Radioactive labelling of borme mosaic virus

Area of Science:

• Plant virology
• Molecular biology
• Biochemistry

Background:

• Brome mosaic virus (BMV) is a significant plant pathogen.
• Radioactive labeling is crucial for studying viral RNA synthesis and structure.

Purpose of the Study:

• To establish an efficient method for radioactive labeling of BMV in barley.
• To determine optimal conditions for incorporating radioactive precursors into BMV particles and RNA.

Main Methods:

• Barley plants were infected with BMV.
• Cut leaves were incubated in solutions containing radioactive precursors ([14C]-leucine and [32P]-ortho-phosphate).
• Virus synthesis and precursor incorporation rates were analyzed at different time points post-inoculation.

Main Results:

• Optimal incorporation of [14C]-leucine and [32P]-ortho-phosphate into BMV particles occurred in the second leaf, 4-5 days after inoculation.
• Delayed labeling reduced precursor incorporation, even when particle assembly continued.
• A 72-hour exposure to 32P yielded highly radioactive BMV RNA (approx. 1 mCi/mg RNA), suitable for sequencing.

Conclusions:

• This method provides a reliable way to produce highly radioactive BMV RNA for molecular studies.
• Timing of labeling is critical for maximizing precursor incorporation into newly synthesized viral components.