Consumption of miRNA-Mediated Insect-Resistant Transgenic Rice Pollen Does Not Harm Adults.

RNAi-based insect-resistant genetically engineered (IRGE) crops represent a promising approach for pest management by suppressing gene expressions or translation. A developed microRNA-mediated IRGE rice line expressing endogenous Csu-novel-260 shows significant resistance to target pests. The nontarget insect is an important pollinator used as a surrogate species for the ecological risk assessment of IRGE plants. To simulate a worst-case scenario, the full-length and () cDNAs were cloned. The 3'-untranslated regions shared 58.06% nucleotide sequence similarity between and . No potential Csu-novel-260 binding site in was detected through the bioinformatics analysis. A dietary RNAi toxicity assay of the impacts of ingested Csu-novel-260 on adults showed that the survival rates of RNAi-treated did not significantly differ from those in the blank control (CK) and negative control (NC) treatments. The Csu-novel-260 uptake by peaked at 8 days postfeeding and then gradually decreased. The expression was not affected by the RNAi assay days or treatments. These results suggest that adults are not susceptible to high doses of Csu-novel-260 in the dietary RNAi assay and that the impact of miRNA-mediated IRGE plants on is negligible.