Browsing by Author "Zamorano, Alan"

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    A remarkable synergistic effect at the transcriptomic level in peach fruits doubly infected by prunus necrotic ringspot virus and peach latent mosaic viroid
    (2013) Herranz, Mari C.; Niehl, Annette; Rosales V., Marlene; Fiore, Nicola; Zamorano, Alan; Granell, Antonio; Pallas, Vicente
    Abstract Background Microarray profiling is a powerful technique to investigate expression changes of large amounts of genes in response to specific environmental conditions. The majority of the studies investigating gene expression changes in virus-infected plants are limited to interactions between a virus and a model host plant, which usually is Arabidopsis thaliana or Nicotiana benthamiana. In the present work, we performed microarray profiling to explore changes in the expression profile of field-grown Prunus persica (peach) originating from Chile upon single and double infection with Prunus necrotic ringspot virus (PNRSV) and Peach latent mosaic viroid (PLMVd), worldwide natural pathogens of peach trees. Results Upon single PLMVd or PNRSV infection, the number of statistically significant gene expression changes was relatively low. By contrast, doubly-infected fruits presented a high number of differentially regulated genes. Among these, down-regulated genes were prevalent. Functional categorization of the gene expression changes upon double PLMVd and PNRSV infection revealed protein modification and degradation as the functional category with the highest percentage of repressed genes whereas induced genes encoded mainly proteins related to phosphate, C-compound and carbohydrate metabolism and also protein modification. Overrepresentation analysis upon double infection with PLMVd and PNRSV revealed specific functional categories over- and underrepresented among the repressed genes indicating active counter-defense mechanisms of the pathogens during infection. Conclusions Our results identify a novel synergistic effect of PLMVd and PNRSV on the transcriptome of peach fruits. We demonstrate that mixed infections, which occur frequently in field conditions, result in a more complex transcriptional response than that observed in single infections. Thus, our data demonstrate for the first time that the simultaneous infection of a viroid and a plant virus synergistically affect the host transcriptome in infected peach fruits. These field studies can help to fully understand plant-pathogen interactions and to develop appropriate crop protection strategies.Abstract Background Microarray profiling is a powerful technique to investigate expression changes of large amounts of genes in response to specific environmental conditions. The majority of the studies investigating gene expression changes in virus-infected plants are limited to interactions between a virus and a model host plant, which usually is Arabidopsis thaliana or Nicotiana benthamiana. In the present work, we performed microarray profiling to explore changes in the expression profile of field-grown Prunus persica (peach) originating from Chile upon single and double infection with Prunus necrotic ringspot virus (PNRSV) and Peach latent mosaic viroid (PLMVd), worldwide natural pathogens of peach trees. Results Upon single PLMVd or PNRSV infection, the number of statistically significant gene expression changes was relatively low. By contrast, doubly-infected fruits presented a high number of differentially regulated genes. Among these, down-regulated genes were prevalent. Functional categorization of the gene expression changes upon double PLMVd and PNRSV infection revealed protein modification and degradation as the functional category with the highest percentage of repressed genes whereas induced genes encoded mainly proteins related to phosphate, C-compound and carbohydrate metabolism and also protein modification. Overrepresentation analysis upon double infection with PLMVd and PNRSV revealed specific functional categories over- and underrepresented among the repressed genes indicating active counter-defense mechanisms of the pathogens during infection. Conclusions Our results identify a novel synergistic effect of PLMVd and PNRSV on the transcriptome of peach fruits. We demonstrate that mixed infections, which occur frequently in field conditions, result in a more complex transcriptional response than that observed in single infections. Thus, our data demonstrate for the first time that the simultaneous infection of a viroid and a plant virus synergistically affect the host transcriptome in infected peach fruits. These field studies can help to fully understand plant-pathogen interactions and to develop appropriate crop protection strategies.
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    Photorhabdus antumapuensissp. nov., a novel symbiotic bacterial species associated with Heterorhabditis atacamensis entomopathogenic nematodes
    (2022) Castaneda-Alvarez, Carlos; Machado, Ricardo A. R.; Morales-Montero, Patricia; Boss, Anja; Muller, Arthur; Prodan, Simona; Zamorano, Alan; San-Blas, Ernesto; Puza, Vladimir; Aballay, Erwin
    One motile, Gram- negative, non- spore- forming and rod- shaped symbiotic bacterium, strain UCH- 936T, was isolated from Het- erorhabditis atacamensis nematodes. Results of biochemical, physiological, molecular and genomic analyses suggest that it represents a new species, which we propose to name Photorhabdus antumapuensis sp. nov. Digital DNA-DNA hybridization shows that strain UCH- 936T is more closely related to Photorhabdus kleinii DSM 23513T, but shares solely 50.5 % similarity, which is below the 70% cut- off value that delimits species boundaries in bacteria. Phylogenetic reconstructions using whole- genome sequences show that strain UCH- 936T forms a unique clade, suggesting its novel and distinct taxonomic status again. Similarly, comparative genomic analyses shows that the virulence factor flagella- related gene fleR, the type IV pili- related gene pilL and the vibriobactin- related gene vibE are present in the genome of strain UCH- 936T but absent in the genomes of its closest relatives. Biochemically and physiologically, UCH- 936T differs also from all closely related Photorhabdus species. Therefore, Photorhabdus antumapuensis sp. nov. is proposed as a new species with the type strain UCH- 936T (CCCT 21.06T=CCM 9188T=CCOS 1991T).