The role of fungi in the oxalate-carbonate pathway

The oxalate-carbonate pathway studied in acid tropical soils necessitates the presence of plants, fungi, and bacteria. All the studies in this aera are interdisciplinary by nature. The research centered on mycology aimed at the understanding of ecological and physiological mechanisms is threefold :

• the fungal physiology of crystal production (Figure 1 and 2)
• the mechanisms controlling the transfer of calcium in the soils (geomycology)
• the fungi-bacteria interactions

The model organisms used are mainly white rot basidiomycetes and oxalotrophic bacteria from tropical soils. The investigations concern (i) the diversity of strains capable of producing oxalates among the different groups of fungi, (ii) the dynamics of production and aboveall of oxidation of calcium oxalate, (iii) the characterization of fungal crystals (type, composition, distribution, kinetics, and quantification), (iv) the nature of the interaction between the fungi and the laboratory bacteria (Petri dish/microcosms), (v) the importance of calcium transportation to the interior of the hyphae for the formation of oxalates, and finally (iv) the isolation of autochtonous fungi (culture method) under biomineralizing trees.

SEM image of an oxalate crystal released from wood due to fungal activity


Three types of oxalate crystals related to fungal activity


Participant: Eric Verrecchia
Collaborations: Saskia Bindschedler, Matteo Guggiari, Daniel Job


For more information

Guggiari M., Martin G., Aragno M., Verrecchia, E. & Job, D. (2010): Assessment of the collaboration between fungi and bacteria during the oxalate-carbonate pathway in microcosms. Proceedings Book of the IIIrd International Conference on Environmental, Industrial and Applied Microbiology. World Scientific Publishing Group, in press.
Guggiari M., Bloque R., Aragno M., Verrecchia E. & Job D. (2009): Role and dynamics of calcium oxalate production by selected Fungi. Bulletin de la Société Suisse de Pédologie 30, in press.
Verrecchia E.P., Braissant O., & Cailleau G. (2006): The oxalate-carbonate pathway in soil carbon storage : the role of fungi and oxalotrophic bacteria. pp.289-310 in Gadd G.M. (eds.) Fungi in Biogeochemical Cycles. Cambridge University Press.