Beet necrotic yellow vein virus accumulates inside resting spores and zoosporangia of its vector Polymyxa betae BNYVV infects P. betae.
BACKGROUND
Plasmodiophorids and chytrids are zoosporic parasites of algae and land plant and are distributed worldwide. There are 35 species belonging to the order Plasmodiophorales and three species, Polymyxa betae, P. graminis, and Spongospora subterranea, are plant viral vectors. Plasmodiophorid transmitted viruses are positive strand RNA viruses belonging to five genera. Beet necrotic yellow vein virus (BNYVV) and its vector, P. betae, are the causal agents for rhizomania.


RESULTS
Evidence of BNYVV replication and movement proteins associating with P. betae resting spores was initially obtained using immunofluorescence labeling and well characterized antisera to each of the BNYVV proteins. Root cross sections were further examined using immunogold labeling and electron microscopy. BNYVV proteins translated from each of the four genomic and subgenomic RNAs accumulate inside P. betae resting spores and zoospores. Statistical analysis was used to determine if immunolabelling detected viral proteins in specific subcellular domains and at a level greater than in control samples.


CONCLUSIONS
Virus-like particles were detected in zoosporangia. Association of BNYVV replication and movement proteins with sporangial and sporogenic stages of P. betae suggest that BNYVV resides inside its vector during more than one life cycle stage. These data suggest that P. betae might be a host as well as a vector for BNYVV.
Lubicz
Jeanmarie Verchot
JV
Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA. verchot.lubicz@okstate.edu
Rush
Charles M
CM
Payton
Mark
M
Colberg
Terry
T
D027461:Beta vulgaris / Q000821:virology*; D005455:Fluorescent Antibody Technique; D005658:Fungi / Q000821:virology*; D007150:Immunohistochemistry; D010942:Plant Viruses / Q000302:isolation & purification* / Q000502:physiology; D012328:RNA Viruses / Q000302:isolation & purification* / Q000502:physiology; D013172:Spores, Fungal / Q000821:virology; D014764:Viral Proteins / Q000032:analysis; D019065:Virus Assembly
D014764:Viral Proteins