CPK1 activates CNGCs through phosphorylation for Ca2+ signaling to promote root hair growth in Arabidopsis

Abstract Cyclic nucleotide-gated channel 5 (CNGC5), CNGC6, and CNGC9 (CNGC5/6/9 for simplicity) control Arabidopsis root hair (RH) growth by mediating the influx of external Ca2+ to establish and maintain a sharp cytosolic Ca2+ gradient at RH tips. However, the underlying mechanisms for the regulati...

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Bibliographic Details
Main Authors: Meijun Zhu, Bo-Ya Du, Yan-Qiu Tan, Yang Yang, Yang Zhang, Yong-Fei Wang
Format: Article
Language:English
Published: Nature Portfolio 2025-01-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-56008-4
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Summary:Abstract Cyclic nucleotide-gated channel 5 (CNGC5), CNGC6, and CNGC9 (CNGC5/6/9 for simplicity) control Arabidopsis root hair (RH) growth by mediating the influx of external Ca2+ to establish and maintain a sharp cytosolic Ca2+ gradient at RH tips. However, the underlying mechanisms for the regulation of CNGCs remain unknown. We report here that calcium dependent protein kinase 1 (CPK1) directly activates CNGC5/6/9 to promote Arabidopsis RH growth. The loss-of-function mutants cpk1-1, cpk1-2, cngc5-1 cngc6-2 cngc9-1 (shrh1/short root hair 1), and cpk1 shrh1 show similar RH phenotypes, including shorter RHs, more RH branching, and dramatically attenuated cytosolic Ca2+ gradients at RH tips. The main CPK1-target sites are identified as Ser20, Ser27, and Ser26 for CNGC5/6/9, respectively, and the corresponding alanine substitution mutants fail to rescue RH growth in shrh1 and cpk1-1, while phospho-mimic versions restore the cytosolic Ca2+ gradient at RH apex and rescue the RH phenotypes in the same Arabidopsis mutants. Thus we discover the CPK1-CNGC modules essential for the Ca2+ signaling regulation and RH growth in Arabidopsis.
ISSN:2041-1723