Functional immobilization of plant receptor-like kinase onto microbeads towards receptor array construction and receptor-based ligand fishing.

Despite the large number of receptor-like kinases (RLKs) in plants, few of their specific ligands are known. Ligand fishing is one of the most challenging post-genomic technologies. Here, we report a strategy for functional immobilization of plant RLKs on microbeads via covalent linkage. Because of the high density of immobilized RLKs, ligand-receptor interaction can be visualized at high sensitivity using fluorescent-labeled ligands under the confocal laser scanning microscope. Moreover, using a receptor-based affinity chromatography system with RLK microbeads, the ligand of the receptor was directly retrieved at high purity from complex natural samples. Our RLK microbeads and receptor-based ligand fishing approach is a feasible alternative to conventional forward genetics and bioassay-based biochemical purification for identification of novel ligand-receptor pairs in plants.