From lateral root density to nodule number, the strigolactone analogue GR24 shapes the root architecture of Medicago truncatula

De Cuyper, CarolienFromentin, JustineYocgo, Rosita EndahDe Keyser, AnnickGuillotin, BrunoKunert, Karl J.Boyer, François-DidierGoormachtig, Sofie2015-03-102015-03-102015-01De Cuyper, C, Fromentin, J, Yocgo, RE, De Keyser, A, Guillotin, B, Kunert, K, Boyer, FD & Goormachtig, S 2015, 'From lateral root density to nodule number, the strigolactone analogue GR24 shapes the root architecture of Medicago truncatula', Journal of Experimental Botany, vol. 66, no. 1, pp. 137-146.0022-0957 (print)1460-2431 (online)10.1093/jxb/eru404http://hdl.handle.net/2263/43926In the rhizosphere, strigolactones not only act as crucial signalling molecules in the communication of plants with parasitic weeds and arbuscular mycorrhiza, but they also play a key role in regulating different aspects of the root system. Here we investigated how strigolactones influence the root architecture of Medicago truncatula. We provide evidence that addition of the synthetic strigolactone analogue GR24 has an inhibitory effect on the lateral root density. Moreover, treatment with GR24 of Sinorhizobium meliloti-inoculated M. truncatula plants affects the nodule number both positively and negatively, depending on the concentration. Plants treated with 0.1 μM GR24 had a slightly increased number of nodules, whereas concentrations of 2 and 5 μM strongly reduced it. This effect was independent of the autoregulation of nodulation mechanism that is controlled by SUPER NUMERIC NODULE. Furthermore, we demonstrate that GR24 controls the nodule number through crosstalk with SICKLE-dependent ethylene signalling. Additionally, because the expression of the nodulation marker EARLY NODULATION11 was strongly reduced in GR24-treated plants, we concluded that strigolactones influence nodulation at a very early stage of the symbiotic interaction.en© The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Journal of Experimental Botany following peer review. The definitive publisher-authenticated version Journal of Experimental Botany, vol. 66, no. 1, pp. 137-146, 2015. doi : 10.1093/jxb/eru404. Journal of Experimental Botany is available online at : http://jxb.oxfordjournals.orgENOD11EthyleneGR24Medicago truncatulaNodulationRoot architectureFrom lateral root density to nodule number, the strigolactone analogue GR24 shapes the root architecture of Medicago truncatulaPostprint Article