Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2011
Publication Date: 8/1/2011
Publication URL: http://handle.nal.usda.gov.d2.nal.usda.gov/10113/53826
Citation: Bekal, S., Domier, L.L., Niblack, T.L., Lambert, K.N. 2011. Discovery and initial analysis of novel viral genomes in the soybean cyst nematode. Journal of General Virology. 92(8):1870-1879. Interpretive Summary: Nematodes are the most abundant multi-cellular animals on earth, yet little is known about their natural viral pathogens and no nematode virus genomes have been published. This paucity of information has allowed nematode viruses to be overlooked, thus eliminating an important biotic factor for consideration in the study of nematode ecology. Here we show that one plant parasitic nematode species, the soybean cyst nematode (SCN), contains four different RNA viruses. The nematode virus genomes were discovered in SCN after high-throughput sequencing of RNAs present in SNC eggs and juveniles. The nematode virus sequences were related to viruses that replicate in insects, some of which cause significant diseases in animals and plants. This discovery suggests nematode viruses could be common and thus the study of SCN agroecology, and possibly nematode ecology as a whole, will need to be reassessed to take nematode viruses into account. These nematode viruses may have significant impact for the control of SCN, the most damaging pathogen of soybean in the US, since they could be useful as biological control agents or used as vectors to deliver or silence genes in the nematode. The findings presented here will be of interest to scientists who are interested in understanding and manipulating factors affecting the virulence of SCN and those studying the biology and epidemiology of invertebrate viruses.
Technical Abstract: Nematodes are the most abundant multi-cellular animals on earth, yet little is known about their natural viral pathogens and no nematode virus genomes have been published. Consequently, nematode viruses have been overlooked as important biotic factors in the study of nematode ecology. Here we show that one plant parasitic nematode species, Heterodera glycines, the soybean cyst nematode (SCN), contains four different RNA viruses. The nematode virus genomes were discovered in the SCN transcriptome after high-throughput sequencing and assembly. All four viruses had negative-sense single-stranded RNA genomes and were related to viruses in the Bornaviridae, Bunyaviridae, and Rhabdoviridae that replicate in insects, some of which cause significant diseases in animals and plants. No evidence of integration of viral sequences into the nematode genome was detected. This discovery highlights the need for further exploration for nematode viruses in all tropic groups of these diverse and abundant animals.