|NIBERT, MAX - Harvard Medical School|
|VONG, MINH - Harvard Medical School|
|DEBAT, HUMBERTO - Instituto Nacional De Tecnologia Agropecuaria|
Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2018
Publication Date: 3/1/2018
Citation: Nibert, M.L., Vong, M., Fugate, K.K., Debat, H.J. 2018. Evidence for contemporary plant mitoviruses. Virology. 518:14-24.
Interpretive Summary: Mitoviruses are small RNA-encoded viruses that replicate in mitochondria. Prior to this study, mitoviruses were known to infect only fungi, even though RNA sequences similar to fungal mitovirus sequences are widespread in plants. Mitoviral-like RNA sequences found in plants were believed to originate from an ancient incorporation of mitoviral RNA sequences from a plant symbiotic fungus into the DNA of a plant since no evidence of functional plant mitoviruses had been previously found. Data presented in this manuscript, however, provides evidence that functional mitoviruses exist in plants and that mitoviral-like sequences in plant genomes likely originated from plant mitoviruses rather than fungal mitoviruses. Mitoviruses can affect the virulence of plant pathogenic fungi. How mitoviruses affect plants remains to be determined.
Technical Abstract: Mitoviruses have small RNA(+) genomes, replicate in mitochondria, and have to date been directly shown to infect only fungi. For this report, sequences that appear to represent approximately complete mitovirus genomes were discovered in plant transcriptome data at GenBank. At least 17 of the refined sequences, 2684-2944 nt long and derived from 10 plant species, appear to encompass the unique, complete coding regions of extant plant mitoviruses, which moreover constitute a monophyletic cluster within a subclade of genus Mitovirus. Complete coding sequences of several of these viruses were identified in multiple plant tissues. Crop plants among implicated hosts include beet and hemp. The beet mitovirus was validated experimentally. Other results suggest that genuine plant mitoviruses were likely the immediate ancestors to many of the endogenized mitovirus elements now widespread in plant genomes. Whether plant mitoviruses are wholly cryptic with regard to plant health remains to be investigated.