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

Abstract

* 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.

• Authors: Juan Antonio López-Ráez, Tatsiana Charnikhova, Victoria Gómez-Roldán, Radoslava Matusova, Wouter Kohlen, Ric De Vos, Francel Verstappen, Virginie Puech-Pages, Guillaume Bécard, Patrick Mulder, Harro Bouwmeester
• Journal: The New phytologist (New Phytol) Vol. 178 Issue 4 Pg. 863-874 ( 2008) ISSN: 1469-8137 [Electronic] England
• PMID: 18346111 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Lactones
• Phosphates
• Plant Exudates
• Carotenoids

Topics

• Biological Assay
• Carotenoids (metabolism)
• Chromatography, Liquid
• Germination
• Lactones (analysis, chemistry, metabolism)
• Solanum lycopersicum (drug effects, metabolism)
• Mycorrhizae (physiology)
• Orobanche (growth & development)
• Phosphates (deficiency, pharmacology)
• Plant Exudates (metabolism)
• Plant Roots (microbiology)
• Tandem Mass Spectrometry