VIRUS INDUCED RNA SILENCING AND SUPPRESSION: DEFENCE AND COUNTER DEFENCE
In plants, the mechanism of RNA silencing has evolved to defend plants against viral infection as well as to regulate of gene expression for growth and development. However, viruses counteract this antiviral defence by expressing silencing suppressor proteins, which are potent weapons in the ‘arms’ race between plants and invading viruses. These proteins efficiently inhibit RNA silencing by interacting with various steps of the different silencing pathways and these mechanisms of suppression are being unravelled progressively. Our better understanding the molecular bases of the induction and the suppression of RNA silencing dramatically improved our basic knowledge about intimate plant-virus interactions and also provide valuable tools to unravel the diversity, regulation and evolution of RNA-silencing pathways.