Simultaneous resistance against the two viruses causing rice tungro disease using RNA interference

Area of Science:

• Plant Pathology
• Molecular Biology
• Biotechnology

Background:

• Rice tungro disease, caused by RTBV and RTSV, is a major threat to rice production in Asia.
• Previous research developed RNAi resistance against individual tungro viruses.
• A need exists for simultaneous resistance against both viruses.

Purpose of the Study:

• To develop transgenic rice plants with simultaneous RNAi resistance against both RTBV and RTSV.
• To evaluate the efficacy of this dual-targeting RNAi approach in conferring resistance.

Main Methods:

• Constructed a DNA molecule with RTBV and RTSV sequences in hairpin orientation for RNAi.
• Generated transgenic rice plants using this construct.
• Quantified viral load, stunting, and chlorophyll levels in T1 transgenic plants post-infection.
• Analyzed small interfering RNAs (siRNAs) to confirm RNAi mechanism.

Main Results:

• Transgenic rice plants exhibited 100- to 500-fold reduction in RTBV and RTSV nucleic acid levels.
• Significant amelioration of stunting and higher chlorophyll retention were observed in transgenic plants.
• siRNA analysis confirmed the presence of virus-specific 21 nt and 22 nt siRNAs.

Conclusions:

• Simultaneous RNAi targeting both RTBV and RTSV is effective in conferring resistance to rice tungro disease.
• This approach offers a promising strategy for genetic improvement of rice against tungro viruses.
• The results indicate an active RNA interference mechanism underlies the observed resistance.