In plants, transcripts move to distant body parts to potentially act as systemic signals regulating development and growth. Thousands of messenger RNAs (mRNAs) are transported across graft junctions via the phloem to distinct plant parts. Little is known regarding features, structural motifs, and potential base modifications of transported transcripts and how these may affect their mobility. We identified Arabidopsis thaliana mRNAs harboring the modified base 5-methylcytosine (m5C) and found that these are significantly enriched in mRNAs previously described as mobile, moving over graft junctions to distinct plant parts. We confirm this finding with graft-mobile methylated mRNAs TRANSLATIONALLY CONTROLLED TUMOR PROTEIN 1 (TCTP1) and HEAT SHOCK COGNATE PROTEIN 70.1 (HSC70.1), whose mRNA transport is diminished in mutants deficient in m5C mRNA methylation. Together, our results point toward an essential role of cytosine methylation in systemic mRNA mobility in plants and that TCTP1 mRNA mobility is required for its signaling function.
Keywords: grafting; long-distance transport; m(5)C; mRNA methylation; mRNA modification; mRNA transport; phloem; plasmodesmata; root development.
Copyright © 2019 The Author(s). Published by Elsevier Ltd.. All rights reserved.