{
  "abstract": "Background\n\nPipecolic acid (Pip) functions as a precursor of key signalling metabolites involved in systemic acquired resistance; however, its broader role in modulating plant metabolism under biotic stress remains poorly understood. Here, we investigated how Pip influences metabolic and physiological responses to bacterial challenge in Mesembryanthemum crystallinum (ice plant), a semihalophytic species capable of shifting from C₃ photosynthesis to CAM through regulation of photosynthetic enzymes and stomatal opening rhythms under stress conditions.Results\n\nProlonged exogenous pipecolic acid (Pip) supplementation induced several CAM-associated traits in C₃ plants, including nocturnal malate accumulation, diurnal fluctuations in cell-sap acidity, and increased phosphoenolpyruvate carboxylase (PEPC) levels, suggesting a partial shift toward CAM-like metabolism. In both C₃ and CAM plants, Pip treatment increased RuBisCO activity while reducing the abundance of the large RuBisCO subunit (LSU), indicating differential regulation of photosynthetic carbon assimilation. Gas-exchange measurements showed that Pip-treated plants maintained higher net photosynthetic rates (PN) and improved water-use efficiency (WUE) under bacterial stress. The effects of Pip on stomatal morphology, photosynthetic pigment content, and photosynthesis-related proteins differed between C₃ and CAM species, highlighting photosynthetic type-dependent responses. Salicylic acid (SA) accumulation following Pip treatment was detected only in C₃ plants, whereas endogenous Pip levels increased in both photosynthetic types after bacterial challenge, with a more pronounced response in CAM plants.Conclusions\n\nOur findings identify pipecolic acid as metabolic regulator that integrates defence signalling with photosynthetic plasticity, thereby coordinating plant responses to environmental stress. This highlights Pip as a promising target for strategies aimed at enhancing stress resilience while maintaining efficient carbon assimilation and photosynthetic performance.",
  "abstract_shown": true,
  "affiliations": [
    "The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, Kraków, 30-239, Poland.",
    "Department of Biology, Institute for Molecular Ecophysiology of Plants, Heinrich Heine University, Universitätsstraße 1, Düsseldorf, D-40225, Germany.",
    "Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, Universitätsstraße 1, Düsseldorf, D-40225, Germany.",
    "Department of Plant Breeding, Physiology and Seed Science, Faculty of Agriculture and Economics, University of Agriculture, Podłużna 3, Kraków, 30-239, Poland.",
    "Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University, Gronostajowa 9, Kraków, 30-387, Poland.",
    "The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, Kraków, 30-239, Poland. m.libik@ifr-pan.edu.pl."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Emilia Gula",
      "orcid": "0000-0002-9964-3094"
    },
    {
      "affs": [
        0
      ],
      "name": "Agnieszka Ostrowska",
      "orcid": "0000-0002-9611-6336"
    },
    {
      "affs": [
        1
      ],
      "name": "Elke Reinartz"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Jürgen Zeier",
      "orcid": "0000-0002-8703-5403"
    },
    {
      "affs": [
        3
      ],
      "name": "Ewa Pociecha",
      "orcid": "0000-0003-1093-8150"
    },
    {
      "affs": [
        4
      ],
      "name": "Monika Tuleja",
      "orcid": "0000-0002-4479-176X"
    },
    {
      "affs": [
        4
      ],
      "name": "Bartosz J Płachno",
      "orcid": "0000-0001-5579-5101"
    },
    {
      "affs": [
        0
      ],
      "name": "Ewa Niewiadomska",
      "orcid": "0000-0002-6692-9758"
    },
    {
      "affs": [
        5
      ],
      "name": "Marta Libik-Konieczny",
      "orcid": "0000-0003-0378-2960"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bcf9dwphgx6ph.bib",
  "cited_by": 0,
  "doi": "10.1186/s12870-026-09590-8",
  "fulltext_url": "https://europepmc.org/articles/PMC13679241",
  "id": "bcf9dwphgx6ph",
  "issns": [
    "1471-2229"
  ],
  "landing_url": "https://europepmc.org/article/MED/42894130",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "lcc",
      "QK1-989"
    ],
    [
      "openalex",
      "1110|Plant-Microbe Interactions and Immunity"
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  "openalex": "W7170146330",
  "pdf_url": "https://europepmc.org/articles/PMC13679241?pdf=render",
  "pmcid": "PMC13679241",
  "pmid": "42894130",
  "published": "2026-07-01",
  "publisher": "BMC",
  "ris": "https://research.draconitic.com/paper/bcf9dwphgx6ph.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:42Z",
      "native_id": "MED:42894130",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42894130"
    },
    {
      "first_seen": "2026-10-30T13:45:42Z",
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      "url": "https://doi.org/10.1186/s12870-026-09590-8"
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  "subjects": [
    {
      "field": "biology",
      "origin": "openalex:1110|Plant-Microbe Interactions and Immunity",
      "subfield": "plant-biology"
    }
  ],
  "title": "Pipecolic acid modulates physiological parameters and biotic stress resilience in Mesembryanthemum crystallinum in a photosynthetic mode-dependent manner.",
  "title_text": "Pipecolic acid modulates physiological parameters and biotic stress resilience in Mesembryanthemum crystallinum in a photosynthetic mode-dependent manner.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T13:45:42Z",
  "url": "https://research.draconitic.com/paper/bcf9dwphgx6ph",
  "venue": "BMC plant biology",
  "versions": []
}