Citrus tristeza virus infection induces the accumulation of viral small RNAs (21- 24-nt) mapping preferentially at the 3’-terminal region of the genomic RNA and affects the host small RNA profile
To get an insight into the host RNA silencing defense induced by Citrus tristeza virus (CTV) and into the counter defensive reaction mediated by its three silencing suppressors (p25, p20 and p23), we have examined by deep sequencing (Solexa - Illumina) the small RNAs (sRNAs) in three virus-host comb...
| Autores: | , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/48527 |
| Acceso en línea: | http://hdl.handle.net/10261/48527 |
| Access Level: | acceso abierto |
| Palabra clave: | Closteroviruses MicroRNAs RNA silencing Small interfering RNAs |
| Sumario: | To get an insight into the host RNA silencing defense induced by Citrus tristeza virus (CTV) and into the counter defensive reaction mediated by its three silencing suppressors (p25, p20 and p23), we have examined by deep sequencing (Solexa - Illumina) the small RNAs (sRNAs) in three virus-host combinations. Our data show that CTV sRNAs: i) represent more than 50% of the total sRNAs in Mexican lime and sweet orange (where CTV reaches relatively high titers), but only 3.5% in sour orange (where the CTV titer is significantly lower), ii) are predominantly of 21- 22-nt, with a biased d istribu tion of th eir 5’ n u cleotid e an d w ith th ose of (+) p olarity accu m u latin g in a moderate excess, and iii) derive from essentially all the CTV genome (ca. 20 kb), as revealed by its complete reconstruction from viral sRNA contigs, but adopt an asym m etric d istribu tion w ith a p rom in en t hotsp ot coverin g ap p roxim ately th e 3’- terminal 2500 nt. These results suggest that the citrus homologues of Dicer -like (DCL) 4 and 2 most likely mediate the genesis of the 21 and 22 nt CTV sRNAs, respectively, and show that both ribonucleases act not only on the genomic RNA but also on th e 3’ co-terminal subgenomic RNAs and, particularly, on their doublestranded forms. The plant sRNA profile, very similar and dominated by the 24-nt sRNAs in the three mock-inoculated controls, was minimally affected by CTV infection in sour orange, but exhibited a significant reduction of the 24-nt sRNAs in Mexican lime and sweet orange. We have also identified novel citrus miRNAs and determined how CTV influences their accumulation. |
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