Navegando por Autor "Alfenas‐Zerbini, Poliane"
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Item Characterization of CRISPR-Cas systems in the Ralstonia solanacearum species complex(Molecular Plant Pathology, 2019-02) Xavier, André da Silva; Almeida, Juliana Cristina Fraleon de; Melo, Alessandra Gonçalves de; Rousseau, Geneviève M.; Tremblay, Denise M.; Rezende, Rafael Reis de; Moineau, Sylvain; Alfenas‐Zerbini, PolianeClustered regularly interspaced short palindromic repeats (CRISPRs) are composed of an array of short DNA repeat sequences separated by unique spacer sequences that are flanked by associated (Cas) genes. CRISPR-Cas systems are found in the genomes of several microbes and can act as an adaptive immune mechanism against invading foreign nucleic acids, such as phage genomes. Here, we studied the CRISPRCas systems in plant-pathogenic bacteria of the Ralstonia sola- nacearum species complex (RSSC). A CRISPR-Cas system was found in 31% of RSSC genomes present in public databases. Specifically, CRISPR-Cas types I-E and II-C were found, with I-E being the most common. The presence of the same CRISPRCas types in distinct Ralstonia phylotypes and species suggests the acquisition of the system by a common ancestor before Ralstonia species segregation. In addition, a Cas1 phylogeny (I-E type) showed a perfect geographical segregation of phylotypes, supporting an ancient acquisition. Ralstonia solanacearum strains CFBP2957 and K60 T were challenged with a virulent phage, and the CRISPR arrays of bacteriophage insensitive mutants (BIMs) were analysed. No new spacer acquisition was detected in the analysed BIMs. The functionality of the CRISPR-Cas interference step was also tested in R. solanacearum CFBP2957 using a spacer-protospacer adjacent motif (PAM) delivery system, and no resistance was observed against phage phiAP1. Our results show that the CRISPR-Cas system in R. solanacearum CFBP2957 is not its primary antiviral strategy.Item Taxonomy of prokaryotic viruses: 2017 update from the ICTV Bacterial and Archaeal Viruses Subcommittee(Archives of Virology, 2018-01-22) Alfenas‐Zerbini, Poliane; Adriaenssens, Evelien M.; Wittmann, Johannes; Kuhn, Jens H.; Turner, Dann; Sullivan, Matthew B.; Dutilh, Bas E.; Jang, Ho Bin; Zyl, Leonardo J. van; Klumpp, Jochen; Lobocka, Malgorzata; Switt, Andrea I. Moreno; Rumnieks, Janis; Edwards, Robert A.; Uchiyama, Jumpei; Petty, Nicola K.; Kropinski, Andrew M.; et al.The prokaryotic virus community is represented at the Inter- national Committee on Taxonomy of Viruses (ICTV) by the Bacterial and Archaeal Viruses Subcommittee. Since our last report [5], the committee composition has changed, and a large number of taxonomic proposals (TaxoProps) were submitted to the ICTV Executive Committee (EC) for approvalItem Translationally controlled tumour protein (TCTP) from tomato and Nicotiana benthamiana is necessary for successful infection by a potyvirus(Molecular Plant Pathology, 2016-05-09) Bruckner, Fernanda Prieto; Xavier, André Da Silva; Cascardo, Renan De Souza; Otoni, Wagner Campos; Zerbini, Francisco Murilo; Alfenas‐Zerbini, PolianeTranslationally controlled tumour protein (TCTP) is a ubiquitously distributed protein in eukaryotes, involved in the regulation of several processes, including cell cycle progression, cell growth, stress protection, apoptosis and maintenance of genomic integrity. Its expression is induced during the early stages of tomato (Solanum lycopersicum) infection by the potyvirus Pepper yellow mosaic virus (PepYMV, a close relative of Potato virus Y). Tomato TCTP is a protein of 168 amino acids, which contains all the conserved domains of the TCTP family. To study the effects of TCTP silencing in PepYMV infection, Nicotiana benthamiana plants were silenced by virus‐induced gene silencing (VIGS) and transgenic tomato plants silenced for TCTP were obtained. In the early stages of infection, both tomato and N. benthamiana silenced plants accumulated less virus than control plants. Transgenic tomato plants showed a drastic reduction in symptoms and no viral accumulation at 14 days post‐inoculation. Subcellular localization of TCTP was determined in healthy and systemically infected N. benthamiana leaves. TCTP was observed in both the nuclei and cytoplasm of non‐infected cells, but only in the cytoplasm of infected cells. Our results indicate that TCTP is a growth regulator necessary for successful PepYMV infection and that its localization is altered by the virus, probably to favour the establishment of virus infection. A network with putative interactions that may occur between TCTP and Arabidopsis thaliana proteins was built. This network brings together experimental data of interactions that occur in other eukaryotes and helps us to discuss the possibilities of TCTP involvement in viral infection.