Skip to main content
APS Plant Health 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

POSTERS: Bacteriology II

P-032 - Xanthomonas translucens Host Shift Mediated by Loss of an Immune-Triggering Effector

Tuesday, August 5, 2025
9:30 AM - 10:15 AM HST
Location: Exhibit Hall 3
Abstract Text: Understanding how bacterial pathogens expand their host range is critical for predicting and mitigating emerging plant diseases. Bacterial pathogens colonize hosts by delivering virulence factors that alter plant cellular processes, but these same factors can also trigger plant immune responses that restrict infection. In this study, we demonstrate how the loss of a single effector gene contributed to the emergence of a broad-host-range subgroup in the re-emerging bacterial plant pathogen Xanthomonas translucens. Comparative genomic analysis of the barley-infecting X. translucens pv. translucens (Xtt) and the wheat-infecting X. translucens pv. undulosa (Xtu) identified xopAL1 as a key determinant of host range. Targeted deletion of xopAL1 in Xtt enabled infection of wheat, while its introduction into Xtu rendered the pathogen unable to infect wheat. RNA-seq analysis revealed that xopAL1 triggers a major transcriptional reprogramming in wheat, with strong upregulation of defense-related genes. Artificial induction of select xopAL1-induced genes was sufficient to restore the non-host phenotype in the absence of xopAL1, highlighting their contribution to the non-host response. These findings suggest that effector loss can influence host range by altering plant immune activation, providing insight into pathogen adaptation mechanisms.