Directional transport of the phytohormone auxin is a versatile, plant-specific mechanism regulating many aspects of plant development. The recently identified plant hormones, strigolactones (SLs), are implicated in many plant traits; among others, they modify the phenotypic output of PIN-FORMED (PIN) auxin transporters for fine-tuning of growth and developmental responses. Here, we show in pea and Arabidopsis that SLs target processes dependent on the canalization of auxin flow, which involves auxin feedback on PIN subcellular distribution. D14 receptor- and MAX2 F-box-mediated SL signaling inhibits the formation of auxin-conducting channels after wounding or from artificial auxin sources, during vasculature de novo formation and regeneration. At the cellular level, SLs interfere with auxin effects on PIN polar targeting, constitutive PIN trafficking as well as clathrin-mediated endocytosis. Our results identify a non-transcriptional mechanism of SL action, uncoupling auxin feedback on PIN polarity and trafficking, thereby regulating vascular tissue formation and regeneration.

• MeSH
• Arabidopsis genetics   metabolism   MeSH
• Heterocyclic Compounds, 3-Ring metabolism   MeSH
• Pisum sativum genetics   metabolism   MeSH
• Indoleacetic Acids metabolism   MeSH
• Lactones metabolism   MeSH
• Arabidopsis Proteins genetics   metabolism   MeSH
• Gene Expression Regulation, Plant genetics   physiology   MeSH
• Plant Growth Regulators metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• GR24 strigolactone MeSH Browser
• Heterocyclic Compounds, 3-Ring MeSH
• Indoleacetic Acids MeSH
• Lactones MeSH
• Arabidopsis Proteins MeSH
• Plant Growth Regulators MeSH