Dexamethasone-inducible LhGR/pOp system: simple and flexible spatiotemporal control of gene expression

MAIN CONCLUSION: Our review illustrates how the dexamethasone-inducible LhGR/pOp system has been used across numerous tissues/organs and plant species, and summarizes the resources and inducer application procedures established to date. The establishment of groundbreaking molecular biology tools has enabled the rapid advancement of research based on the model plant Arabidopsis, which currently strongly benefits non-model but economically important species. Spatiotemporal control of transgene expression via the chemically inducible system GR-LhG4/pOp has proven to be a particularly powerful, universal and non-invasive experimental approach. This review characterizes the mechanism of action of GR-LhG4/pOp and synthesizes information on available GR-LhG4 transgenic lines and inductor (dexamethasone) application procedures across various plant tissues. Moreover, feasible experimental approaches are depicted that range from classical ones aiming at selected genes overexpression or silencing to highly innovative ones, like those integrating the GR-LhG4/pOp system with CRISPR-Cas for targeted ablation of specific cell types. Information about the existing GR-LhG4/pOp lines from non-Arabidopsis plants is also provided, in hope that this sophisticated but universal research tool will become more exploited in crop research.