Danger-Associated Peptide Regulates Root Growth by Promoting Protons Extrusion in an AHA2-Dependent Manner in Arabidopsis.

Nuo Shen,Aigen Fu,Yanping Jing,Guoqing Tu,Wenzhi Lan

doi:10.3390/ijms21217963

Abstract

Plant elicitor peptides (Peps) are damage/danger-associated molecular patterns (DAMPs) that are derived from precursor proteins PROPEPs and perceived by a pair of leucine-rich repeat receptor-like kinases (LRR-RLKs), PEPR1 and PEPR2, to enhance innate immunity and to inhibit root growth in Arabidopsis thaliana. In this study, we show that Arabidopsis Pep1 inhibits the root growth by interfering with pH signaling, as acidic condition increased, but neutral and alkaline conditions decreased the Pep1 effect on inhibiting the root growth. The perception of Pep1 to PEPRs activated the plasma membrane-localized H+-ATPases (PM H+-ATPases) —the pump proton in plant cell—to extrude the protons into apoplast, and induced an overly acidic environment in apoplastic space, which further promoted the cell swelling in root apex and inhibited root growth. Furthermore, we revealed that pump proton AUTOINHIBITED H+-ATPase 2 (AHA2) physically interacted with PEPR2 and served downstream of the Pep1-PEPRs signaling pathway to regulate Pep1-induced protons extrusion and root growth inhibition. In conclusion, this study demonstrates a previously unrecognized signaling crosstalk between Pep1 and pH signaling to regulate root growth.

Highlights

Under natural conditions, plants’ growth is threatened by kinds of pathogenic bacteria
To investigate whether Pep1 interacts with pH signaling to regulate the root growth, we examined the effects of 100 nM Pep1 in the plant growth medium with different pH (4.5 to 8.0) on the growth of wild-type (WT) seedlings
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Summary

Introduction

Plants’ growth is threatened by kinds of pathogenic bacteria. To protect against pathogens threat, plants have evolved specialized plasma membrane-localized pattern recognition receptors (PRRs) to recognize the pathogen-associated molecular patterns (PAMPs) from pathogens and induce pattern-triggered immunity defense processes [1]. In addition to PAMPs, plants release specialized molecules known as danger- or damage-associated molecular patterns (DAMPs), such as cell wall fragments or plant peptides, that could activate pattern-triggered immunity [4,5]. There are eight Peps (Pep1–Pep8) in Arabidopsis that are perceived by two closely related receptor kinases, PEPR1 and PEPR2 [6] Both PROPEPs and PEPRs are transcriptional-activated by wounding, pathogens infection, or the defense hormone, including salicylate acid (SA) and jasmonic acid (JA) [9,10,11,12]. PEPR2 primarily detects Pep and Pep ligands and functions in root to regulate the root immunity and growth [14,15,16]

Methods

Results

Conclusion