Transcriptional Regulatory Systems Involved in the Infection Process of Dickeya dadantii

抄録

Dickeya dadantii is a destructive bacterial phytopathogen responsible for soft rot and blackleg diseases in numerous crops worldwide. Its pathogenicity depends largely on the massive secretion of cell wall-degrading enzymes via complex regulatory networks in response to environmental and host-derived signals. Previous studies have mainly examined regulatory systems and virulence factors separately at the individual level, resulting in a fragmented understanding of virulence regulation in D. dadantii. However, pathogen infection is a dynamic and stage-dependent process. Here, we propose a structured framework that organizes D. dadantii regulatory networks into four infection stages: prepenetration, penetration, infection, and colonization. In this review, the stage-based infection framework is applied to explain dynamic shifts in virulence regulation during host colonization. Furthermore, the major regulatory pathways that control virulence in D. dadantii are discussed, including quorum-sensing systems (N-acyl homoserine lactone [AHL] and virulence factor modulating [VFM]), transcriptional regulators (e.g., KdgR, PecS, and PecT), the second messenger c-di-GMP, and two-component regulatory systems. Understanding these pathways provides a foundation for the development of disease management strategies targeting virulence regulation, such as interfering with signal transduction pathways, disrupting virulence activation, suppressing virulence gene expression, and targeting quorum-sensing signaling.