A Peep into the Plant miRNA World

Abstract

microRNAs constitute a major class of the small regulatory molecules that are involved in regulating the intrin- sic normal growth of cells and development of organisms as well as in maintaining the integrity of genomes. The plant miRNA research gained momentum, 2002 onwards with identification of new miRNA molecules and their targets. This was accompanied by the discovery of plant homologs of proteins involved in miRNA biogenesis, including a new mem- ber SERRATE. The identification of several diverging and converging functions of miRNAs indicate that they play versa- tile roles in regulating cell differentiation and tissue development. This article provides an update on the conservation and identification of plant miRNAs. The classical miRNA biogenesis pathway and the associated proteins are discussed along with the emerging concept on the processing of miRNA-encoding introns (mirtrons). It also contains a concise account of plant miRNA targets and functions with focus on the recent successful attempt on engineering synthetic miRNAs to study gene function as well as to impart virus resistance in plants.