Ligand-Induced Receptor-like Kinase Complex Regulates Floral Organ Abscission in Arabidopsis

Publication date: Available online 4 February 2016
Source:Cell Reports
Author(s): Xiangzong Meng, Jinggeng Zhou, Jiao Tang, Bo Li, Marcos V.V. de Oliveira, Jijie Chai, Ping He, Libo Shan
Abscission is a developmental process that enables plants to shed unwanted organs. In Arabidopsis, the floral organ abscission is regulated by a signaling pathway consisting of the peptide ligand IDA, the receptor-like kinases (RLKs) HAE and HSL2, and a downstream MAP kinase (MAPK) cascade. However, little is known about the molecular link between ligand-receptor pairs and intracellular signaling. Here, we report that the SERK family RLKs function redundantly in regulating floral organ abscission downstream of IDA and upstream of the MAPK cascade. IDA induces heterodimerization of HAE/HSL2 and SERKs, which transphosphorylate each other. The SERK3 residues mediating its interaction with the immune receptor FLS2 and the brassinosteroid receptor BRI1 are also required for IDA-induced HAE/HSL2-SERK3 interaction, suggesting SERKs serve as co-receptors of HAE/HSL2 in perceiving IDA. Thus, our study reveals the signaling activation mechanism in floral organ abscission by IDA-induced HAE/HSL2-SERK complex formation accompanied by transphosphorylation.

Graphical abstract

Teaser

Meng et al. show that the Arabidopsis SERK family receptor-like kinases (RLKs) regulate floral organ abscission via the ligand-induced interaction and transphosphorylation with the HAE and HSL2 receptors and reveal the receptor activation mechanism in an important plant developmental process.


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