Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/3420
Title: Endogenous pararetroviral sequences in tomato (Solanum lycopersicum) and related species
Authors: Staginnus, Christina
Gregor, Wolfgang
Mette, M. Florian
Teo, Chee How
Borroto-Fernández, Eduviges Glenda
Laimer da Câmara Machado, Margit
Matzke, Marjori
Schwarzacher, Trude
First Published: 21-May-2007
Publisher: BioMed Central Ltd.
Citation: BMC Plant Biology 2007, 7 : 24
Abstract: Background: Endogenous pararetroviral sequences (EPRVs) are a recently discovered class of repetitive sequences that is broadly distributed in the plant kingdom. The potential contribution of EPRVs to plant pathogenicity or, conversely, to virus resistance is just beginning to be explored. Some members of the family Solanaceae are particularly rich in EPRVs. In previous work, EPRVs have been characterized molecularly in various species of Nicotiana including N.tabacum (tobacco) and Solanum tuberosum (potato). Here we describe a family of EPRVs in cultivated tomato (Solanum lycopersicum L.) and a wild relative (S.habrochaites). Results: Molecular cloning and DNA sequence analysis revealed that tomato EPRVs (named LycEPRVs) are most closely related to those in tobacco. The sequence similarity of LycEPRVs in S.lycopersicum and S.habrochaites indicates they are potentially derived from the same pararetrovirus. DNA blot analysis revealed a similar genomic organization in the two species, but also some independent excision or insertion events after species separation, or flanking sequence divergence. LycEPRVs share with the tobacco elements a disrupted genomic structure and frequent association with retrotransposons. Fluorescence in situ hybridization revealed that copies of LycEPRV are dispersed on all chromosomes in predominantly heterochromatic regions. Methylation of LycEPRVs was detected in CHG and asymmetric CHH nucleotide groups. Although normally quiescent EPRVs can be reactivated and produce symptoms of infection in some Nicotiana interspecific hybrids, a similar pathogenicity of LycEPRVs could not be demonstrated in Solanum L. section Lycopersicon [Mill.] hybrids. Even in healthy plants, however, transcripts derived from multiple LycEPRV loci and short RNAs complementary to LycEPRVs were detected and were elevated upon infection with heterologous viruses encoding suppressors of PTGS. Conclusion: The analysis of LycEPRVs provides further evidence for the extensive invasion of pararetroviral sequences into the genomes of solanaceous plants. The detection of asymmetric CHH methylation and short RNAs, which are hallmarks of RNAi in plants, suggests that LycEPRVs are controlled by an RNA-mediated silencing mechanism.
DOI Link: 10.1186/1471-2229-7-24
ISSN: 8756-3282
Links: http://hdl.handle.net/2381/3420
http://www.biomedcentral.com/1471-2229/7/24
Version: Publisher Version
Status: Peer-reviewed
Type: Article
Rights: Copyright © 2007 Staginnus et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Appears in Collections:Published Articles, Dept. of Biology

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