Evasion of short Interfering RNA-directed antiviral silencing in Musa acuminata persistently infected with six distinct banana streak pararetroviruses

Rajeswaran Rajendran, Seguin Jonathan, Chabannes Matthieu, Duroy Pierre-Olivier, Laboureau Nathalie, Farinelli Laurent, Iskra Caruana Marie-Line, Pooggin Mikhail. 2014. Evasion of short Interfering RNA-directed antiviral silencing in Musa acuminata persistently infected with six distinct banana streak pararetroviruses. Journal of Virology, 88 (19) : 11516-11528.

Quartile : Q1, Sujet : VIROLOGY

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie

Résumé : Vegetatively propagated crop plants often suffer from infections with persistent RNA and DNA viruses. Such viruses appear to evade the plant defenses that normally restrict viral replication and spread. The major antiviral defense mechanism is based on RNA silencing generating viral short interfering RNAs (siRNAs) that can potentially repress viral genes posttranscriptionally through RNA cleavage and transcriptionally through DNA cytosine methylation. Here we examined the RNA silencing machinery of banana plants persistently infected with six pararetroviruses after many years of vegetative propagation. Using deep sequencing, we reconstructed consensus master genomes of the viruses and characterized virus-derived and endogenous small RNAs. Consistent with the presence of endogenous siRNAs that can potentially establish and maintain DNA methylation, the banana genomic DNA was extensively methylated in both healthy and virus-infected plants. A novel class of abundant 20-nucleotide (nt) endogenous small RNAs with 5?-terminal guanosine was identified. In all virus-infected plants, 21- to 24-nt viral siRNAs accumulated at relatively high levels (up to 22% of the total small RNA population) and covered the entire circular viral DNA genomes in both orientations. The hotspots of 21-nt and 22-nt siRNAs occurred within open reading frame (ORF) I and II and the 5? portion of ORF III, while 24-nt siRNAs were more evenly distributed along the viral genome. Despite the presence of abundant viral siRNAs of different size classes, the viral DNA was largely free of cytosine methylation. Thus, the virus is able to evade siRNA-directed DNA methylation and thereby avoid transcriptional silencing. This evasion of silencing likely contributes to the persistence of pararetroviruses in banana plants.

Mots-clés Agrovoc : Musa acuminata, virus des végétaux, multiplication végétative, mécanisme de défense

Mots-clés complémentaires : Banana streak virus, Pararétrovirus, Endovirus

Classification Agris : H20 - Maladies des plantes
F02 - Multiplication végétative des plantes

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

Auteurs et affiliations

• Rajeswaran Rajendran, University of Basel (CHE)
• Seguin Jonathan, University of Basel (CHE)
• Chabannes Matthieu, CIRAD-BIOS-UMR BGPI (FRA) ORCID: 0000-0001-5754-5982
• Duroy Pierre-Olivier, Bayer (FRA)
• Laboureau Nathalie, CIRAD-BIOS-UMR BGPI (FRA) ORCID: 0000-0002-0105-3919
• Farinelli Laurent, Fasteris (CHE)
• Iskra Caruana Marie-Line, CIRAD-BIOS-UMR BGPI (FRA) ORCID: 0000-0003-4486-2449
• Pooggin Mikhail, University of Basel (CHE)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/573816/)

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