Deoxynivalenol Biosynthesis in Fusarium pseudograminearum Significantly Repressed by a Megabirnavirus

Abstract

Deoxynivalenol (DON) is a mycotoxin widely detected in cereal products contaminated by Fusarium. Fusarium pseudograminearum megabirnavirus 1 (FpgMBV1) is a double-stranded RNA virus infecting Fusarium pseudograminearum. In this study, it was revealed that the amount of DON in F. pseudograminearum was significantly suppressed by FpgMBV1 through a high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) assay. A total of 2564 differentially expressed genes were identified by comparative transcriptomic analysis between the FpgMBV1-containing F. pseudograminearum strain FC136-2A and the virus-free strain FC136-2A-V-. Among them, 1585 genes were up-regulated and 979 genes were down-regulated. Particularly, the expression of 12 genes (FpTRI1, FpTRI3, FpTRI4, FpTRI5, FpTRI6, FpTRI8, FpTRI10, FpTRI11, FpTRI12, FpTRI14, FpTRI15, and FpTRI101) in the trichothecene biosynthetic (TRI) gene cluster was significantly down-regulated. Specific metabolic and transport processes and pathways including amino acid and lipid metabolism, ergosterol metabolic and biosynthetic processes, carbohydrate metabolism, and biosynthesis were regulated. These results suggest an unrevealing mechanism underlying the repression of DON and TRI gene expression by the mycovirus FpgMBV1, which would provide new methods in the detoxification of DON and reducing the yield loss in wheat.

Experimental verification of strain-dependent relationship between mycovirus and its fungal host

“…Virus infection is known to trigger RNA silencing in plants and fungi. 11 , 34 , 35 , 36 , 37 Thus, we focused on virus effects on host genes related to RNA silencing. In A. flavus , genes involved in the RNA silencing system were not defined; thus, we searched for candidate genes by referring to the genes of A. nidulans and A. fumigatus .…”

“…Besides phenotypic evaluation, comparative transcriptome analyses have been conducted between virus-infected and -free isolates in several studies. 10 , 11 , 25 , 26 These reports demonstrated that mycoviruses drastically affect host gene expression, regardless of the phenotypic changes observed between the virus-infected and -free isolates. Although reports of transcriptomic analyses are accumulating, comparisons of inter-laboratory and different virus-related data have been difficult to make when attempting to extract key factors for virus effects on host cells.…”

“…Several viruses are known to affect host biology such as vegetative growth, pathogenicity, metabolite production, and stress tolerance. For example, virus-infected strains showed decreased pathogenicity in Cryphonectria parasitica , Alternaria alternata , Aspergillus fumigatus , and Pestalotiopsis theae 6 , 7 , 8 , 9 and decreased production of secondary metabolites (SMs), e.g., trichothecenes in Fusarium graminearum 10 and deoxynivalenol in Fusarium pseudograminearum , 11 but increased tenuazonic acid in Magnaporthe oryzae . 12 In Stemphylium lycopersici , viral infection reduced growth and altersolanol A production.…”

Fusarium mycotoxins: The major food contaminants

“…Moreover, FgV1 and FgHV2 infections can reduce DON production in F. graminearum 226 , 227 . Li et al 228 found that FpgMBV1 eliminates DON accumulation by downregulating the expression of TRI biosynthetic genes. However, most research in this area is still in the laboratory stage and has not been applied in the field.…”

Overview of Diverse Universe of Mycoviruses and Their Role in Pathogenesis of Fungi

“…Cryphonectria parasitica, an ascomycetes fungus, causative agent of chestnut blight [64,65], which has been a catastrophe for Castanea dentata (American chestnut) in together North America as well as Europe [66,67]. Cryphonectria hypovirulence virus-1 CHV1 is hypovirulence-related mycovirus of the C. parasitica and it was initially investigated in 1991 [68][69][70]. Knowing the biological features of CHV1, International Committee on Taxonomy of Viruses (ICTV) recognized a new family Hypoviridae [71,72].…”