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Journal of Lipids
Volume 2012, Article ID 236807, 8 pages
http://dx.doi.org/10.1155/2012/236807
Research Article

Use of the Signature Fatty Acid 16:1ω5 as a Tool to Determine the Distribution of Arbuscular Mycorrhizal Fungi in Soil

1Institute of Biology, Ecology Group, Humboldt-Universität zu Berlin, Philippstraße 13, 10115 Berlin, Germany
2Department of Natural Resource Sciences, MacCampus, McGill University, 21,111 Lakeshore Road, Ste Anne de Bellevue, QC, Canada H9X 3V9
3Institute of Vegetable and Ornamental Crops Großbeeren, Theodor-Echtermeyer-Weg 1, 14979 Großbeeren, Germany
4Faculty of Food and Agriculture, UAE University, Jimi 1 Campus, Building 52, P.O. Box 17555, Al Ain, Abu Dhabi, UAE

Received 28 March 2012; Accepted 14 May 2012

Academic Editor: Paul R. Herron

Copyright © 2012 Christopher Ngosong et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Biomass estimation of arbuscular mycorrhiza (AM) fungi, widespread plant root symbionts, commonly employs lipid biomarkers, predominantly the fatty acid 16:1ω5. We briefly reviewed the application of this signature fatty acid, followed by a case study comparing biochemical markers with microscopic techniques in an arable soil following a change to AM non-host plants after 27 years of continuous host crops, that is, two successive cropping seasons with wheat followed by amaranth. After switching to the non-host amaranth, spore biomass estimated by the neutral lipid fatty acid (NLFA) 16:1ω5 decreased to almost nil, whereas microscopic spore counts decreased by about 50% only. In contrast, AM hyphal biomass assessed by the phospholipid (PLFA) 16:1ω5 was greater under amaranth than wheat. The application of PLFA 16:1ω5 as biomarker was hampered by background level derived from bacteria, and further enhanced by its incorporation from degrading spores used as microbial resource. Meanwhile, biochemical and morphological assessments showed negative correlation for spores and none for hyphal biomass. In conclusion, the NLFA 16:1ω5 appears to be a feasible indicator for AM fungi of the Glomales group in the complex field soils, whereas the use of PLFA 16:1ω5 for hyphae is unsuitable and should be restricted to controlled laboratory studies.