MicroRNA miR394 regulates flowering time in Arabidopsis thaliana

Abstract

Plant development occurs throughout its entire life cycle and involves a phase transition between vegetative and reproductive phases, leading to the fowering process, fruit formation and ultimately seed production. It has been shown that the microRNA394 (miR394) regulates the accumulation of the transcript coding for LEAF CURLING RESPONSIVENESS, a member of a family of F-Box proteins. The miR394 pathway regulates several processes including leaf morphology and development of the shoot apical meristem during embryogenesis, as well as having been assigned a role in the response to biotic and abiotic stress in Arabidopsis thaliana and other species. Here, we characterized plants harboring mutations in MIR394 precursor genes and demonstrate that mir394a mir394b double mutants display an early fowering phenotype which correlates with a lower expression of FLOWERING LOCUS C earlier in development and higher expression of the foral integrators FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1. Consequently, mutant plants produce fewer branches and exhibit lower seed production. Our work reveals previously unknown developmental aspects regulated by the miR394 pathway, in an LCR-independent manner, contributing to the characterization of the multiple roles of this versatile plant regulatory miRNA.