Phytoreovirus-like sequences from glassy-winged sharpshooter salivary glands

• Author(s): Hunter, Wayne; Sinisterra, X.;
• Abstract: The salivary glands of the Glassy-winged sharpshooter (GWSS), Homalodisca vitripennis Germar 1821, ( syn. H. coagulata, Hemiptera: Cicadellidae) were collected and used to produce a cDNA library. Examination by BLASTX analyses identified two viral sequences, one a 610 base pair fragment and a second 839 base pair fragment, both of which had significant homology to viruses within the genus, Phytoreovirus. Resequencing of the fragments confirmed sequence validities, which were used for in silico protein translation and BLASTP analysis to the Phytoreoviruses. While the GWSS is the primary vector of Pierce's disease of grapes, this is the first report that GWSS may be a vector of a phytoreoviruses. Phylogenetic and homology comparisons using BLASTX, BLASTP and PAUP analyses indicated that the viral sequences were closely related to the viruses in the Family, Reoviridae, Genus, Phytoreovirus, specifically Rice Dwarf Phytoreovirus (RDV). RDV is the only plant reovirus that is not limited to the phloem. The GWSS, although considered to feed primarily from the xylem, ingests from other plant tissues, such as the phloem and mesophyll during probing similar to other leafhoppers. Phytoreoviruses are transmitted in a propagative manner by cicadellid leafhoppers (Hemiptera: Cicadellidae), being acquired and transmitted during feeding. Phytoreoviruses have been reported from Agallian, Agalliopsis, Nephotettix, and Recilia, genera of leafhoppers, with evidence for transovarial transmission. The Phytoreovirus, wound tumor virus, WTV has been reported to occur in North America and infects the phloem of dicotyledonous plants, thus causing leaf and root galling. The feeding behavior and wide host range of the GWSS which will feed from grasses as a transitory host, and on herbaceous and woody plants as primary hosts, provides an overlapping condition for these two organisms, leafhopper and virus, such that it may favor the acquisition and transmission of Phytoreovirus by the GWSS. Monitoring for an increase of Phytoreovirus spread in graminaceous crops that are in close proximity to vineyards or tree crop orchards, where GWSS occurs, such as in southern California, will provide a better understanding of the potential role of the GWSS as a disease vector in the spread of phytoreoviruses and other plant pathogens.
• Publication Date: Mar 2007
• Journal: Florida Entomologist