The <i>HEX1</i> Gene of <i>Fusarium graminearum</i> Is Required for Fungal Asexual Reproduction and Pathogenesis and for Efficient Viral RNA Accumulation of <i>Fusarium graminearum</i> Virus 1

다국어 초록 (Multilingual Abstract)

<P>The accumulation of viral RNA depends on many host cellular factors. The hexagonal peroxisome (Hex1) protein is a fungal protein that is highly expressed when the DK21 strain of <I>Fusarium graminearum</I> virus 1 (FgV1) infects its host, and Hex1 affects the accumulation of FgV1 RNA. The Hex1 protein is the major constituent of the Woronin body (WB), which is a peroxisome-derived electron-dense core organelle that seals the septal pore in response to hyphal wounding. To clarify the role of Hex1 and the WB in the relationship between FgV1 and <I>Fusarium graminearum</I>, we generated targeted gene deletion and overexpression mutants. Although neither <I>HEX1</I> gene deletion nor overexpression substantially affected vegetative growth, both changes reduced the production of asexual spores and reduced virulence on wheat spikelets in the absence of FgV1 infection. However, the vegetative growth of deletion and overexpression mutants was increased and decreased, respectively, upon FgV1 infection compared to that of an FgV1-infected wild-type isolate. Viral RNA accumulation was significantly decreased in deletion mutants but was significantly increased in overexpression mutants compared to the viral RNA accumulation in the virus-infected wild-type control. Overall, these data indicate that the <I>HEX1</I> gene plays a direct role in the asexual reproduction and virulence of <I>F. graminearum</I> and facilitates viral RNA accumulation in the FgV1-infected host fungus.</P>