METTL5-mediated 18S rRNA mA modification enhances ribosome assembly and ABA response in .

METTL5 catalyzes the -methyladenosine (mA) methylation at A in 18S rRNA, a modification essential for its association with the ribosomal protein RPL24A, facilitating the assembly of 80S ribosome. This facilitates the translation of mRNAs encoding the detoxifying glutathione S-transferase (GST) enzymes, thereby maintaining normal reactive oxygen species (ROS) levels and ensuring proper abscisic acid (ABA) responses. In mutants, the absence of mA compromises RPL24A incorporation and ribosome assembly, impairing the translation of GSTs. This results in ROS excessive accumulation and hypersensitivity to ABA.