RNAi to Combat the Rice Dwarf Virus

Rice dwarf is one of the most economically damaging viruses of rice plants in Southeast Asia, Japan and China. Plants infected with the rice dwarf virus (RDV) are stunted and fail to bear seeds. The virus also causes delayed flowering and incomplete panicle emergence, which may lead to yield loss of up to 4000 kg/ha. RDV is transmitted to rice plants exclusively by leafhoppers (Nephotettix). A group of scientists from the Japanese National Agricultural Research Center employed RNA interference (RNAi) to develop plants resistant to the RDV.

Genetic resistance is one of the most effective approaches to the protection of crop plants from viral infection. Shimizu and colleagues, however, noted that there are no reports of naturally occurring genes that endow resistance to RDV. The scientists resorted to gene silencing via RNAi. They specifically targeted the viral genes that encode for the Pns12 and Pns4, RDV non-structural proteins that plays essential roles in viral replication.

Rice plants that accumulated small interfering RNAs (SiRNA) specific to the Pns12 constructs, after self-fertilization, were found to be strongly resistant to viral infection. The study demonstrates that silencing a protein critical for the viral replication cycle provides an effective strategy for engineering resistance to virus-caused plant diseases.

Read the paper published by the Plant Biotechnology Journal at http://dx.doi.org/10.1111/j.1467-7652.2008.00366.x