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SPP 1090 Böden als Quelle und Senke von CO2
Diversity of basidiomycete laccase genes in soil
samples
Patricia Luis1,2, Grit Walther1, Francis Martin2
and François Buscot1 1 Friedrich Schiller
University of Jena, Institute of Ecology,
Department of Environmental Sciences 2 Centre
INRA of Nancy, UMR INRA/UHP 1136 Interactions
Arbres/Micro-organismes
Summary
Vertical diversity of laccase genes in 2 forest
soils

• Introduction and goal
• Fungi are one of the major organism groups
  involved in formation and decomposition of soil
  organic matter (SOM)
• By producing oxidative exo-enzymes without
  substrate specificity, they fully mineralize
  organic compounds or recombine organic radicals
  in stable polymers
• Among the exo-enzymes, phenol oxidases (laccases)
  are produced by the broadest range of fungi.
  Therefore, they were chosen as model to develop a
  technique to monitor fungi with an oxidative
  potential in soils, without taking them in culture

Comparison Podzolic\Brown forest soil
Design of degenerated primers specific for
basidiomycetes
Brown forest soil replicates
? Higher diversity in O horizons ? Stronger
horizon specificity in the Podzol ? Small number
of common laccases between soils ? Replicate
heterogeneity ? Diversity decreases with the
depth
? The primers appear adequate to specifically
amplify laccase genes from basidiomycetes
? For both soils, the diversity is stronger in O
horizons (highest concentration of SOM) and
generally decreases with the depth
Comparing laccase-genes of soil fruit-bodies
First extraction of soil RNA PCR on cDNA
? Laccase gene sequences are species specific ?
Most fungi possess a family of laccase genes ?
Sequence and genera clades rarely overlap ?
Diversity of laccase genes is higher than the one
of fungi ? Off 70 soil sequences, only 18
correspond to laccases of the collected
fruit-bodies(12 saprophytic, 1 pathogen 5
ectomycorrhizal fungi) ? Fruit bodies dont
reflect correctly the soil fungi community
(seasonal fruiting) ? Unknown groups of laccase
genes (bold bars) were detected, especially in
mycorrhizal fungi ? Ectomycorrhizal fungi seem
to have a wide vertical distribution
? Analysis of fungal laccase gene expression in
soils seems feasible
? The primers detect laccases in a broad range of
Basidiomycota of all functional groups
(saprophytes, pathogens mycorrhiza)
Contact Prof. Dr. François Buscot, Institute of
Ecology, Department of Environmental Sciences,
Friedrich-Schiller-University of Jena, Dornburger
Str. 159, D-07743 Jena / Mail francois.buscot_at_uni
-jena.de