Abstract:
N6-methyladenosine (m⁶A) is the most prevalent and dynamically regulated internal modification of eukaryotic mRNAs, playing essential roles in RNA metabolism, including stability, splicing, translation, and degradation. This modification is catalyzed by methyltransferase known as “writers,” removed by “erasers,” and interpreted by YTH domain-containing proteins referred to as “readers”. m⁶A marks orchestrate complex gene regulatory networks. While its importance in animal virus replication and immune evasion is well established, its role in plant-virus interactions remains comparatively underexplored.

In this study, we examine the involvement of m⁶A methylation in the infection cycle of Turnip mosaic virus (TuMV), a positive-sense RNA virus, using Arabidopsis thaliana and Nicotiana benthamiana as model hosts. We show that TuMV relies on the host m⁶A machinery for successful replication and translation. Writer components mutants, like the core methyltransferase mutant mta, significantly impairs viral replication, while reader mutants display different viral protein translation and viral titer. Conversely, overexpression of MTA enhances TuMV accumulation and fitness.

Using MeRIP-Seq, we identified four distinct and dynamically methylated m⁶A peaks on the TuMV genome. Mutations in these methylation sites led to decreased viral protein synthesis and reduced genome replication, confirming their functional relevance. Furthermore, TuMV particles derived from m⁶A-competent or overmethylating hosts exhibited enhanced infectivity in subsequent infections, indicating that m⁶A modification primes the viral genome for efficient propagation.

Altogether, our findings reveal that TuMV actively hijacks the host m⁶A pathway to boost its infection efficiency and highlight m⁶A as a critical regulator of plant-virus interactions. This work opens new avenues for understanding epitranscriptomic control in plant immunity and offers potential targets for engineering viral resistance in crops.

Bio:
My name is Nicola Secco, and I am a PhD student at King Abdullah University of Science and Technology (KAUST). I earned my Bachelor's degree in Biomolecular Sciences from the University of Trento, Italy, and my Master's degree in Industrial and Molecular Biotechnologies from the Alma Mater Studiorum, University of Bologna, graduating with the highest distinction. Currently, my research at KAUST focuses on unraveling the complex mechanisms that govern plant–virus interactions, with a particular emphasis on the epitranscriptomic pathways that distinguish susceptibility from resistance. My passion for this field arises from a longstanding fascination with viruses and molecular biology, which has guided and sustained my academic journey.