Functional analysis of two host genes that were up-regulated upon Fusarium graminearum virus1 infection

Abstract

Fusarium graminearum virus 1(FgV1) is a mycovirus that isolated from Fusarium boothii. It has 6.6kb double stranded RNA as a genome, including putative four open reading frames. Along with FgV1, three other mycoviruses have been reported including FgV2, FgV3, and FgV4. Among four reported viruses, FgV1 and FgV2 infection shows hypovirulence such as a reduction in growth rate, conidiation, and virulence to their host fungi. But infection with the other two viruses, FgV3 and FgV4,makes no dramatic morphological change. Based upon RNA-sequence analyses of the host transcriptome upon combination of those four mycovirus infection, ten genes that might have relationship with mycovirus infection and/or defense responses of the host fungi are selected. These genes were assorted into four groups depending on their changes of expression level upon virus infection. To investigatepossible functional roles of these genes involved inrelationship between host fungi and virus, targetgene deletion mutants were generated. FgV1 infected deletion mutants were constructed using hyphal fusion mediated mycovirus transmission. While deletion mutants did not show significant alterationin colony morphology and radial growth on solid comparing with wild-type strain, viral RNA accumulations in fgsg_05076 and fgsg_10551 deletion mutantswere decreased comparing with those of virus infected wild-type strain. This study can provide experimental support for RNA-sequence analysis and investigation of individual gene functions which related to FgV1 accumulation in host fungi, F. graminearum.