MTA1-mediated RNA m 6 A modification regulates autophagy and is required for infection of the rice blast fungus

  • In eukaryotes, N6-methyladenosine (m6A) is abundant on mRNA, and plays key roles in the regulation of RNA function. However, the roles and regulatory mechanisms of m6A in phytopathogenic fungi are still largely unknown.
  • Combined with biochemical analysis, MeRIP-seq and RNA-seq methods, as well as biological analysis, we showed that Magnaporthe oryzae MTA1 gene is an orthologue of human METTL4, which is involved in m6A modification and plays a critical role in autophagy for fungal infection.
  • The Δmta1 mutant showed reduced virulence due to blockage of appressorial penetration and invasive growth. Moreover, the autophagy process was severely disordered in the mutant. MeRIP-seq identified 659 hypomethylated m6A peaks covering 595 mRNAs in Δmta1 appressoria, 114 m6A peaks was negatively related to mRNA abundance, including several ATG gene transcripts. Typically, the mRNA abundance of MoATG8 was also increased in the single m6A site mutant ∆atg8/MoATG8A982C, leading to an autophagy disorder.
  • Our findings reveal the functional importance of the m6A methylation in infection of M. oryzae and provide novel insight into the regulatory mechanisms of plant pathogenic fungi.