The Phloem Intercalated With Xylem-Correlated 3 Receptor-Like Kinase Constitutively Interacts With Brassinosteroid Insensitive 1-Associated Receptor Kinase 1 and Is Involved in Vascular Development in Arabidopsis.

Ke Xu,Long Nguyen,Joris Jourquin,Maria Fransiska Njo,Ana Ibis Fernandez,Tom Beeckman

doi:10.3389/fpls.2021.706633

Abstract

Leucine-rich repeat receptor-like kinases (LRR-RLKs) play fundamental roles in cell-to-cell and plant-environment communication. LRR-RLKs can function as receptors perceiving endogenous or external ligands, or as coreceptors, which stabilize the complex, and enhance transduction of the intracellular signal. The LRR-RLK BAK1 is a coreceptor for different developmental and immunity pathways. In this article, we identified PXY-CORRELATED 3 (PXC3) as a BAK1-interacting LRR-RLK, which was previously reported to be transcribed in vascular tissues co-expressed with PHLOEM INTERCALATED WITH XYLEM (PXY), the receptor of the TDIF/CLE41 peptide. Characterization of pxc3 loss-of-function mutants revealed reduced hypocotyl stele width and vascular cells compared to wild type, indicating that PXC3 plays a role in the vascular development in Arabidopsis. Furthermore, our data suggest that PXC3 might function as a positive regulator of the CLE41/TDIF–TDR/PXY signaling pathway.

Highlights

Plants are sessile multicellular organisms and to perceive developmental cues and environmental stimuli, they rely on numerous sensory proteins on their cell surfaces
We identified PHLOEM INTERCALATED WITH XYLEM (PXY)-CORRELATED 3 (PXC3) as a BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) interactor and revealed that it functions in vascular development in a similar manner as TRACHEARY ELEMENT DIFFERENTIATION FACTOR (TDIF) RECEPTOR (TDR)/PXY
In a similar experiment where a SERK1-CFP fusion was used as a bait, five of these receptors coeluted with SERK1, and four of them (BIR2, BIR3, LYSM RLK1-INTERACTING KINASE 1 (LIK1), and PXC3) were significantly enriched compared to the control (Smaczniak et al, 2012)

Summary

Introduction

Plants are sessile multicellular organisms and to perceive developmental cues and environmental stimuli, they rely on numerous sensory proteins on their cell surfaces. Receptor-like kinases (RLKs), one of the most important sensory protein groups in plants, play fundamental roles in cell-tocell and plant–environment communication (van der Burgh and Joosten, 2019; Xi et al, 2019; Ou et al, 2021). The Arabidopsis genome encodes more than 200 LRR-RLKs, which can be further grouped into 13 subfamilies (Shiu and Bleecker, 2001, 2003) Many of these LRR-RLKs function as receptors for phytohormones, endogenous peptides, PXC3 Regulates Vascular Development and pathogen-derived molecules, regulating plant growth and defense responses (De Smet et al, 2009; Couto and Zipfel, 2016; He et al, 2018). LRR-RLKs sensing ligand signals in plants include BRASSINOSTEROID INSENSITIVE 1 (BRI1) for the phytohormone brassinosteroid (Li and Chory, 1997), PHYTOSULFOKINE RECEPTOR (PSKR) for endogenous PHYTOSULFOKINE peptides (Matsubayashi et al, 2002), FLAGELLIN SENSING 2 (FLS2) for the pathogen-derived flagellin (Gomez-Gomez and Boller, 2000; Chinchilla et al, 2006), and many more

Methods

Results

Conclusion