The central goal of project A1 is the integration of existing transcriptional data of the SFB under the influence of abiotic (Ozone, CO₂, sun/shadow, N) and biotic (P. citricola, A. errabunda, P. infestans, V. inaequalis) stress scenarios of European beech, potato and apple. Results of phase II-III (induction of the shikimate pathway and numerous ozone-responsive transcripts after ozone exposure of beech), inclusion of P. infestans up-regulated transcripts and V. inaequalis-responsive cDNA libraries of apple will be integrated, resulting in an extensive transcript analysis of these plants. Transcript expression profiling of European beech after ozone/CO₂ exposure and pathogen attack will be carried out by using the existing plant material and gene clones. Cluster analysis and construction of transcriptional neuronal networks including existing database information will be carried out to check the central hypothesis of the SFB. Gene expression profiles of the respective scenarios will be compared and transcriptional changes of the stress and pathogene defence will be analyzed.

The resulting data will be analyzed by bioinformatic tools like hierarchical and non-hierarchical cluster analysis. The intended meta-analysis after ozone and CO₂ exposure will allow a comprehensive statement referring to these abiotic stress scenarios.

In addition project A1 will integrate existing and indispensable protein data in the analysis and together with project A6 connect the existing data of secondary metabolites. This strong cooperation will finally result in a connection of the transcriptome, proteome, metabolome and physiological reactions.

Transcript responses in leaves of ozone-treated beech saplings at an outdoor free air model fumigation site over two growing seasons (together with A6, B5, B12, C2)

To investigate the ozone responsiveness of trees, we carried out a microarray analysis of beech saplings, grown around a free air lysimeter station in the years 2005 and 2006. Chronic ozone exposure effects were investigated at different time points throughout the whole vegetation period in 2005 and 2006. Different transcript patterns in both years could be related to weather conditions and consequential a different ozone uptake. Fewer transcriptome changes were found in 2005 compared to 2006 (Fig. 1, 2). This study demonstrated a clear transcriptional ozone response of juvenile beech, the most important deciduous tree in Central Europe, under free air conditions (Pritsch et al. 2008, Water Air & Soil Pollution Focus 8; Olbrich et al. 2009, Plant and Soil 323).


Transcriptional signatures in leaves of adult European beech trees (Fagus sylvatica L.) in an experimentally enhanced free air ozone setting (together with B2, B4)

To investigate the transcriptional responsiveness of adult trees to ozone, fully-expanded sun and shade leaves of mature beech trees were harvested at four time points over the entire vegetation period in 2005 and 2006 at Kranzberger Forst. Microarray analyses were conducted on leaves from trees grown in the field under ambient and twice-ambient ozone concentrations at Kranzberger Forst. Transcriptional differences between sun and shade leaves, as well as between different growing years, were observed. Altogether, this may indicate that external factors, in addition to ozone, affected gene expression. Furthermore, the leaves of adult trees had drastically smaller transcriptional changes than the leaves of juvenile trees; this may be explained by the lower flux-related detoxification capacity of the juvenile beech (Olbrich et al. 2010a, Environmental Pollution 158).


Ozone fumigation (twice ambient) reduces leaf infestation following natural and artificial inoculation by the endophytic fungus Apiognomonia errabunda of adult European beech trees (together with A9, B2, B4)

In 2006, a controlled infection study was performed in the ‘Kranzberger Forst’  (Fig. 3) to address the following questions:(1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2x ozone) and three control trees (ambient = 1x ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninnoculated control branches, were enclosed in 100 liter plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation (Fig. 4). A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone (Fig. 5). Only a few transcripts changed their expression level after the infection with A. errabunda. The ozone treatment and the difference between shade and sun leaves had a greater influence on gene expression than infection method (Fig. 6). Cell wall components and ACC (ethylene precursor) increased upon ozone fumigation and may in part lead to the repression of fungal infection (Fig. 7). (Olbrich et al. 2010b, Environmental Pollution 158).