Arabidopsis TRM5 encodes a nuclear-localised bifunctional tRNA guanine and inosine-N1-methyltransferase that is important for growth

PLoS One. 2019 Nov 22;14(11):e0225064. doi: 10.1371/journal.pone.0225064. eCollection 2019.


Modified nucleosides in tRNAs are critical for protein translation. N1-methylguanosine-37 and N1-methylinosine-37 in tRNAs, both located at the 3'-adjacent to the anticodon, are formed by Trm5. Here we describe Arabidopsis thaliana AtTRM5 (At3g56120) as a Trm5 ortholog. Attrm5 mutant plants have overall slower growth as observed by slower leaf initiation rate, delayed flowering and reduced primary root length. In Attrm5 mutants, mRNAs of flowering time genes are less abundant and correlated with delayed flowering. We show that AtTRM5 complements the yeast trm5 mutant, and in vitro methylates tRNA guanosine-37 to produce N1-methylguanosine (m1G). We also show in vitro that AtTRM5 methylates tRNA inosine-37 to produce N1-methylinosine (m1I) and in Attrm5 mutant plants, we show a reduction of both N1-methylguanosine and N1-methylinosine. We also show that AtTRM5 is localized to the nucleus in plant cells. Proteomics data showed that photosynthetic protein abundance is affected in Attrm5 mutant plants. Finally, we show tRNA-Ala aminoacylation is not affected in Attrm5 mutants. However the abundance of tRNA-Ala and tRNA-Asp 5' half cleavage products are deduced. Our findings highlight the bifunctionality of AtTRM5 and the importance of the post-transcriptional tRNA modifications m1G and m1I at tRNA position 37 in general plant growth and development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis Proteins / metabolism*
  • Base Sequence
  • Cell Nucleus / metabolism*
  • Circadian Clocks / genetics
  • Conserved Sequence
  • Flowers / physiology
  • Gene Expression Regulation, Plant
  • Genes, Plant
  • Guanine / metabolism*
  • Inosine / metabolism*
  • Phenotype
  • Photosynthesis / genetics
  • Plant Leaves / growth & development
  • Plant Roots / growth & development
  • RNA, Plant / metabolism
  • tRNA Methyltransferases / metabolism*


  • Arabidopsis Proteins
  • RNA, Plant
  • Inosine
  • Guanine
  • tRNA Methyltransferases
  • AT3G56120 protein, Arabidopsis

Grants and funding

The research was partially supported by ARC grant FT130100525, partially funded an Australia-China Science and Research Fund grant ACSRF48187 awarded to I.S. and an APA awarded to PQ.N and J.L. This research was also partially supported by the National Natural Science Foundation (31570234) awarded to W.Z., W.Z. was supported by the Innovation Program of Chinese Academy of Agricultural Sciences and the Elite Youth Program of the Chinese Academy of Agricultural Science.