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Vector Relations

Importance of Capsid Integrity for Interference Between Two Isolates of Barley Yellow Dwarf Virus in an Aphid. F. E. Gildow, Graduate research assistant, Department of Plant Pathology, Cornell University, Ithaca, NY 14853; W. F. Rochow, research plant pathologist, Agricultural Research, Science and Education Administration, U. S. Department of Agriculture, and professor of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 70:1013-1015. Accepted for publication 15 April 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/Phyto-70-1013.

Recently we showed that fewer aphids (Macrosiphum avenae) transmitted the PAV isolate of barley yellow dwarf virus (BYDV) if they had first acquired the MAV isolate, than if they had previously fed on healthy oats or on oats infected with other BYDV isolates. MAV irradiated with ultraviolet light for 30 sec or more, no longer interfered with PAV transmission when the two viruses were injected simultaneously into aphids. Irradiation of MAV also decreased both MAV transmission by injected aphids and recognition by MAV-specific antibody; these results indicate alteration of MAV capsid conformation. No morphological differences between particles irradiated for 15–60 sec and those of nonirradiated controls were detected by electron microscopy. Some particles irradiated for 120 sec appeared to be swollen. Several minutes of irradiation were required for particle disruption. We suggest that the altered MAV particles do not attach to receptors in aphid salivary glands and thus are neither transmitted nor able to compete with PAV for common receptor sites that recognize both viruses.