Plant tRNA functions beyond their major role in translation

Transfer RNAs (tRNAs) are well known for their essential function as adapters in delivering amino acids to ribosomes and making the link between mRNA and protein according to the genetic code. Besides this central role in protein synthesis, other functions are attributed to these macromolecules, or their genes, in all living organisms. This review focuses on these extra functions of tRNAs in photosynthetic organisms. For example, tRNAs are implicated in tetrapyrrole biosynthesis, mRNA stabilization or transport, and priming the reverse transcription of viral RNAs, and tRNA-like structures play important roles in RNA viral genomes. Another important function of tRNAs in regulating gene expression is related to their cleavage allowing the production of small non-coding RNAs termed tRNA-derived RNAs. Here, we examine in more detail the biogenesis of tRNA-derived RNAs and their emerging functions in plants.