PAMP-INDUCED SECRETED PEPTIDE 3 (PIP3) modulates immunity in Arabidopsis thaliana

Abstract

Small post-translationally modified peptides are important signalling components of plant defence responses against phytopathogens, acting both as positive and negative modulators. PAMP-INDUCED SECRETED PEPTIDE (PIP) 1 and 2 has been shown to amplify plant immunity. Here we investigate the role of the related peptide PIP3 in the regulation of immune response in Arabidopsis. Treatment with synthetic PIP peptides led to similar transcriptome reprogramming, indicating an effect on innate immunity-related processes and phytohormones, including jasmonic acid (JA) biosynthesis and signalling. PIP3 overexpressing (OX) plants showed enhanced growth inhibition in response to flg22 exposure. In addition, flg22-induced production of reactive oxygen species and callose deposition were significantly reduced in PIP3-OX plants. Interestingly, PIP3-OX plants showed increased susceptibility both toward Botrytis cinerea and the biotrophic pathogen Pseudomonas syringae. Expression of both JA and salicylic acid biosynthesis and signalling genes was more induced during B. cinerea infection in PIP3-OX plants compared with wild-type plants. Promoter and ChIP-seq analyses indicated that the transcription factors WRKY18, WRKY33 and WRKY40 cooperatively act as repressors for PIP3. The results point to a fine-tuning role for PIP3 in modulation of immunity through the regulation of SA and JA biosynthesis and signalling pathways in Arabidopsis.

Full-Length Transcriptome-Wide Characteristic and Functional Identification of WRKY Family in Malus sieversii during the Valsa Canker Disease Response

“…The co-regulation of AtWRKY33 and AtMYB46 mediates the coordination of SA and JA/ET pathways to orchestrate the defense against the phytopathogen [58]. The AtWRKY18, AtWRKY40 and AtWRKY33 act as repressors for PAMP-induced secreted peptide 3 (PIP3) to turn on the immunity via regulating SA and JA biosynthesis and signaling [59]. EF-Tu receptor (EFR) activates the SA and JA synthesis to defense against the infection, through the direct phosphorylation of a receptorlike cytoplasmic kinase (BIK1) and WRKY33, WRKY50 and WRKY57 [60].…”

PIP2, An Auxin Induced Plant Peptide Hormone Regulates Root and Hypocotyl Elongation in Arabidopsis

“…It is possible that PIP2 and PIP3 may have different functions and/or functional mechanisms in regulating plant growth and development. As a matter of fact, it has been shown that PIP2 and PIP3 regulate plant biotic response in different ways, PIP2 regulates antipathogen activity by regulating the expression of some PTI-related genes, WRKY genes, flg22-induced receptor-like kinase 1 (FRK1) and the SAR marker gene PR-1 (Chen et al, 2019b), whereas PIP3 regulates immunity by regulating the biosynthesis and signaling of SA and JA in Arabidopsis (Najafi et al, 2020). On the other hand, both PIP2 and PIP3 contain two conserved SGPS motifs (Vie et al, 2015), and may able to produce two mature peptides, which may have different functions.…”

“…Both PIP and PIPL propeptides have an N-terminal signal peptide and a C-terminal SGPS motif, which is part of the biologically active peptides, with an exception of PIP2 and PIP3 prepropeptides, which have two SGPS motifs (Hou et al, 2014;Vie et al, 2015). The PIP peptides including PIP1, PIP2 and PIP3 have been shown to modulate immunity (Hou et al, 2014;Najafi et al, 2020), and the expression of several PIPs and PIPLs family genes is induced by biotic and/or abiotic stresses (Hou et al, 2014;Vie et al, 2015). On the other hand, it has been reported that the PIPL3/TARGET OF LBD SIXTEEN 2(TOLS2) is able to regulate lateral root formation (Toyokura, et al, 2019).…”

Mining the Conserved Transcriptional Response to Phytophthora Infection for Factors Beyond the Known PR Genes

“…There were no major differences between the different time points in the Arabidopsis model (Attard et al, 2014), between P. palmivora and P. megakarya infections in the Theobroma model (Ali et al, 2017), or between resistant and susceptible Soybean lineages (Lin et al, 2014) (Figure 2a). The two Arabidopsis members of this cluster have been described previously as the source of the PAMP-induced peptides PIP2 and PIP3; the corresponding gene names are PREPIP2 and PREPIP3 (Vie et al, 2015;Najafi et al, 2020;Hussain et al, 2021). A third published PIP-encoding gene, AT4G28460/PREPIP1 (Hou et al, 2019;Shen et al, 2020), is more divergent and therefore not a member of the upregulated PREPIP2/3 sequence cluster.…”