First indications for the involvement of strigolactones on nodule formation in alfalfa ( Medicago sativa)

• Published in: Soil biology & biochemistry 2010-02, Vol.42 (2), p.383-385
• Main Authors: Soto, María J., Fernández-Aparicio, Mónica, Castellanos-Morales, Vilma, García-Garrido, José M., Ocampo, Juan A., Delgado, María J., Vierheilig, Horst
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; alfalfa; Bacteria; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; forage crops; Fundamental and applied biological sciences. Psychology; gene expression; lactones; mechanism of action; Medicago sativa; mycorrhizal fungi; nitrogen-fixing bacteria; Nodulation; Orobanche; Physics, chemistry, biochemistry and biology of agricultural and forest soils; plant growth; plant hormones; rhizosphere; root exudates; root nodules; seed germination; Sinorhizobium meliloti; Soil science; Striga; Strigolactones; symbionts; symbiosis
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2009.11.007

Strigolactones have recently been suggested to be phytohormones that are present in all plants. Strigolactones are released by roots into the rhizosphere, stimulating the seed germination of parasitic plants such as Striga spp. and Orobanche spp. and play a crucial role in the interaction between plants and symbiotic arbuscular mycorrhizal fungi. By applying different concentrations of the synthetic strigolactone analogue GR24 to alfalfa ( Medicago sativa) inoculated with Sinorhizobium meliloti we could show that in alfalfa nodulation is positively affected by the presence of the strigolactone analogue GR24. Moreover, we could show that this increased nodulation cannot be linked with a stimulatory effect of GR24 on the growth or the expression of nod genes of S. meliloti. Putative mechanisms operating in the plant in response to the addition of GR24 and leading to increased nodule formation by rhizobia are discussed.