Evidence map›Paper›PMID 41854099›Full record

ArticleMolecular ecology2026

Divergent Transcriptional Architectures Beyond Core CAM Genes in Facultative and Constitutive CAM Species in Tillandsia L.

Clara Groot-Crego, Sarah Saadain, Marylaure De La Harpe, Jaqueline Hess, Michael H J Barfuss, Walter Till, Gert Bachmann, Wolfram Weckwerth, Christian Lexer, Ovidiu Paun

Abstract read
In one paragraph

Article in Molecular ecology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors.

Clara Groot-CregoDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.ORCID https://orcid.org/0000-0002-4547-3608
Sarah SaadainDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.ORCID https://orcid.org/0000-0001-7517-9103
Marylaure De La HarpeDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Jaqueline HessDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Michael H J BarfussDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.ORCID https://orcid.org/0000-0001-7172-9454
Walter TillDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Gert BachmannDepartment of Functional and Evolutionary Ecology, Molecular Systems Biology (MOSYS), University of Vienna, Vienna, Austria.
Wolfram WeckwerthDepartment of Functional and Evolutionary Ecology, Molecular Systems Biology (MOSYS), University of Vienna, Vienna, Austria.ORCID https://orcid.org/0000-0002-9719-6358
Christian LexerDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
Ovidiu PaunDepartment of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.ORCID https://orcid.org/0000-0002-8295-4937

Funding

Agence Nationale de la Recherche ANR-23-CE02-0032Austrian Science Fund I6765Austrian Science Fund P35275Austrian Science Fund W1225
6 · The paper itself

Abstract

Crassulacean acid metabolism (CAM) is a water-efficient photosynthetic strategy involving a coordinated suite of complex traits including metabolic, anatomical and regulatory aspects that shift across the diel cycle. While CAM has evolved repeatedly in land plants, the evolutionary routes enabling this convergence remain elusive. Whereas the same core CAM (de)carboxylation genes are consistently involved, a key question is whether distinct CAM phenotypes also depend on a shared set of auxiliary genes, reflecting a quantitative continuum of expression, or whether they can instead emerge through divergent or redundant peripheral solutions. The bromeliad subgenus Tillandsia, with diverse photosynthetic strategies, offers an ideal system to explore this question. Using physiological and transcriptomic analyses of well-watered and water-limited accessions of two closely related species, we characterised facultative and constitutive CAM. By comparing orthologous gene expression and orthogroup recruitment, we found that while both species performed CAM upon water-withholding, transcriptional shifts in pathways related to stomatal movement, sugar/malate transport, aquaporins and starch metabolism showed minimal overlap. Core enzymes involved in the CAM (de)carboxylation cycle exhibited broadly shared expression patterns, yet the facultative CAM species uniquely upregulated PPC2 at night instead of the canonical CAM-related PEPC ortholog PPC1. Our study reveals that, while the expression of certain core CAM enzymes is conserved, the surrounding transcriptional architecture can differ substantially even between closely related species. This supports a model in which CAM evolves through a mosaic recruitment of functionally equivalent, yet nonorthologous genes-underscoring its flexible and modular genetic architecture. These insights advance our understanding of the mechanisms enabling the repeated evolution of CAM and its capacity to facilitate adaptive diversification.

Indexed as

BromeliaceaeCrassulacean Acid MetabolismEvolution, MolecularGene Expression ProfilingGene Expression Regulation, PlantGenes, PlantPhenotypePhotosynthesisTranscriptomeWaterWateradaptive radiationBromeliaceaeCrassulacean acid metabolismdrought tolerancegenetic redundancykey innovation trait

Identifiers

PMID41854099
PMCPMC13000999

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