RESUMO
MAIN CONCLUSION: In the present study, miRNA precursors in the genomes of three palm species were identified. Analyzes of sequence conservation and biological function of their putative targets contribute to understand the roles of miRNA in palm biology. MicroRNAs are small RNAs of 20-25 nucleotides in length, with important functions in the regulation of gene expression. Recent genome sequencing of the palm species Elaeis guineensis, Elaeis oleifera and Phoenix dactylifera have enabled the discovery of miRNA genes, which can be used as biotechnological tools in palm trees breeding. The goal of this study is the identification of miRNA precursors in the genomes of these species and their possible biological roles suggested by the mature miRNA-based regulation of target genes. Mature miRNA sequences from Arabidopsis thaliana, Oryza sativa, and Zea mays available at the miRBase were used to predict microRNA precursors in the palm genomes. Three hundred and thirty-eight precursors, ranging from 76 to 220 nucleotide (nt) in size and distributed in 33 families were identified. Moreover, we also identified 266 miRNA precursors of Musa acuminata, which are phylogenetically close to palms species. To understand the biological function of palm miRNAs, 374 putative miRNA targets were identified. An enrichment analysis of target-gene function was carried out using the agriGO tool. The results showed that the targets are involved in plant developmental processes, mainly regulating root development. Our findings contribute to increase the knowledge on microRNA roles in palm biology and could help breeding programs of palm trees.