Activation of Innate Immune Responses in Plants by Lipopolysaccharides

• Applicant: Professor Dr. Jörg Durner
• Subject Area: Immunology
• Term: from 2002 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5358199

The past few years have seen dramatic changes in our understanding of the molecular principles of host resistance. A growing body of evidence indicates that some of the molecular mechanisms involved in innate immunity in mammalian and insect systems are strikingly similar to the molecular mechanisms underlying plant disease-resistance responses. It has been proposed, therefore, that innate immunity might be an evolutionarily ancient system of host defense. This research proposal suggests to elucidate aspects of plant pathogen interactions which belong to innate immune responses: 1) A major objective of this project is to explore how exactly type III effectors of the YopJ class such as the plant pathogen homologue AvrBsT modulate the hypersensitive response and apoptosis in plants. 2) We will also elucidate the action of the harpin protein from Pseudomonas ssp., which is like AvrBsT (and YopJ) an inducer of apoptosis. However, for this protein there is no animal homologue known. 3) Another objective is to characterize the response of plant cells to lipopolysaccharides (LPS). We will analyze the effects of these effector proteins regarding hallmarks of defense such as production of nitric oxide (NO) and reactive oxygen, induction of cell death, and expression of defense genes. To get insight into the (disrupted) signaling mechanisms, we will use pathogen mutants with altered avr genes, i.e. inactive AvrBsT and harpin. In addition, our studies will include signal transduction host mutants (Arabidopsis) such as the "defense but no death" and the "no pathogen response" lines. Studying innate immunity in plants will contribute to our understanding of the general principles of innate immunity in plants and animals.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1110: Innate Immunity