Plant Innate Immunity

Project team leader: Prof. T. Boller

Project team members: Dr. Sebastian Bartels (Postdoc)

Lay Summary:

Plants are exposed to myriads of potential microbial pathogens, but the world is still green. Why? One reason is that the plants have a highly efficient innate immunity system to ward off potential pathogens. The term "innate immunity", widely used in medicine as well as plant biology, stands for an active defense response against microbial attack. It is based on the perception of characteristic microbial molecules, collectively called "MAMPs" ("microbe-associated molecular patterns"). These "MAMPs" are recognized by so-called "pattern-recognition receptors", receptors at the cell surface that recognize the MAMP and send a danger signal to the cell's interior. Bacterial flagellin acts as such a MAMP, both in plants and animals. In our previous work supported by the SNF, we have identified the PRR responsible for flagellin perception in the model plant Arabidopsis, namely the leucine-rich repeat receptor kinase FLS2. We have analyzed flagellin perception by FLS2 extensively already, as summarized in a recent scientific review (Boller and Felix, Annual Review of Plant Biology, 60, 379-406, 2009).

In the current project, we want to address a question that has thus far received little attention in plant innate immunity but seems to become an emerging field in biomedical research, namely innate-immunity stimulation through "damage-associated molecular patterns" (DAMPs). DAMPs are molecules that are released from within the cells into the extracellular space, due to damage caused by an invading pathogen, and then are perceived by PRRs on the surface of neighboring cells. In this respect, we want to take up fascinating work by the group of Clarence A. Ryan, who has described such a DAMP, AtPep1, and its PRR, PEPR1, in the model plant Arabidopsis, shortly before his untimely death in 2007. We want to compare the signal pathways induced by MAMPs (such as flagellin) and DAMPs (such as AtPep1).

Do these signaling pathways converge at some point? Do they act synergistically or independently? Overall, our research helps to make use of the plants' natural resistance mechanisms as an environmentally friendly alternative to chemical plant protection. Because of the striking similarities of the innate immunity pathways in animals and plants, our work is not only relevant to plant biology per se, but also to animal science and human medicine.