Artificial defective interfering RNAs derived from brome mosaic virus

Area of Science:

• Plant virology
• Molecular biology
• Biotechnology

Background:

• Naturally occurring defective interfering RNAs (DI-RNAs) reduce helper virus accumulation but are uncommon in plant positive-strand RNA viruses.
• Brome mosaic virus (BMV) genomic RNA-2 deletion mutants, termed parasitic RNAs (pRNAs), were studied for their interference capabilities.

Purpose of the Study:

• To investigate the potential of engineered pRNAs as artificial DI-RNAs for inducing plant virus resistance.
• To characterize the replication and interference mechanisms of BMV-derived pRNAs.

Main Methods:

• Deletion mutants (pRNA-2 M/S and pRNA-2 E/S) of BMV RNA-2 were created and replicated in barley protoplasts dependent on BMV RNA-1 and -2.
• The effect of pRNA concentration on helper virus RNA accumulation was quantified.
• Mutations affecting pRNA translation and replication were analyzed for their impact on interference.

Main Results:

• pRNA-2 M/S and pRNA-2 E/S significantly reduced BMV RNA-2 accumulation (37% and 64% respectively) at low inoculum amounts.
• Higher pRNA concentrations completely inhibited replication of all helper virus RNAs (RNA-1, -2, and -3).
• Interference was dependent on pRNA replication, not on the translation of truncated proteins, and was independent of encapsidation.

Conclusions:

• pRNAs function as effective artificial DI-RNAs against BMV in barley protoplasts.
• Engineered pRNAs hold potential for developing broad-spectrum virus resistance in transgenic plants.
• This strategy offers a novel approach for controlling plant RNA virus infections.