Abstract

The Argonaute1 (ago1) gene was first discovered in Arabidopsis thaliana and further described trough plant mutants that showed pleiotropic developmental anomalies of all plant organs. In fact, most miRNAs are incorporated into AGO1 and guide the RNA Induced Silencing Complex (RISC) to its mRNA target through sequence complementarity; as a result, the mRNA translation is regulated by endonucleolytic cleavage or other yet incompletely characterized mechanisms. AGO1 homeostasis is in part coordinated through a feedback mechanism. Thus, miR168-guided cleavage of ago1 mRNA was demonstrated to ensure an optimal balance of miRNA steady-state levels for plant development and in response to environmental stimuli (rev. in [1]). Beside its role in PTGS and in concert with other proteins of the Argonaute clade, AGO1 plays a key role in the plant RNA silencing-based antiviral defence: similar to miRNAs, viral-derived (v)siRNAs are incorporated into AGO1-containing RISC leading to inactivation of viral RNAs by cleavage (rev. in [2] and [3]).Here we show that N. benthamiana possesses two ago1-1 homeolog genes, which differ mainly by one 18-nucleotide long insertion/deletion (indel). The indel is located close to the miR168 target site and our data suggests that its presence considerably affects the miR168-guided post-transcriptional regulation of ago1 mRNA. The indel effect is here highlighted during a viral infection, which increases miR168 accumulation. The two NbAGO1 homeologs show full functionality in reconstituted, catalytically active RISC following the incorporation of siRNAs. Moreover, Virus-Induced Gene Silencing (VIGS) experiments suggest a specific, redundant involvement of the ago1 homeologs in susceptibility to the viral infection but a divergent involvement in symptom development. The expression of two types of Nbago1-1 mRNAs is proposed to represent a case of diversity and of evolutionary adaptation to improve resilience measures of the plant during viral infections or other stresses accompanied by miR168 up-regulation. (the participation of VP to sfb648 is in part supported by project SaVeGrainIN- Puglia Reg. (CE) 1698/2005)

Autore Pugliese

• Pantaleo Vitantonio

Tutti gli autori

• Gursinski T.; Pirovano W.; Gambino G.; Friedrich S.; Behrens S.; Pantaleo V.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2015

ISSN

Non Disponibile

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

Non Disponibile

Ultimo Aggiornamento Citazioni

Non Disponibile

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile