Özet:

MicroRNAs (miRNAs) are a class of endogenous, non-coding, short RNAs found in eukaryotic cells. Mature miRNA is an around 22nucleotides (nt) long and they are identified in nearly all plants where they play important roles in growth, development and stress responses byguiding mRNA cleavage or by repressing translation. However, only limited studies are existent about origin and evolution of miRNAs in plantgenomes. In recent years, high throughput discovery tools such as next-generation sequencing significantly increased the number of knownmiRNAs and their evolutionary changes in different organisms. To date, many data demonstrate that subsets of miRNA families, which regulateancestral transcription factors, are conserved between plant families, indicating their very ancient origin. In contrast, multiple non-conservedmiRNAs expressed by any given plant species have a limited phylogenetic distribution, suggesting they are evolutionary young miRNAs. Severalstudies have shown that plants non-conserved miRNAs already largely outnumber their conserved counterparts and plants use highly conservedas well as young, lineage specific miRNAs to regulate numerous biological processes. The aim of this review is to summarize the conservationand divergence in plant miRNAs in evolutionary perspectives.

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