A novel partitivirus induces hypovirulence and increases pyraclostrobin sensitivity in the phytopathogenic fungus Lasiodiplodia ziziphi

Lasiodiplodia ziziphi causes canker disease in jujube and other woody plants. Its control relies mainly on fungicides. Mycoviruses that cause hypovirulence are an emerging option for the biological control of fungal diseases. In this study, we identified a novel double-stranded RNA (dsRNA) mycovirus, Lasiodiplodia ziziphi partitivirus 1 (LzPV1), from L. ziziphi strain CDZM004. The LzPV1 genome consists of two dsRNA segments. dsRNA1 (1,905 bp) encodes an RNA-dependent RNA polymerase (RdRp), and dsRNA2 (1,773 bp) encodes a capsid protein (CP). The genome is packaged into isometric virions about 32 nm in diameter. Phylogenetic analysis of the RdRp and CP placed LzPV1 in the genus Alphapartitivirus of the family Partitiviridae. LzPV1 was transmitted horizontally through hyphal anastomosis and vertically through conidia. LzPV1 infection reduced the virulence of L. ziziphi, changed its hyphal morphology, and increased fungal sensitivity to the fungicide pyraclostrobin. This is the first mycovirus reported in L. ziziphi and the first partitivirus described in the genus Lasiodiplodia. LzPV1 is a promising biocontrol resource for jujube canker disease.