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Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-164 - From host signals to parasitism: a transcription factor duet regulates sequential effector deployment

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Microbial infection strategies (pathogens & non-pathogens)
Abstract Text:

Many pathogens secrete discrete and sequential waves of effectors to manipulate their host. However, the regulators and signals that shape this sophisticated trans-kingdom dialogue are poorly understood. Here, we show that a pair of transcription factors in the plant-parasitic cyst nematodes are stimulated by discrete plant signals termed effectostimulins: small, host-specific molecules that vary in natural populations. We use comparative RNAseq analysis to show that these effectostimulin-activated transcription factors work in concert to regulate the sequential deployment of effectors. The nuclear hormone receptor SUGR-1 activates early-stage effector expression required for plant invasion. Subsequently, its homologue DGR-1 represses these early-stage effectors and activates later-stage effectors, defining a critical switch in effector deployment associated with immune suppression. Together, these data allow us to build a conceptual model of effector production, highlighting crucial checkpoints and showing how pathogens adapt to spare resources when they must and promote parasitism only when it counts. Importantly, given that knockdown of sugr-1 reduces root penetration by 80%, blocking the regulators of effector deployment may open novel and generalisable control mechanisms to pathogens that secrete effectors.