Bitki MikroRNA’ları: Biyogenezi, Köken ve Evrimi

Abstract

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