Emergence and host range expansion of an epidemic lineage of Ralstonia solanacearum

Thursday, July 17, 2025

11:30 - 11:40

Location: Room M+N

Presenting Author(s)

DE

Daria Evseeva

Max Planck Institute for Biology
Tübingen, Baden-Wurttemberg, Germany

Author(s)

YP

Yann Pecrix

CIRAD UMR-PVBMT
Réunion, French Southern Territories, French Southern and Antarctic Lands
MK

Marek Kucka

Friedrich Miescher Laboratory of the Max Planck Society
Tübingen, Baden-Wurttemberg, Germany
CW

Catrin Weiler

Max Planck Institute for Biology
Tübingen, Baden-Wurttemberg, Germany
CF

Carolin Franzl

Max Planck Institute for Biology
Tübingen, Baden-Wurttemberg, Germany
MV

Markéta Vlková

Max Planck Institute for Biology
Tübingen, Baden-Wurttemberg, Germany
EC

Elena Colombi

Macquarie University
Sydney, New South Wales, Australia
YC

Yingguang Frank Chan

Friedrich Miescher Laboratory of the Max Planck Society
Tübingen, Baden-Wurttemberg, Germany
SP

Stéphane Poussier

CIRAD UMR-PVBMT
Réunion, French Southern Territories, French Southern and Antarctic Lands
EW

Emmanuel Wicker

CIRAD UMR-PHIM
Montpellier, Limousin, France
HM

Honour McCann

Max Planck Institute for Biology
Tübingen, Baden-Wurttemberg, Germany

Abstract Text: Members of the Ralstonia solanacearum species complex are soil-borne pathogens of important crop plants. Strain-level host specialization is considered typical, yet outbreak monitoring in Martinique revealed the emergence of a new lineage with dramatically expanded host range. We show the outbreak was caused by the parallel expansion of lineages from two different Ralstonia species. One lineage of Asian origin retains a signature of host specialization, while the emergent broad host range lineage originated in the Americas. The presence of similar integrative and conjugative elements in both lineages suggests they are exchanging genetic material. The emergent lineage acquired genes encoding novel catalytic and metabolic functions, but shows little variation among virulence genes considered host specificity determinants. The host range expansion event was not caused by the evolution of a virulence strategy targeting host immunity, but is more likely due to the acquisition of novel substrate utilization pathways enhancing pathogen fitness in soil or plant tissues.