Cell-surface receptors enable perception of extracellular cytokinins

Nat Commun. 2020 Aug 27;11(1):4284. doi: 10.1038/s41467-020-17700-9.


Cytokinins are mobile multifunctional plant hormones with roles in development and stress resilience. Although their Histidine Kinase receptors are substantially localised to the endoplasmic reticulum, cellular sites of cytokinin perception and importance of spatially heterogeneous cytokinin distribution continue to be debated. Here we show that cytokinin perception by plasma membrane receptors is an effective additional path for cytokinin response. Readout from a Two Component Signalling cytokinin-specific reporter (TCSn::GFP) closely matches intracellular cytokinin content in roots, yet we also find cytokinins in extracellular fluid, potentially enabling action at the cell surface. Cytokinins covalently linked to beads that could not pass the plasma membrane increased expression of both TCSn::GFP and Cytokinin Response Factors. Super-resolution microscopy of GFP-labelled receptors and diminished TCSn::GFP response to immobilised cytokinins in cytokinin receptor mutants, further indicate that receptors can function at the cell surface. We argue that dual intracellular and surface locations may augment flexibility of cytokinin responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenine / analogs & derivatives
  • Adenine / pharmacology
  • Arabidopsis / cytology
  • Arabidopsis / drug effects
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Cytokinins / metabolism*
  • Extracellular Fluid / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Histidine Kinase / genetics
  • Histidine Kinase / metabolism
  • Mutation
  • Plants, Genetically Modified
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism*
  • Signal Transduction


  • 2-chloro-6-(3-methoxyphenyl)aminopurine
  • Arabidopsis Proteins
  • Cytokinins
  • Recombinant Proteins
  • Green Fluorescent Proteins
  • Histidine Kinase
  • AHK2 protein, Arabidopsis
  • AHK3 protein, Arabidopsis
  • Adenine