Skip to content
DraconiticResearch
Search Sources API
190,851 studies31 sourcesUpdated 57 min ago
Peer-reviewedCC BYPLOS Biology

Type III effectors of symbiotic Rhizobia include diverse predicted transcriptional and post-transcriptional modulators

  • Albin Teulet1,2
  • Sebastian Schornack1
  1. 1Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom.
  2. 2PHIM Plant Health Institute, Université de Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France.
Read full textPDFDOICite

Abstract

Rhizobia are soil bacteria that establish nitrogen-fixing symbioses with legumes. While many rhizobia use a Type III Secretion System to deliver “Nodulation Outer Protein” (Nop) effectors, some uniquely use these proteins to initiate nodule organogenesis, bypassing classical signalling. The molecular functions of these effectors remain largely unknown due to extreme sequence divergence. Using AlphaFold2-mediated structural proteomics, we identified a modular architecture in rhizobial effectors composed of 22 distinct structural units. We reveal that many Nop effectors are cryptic transcriptional or post-transcriptional regulators, harbouring unrecognised nucleic acid–binding modules and RNA-dependent RNA polymerase domains. Crucially, these modules are conserved in specific plant pathogens, such as gall-inducing Pantoea, where our predicted structural units align with experimentally validated DNA-binding domains. Furthermore, we discovered the BPN (B3 and PUA-like nucleic acid binding) domain as a structural mimic of plant B3-domain transcription factors, pointing to a direct mechanism for hijacking legume development. Our findings strongly suggest that rhizobia employ a modular domain-fusion strategy to act as direct genetic modulators, uncovering a conserved mechanism used by both symbionts and pathogens to hijack host developmental programmes.

Symbiotic rhizobia form nitrogen-fixing partnerships with plant roots but how they reprogram plant development remains unclear. This study uses structural modelling to predict that many of their secreted proteins may act as genetic regulators, mimicking plant factors in a strategy shared with pathogens.

Related

  1. Minimal indel-inducing and window-adjustable base editing using inactive Cas12b effectors
    Wi-jae Lee, Yun Gyeong Kim, Yeounsun Oh +5
    Molecular therapy. Nucleic acidsPeer-reviewedCC BY-NC-NDFull textMolecular biology & gene regulationEurope PMC
  2. Bacterial effectors targeting the host ubiquitin system
    Paula Eschger, Thomas Hermanns, Kay Hofmann
    Biochemical Society TransactionsPeer-reviewedCC BY 4.0Full textEnzymology & metabolismMicrobiologyPMC
  3. Translational isoforms of mammalian heterochromatin protein 1 (HP1) tune its interactions with chromatin effectors
    E. M. Smith, E. Khalizeva, S. Haug +1
    bioRxivPreprintCC BY-NCFull textMolecular biology & gene regulationbioRxiv
  4. RhoA effectors ROCK and SLK/LOK oppositely regulate VE-cadherin mobility at endothelial junctions
    T. Nelson, Q. Lin, Z. Quddoos +4
    bioRxivPreprintCC BY-NC-NDFull textBiophysicsbioRxiv
  5. Exercise and immune system as modulators of intestinal microbiome: implications for the gut-muscle axis hypothesis
    Andrea Ticinesi, Fulvio Lauretani, Claudio Tana +3
    PubMedPeer-reviewedLicence not stated146 citedMolecular biology & gene regulationOpenAlex

Cite

BibTeXRIS
BibTeX
@article{teulet2026type,
  title = {{Type III effectors of symbiotic Rhizobia include diverse predicted transcriptional and post-transcriptional modulators}},
  author = {Albin Teulet and Sebastian Schornack},
  journal = {PLOS Biology},
  year = {2026},
  month = oct,
  doi = {10.1371/journal.pbio.3004038},
  url = {https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3004038},
  note = {CC BY},
}
RIS
TY  - JOUR
TI  - Type III effectors of symbiotic Rhizobia include diverse predicted transcriptional and post-transcriptional modulators
AU  - Albin Teulet
AU  - Sebastian Schornack
PY  - 2026
DA  - 2026/10/08
JO  - PLOS Biology
DO  - 10.1371/journal.pbio.3004038
UR  - https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3004038
AB  - Rhizobia are soil bacteria that establish nitrogen-fixing symbioses with legumes. While many rhizobia use a Type III Secretion System to deliver “Nodulation Outer Protein” (Nop) effectors, some uniquely use these proteins to initiate nodule organogenesis, bypassing classical signalling. The molecular functions of these effectors remain largely unknown due to extreme sequence divergence. Using AlphaFold2-mediated structural proteomics, we identified a modular architecture in rhizobial effectors composed of 22 distinct structural units. We reveal that many Nop effectors are cryptic transcriptional or post-transcriptional regulators, harbouring unrecognised nucleic acid–binding modules and RNA-dependent RNA polymerase domains. Crucially, these modules are conserved in specific plant pathogens, such as gall-inducing Pantoea, where our predicted structural units align with experimentally validated DNA-binding domains. Furthermore, we discovered the BPN (B3 and PUA-like nucleic acid binding) domain as a structural mimic of plant B3-domain transcription factors, pointing to a direct mechanism for hijacking legume development. Our findings strongly suggest that rhizobia employ a modular domain-fusion strategy to act as direct genetic modulators, uncovering a conserved mechanism used by both symbionts and pathogens to hijack host developmental programmes.  Symbiotic rhizobia form nitrogen-fixing partnerships with plant roots but how they reprogram plant development remains unclear. This study uses structural modelling to predict that many of their secreted proteins may act as genetic regulators, mimicking plant factors in a strategy shared with pathogens.
SN  - 1545-7885
SN  - 1544-9173
ER  -