Comparative oxidation proteomics analyses suggest redox regulation of cytosolic translation in rice leaves upon Magnaporthe oryzae infection

Pathogen attack can increase plant levels of reactive oxygen species (ROS), which then act as signaling molecules activating plant defense. Elucidating these processes is crucial to understanding the redox signaling pathways in plant defense responses. By an iodo TMT–based quantitative proteomic approach, we mapped 3,362 oxidized cysteine sites in 2,275 proteins in rice leaves. Oxidized proteins were involved in gene expression, peptide biosynthetic processes, stress responses, ROS metabolic processes, and translation pathways. Magnaporthe oryzae infection led to increased oxidation modification levels of 512 cysteine sites in 438 proteins, including many transcriptional regulators and ribosomal proteins. Ribo-seq analysis revealed that the oxidation modification of ribosomal proteins promoted the translational efficiency of many mRNAs involved in defense response pathways, thereby affecting rice immunity. Our results suggest that increased oxidative modification of ribosomal proteins in rice leaves promotes cytosolic translation, revealing a novel function of post-translational modifications. Furthermore, the oxidation-sensitive proteins identified here provided a valuable research resource of research on protein redox regulation and could guide future mechanistic studies.