Bactericera cockerelli picorna-like virus and three new viruses found circulating in populations of potato/tomato psyllids (Bactericera cockerelli)

Authors: DAHAN, JENNIFER - University Of Idaho; ORELLANA, GARDENIA - University Of Idaho; WALD, KALEIGH - University Of Idaho; WENNINGER, ERIC - University Of Idaho; Cooper, William - Rodney; KARASEV, ALEXANDER - University Of Idaho

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2024
Publication Date: 3/8/2024
Citation: Dahan, J., Orellana, G.E., Wald, K., Wenninger, E.J., Cooper, W.R., Karasev, A.V. 2024. Bactericera cockerelli picorna-like virus and three new viruses found circulating in populations of potato/tomato psyllids (Bactericera cockerelli). Viruses. 16(3). https://doi.org/10.3390/v16030415.
DOI: https://doi.org/10.3390/v16030415

Interpretive Summary: Potato psyllid is an important pest of potato because it is a vector of the pathogen that causes zebra chip disease. New tools to control potato psyllid and zebra chip would reduce reliance on chemical insecticides. Insect-attacking viruses provide a promising alternative to insecticides, but little is known about viruses that target potato psyllid. A researcher at the USDA-ARS in Wapato WA collaborated with a research team from University of Idaho discovered three previously undescribed viruses in potato psyllids. They found that all three new viruses and one virus previously discovered by the team regularly circulate in wild potato psyllid populations. They will next investigate whether these viruses impact or kill potato psyllids and assess the possibility for using these viruses to control potato psyllids and zebra chip disease of potato.

Technical Abstract: Bactericera cockerelli (potato/tomato psyllid) is a serious potato pest vectoring ‘Candidatus Liberibacter solanacearum’ bacterium associated with the Zebra Chip disease of potato. An investigation of viruses circulating in populations of field and laboratory psyllids was conducted using the high-throughput sequencing (HTS) technology and conventional RT-PCR. Three new viruses were discovered, one from the family Tymoviridae and two from the family Solemoviridae. A tymo-like virus sequence represented a nearly complete, 6,843-nt genome named Bactericera cockerelli tymo-like virus (BcTLV) that spanned five open reading frames (ORFs) which encoded RNA-dependent RNA polymerase (RdRP), helicase, protease, methyltransferase, and a capsid protein. Phylogenetic analyses placed RdRP of BcTLV inside a divergent lineage of the viruses from the family Tymoviridae found in insect and plant hosts in a sister clade to the genera Tymovirus, Marafivirus, and Maculavirus. Four solemo-like virus sequences were identified in HTS outputs representing two new viruses. One virus found only in field-collected psyllids and named Bactericera cockerellii solemo-like virus 1 (BcSLV-1) had a 5,479-nt genome which spanned four ORFs encoding protease and RdRP. Three solemo-like sequences displayed 87.4-99.7% nucleotide sequence identity among themselves, representing variants or strains of the same virus named Bactericera cockerelli solemo-like virus 2 (BcSLV-2). The genome of BcSLV-2 spanned only two ORFs that encoded a protease and an RdRP. Phylogenetic analysis placed RdRPs of BcSLV-1 and BcSLV-2 in two separate lineages as sister clades to viruses from the genus Sobemovirus found in plant hosts. All three new psyllid viruses were found circulating in psyllids collected from potato fields in southern Idaho along with a previously identified Bactericera cockerelli picorna-like virus. Any possible role of the three viruses in controlling populations of the field psyllids remains to be elucidated.