CLERK is a novel receptor kinase required for sensing of root-active CLE peptides in Arabidopsis

Development. 2018 May 22;145(10):dev162354. doi: 10.1242/dev.162354.

Abstract

CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptides are secreted endogenous plant ligands that are sensed by receptor kinases (RKs) to convey environmental and developmental inputs. Typically, this involves an RK with narrow ligand specificity that signals together with a more promiscuous co-receptor. For most CLEs, biologically relevant (co-)receptors are unknown. The dimer of the receptor-like protein CLAVATA 2 (CLV2) and the pseudokinase CORYNE (CRN) conditions perception of so-called root-active CLE peptides, the exogenous application of which suppresses root growth by preventing protophloem formation in the meristem. clv2 as well as crn null mutants are resistant to root-active CLE peptides, possibly because CLV2-CRN promotes expression of their cognate receptors. Here, we have identified the CLE-RESISTANT RECEPTOR KINASE (CLERK) gene, which is required for full sensing of root-active CLE peptides in early developing protophloem. CLERK protein can be replaced by its close homologs, SENESCENCE-ASSOCIATED RECEPTOR-LIKE KINASE (SARK) and NSP-INTERACTING KINASE 1 (NIK1). Yet neither CLERK nor NIK1 ectodomains interact biochemically with described CLE receptor ectodomains. Consistently, CLERK also acts genetically independently of CLV2-CRN We, thus, have discovered a novel hub for redundant CLE sensing in the root.

Keywords: Arabidopsis; BAM3; CLE peptide; Protophloem; Receptor kinase; Root.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / genetics*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Genome, Plant / genetics
  • Membrane Proteins / genetics
  • Plant Roots / enzymology*
  • Plants, Genetically Modified
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*

Substances

  • Arabidopsis Proteins
  • CLE26 protein, Arabidopsis
  • CLE45 protein, Arabidopsis
  • CLV2 protein, Arabidopsis
  • CLV3 protein, Arabidopsis
  • Membrane Proteins
  • At2g23950 protein, Arabidopsis
  • NIK1 protein, Arabidopsis
  • Protein-Serine-Threonine Kinases
  • SARK protein, Arabidopsis