Enhancing plant antiviral responses and productivity through the elimination of m⁵C methyltransferase.

Abstract

RNA 5-methylcytosine (m⁵C) plays an undefined role in plant antiviral defense. Here, we reveal that the wheat methyltransferase NOP2/Sun RNA methyltransferase 2 (TaNSUN2) is an RNA m⁵C methyltransferase recruited by eukaryotic elongation factor 1-alpha (TaeEF1A) into Chinese wheat mosaic virus (CWMV) replication complexes (VRCs). TaNSUN2 promotes the m⁵C modification of CWMV RNAs to stabilize them and enhance their translational efficiency. Moreover, m⁵C modification in RNA 3' untranslated region strengthens both TaeEF1A binding, promoting viral replication, and viral coat protein interaction, facilitating viral assembly. A major allele of <i>TaNSUN2</i> prevents its interaction with TaeEF1A and hinders its entry into the VRCs to suppress m⁵C modification of viral RNAs. <i>TaNSUN2</i> knockout enhances wheat resistance to CWMV and increases the weight and size of wheat grains. Our findings provide mechanistic insights into the function of RNA modifications in plant virus infection and a valuable genetic resource for future wheat breeding projects.