Banana plants use post-transcriptional gene silencing to control banana streak virus infection

Chabannes Matthieu, Duroy Pierre-Olivier, Seguin Jonathan, Rajendran Rajeswaran, Laboureau Nathalie, Pooggin Mikhail, Iskra Caruana Marie-Line. 2013. Banana plants use post-transcriptional gene silencing to control banana streak virus infection. In : 14èmes Rencontres de virologie végétale (RVV 2013) : Aussois, France, 13-17 janvier 2013. Marais Armelle (ed.), Revers Frédéric (ed.). SFP, INRA. Paris : SFP, Résumé, 87. Rencontres de Virologie Végétale. 14, Aussois, France, 13 Janvier 2013/17 Janvier 2013.

Résumé : Banana streak virus (BSV), the causative agent of banana streak disease, is a plant pararetrovirus belonging to the family Caulimoviridae, genus Badnavirus. The genome of BSV is a circular double-stranded DNA of 7.4 kbp made of three ORFs and like other pararetroviruses replicates via reverse transcription of viral pregenomic RNA (Lockhart, 1990). While the first two ORFs encode two small proteins of unknown function, the third ORF (~210 kD) encodes a polyprotein that can be cleaved to yield the viral coat protein and proteins with homology to aspartic protease, reverse transcriptase and RNaseH. Little information is available about antiviral defense response of the host plant on BSV or other members of Caulimoviridae. RNA silencing, also known as RNA interference (RNAi), is an ancient gene regulation and cell defense mechanism, which exists in most eukaryotes (Xie and Qi, 2008). Plants have adapted the RNA silencing machinery into an antiviral defense system. Interestingly, Arabidopsis plants infected with Cauliflower mosaic virus (CaMV), a type member of the genus Caulimovirus in the family Caulimoviridae, accumulate siRNAs of 21, 22 and 24 nt size classes, where the 24 nt species are the most predominant ones (Blevins et al., 2006; Moissiard and Voinnet, 2006). Further analysis showed that, the leader region (600 nt) of CaMV pregenomic RNA produces massive amounts of siRNAs with several hot and cold spots of siRNA generation (Blevins et al., 2011) to function as a decoy for the RNA silencing defense system of the plant. To determine whether the viral decoy strategy was universally used among viruses belonging to the family Caulimoviridae, we have performed a deep sequencing of total siRNAs of 6 Cavendish banana plants infected independently with one of the 6 BSV species we own in the laboratory. We obtained for the first time, experimental evidence of virus-derived small RNA (vsRNA) from those 6 BSV species by blasting sequencing data against the 6 BSV species genomes. vsRNA are enriched in 21-nt class thus BSV are likely silenced at the post-transcriptional level. Besides, our data unequivocally show that the decoy strategy used by the CaMV is not employed by the BSV since most of the hot spots of siRNA production are located in ORF1 and 2. Information generated about siRNAs derived from BSV genome could help us to design silencing-based transgenic and non-transgenic (RNA vaccination) approaches to obtain BSV resistance in banana crop. (Texte intégral)

Classification Agris : F30 - Génétique et amélioration des plantes
H20 - Maladies des plantes

Auteurs et affiliations

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

Source : Cirad - Agritrop (https://agritrop.cirad.fr/567990/)

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