Characterization of RNA silencing components in the plant pathogenic fungus Fusarium graminearum

Abstract

The RNA interference (RNAi) plays a critical role in gene regulation in a variety of eukaryotic organisms. However, the role of RNAi remains largely unclear in plant pathogenic fungi. In this study, we explored the roles of core components of the RNAi pathway in Fusarium graminearum, the major causal agent of wheat head blight. Our results demonstrated that the hairpin RNA (hpRNA) can efficiently silence the expression level of target gene, and the argonaute protein FgAgo1 and dicer protein FgDicer2 are important in this silencing process. RNAi machinery was not involved in growth, abiotic stress and pathogenesis in F. graminearum under tested conditions. We firstly applied high-throughput sequencing technology to elucidate small RNA (17–40 nucleotides) (sRNA) transcriptome in F. graminearum, and found that a total of forty-nine micro-like-RNA (milRNA) candidates were identified in the wild-type and ∆FgDICER2, and twenty-four of them were FgDicer2-dependent. Fg-milRNA-4 negatively regulated expression of its target gene. Taken together, our results indicated that the hpRNA-induced gene silencing was a valuable genetic tool for exploring gene function in F. graminearum. FgAgo1 and FgDicer2 proteins played a critical role in the hpRNA mediated gene silencing process. In addition, FgDicer2 was involved in sRNA transcription and milRNA generation in this fungus.

The tRNA-Derived Small RNAs Regulate Gene Expression through Triggering Sequence-Specific Degradation of Target Transcripts in the Oomycete Pathogen Phytophthora sojae

“…In fungi, several classes of sRNAs, including miRNA-like RNAs, Dicer-independent siRNAs (Lee et al, 2010), qiRNA, esRNA (Lee H.C. et al, 2009; Nicolas et al, 2010; Nunes et al, 2011b; Chen et al, 2015), and tsRNAs (Jochl et al, 2008; Thompson et al, 2008; Thompson and Parker, 2009; Nunes et al, 2011a) have been identified. However, no canonical miRNAs have been reported (Nunes et al, 2011b).…”

RNA-based disease control as a complementary measure to fight Fusarium fungi through silencing of the azole target Cytochrome P450 Lanosterol C-14 α-Demethylase

“…Possible transfer routes for both mechanisms via vesicles or RNA-transporters are indicated. AGO1 seems to be essential for the RNAi response in Fusarium (Chen et al 2015) FgCYP51B is most important for ergosterol biosynthesis and thus survival of the fungus (Fan et al 2013;Liu et al 2011;Machado et al 2018).…”

Dicer and Argonaute Genes Involved in RNA Interference in the Entomopathogenic Fungus Metarhizium robertsii

“…Moreover, several sRNAs show differential expression in the Δdcl2 mutant and WT, which suggests that the sRNAs generated by Mrdcl2 may be associated with the regulation of conidiation in M. robertsii (see Table S6 in the supplemental material). In particular, milRNAs, including those in N. crassa (40), Penicillium marneffei (43), Sclerotinia sclerotiorum (44), and Fusarium graminearum (45), have been identified, and they have an important function in regulating different biological processes in these fungi. Previously, it was discovered by our group that milRNAs may play an important role in the regulation of conidiation in M. robertsii (24).…”