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I II III IV. DNA. d>2m. 30 cm. 30 cm. x 5-8. 3 subsamples= 1 mixed probe. TTIHWHGFFQ ATTNWADGRAFVNQCPIAANNSFLYNFNVPGQA GTFWYHS TSIHWHGFFQ STTNWADGPAFVTQCPIMPNDSFSYEFEVPNQA GTFWYHS
I II III IV
3 subsamples= 1 mixed probe
Spatiotemporal diversity and activity patterns of laccase genes in a forest soil
H. Kellner, P. Luis, B. Zimdars and F. Buscot - Terrestrial Ecology, Institute of Botany, University of Leipzig, Germany
Temporal laccase activity
Fungal laccases catalyze oxidation of phenolic compounds and aromatic amines coupled to reduction of molecular oxygen to water. Laccase can completely degrade lignins and appear to be an important actor in SOM turnover. Here we analyze variations of distribution and expression of fungal genes encoding laccases in time and space.
T1 – March 04
T2 – June 04
T3 – August 04
T4 – October 04
T5 – January 05
T6 – April 05
An experimental station of the Institute of Ecosystem Research (BITÖK) from the University of Bayreuth located at 460 m above the sea level in Steigerwald / Ebrach (49°52'26''N, 10°27'54''E). The site is covered by a mixed stand of European beech (Fagus sylvatica L.) and European oak (Quercus robur L.) with little ground vegetation. The soil, Dystric Cambisol (FAO-UNESCO, 1990), is characterized by a fine moder humus layer and a pH between 3.2 and 4.2.
Expression profile: O-horizon
Laccase activity decreases with depth, whereby in general the activity within the O-horizon is around 20 times higher as compared to the A-horizon. The activity of each sample date shows great variability – some spots display 5 to 10 times more activity than the average. T1, T3 & T6 for the O-horizon and T1 & T6 for the A-horizon displayed the highest temporal soil laccase activities.
For fungal tubulin, gene expression was found throughout the whole year. The expression profile of laccase genes showed a different pattern. Highest expression were detected for T3 and T5 with both primer pairs, medium expression occurred for T1, T4 and T6 and no expression was found for T2. Summarizing: a high laccase expression does not correspond to high soil laccase activity – like observed for T5 and T6.
This work is supported by the German Science foundation DFG (SPP 1090, grand Bu 941 2-1, 2-2 & 2-3)
Harald Kellner / Dr. Patricia Luis / Prof. Dr. F. Buscot
University of Leipzig, Institute of Botany, Johannisallee 21, 04103 Leipzig, Germany
Luis et al. (2004): Diversity of laccase genes from basidiomycetes in a forest soil. Soil Biology & Biochemistry 36, 1025–1036
Luis et al. (2005): A molecular method to evaluate basidiomycete laccase gene expression in forest soils. Geoderma, (Online)
Saprotrophic fungi detected through their laccase genes were restricted to the upper horizons (e.g. Mycena zephirus). ECM fungi had a broader vertical distribution. Lactarius subdulcis colonized preferably the organic horizons (Oh), while the Russulaceae type 1 rather occupied the mineral part of the soil cores (Bv). Most detected fungi were aggregated in small patches (<0,77 m2).
Laccase gene typification