The role of microRNAs in the control of flowering time.

The onset of flowering in plants is regulated by complex gene networks that integrate multiple environmental and endogenous cues to ensure that flowering occurs at the appropriate time. This is achieved by precise control of the expression of key flowering genes at both the transcriptional and post-transcriptional level. In recent years, a class of small non-coding RNAs, called microRNAs (miRNAs), has been shown to regulate gene expression in a number of plant developmental processes and stress responses. MiRNA-based biotechnology, which harnesses the regulatory functions of such endogenous or artificial miRNAs, therefore represents a highly promising area of research. In this review, the process of plant miRNA biogenesis, their mode of action, and multiple regulatory functions are summarized. The roles of the miR156, miR172, miR159/319, miR390, and miR399 families in the flowering time regulatory network in Arabidopsis thaliana are discussed in depth.