A Phelipanche ramosa KAI2 protein perceives strigolactones and isothiocyanates enzymatically

Plant Commun. 2021 Feb 5;2(5):100166. doi: 10.1016/j.xplc.2021.100166. eCollection 2021 Sep 13.


Phelipanche ramosa is an obligate root-parasitic weed that threatens major crops in central Europe. In order to germinate, it must perceive various structurally divergent host-exuded signals, including isothiocyanates (ITCs) and strigolactones (SLs). However, the receptors involved are still uncharacterized. Here, we identify five putative SL receptors in P. ramosa and show that PrKAI2d3 is involved in the stimulation of seed germination. We demonstrate the high plasticity of PrKAI2d3, which allows it to interact with different chemicals, including ITCs. The SL perception mechanism of PrKAI2d3 is similar to that of endogenous SLs in non-parasitic plants. We provide evidence that PrKAI2d3 enzymatic activity confers hypersensitivity to SLs. Additionally, we demonstrate that methylbutenolide-OH binds PrKAI2d3 and stimulates P. ramosa germination with bioactivity comparable to that of ITCs. This study demonstrates that P. ramosa has extended its signal perception system during evolution, a fact that should be considered for the development of specific and efficient biocontrol methods.

Keywords: Phelipanche ramosa; isothiocyanates; receptor; seed germination stimulant; strigolactones; α/β-hydrolase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Europe
  • Heterocyclic Compounds, 3-Ring / metabolism*
  • Hydrolases / chemistry
  • Hydrolases / genetics*
  • Hydrolases / metabolism
  • Isothiocyanates / metabolism*
  • Lactones / metabolism*
  • Orobanchaceae / genetics*
  • Orobanchaceae / metabolism
  • Phylogeny
  • Plant Proteins / chemistry
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plant Weeds / genetics
  • Plant Weeds / metabolism
  • Sequence Alignment


  • GR24 strigolactone
  • Heterocyclic Compounds, 3-Ring
  • Isothiocyanates
  • Lactones
  • Plant Proteins
  • Hydrolases