Some properties, relationships and interactions of barley yellow dwarf viruses
Abstract
Barley yellow dwarf virus is a term that embraces a cluster of variously interrelated viruses. Comparative characterization of selected types (MAV, PAV and RPV), indicated similarities with respect to virion sedimentation pattern, and RNA and protein molecular weights. However, the MAV and PAV types were distinguished by the numbers of ds RNA species extractable from infected leaves. ELISA tests with a polyclonal antiserum produced to dissociated MAV virions, indicated that all three viruses share common antigenic determinants internally oriented in the capsid. $\sp{32}$P-labelled cloned BYDV cDNAs were effectively used as diagnostic tools for the detection of BYDV in fresh, frozen or dried infected tissue, and also in extracts of viruliferous aphid vectors. The results of reciprocal dot-blot hybridization tests using cDNAs derived from the three virus types were consistent with their grouping, by serology and other characteristics. Thus, cDNAs derived from the non-immunogenic regions of the genomes of the MAV or PAV viruses reacted homologously and also heterologously. MAV cDNAs from the non-immunogenic region also weakly detected another BYDV type, namely SGV. However, representative cDNAs derived from the immunogenic regions of the MAV or PAV genomes reacted significantly only to the homologous viruses. No MAV or PAV-derived cDNAs detected RPV. Also, no RPV cDNAs, derived from any part of its genome, detected either MAV or PAV. In tests of infected tissue samples cDNAs representative of the MAV or RPV genomes did not detect any other luteoviruses tested. MAV and PAV cDNAs were used in investigations of cross-protection between these two viruses. Results confirmed that reciprocal cross-protection occurs between them. When PAV was used as challenge virus, efficient cross-protection occurred when the interval between inducer and challenge inoculations was three days or more; it broke down over time in some plants, but persisted in others at least 30 days post challenge inoculation. Comparisons of the results of cDNA and ELISA studies allowed exploration of some of the possible mechanisms that might be involved in this phenomenon.
Degree
Ph.D.
Advisors
Lister, Purdue University.
Subject Area
Plant pathology
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.