Summary
Plants produce molecular signals called effectostimulins that activate SUGR-1, the first known positive regulator of plant-parasitic nematode effectors. SUGR-1 controls a transcriptional network driving early-stage effector gene expression, essential for successful host infection.
Highlights
- Discovery of effectostimulins, plant-derived signals activating nematode effector production.
- Identification of SUGR-1 as the master transcriptional regulator of 58 nematode effector genes.
- SUGR-1 directly binds conserved DNA motifs in effector promoters, orchestrating early infection stages.
- Effectostimulins stimulate sugr-1 expression specifically in host plant roots, not non-hosts.
- Silencing sugr-1 significantly reduces nematode infection success and effector expression.
- The effector regulation mechanism is conserved in economically important cyst nematodes like H. glycines.
- Targeting SUGR-1 and effectostimulins offers a promising strategy for durable nematode control and food security.
Key Insights
- Effectostimulins as Host Signals: Effectostimulins are root-derived molecular signals distinct from attraction cues that induce nematode effector gene expression just before host invasion, ensuring resource-efficient pathogenicity activation.
- SUGR-1 Master Regulator Role: SUGR-1 is a nuclear hormone receptor-type transcription factor that activates a broad set of effectors, including key enzymes for root penetration, highlighting its central role in nematode parasitism.
- Direct DNA Binding Mechanism: SUGR-1 binds a conserved promoter motif (CTGAACAA[A|T]) in multiple effector genes, with mutation in this motif disrupting DNA interaction, confirming specific transcriptional regulation.
- Host Specificity in Activation: Root extracts from host plants like Arabidopsis and mustard activate sugr-1, while non-host plants do not, suggesting co-evolution and specificity in nematode-host signaling.
- Impact of sugr-1 Silencing: RNAi-mediated knockdown of sugr-1 reduces effector gene expression and nematode infectivity by over 80%, demonstrating its essential role and potential as a control target.
- Conservation Across Nematodes: The SUGR-1 regulatory pathway is conserved in soybean cyst nematode H. glycines, the most damaging cyst nematode to US soy, emphasizing the broad agricultural relevance.
- Strategic Pest Management Implications: Disrupting effectostimulins or SUGR-1 function could block entire effector repertoires simultaneously, providing a robust, evolutionarily constrained strategy for sustainable nematode resistance and enhanced food security.
Mindmap
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Citation
Pellegrin, C., Damm, A., Sperling, A. L., Molloy, B., Shin, D. S., Long, J., … Eves-van den Akker, S. (2025, March 10). The SUbventral-Gland Regulator (SUGR-1) of nematode virulence. Proceedings of the National Academy of Sciences. Proceedings of the National Academy of Sciences. http://doi.org/10.1073/pnas.2415861122