Effects of two contrasted arbuscular mycorrhizal fungal isolates on nutrient uptake by Sorghum bicolor under drought
Drought is a limiting factor for crop production, especially in arid and semi-arid climates. In this study, Sorghum bicolor plants were inoculated, or not, with Rhizophagus irregularis, an arbuscular mycorrhizal (AM) strain typical for temperate climates, or Rhizophagus arabicus, a strain endemic to hyper-arid ecosystems. Plants were grown under well-watered or drought conditions in compartmented microcosms. Transpiration rates, plant growth, and nutrient uptake (using 15N as a tracer) were determined to assess the impact of drought stress on sorghum plants in AM symbiosis. Although AM colonization did not affect the bulk biomass of host plants, R. arabicus improved their transpiration efficiency and drought tolerance more than R. irregularis. Moreover, R. arabicus was able to extract more 15N from the soil under both water regimes, and AM-driven enhancement of the nitrogen and phosphorus content of sorghum, especially when water was limiting, was greater for R. arabicus-inoculated plants than for R. irregularis-inoculated plants. Our work demonstrates close links between AM hyphal phosphorus and nitrogen transport and uptake by AM plants for both AM fungal species. It also underscores that, under the drought stress conditions we applied, R. arabicus transfers significantly more nitrogen to sorghum than R. irregularis.
KeywordsArbuscular mycorrhizal symbiosis Sorghum Drought Isotopes Nitrogen transfer
We thank Mark Rollog and T. Kuhn for laboratory assistance and scientific support in the stable isotope lab.
This project was supported by the Swiss National Science Foundation (grant nos. 127563 to T. Boller, PZ00P3_136651 to P.-E. Courty, 130794 to A. Wiemken and the R’Equip grant no. 121258 to M. F. Lehmann and T. Boller)
- Bárzana G, Aroca R, Paz JA, Chaumont F, Martinez-Ballesta MC, Carvajal M, Ruiz-Lozano JM (2012) Arbuscular mycorrhizal symbiosis increases relative apoplastic water flow in roots of the host plant under both well-watered and drought stress conditions. Ann Bot-London 109:1009–1017CrossRefGoogle Scholar
- Brito I, de Carvalho M, Goss MJ (2011) Summer survival of arbuscular mycorrhiza extraradical mycelium and the potential for its management through tillage options in Mediterranean cropping systems. Soil Use Manage 27:350–356Google Scholar
- Gamborg OL, Wetter LR (1975) Plant tissue culture methods (OL Gamborg and LR Wetter, Eds.). Saskatoon, Sask.:National Research Council of Canada, Prairie Regional Laboratory.Google Scholar
- Koide R, Elliott G (1989) Cost, benefit and efficiency of the vesicular-arbuscular mycorrhizal symbiosis. Funct Ecol 3:252–255Google Scholar
- Marschner H (1995) Mineral nutrition of higher plants. Academic Press, LondonGoogle Scholar
- Neumann E, George E (2004) Colonisation with the arbuscular mycorrhizal fungus Glomus mosseae (Nicol. & Gerd.) enhanced phosphorus uptake from dry soil in Sorghum bicolor (L.). Plant Cell Environ 261:245–255Google Scholar
- Paterson AH, Bowers JE, Bruggmann R, Dubchak I, Grimwood J, Gundlach H, Haberer G, Hellsten U, Mitros T, Poliakov A, Schmutz J, Spannagl M, Tang H, Wang X, Wicker T, Bharti AK, Chapman J, Feltus FA, Gowik U, Grigoriev IV, Lyons E, Maher CA, Martis M, Narechania A, Otillar RP, Penning BW, Salamov AA, Wang Y, Zhang L, Carpita NC, Freeling M, Gingle AR, Hash CT, Keller B, Klein P, Kresovich S, McCann MC, Ming R, Peterson DG, Mehboob-ur-Rahman, Ware D, Westhoff P, Mayer KFX, Messing J, Rokhsar DS (2009) The Sorghum bicolor genome and the diversification of grasses. Nature 457:551–556CrossRefPubMedGoogle Scholar
- Ruiz-Lozano JM, Aroca R (2010) Modulation of aquaporin genes by the arbuscular mycorrhizal symbiosis in relation to osmotic stress tolerance. In: Seckbach J, Grue M (eds) Symbiosis and stress: joint ventures in biology, cellular origin, life in extreme habitats and astrobiology. Springer Science+Business Media, Dordrecht, pp 358–374Google Scholar
- Ruiz-Lozano JM, Azcon R, Gomez M (1995) Effects of arbuscular-mycorrhizal glomus species on drought tolerance: physiological and nutritional plant responses. Appl Environ Microb 61:456–460Google Scholar
- Smith SE, Read DJ (2008) Mycorrhizal symbiosis. Academic PressGoogle Scholar