A Trojan horse pathogen breaking through partner-choice barriers in the insect gut

K Kota Ishigami (Faculty of Agriculture, University of the Ryukyus) S Seonghan Jang (Biomanufacturing Process Research Center, National Institute of Advanced Industrial Science and Technology, Hokkaido Center) A Aoba Yoshioka (Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications) H Hiroyuki Morimura (Biomanufacturing Process Research Center, National Institute of Advanced Industrial Science and Technology, Hokkaido Center) A Aya Yokota (Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell) L Lionel Moulin (Plant Health Institute of Montpellier (PHIM), IRD, CIRAD, INRAE, Institut Agro, Univ Montpellier) A Antoine-Olivier Lirette (Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University) K Kazutaka Takeshita (Faculty of Bioresource Sciences, Akita Prefectural University) D Daisuke Nakane (Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications) P Peter Mergaert (Commissariat à l’énergie atomique et aux énergies alternatives, CNRS, Institute for Integrative Biology of the Cell, Université Paris-Saclay) Y Yoshitomo Kikuchi (Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University)

Abstract

Mutualistic symbioses are potentially vulnerable to exploitation, particularly in hosts that acquire symbionts from the environment, where harmful exploiters inhabit. The independent evolution and persistence of intricate partner-choice mechanisms in many symbioses testify the threat by specialized exploiters of mutualisms, although only few have been documented in nature. We report here a lethal “Trojan horse” pathogen, Burkholderia sp. SJ1, exploiting the stinkbug– Caballeronia gut symbiosis. This bacterium resembles symbionts by using wrapping motility to traverse the host’s sorting organ, inducing symbiotic organ morphogenesis and colonizing it. Unlike mutualists, however, it resists host digestion for nutrient acquisition, breaches the gut epithelium, and causes sepsis, rapidly killing the host. Colonization of the symbiotic organ is essential for its lethality. This case shows how pathogens can exploit mutualisms, highlighting the evolutionary pressures shaping partner-choice mechanisms and the fragility of even highly specialized mutualisms.

Article Details

Volume / Issue Vol. 123, Issue 18
Published May 05, 2026
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (11)

K

Kota Ishigami

Faculty of Agriculture, University of the Ryukyus

S

Seonghan Jang

Biomanufacturing Process Research Center, National Institute of Advanced Industrial Science and Technology, Hokkaido Center

A

Aoba Yoshioka

Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications

H

Hiroyuki Morimura

Biomanufacturing Process Research Center, National Institute of Advanced Industrial Science and Technology, Hokkaido Center

A

Aya Yokota

Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell

L

Lionel Moulin

Plant Health Institute of Montpellier (PHIM), IRD, CIRAD, INRAE, Institut Agro, Univ Montpellier

A

Antoine-Olivier Lirette

Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University

K

Kazutaka Takeshita

Faculty of Bioresource Sciences, Akita Prefectural University

D

Daisuke Nakane

Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications

P

Peter Mergaert

Commissariat à l’énergie atomique et aux énergies alternatives, CNRS, Institute for Integrative Biology of the Cell, Université Paris-Saclay

Y

Yoshitomo Kikuchi

Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University