Engineered Resistance Against Papaya ringspot virus in Venezuelan Transgenic Papayas

Area of Science:

• Agricultural Science
• Plant Virology
• Biotechnology

Background:

• Papaya cultivation faces significant threats from Papaya ringspot virus (PRSV).
• Genetic modification offers a potential strategy for developing virus-resistant papaya varieties.
• Coat protein (CP) gene-mediated resistance is a promising approach in plant virology.

Purpose of the Study:

• To genetically transform local Venezuelan papaya varieties with the PRSV coat protein (CP) gene.
• To evaluate the efficacy of CP gene-mediated resistance against different PRSV isolates.
• To assess the influence of sequence similarity on resistance effectiveness.

Main Methods:

• Agrobacterium tumefaciens-mediated transformation of local papaya with PRSV CP genes (VE and LA isolates).
• Generation of R0 resistant plants through intercrossing and selfing.
• Greenhouse inoculation assays using homologous (VE, LA) and heterologous (HA, TH) PRSV isolates.

Main Results:

• Transformed papaya plants exhibited varying degrees of resistance to PRSV infection.
• Resistance was highest against homologous isolates (92-100% sequence similarity).
• Significant resistance was observed against heterologous isolates, though influenced by sequence similarity (94% for HA, 88-89% for TH).

Conclusions:

• The PRSV CP gene effectively confers resistance in local papaya varieties.
• CP gene-mediated resistance is influenced by the sequence similarity between the transgene and the challenging virus isolate.
• This approach holds potential for sustainable papaya production by managing PRSV.