Use of RNAi technology to develop a PRSV-resistant transgenic papaya

Area of Science:

• Plant Pathology
• Molecular Biology
• Biotechnology

Background:

• Papaya Ringspot Virus (PRSV) significantly impacts global papaya production.
• Existing Coat Protein (CP)-mediated transgenic resistance is overcome by genetic divergence in Hainan PRSV isolates.

Purpose of the Study:

• To develop broader-spectrum transgenic resistance against Hainan PRSV isolates.
• To engineer papaya with an RNAi strategy targeting the conserved domain of the PRSV CP gene.

Main Methods:

• Optimized particle-bombardment transformation to create RNAi-CP-transgenic papaya lines.
• Southern blot and Droplet Digital PCR to confirm transgene integration (single insert in line 474).
• Greenhouse challenge assays with PRSV isolates and Northern blot analysis to detect siRNA accumulation.

Main Results:

• Transgenic papaya line 474 demonstrated resistance to multiple Hainan PRSV subgroups.
• siRNA products were detected in virus-free and PRSV-infected transgenic papaya tissues.
• Line 474 showed a single transgene insert, indicating genetic stability.

Conclusions:

• The developed RNAi-CP-transgenic papaya line offers effective resistance to PRSV.
• This transgenic line has practical applications for papaya cultivation in Hainan, China.
• The RNAi strategy provides a promising approach for durable PRSV resistance in papaya.