Plant P58IPK is a suppressor of RNA silencing

Rajendra Marathe, Radhamani Anandalakshmi and S.P. Dinesh-Kumar

Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven CT

A plant homolog of the bovine P58IPK, a cellular inhibitor of Protein Kinase R (PKR) is a positive regulator of viral pathogenesis. The expression of P58IPK is down-regulated during RNA silencing, an antiviral defense mechanism in plants. When overexpressed, using viral vectors or under constitutive promoter, P58IPK suppresses transgene RNA silencing. The P58IPK-mediated suppression of RNA silencing is correlated with significant reduction but not complete elimination of siRNA. The transgenic plants overexpressing P58IPK show developmental defects.