Project description:Here we describe the identification and regulation of a novel dsRNA virus in Colletotrichum higginsianum. High throughput sequencing of small RNAs and strand-specific RNA-seq was performed on single gene knock-out mutants created for each RNAi component gene: rdr1, rdr2, rdr3, dcl1, dcl2, ago1, and ago2, and the double mutant: ∆dcl1∆dcl2. De novo assembly of the ∆dcl1 RNA-seq data identified two contigs that represented the forward and reverse strands of an uncharacterized dsRNA virus, designated here as Colletotrichum higginsianum non-segmented dsRNA virus 1 (ChNRV1). We found increased presence of the viral RNA in the RNA-seq datasets of the ∆dcl1, ∆dcl1dcl2, and ∆ago1 strains, suggesting that these genes are required for control of the virus. We show that viral small RNAs co-immunoprecipitate with a 6xFLAG-3xHIS-tagged AGO1 protein by sequencing the small RNAs from immunoprecipitated fractions. Additionally, analyses of the small RNA datasets from the RNAi mutants revealed control of the virus through small RNA-mediated silencing required both AGO1 and DCL1.
