ATP-competitive mTOR kinase inhibitors delay plant growth by triggering early differentiation of meristematic cells but no developmental patterning change

International audienceThe TOR (target of rapamycin) protein, a large phosphatidylinositol 3-kinase-like protein kinase (PIKK) that is conserved in eukaryotes and is a central regulator of growth and metabolism. The analysis of function of TOR in plant growth and development has been limited by the fact that plants are very poorly sensitive to rapamycin. As the kinase domain of TOR is highly conserved, this study analysed the dose-dependent effect of three sets of first- and second-generation ATP-competitive inhibitors (called asTORis for active-site TOR inhibitors) recently developed for the human TOR kinase on Arabidopsis thaliana growth. All six asTORis inhibited plant root growth in a dose-dependent manner, with 50% growth inhibitory doses (GI50) of <10 μM and