miR394 enhances WUSCHEL-induced somatic embryogenesis in Arabidopsis thaliana

center dot Many plant species can give rise to embryos from somatic cells after a simple hormone treatment, illustrating the remarkable developmental plasticity of differentiated plant cells. However, many species are recalcitrant to somatic embryo formation for unknown reasons, which poses a significant challenge to agriculture, where somatic embryogenesis is an important tool to propagate desired genotypes. The micro-RNA394 (miR394) promotes shoot meristem maintenance in Arabidopsis thaliana, but the underlying mechanisms have remained elusive.center dot We analyzed whether miR394 affects indirect somatic embryogenesis and determined the transcriptome of embryogenic callus upon miR394-enhanced somatic embryogenesis.We show that ectopic miR394 expression enhances somatic embryogenesis in the recalcitrant Ler accession when co-expressed with the transcription factor WUSCHEL (WUS) and that miR394 acts in this process through silencing the target LEAF CURLING RESPONSIVENESS (LCR). Furthermore, we show that higher endogenous miR394 levels are required for the elevated embryogenic potential of the Columbia accession compared with Ler, providing a mechanistic explanation for this natural variation.center dot Our transcriptional analysis provides a framework for miR394 function in regulating pluripotency by expanding WUS-mediated direct transcriptional repression.

Automated summary

Many plant species have the ability to produce embryos from somatic cells with hormone treatment, showing the developmental plasticity of differentiated plant cells. However, the reasons why some species are unable to form somatic embryos remains unknown, which is a challenge for agriculture where somatic embryogenesis is used for propagating desired genotypes. The micro-RNA394 (miR394) enhances somatic embryogenesis in Arabidopsis thaliana by silencing the target gene LEAF CURLING RESPONSIVENESS (LCR).