Tomato strigolactones are derived from carotenoids and their biosynthesis is promoted by phosphate starvation

Authors

  • Juan Antonio López-Ráez,

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
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  • Tatsiana Charnikhova,

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
    2. Laboratory for Plant Physiology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands;
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  • Victoria Gómez-Roldán,

    1. Laboratory of Cell Surfaces and Signalling in Plants, UMR 5546 Toulouse 3 University-CNRS, Castanet-Tolosan, France;
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  • Radoslava Matusova,

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
    2. Laboratory for Plant Physiology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands;
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  • Wouter Kohlen,

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
    2. Laboratory for Plant Physiology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands;
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  • Ric De Vos,

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
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  • Francel Verstappen,

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
    2. Laboratory for Plant Physiology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands;
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  • Virginie Puech-Pages,

    1. Laboratory of Cell Surfaces and Signalling in Plants, UMR 5546 Toulouse 3 University-CNRS, Castanet-Tolosan, France;
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  • Guillaume Bécard,

    1. Laboratory of Cell Surfaces and Signalling in Plants, UMR 5546 Toulouse 3 University-CNRS, Castanet-Tolosan, France;
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  • Patrick Mulder,

    1. RIKILT, Institute of Food Safety, Bornsesteeg 45, NL–6708 PD Wageningen, The Netherlands
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  • Harro Bouwmeester

    1. Plant Research International, P.O Box 16, NL–6700 AA Wageningen, the Netherlands;
    2. Laboratory for Plant Physiology, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands;
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Author for correspondence:
Harro Bouwmeester
Tel:+31 317475882
Fax:+31 317418094
Email: harro.bouwmeester@wur.nl

Summary

  • • Strigolactones are rhizosphere signalling compounds that mediate host location in arbuscular mycorrhizal (AM) fungi and parasitic plants. Here, the regulation of the biosynthesis of strigolactones is studied in tomato (Solanum lycopersicum).
  • • Strigolactone production under phosphate starvation, in the presence of the carotenoid biosynthesis inhibitor fluridone and in the abscisic acid (ABA) mutant notabilis were assessed using a germination bioassay with seeds of Orobanche ramosa; a hyphal branching assay with Gigaspora spp; and by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis.
  • • The root exudates of tomato cv. MoneyMaker induced O. ramosa seed germination and hyphal branching in AM fungi. Phosphate starvation markedly increased, and fluridone strongly decreased, this activity. Exudates of notabilis induced approx. 40% less germination than the wild-type. The LC-MS/MS analysis confirmed that the biological activity and changes therein were due to the presence of several strigolactones; orobanchol, solanacol and two or three didehydro-orobanchol isomers.
  • • These results show that the AM branching factors and parasitic plant germination stimulants in tomato root exudate are strigolactones and that they are biosynthetically derived from carotenoids. The dual activity of these signalling compounds in attracting beneficial AM fungi and detrimental parasitic plants is further strengthened by environmental conditions such as phosphate availability.

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