FROM PATHOGEN RECOGNITION TO SECONDARY PRODUCT ACCUMULATION
K HAHLBROCK, O BATZ, J HAGEMEIER, E KOOPMANN and E LOGEMANN
Max-Pianck lnstitut for Zuchtungsforschung, Carl-von-Linne-Weg 10, D-50829 Koln, Germany
The large diversity of potential plant-pathogen interactions occurring at the whole-organism level is mirrored at the molecular level by a multitude of reactions involved in the sequential steps of recognition, signal transduction, gene expression and product accumulation. In fact. it seems that a challenged plant cell undergoes more or less total reprogramming of its metabolic activity .
The induced shift in metabolism includes a complex mechanism of signal perception and signal conversion in the plant cell membrane. Within a few minutes, these processes trigger, via a network of intracellular signalling cascades, numerous alterations in gene activity. These in turn are rapidly followed by corresponding changes in metabolic activities, including those leading to secondary product accumulation .
Results from studies of two particularly well-suited model systems, Petroselinum crispum and Arabidopsis thaliana, will be presented. In both cases, the large complexity of the overall response was observed at all levels: timing of the induced changes, spatial distribution, and structural and functional variations among the multitude of either transiently or stably accumulating products.