Molecular diversity of arbuscular mycorrhizal fungi in onion roots from organic and conventional farming systems in the Netherlands

G. A. Galván^1,2, I. Parádi^3,6, K. Burger¹, J. Baar^3,7, T. W. Kuyper⁴, O. E. Scholten¹ and C. Kik^1,5

Abstract
Diversity and colonization levels of naturally occurring arbuscular mycorrhizal fungi (AMF) in onion roots were studied to compare organic and conventional farming systems in the Netherlands.

In 2004, 20 onion fields were sampled in a balanced survey between farming systems and between two regions, namely, Zeeland and Flevoland. In 2005, nine conventional and ten organic fields were additionally surveyed in Flevoland. AMF phylotypes were identified by rDNA sequencing.

All plants were colonized, with 60% for arbuscular colonization and 84% for hyphal colonization as grand means. In Zeeland, onion roots from organic fields had higher fractional colonization levels than those from conventional fields. Onion yields in conventional farming were positively correlated with colonization level.

Overall, 14 AMF phylotypes were identified. The number of phylotypes per field ranged from one to six. Two phylotypes associated with the Glomus mosseae–coronatum and the G. caledonium–geosporum species complexes were the most abundant, whereas other phylotypes were infrequently found. Organic and conventional farming systems had similar number of phylotypes per field and Shannon diversity indices. A few organic and conventional fields had larger number of phylotypes, including phylotypes associated with the genera Glomus-B, Archaeospora, and Paraglomus. This suggests that farming systems as such did not influence AMF diversity, but rather specific environmental conditions or agricultural practices.


Source
Mycorrhiza (2009) 19:317-328


Author Locations & Affiliations
(1) Plant Research International, Wageningen University and Research Center, P.O. Box 16, 6700 AA Wageningen, The Netherlands
(2) Dept. Producción Vegetal, CRS, Facultad de Agronomía, Universidad de la República, Progreso, Uruguay
(3) Mushroom Section of Applied Plant Research, Plant Research International, Wageningen University and Research Centre, P.O. Box 16, 6700 AA Wageningen, The Netherlands
(4) Department of Soil Quality, Wageningen University and Research Center, P.O. Box 47, 6700 AA Wageningen, The Netherlands
(5) Centre for Genetic Resources (CGN), Wageningen University and Research Centre, P.O. Box 16, 6700 AA Wageningen, The Netherlands
(6) Present address: Department of Plant Physiology and Molecular Plant Biology, Eötvös Loránd University, P.O. Box 120, H-1518 Budapest, Hungary
(7) Present address: Knowledge Centre Triple E, Sweerts de Landasstraat 46, 6814 DG Arnhem, The Netherlands


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Posted March 2010