VIEW ARTICLE

Etiology

Characterization of an Ilarvirus Associated with a Necrotic Shock Reaction in Blueberry. S. G. MacDonald, Former graduate student, Department of Plant Science, University of British Columbia, Vancouver; R. R. Martin(2), and P. R. Bristow(3). (2)Research scientist, Agriculture Canada Research Station, 6660 N.W. Marine Drive, Vancouver, British Columbia, Canada V6T 1X2; (3)Associate plant pathologist, Washington State University, Puyallup Research and Extension Center, Puyallup 98371. Phytopathology 81:210-214. Accepted for publication 25 October 1990. 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, 1991. DOI: 10.1094/Phyto-81-210.

Blueberry bushes with scorch symptoms were found during a survey of blueberry fields in coastal British Columbia, Washington, and Oregon. Some were infected with blueberry scorch carlavirus; others in Washington and Oregon were found to contain a second virus, for which the name blueberry shock ilarvirus (BSIV) is proposed. BSIV was mechanically transmissible to several Nicotiana species but not to other herbaceous plants tested. BSIV was purified from N. clevelandii and had quasi-isometric particles approximately 27 nm in diameter, a single polypeptide with relative mass (M_r) of 27,300, and four RNA molecules (M_r 1.03, 0.84, 0.57, and 0.3 × 10⁶). BSIV was serologically related to Prunus necrotic ringspot virus in gel double-diffusion tests and to Prunus necrotic ringspot virus and apple mosaic virus in indirect enzyme-linked immunosorbent assay. Because of the host range, particle size and morphology, size and number of RNA and protein components, serology, and lack of aphid transmissibility of this virus, we suggest that BSIV should be considered a new member of the ilarvirus group. In a subsequent survey using enzyme-linked immunosorbent assay, BSIV was found in blueberry plants from both western Washington and Oregon, but it has not yet been found in British Columbia.