Leafhopper Viral Pathogens: Ultrastructure of salivary gland infection of Taastrup-like virus inPsammotettix alienusDahlbom; and a novel Rhabdovirus inHomalodisca vitripennis(Germar) Hemiptera: Cicadellidae

Abstract

15Viruses that are pathogenic to insect pests can be exploited as biological control agents. Viruses that are 16 pathogenic to beneficial insects and other arthropods, as in honey bees, silk worms, and shrimp, cause 17 millions of dollars of losses to those industries. Current advances in next generation sequencing 18 technologies along with molecular and cellular biology have produced a wealth of information about 19 insect viruses and their potential applications. Leafhoppers cause economic losses as vectors of plant 20 pathogens which significantly reduce the worlds' food crops. Each year more viruses are discovered 21 primarily through the use of next generation sequencing of the leafhopper hosts. The diversity of viruses 22 from leafhoppers demonstrates a wide range of taxonomic members that includes genomes of DNA or 23 RNA from families like: Reoviridae, Iridoviridae, Dicistroviridae, Iflaviridae, and others yet to be 24 classified. Discussed is a recent viral pathogen isolated from the leafhopper Psammotettix alienus, name 25 Taastrup Virus. Taastrup virus (TV) is a novel virus with a RNA genome, a Filovirus-like morphology, 26 being tentatively placed within the Mononegavirales. Adult Psammotettix alienus infected with TV, 27 showed the highest concentration of virions in salivary glands, consisting of a principal gland (type I-VI-28 cells) and an accessory gland. Examination of thin sections revealed enveloped particles, about 1300 nm 29 long and 62 nm in diameter, located singly or in paracrystalline arrays in canaliculi of type III-and IV-30 cells. In gland cells with TV particles in canaliculi, granular masses up to 15 µm in diameter were present 31 in the cytoplasm. These masses are believed to be viroplasms, the sites for viral replication. TV particles 32 were observed at the connection between a canaliculus and the salivary duct system. A TV-like virus 33 with strongly similar morphology was discovered in the ornamental plant, Liriope, near Fort Pierce, 34 Florida, USA. When the virus was inoculated to a leafhopper cell culture, HvWH, made from the glassy-35 winged sharpshooter, Homalodisca vitripennis (Germar), the cells rapidly degraded with 100% mortality 36 in 48 hours. These two instances are the only reported cases of this newly discovered viral pathogen of 37 leafhoppers. 38

Transcriptome of the Maize Leafhopper ( Dalbulus maidis ) and Its Transcriptional Response to Maize Rayado Fino Virus (MRFV), Which It Transmits in a Persistent, Propagative Manner

“…We identified sequences with top hits to known viruses with an E value of <10 −5 , including transcripts of MRFV and transcripts with top hits to invertebrate-infecting viruses, including iflaviruses Graminella nigrifrons virus 1 and Scaphoideus titanus iflavirus 1 (Table S3). A wide range of viruses in different families, including Reoviridae , Iridoviridae , Dicistroviridae , and Iflaviridae were previously reported in leafhoppers ( 34 ).…”