive for TMV-U1 detection. In situ RNA hybridization showed differential distribution of TMV-Cg and TMV-U1 in the inoculated leaf and systemic tissues.
Tolerancia a la salinidad en la germinacion de tres especies de Prosopis (P. alba, P. chilensis y... more Tolerancia a la salinidad en la germinacion de tres especies de Prosopis (P. alba, P. chilensis y P. tamarugo)
Seeds of Prosopis chilensis, a leguminous tree from semi-arid regions of Central Chile, were germ... more Seeds of Prosopis chilensis, a leguminous tree from semi-arid regions of Central Chile, were germinated at temperatures of 25-30-35-40-45 and 50{degree}C. Germination was 100% between 25 and 40{degree}C, being faster at 35{degree}C. The best temperature for root growth was also 35{degree}C. There was not germination at 50{degree}C. However, seedlings coming from seeds germinated at 35{degree}C were capable of growing at higher temperatures of 45 and 50{degree}C. Pattern of protein synthesis was followed in roots incubated with {sup 35}S-methionine at increasing temperatures between 35 and 50{degree}C. SDS-PAGE of the proteins followed by fluorography shows that at temperatures above 35{degree}C, new protein bands appear while others become thicker. Most of the protein bands have decreased at 50{degree}C, with the exception of the new bands. A band of 70 KD, that is present at 35{degree}C, is more prominent at 50{degree}C. These proteins may have an important role in the thermotolerance of Prosopis chilensis to stressing temperatures.
Background Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which indu... more Background Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which induces the rapid closure of stomatal pores to prevent water loss. This event is trigged by a series of signals produced inside guard cells which finally reduce their turgor. Many of these events are tightly regulated at the transcriptional level, including the control exerted by MYB proteins. In a previous study, while identifying the grapevine R2R3 MYB family, two closely related genes, VvMYB30 and VvMYB60 were found with high similarity to AtMYB60, an Arabidopsis guard cell-related drought responsive gene. Results Promoter-GUS transcriptional fusion assays showed that expression of VvMYB60 was restricted to stomatal guard cells and was attenuated in response to ABA. Unlike VvMYB30, VvMYB60 was able to complement the loss-of-function atmyb60-1 mutant, indicating that VvMYB60 is the only true ortholog of AtMYB60 in the grape genome. In addition, VvMYB60 was differentially regulated during d...
The tobamovirus TMV-Cg induces an HR-like response in Nicotiana tabacum cv. Xanthi nn sensitive p... more The tobamovirus TMV-Cg induces an HR-like response in Nicotiana tabacum cv. Xanthi nn sensitive plants lacking the N or N′ resistance genes. This response has been characterized by the appearance of necrotic lesions in the inoculated leaf and viral systemic spread, although the defence ...
Viral diseases affect grapevine cultures without inducing any resistance response. Thus, these pl... more Viral diseases affect grapevine cultures without inducing any resistance response. Thus, these plants develop systemic diseases and are chronically infected. Molecular events associated with viral compatible infections responsible for disease establishment and symptoms development are poorly understood. In this study, we surveyed viral infection in grapevines at a transcriptional level. Gene expression in the Vitis vinifera red wine cultivars Carménère and Cabernet-Sauvignon naturally infected with GLRaV-3 were evaluated using a genome-wide expression profiling with the Vitis vinifera GeneChip from Affymetrix. We describe numerous genes that are induced or repressed in viral infected grapevines leaves. Changes in gene expression involved a wide spectrum of biological functions, including processes of translation and protein targeting, metabolism, transport, and cell defense. Considering cellular localization, the membrane and endomembrane systems appeared with the highest number of induced genes, while chloroplastic genes were mostly repressed. As most induced genes associated with the membranous system are involved in transport, the possible effect of virus in this process is discussed. Responses of both cultivars are analyzed and the results are compared with published data from other species. This is the first study of global gene profiling in grapevine in response to viral infections using DNA microarray.
A novel Otubain-like cysteine protease gene is preferentially expressed during somatic embryogene... more A novel Otubain-like cysteine protease gene is preferentially expressed during somatic embryogenesis in Pinus radiata Felipe Aquea Æ Florencia Gutiérrez Æ Consuelo Medina Æ Patricio Arce-Johnson ... Felipe Aquea and Florencia Gutiérrez contributed equally to this work ...
Pinus radiata is one of the most important forestry species in the southern hemisphere. This work... more Pinus radiata is one of the most important forestry species in the southern hemisphere. This work describes the regeneration of this plant via somatic embryogenesis from immature zygotic embryos. To improve this process, somatic embryogenic cell suspensions were established in liquid media for the generation of material for embryo maturation. Each developmental stage of these suspensions was characterized by microscopy and their growth phases quantified. An alginate-containing medium was used as an encapsulation method for the somatic embryos that were then germinated as artificial seeds in vitro. The protocols described in this work are both useful and reliable for industrial purposes.
When inoculated into sensitive tobacco Xanthi-nn plants, the crucifer and garlic-infecting Tobacc... more When inoculated into sensitive tobacco Xanthi-nn plants, the crucifer and garlic-infecting Tobacco mosaic virus (TMV-Cg) induces local necrotic lesions that resemble those seen in the hypersensitive response (HR) of resistant tobacco plants. However, unlike these, tobacco Xanthi-nn ...
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