PARENT SESSION
Posters P1B Photo-oxidative stress, photoinhibition. Abstracts (394-443)

Coordinated network of biotic and abiotic stress responses in Arabidopsis thaliana . Mercedes Tiemblo^*,1, Barbara Karpinska¹, ¹ Stockholm University, Department of Botany, Stockholm, Sweden

ABSTRACT- Laboratory based stress research has traditionally focused on only one well defined response to a single environmental stress. However, plants are subjected to many simultaneous challenges in the natural environment, bringing about the activation of many signalling pathways that are combined in a regulatory network. It has been shown previously that many abiotic stresses, including excess light stress, induce the expression of genes involved in pathogen responses. On the other hand, reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNS) are involved in responses to both biotic and abiotic stress. In this work we show how light intensity influences the amplitude and efficiency of the plant local responses to pathogen attack. Arabidopsis thaliana plants were adapted to high light and infected with Pseudomonas syringae. Plant susceptibility to the pathogen was then monitored by means of bacterial titration measurements. Propagation of bacteria, showed by cfu (colony forming units), was higher in high light acclimated plants, shifted to low light condition for subsequent infection, than in control low light adapted plants.

KEY WORDS: high light, Arabidopsis thaliana, acclimation, biotic stress