LAUSR

Abstract Tung tree (Vernicia fordii Hemsl.) is a potential commercial source of biodiesel which is widely planted in China and many other countries. Investigation of the regulatory mechanism of lipid biosynthesis is an essential prerequisite to improve tung tree varieties by genetic engineering. In this study, the transfer RNA (tRNA) genes were identified in four genome-sequenced species (tung tree, rubber tree, castor bean and physic nut) in Euphorbiaceae. Gene clusters were observed for the four species tRNAs. Though tRNAs were highly conserved, contrasting patterns of nucleotide diversity were observed among the tRNA family. A total of 86 differentially expressed tRNA-derived RNA fragments (tRFs) were identified of which the target genes were enriched in lipid biosynthesis by Gene Ontology (GO) enrichment analysis. Interestingly, 11 lipid genes previously reported were identified and found to be regulated by 17 tRFs. A tRF-mRNA regulatory network was constructed, which provides a new insight into the genetic mechanism of lipid biosynthesis in tung tree.