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Summary Root hair tip‐growth involves coordinated Ca2+and ROS signaling to promote growth while maintaining tip integrity. MILDEW RESISTANCE LOCUS‐O (MLO) proteins act downstream of FERONIA (FER) receptor‐like kinases in pollen tubes and synergids to regulate calcium dynamics. This study uses a constitutively active MLO (faNTA) to identify a new role for the FER/MLO signaling module in regulating [Ca2+]cytoscillations in growing root hairs.faNTA was used as a tool to manipulate Ca2+influx infermutants. Light sheet fluorescence imaging was used to image the reporter R‐GECO1 to observe [Ca2+]cytdynamics during root hair elongation in various genotypes.We show that faNTA is sufficient to restore normal root hair development, [Ca2+]cytoscillations, and ROS levels tofer‐4. MLO15 was identified as a regulator of root hair tip growth based on disrupted root hair growth and [Ca2+]cytsignatures inmlo15‐4. We also link the FER/MLO module to ROS accumulation by showing that faNTA is sufficient to restore ROS levels infer‐4root hairs, but is unable to complement the burst root hairs ofrbohc.We propose that MLOs act downstream of FER to mediate Ca2+influx and promote ROS production to regulate root hair tip growth.
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This content will become publicly available on November 14, 2026
Plant elicitor peptide 2 regulates root hair growth in an auxin-dependent pathway
Abstract Background and AimsPlant elicitor peptides (Peps), which originate from their precursor proteins known as PROPEPs, play essential roles as signaling molecules that modulate both plant defense responses and developmental processes. MethodsIn this study, we investigated the role of PROPEP2 and its derived peptide Pep2, in regulating root hair development in Arabidopsis thaliana. Root hairs at different growth stages along the primary root and in distinct zones of the root tip were analyzed. We further examined the relationship between Pep2 and auxin signaling in regulating root hair growth. Key resultsOur findings indicate that loss of PROPEP2 function results in markedly decreased root hair number and elongation during the primary root development phase, whereas root hair formation during the embryonic root stage remains unaffected. Notably, exogenous Pep2 application rescued these defects and even induced root hair formation in non-hair-forming regions. We further demonstrated that Pep2 enhances root hair growth by stimulating localized auxin production in the root tip region. The mutants defective in auxin production (yuc1 yuc4 and wei8 tar1 tar2) failed to respond to Pep2. Furthermore, we identified the receptor-like kinases FERONIA (FER) and [Ca2+]cyt-associated protein kinase 1 (CAP1) as critical components of the Pep2 signaling pathway, with mutations in these genes impairing root hair growth and rendering plants unresponsive to Pep2. ConclusionsThese results uncover a previously uncharacterized interaction between Pep2 and auxin signaling components in the regulation of root hair development, offering additional insights into the molecular control of root morphology.
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- Award ID(s):
- 2207677
- PAR ID:
- 10701358
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Annals of Botany
- Volume:
- 137
- Issue:
- 4
- ISSN:
- 1095-8290
- Page Range / eLocation ID:
- 1013 to 1025
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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