RESUMO
We investigated the microRNA172 (miR172)-mediated regulatory network for the perception of changes in external and endogenous signals to identify a universally applicable floral regulation system in ornamental plants, manipulation of which could be economically beneficial. Transgenic gloxinia plants, in which miR172 was either overexpressed or suppressed, were generated using Agrobacterium-mediated transformation. They were used to study the effect of altering the expression of this miRNA on time of flowering and to identify its mRNA target. Early or late flowering was observed in transgenic plants in which miR172 was overexpressed or suppressed, respectively. A full-length complementary DNA (cDNA) of gloxinia (Sinningia speciosa) APETALA2-like (SsAP2-like) was identified as a target of miR172. The altered expression levels of miR172 caused up- or down-regulation of SsAP2-like during flower development, which affected the time of flowering. Quantitative real-time reverse transcription PCR analysis of different gloxinia tissues revealed that the accumulation of SsAP2-like was negatively correlated with the expression of miR172a, whereas the expression pattern of miR172a was negatively correlated with that of miR156a. Our results suggest that transgenic manipulation of miR172 could be used as a universal strategy for regulating time of flowering in ornamental plants.
Assuntos
Proteínas de Arabidopsis/genética , Flores/fisiologia , Proteínas de Homeodomínio/genética , Lamiales/fisiologia , MicroRNAs/genética , Proteínas Nucleares/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Clonagem Molecular , DNA Complementar/metabolismo , Flores/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/metabolismo , Lamiales/genética , MicroRNAs/metabolismo , Proteínas Nucleares/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Plasmídeos/metabolismo , Reação em Cadeia da Polimerase , TransgenesRESUMO
MicroRNA*s are about 22nt noncoding RNAs, which are processed from precursors with a characteristic hairpin secondary structure in the biogenesis of microRNAs. Recently, miRNA* strands were shown to mediate post-transcriptional regulatory networks, rather than serve merely as non-functional by-product in general view. Unlike miRNAs bound to AGO1, miRNA* strands are bound to AGO2 to form RISC duplex to mediate RNAi, which is similar to siRNA. This paper mainly reviewed the recent research progresses on miRNA*, such as the biosynthesis, biological characteristics, and functions.