|Weiland, John - NDSU PATH.DEPT FARGO, ND|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 1995
Publication Date: N/A
Technical Abstract: Genetic determinants of barley stripe mosaic virus (BSMV) oat pathogenicity were recently mapped to the alpha a gene, whose product is a putative component of the viral replicase (Weiland & Edwards, Virology 201, 116-126). Alpha-a gene mutants that cannot detachably infect oat plants replicate in oat protoplasts to levels similar to BSMV strains that are systemic pathogens of oat. In order to ascertain whether the mutants that are non-pathogenic to oat are capable of replicating in single cells in planta, a recombinant BSMV RNA-beta (18-beta gus) was constructed in which the triple gene block was replaced with the E. coli beta-glucuronidase gene. 'Rodney' oat and 'Black Hulless' barley plants were inoculated with infectious transcripts of BSMV RNA-alpha, RNA-gamma, and 18-beta gus. Surprisingly, macroscopic blue foci were observed on the inoculated leaves 24 hr post-inoculation following histochemical tissue staining for beta-glucuronidase. A single focus encompassed an ave. of about 50 cells. Electron microscopic examination of cells within and adjacent to the blue foci revealed the presence of typical BSMV rod-shaped virions. The data suggest that the BSMV triple gene block is not required for limited cell-to-cell movement in cereal hosts.