No description available.

No description available.

Real-time RT-PCR was used to assess the effects of interspecific microbial interactions on the expression of genes associated with lignin peroxidase, manganese peroxidase and alcohol oxidase production during the wood decay process. Expression levels of genes encoding the selected lignolytic enzymes were quantitated in one-, two- and multiple-organism interaction tests with the basidiomycetes Trametes elegans, Phanerochaete chrysosporium, Gloeophyllum sepiarium and Gloeophyllum trabeum. Compression strength loss was measured for each decay sample and correlated with gene expression data for each species. Soil microflora actively producing lignolytic enzymes during wood decay were also assessed and identified using degenerative PCR coupled with denaturing gradient gel electrophoresis, cloning and cycle sequencing. Differential expression was detected in three genes in the two-organism interaction tests: manganese peroxidase in T. elegans interactions, lignin peroxidase A in P. chrysosporium interactions and alcohol oxidase in G. sepiarium interactions. A positive linear correlation was observed between lignin peroxidase A expression and compression strength loss in P. chrysosporium interactions.

Lic.-avh. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 2 uppsatser.

Sammanfattning: Wood decay fungi are the main decomposer of lignocellulose material stored in wood. Thus, all factors that affect them could affect their ecological function. This in return, may affect ecosystem functioning in terms of altered carbon emissions from dead wood. Increased temperature is one of the main factors influencing fungal decay. The aim of the current study is to explore the effects of temperature and assembly history (order of species arrival), two important regulators of fungal communities, on wood decomposition. I conducted a microcosm experiment with two temperature treatments and eight assembly histories where each species was allowed to colonize the wood two weeks ahead of the rest of the species. The temperature treatments were set to mimic the effect of climate induced warming. Therefore, I had one treatment with relatively high temperature, representing the expected temperatures year 2100 given the current emission trends of the northern inland of Sweden, and another treatment representing the current normal temperature (1961-1990). The temperature treatments had an average difference of 5°C. In order to see how climate induced warming and fungal assembly history influenced decomposition, I measured and analyzed initial fungal growth, fungal respiration and wood weight loss. Both temperature and assembly history had a significant influence on fungal growth, fungal respiration and wood decomposition. There was also strong interaction between the two factors. The average increase in mass loss under elevated temperature was 19% compared to 14% under normal temperature. The highest mass loss (25%) was when Phlebia centrifuga was the initial species under elevated temperature and the lowest (12%) was when Climacocystis borealis was initial species under normal temperature. All assembly histories had higher mass loss under elevated temperature, but the magnitude varied. For example, when C. borealis was the initial species, mass loss increased by 60% compared to only 7% when Antrodia sinuosa was the initial species. Six out of eight assembly histories had higher CO2 under elevated temperature, with the highest increase (88%) in P. centrifuga histories and the lowest (7%) in C. borealis histories. Even if the results need to be confirmed by field studies, my data illustrates that climate induced warming probably results in higher fungal respiration and deadwood decomposition and that the magnitude of this effect depends on fungal assembly history.