Evolution of Plant MicroRNAs

摘要: Microribonucleic acids (miRNAs) are small noncoding regulatory molecules encoded in the genome and generated through several processing steps. They recognise specific messenger RNAs regulate their expression by cleavage or translational inhibition. MiRNAs were only discovered approximately 10 years ago but it quickly became evident that they play an important role development stress responses. Initially was thought all miRNAs conserved plants because technology allowed to sequence most abundant miRNAs. However, of next generation sequencing technologies researchers generate millions reads a sample, which resulted identification less Analysis large-scale data revealed number nonconserved is much larger than previously thought. This review focuses on evolution plant MIRNA genes from protein-coding describing difference between families. Key Concepts: MicroRNAs molecules. Primary miRNA transcripts folded into stem–loop secondary structure, cleaved twice DICER-LIKE1 releasing microRNA duplex. One strand duplex incorporated ARGONAUTE complex guides mRNAs. The usually cleaves target mRNA also suppresses translation noncleaved mRNAs. Some ancient embryophytes there families angiosperms monocots dicots. A large even divergent dicot families. New can potentially evolve any inverted repeats evidence exists for inverse duplication followed deletions mutations. Indirect suggests rapid birth death genes: 1–3 per million Arabidopsis lineage. Nonconserved weakly expressed, imprecisely processed, show uniform nucleotide divergence many lack targets, suggesting evolving neutrally. Nonconserved could be source ‘regulatory diversity’, selected if acquire advantageous plant, maybe new environment. Keywords: microRNA; evolution; small RNA; gene regulation; siRNA