Analysis of rice endogenous dsRNA in the Oryza sativa Dicer-like 2 (OsDCL2) knock-down strain.

Abstract

The endogenous dsRNA, Oryza sativa endornavirus, has been found in japonica rice. Although dsRNA basically can be substrate for Dicer as a RNA silencing trigger, the endogenous dsRNA is detected in every tissueat a constant copy number. The presences of dsRNA in several knock-down strains of RNA silencing related genes were examined to clarify the relationship between the dsRNA and the RNA silencing systems. As a result, we could not detect the dsRNA in OsDCL2 knock-down T1 plants. In dsRNA introduced F1 and F2 plants, some had lost the dsRNA. To figure out this phenomenon, we detected small RNAs derived from the dsRNA in WT and OsDCL2 knock-down plants. However, the phenomenon of dsRNA loss did not correlate with small RNAs level. These results suggest that accumulation of small RNAs did not cause the instability of the dsRNA, and the dsRNA may exist stably by avoiding RNA silencing system.