Identification of novel peptide ligand-receptor pairs in plants

Funding through DAAD will contribute to the two partners' joint aim of understanding the importance and function of receptor-ligand pairs in plants. More specifically we want to establish a collaboration combining the genetic approach of the Aalen lab, Un iversity of Oslo, with the biochemical approach in the Felix lab, University of Tübingen, that seeks to identify novel receptor-ligand pairs involved in important cell separation processes in plants, whereby entire organs become detached from the plant bo dy when they have served their purpose. However natural, premature abscission of leaves, flowers, fruitlets, fruits or seeds results in quality loss in ornamentals and significant reduction of yield (5-20%) in important crops all over the world (e.g. oils eed rape, soybean, alfalfa, grapevine, poinsettia). The small peptide INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) that signals through the closely related leucine-rich receptor-like kinases (LRR-RLKs) HAESA (HAE) and HAESA-LIKE2 (HLS2), controls the separ ation of sepals, petals and stamens after pollination has taken place in the model plant Arabidopsis thaliana. Our working hypothesis is that IDA-LIKE peptide ligands and HAESA-LIKE receptors are used in signaling pathways in other cell separation process es both in Arabidopsis and other plants species. Molecular understanding of receptor-ligand interactions controlling organ separation will provide knowledge necessary for future translational applications in crops and ornamentals.