A chemical and synthetic biology approach to control plant membrane receptor kinase signaling

Plants have a large family of membrane receptor kinases (RKs) which sense extracellular signals to control plant growth, development, immunity, and stress response. The largest group of RKs contains an extracellular leucine-rich repeat (LRR) domain with over 200 members in Arabidopsis. However, the functional understanding of most of the LRR-RKs has been hampered by their genetic redundancy and the subtle phenotypes of RK overexpression. Here we show that the rapamycin-mediated heterodimerization of chimeric cytosolic kinase domains from receptor/co-receptor pairs in the plasma membrane can activate their downstream cellular signaling pathway, inducing the specific biological responses, including brassinosteroid, plant immunity, stomatal development, and lateral root development. This chemically controlled synthetic biology approach will be useful to investigate biological functions of LRR-RKs and their signaling pathways. Overall design: Arabidopsis seedlings were grown on medium containing 2 µM PPZ with 100 nM brassinolide or 100 nM rapamycin in the dark for 5 days before harvesting for total RNA extraction.