Poster: Diseases of Plants: New & Emerging Diseases
Characterization of viral particles formed by Grapevine vein clearing virus (GVCV)
Y. ZHANG (1), M. Adhab (1), J. Schoelz (1) (1) University of Missouri, U.S.A.
Grapevine vein clearing virus (GVCV) is closely associated with a grapevine vein clearing syndrome observed in Missouri and surrounding states. The virus was initially characterized through deep sequencing of small RNAs isolated from symptomatic grape tissue. Three overlapping fragments of GVCV genomes were cloned and sequenced, from which the GVCV genome was assembled. The nucleotide sequence revealed that GVCV belonged to the Badnavirus genus. However, GVCV virions have never been observed under electron microscope. A GVCV infectious clone has been constructed in order to characterize GVCV virions and to complete Koch’s postulates. The GVCV infectious clone was infiltrated into Nicotiana benthamiana young leaves, and leaves were collected at 7 dpi, followed by a virion purification procedure involving ultracentrifugation through sucrose gradients. In contrast to the expected bacilliform virions, a flexuous rod structure was observed that had a 15nm diameter and varied in length from 83 to 930 nm. The same virion purification procedure was applied to GVCV-infected grape leaves showing typical vein clearing symptoms and two types of virion particles were observed from a single virion prep: a flexuous rod 15nm in width and up to 8,025 nm in length, as well as the typical bacilliform structure. Antibodies targeting the GVCV coat protein were designed from the GVCV coding sequence and will be applied to test the nature of these two potential GVCV particles.