The insect- and plant-associated lifestyles of Pseudomonas protegens CHA0 are preserved following serial passage through insect larvae
4 affiliations
- 1Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland
- 2Plant-Microbe Interactions, Department of Biology, Science for Life, Utrecht University, Utrecht, The Netherlands
- 3AI Technologies for Life, Department of Information and Computing Sciences, Science for Life, Utrecht University, Utrecht, The Netherlands
- 4Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
Abstract
The plant-beneficial bacterium Pseudomonas protegens CHA0 (CHA0) is widely studied for the biological control of soil-borne plant diseases. Beyond its root-colonising capabilities, CHA0 can also infect and kill insect larvae and thus exhibits a multi-host lifestyle shared with other plant- and insect-colonising bacteria. To better understand the robustness of this multi-host lifestyle, we subjected CHA0 to ten consecutive passages through larvae of the pest insect Plutella xylostella via repeated cycles of insect colonisation and killing forcing it into an insect-only lifestyle. Overall, serial passaging did not result in consistent changes in insect killing speed, larval or root colonisation, plant protection efficiency, microbial antagonism or in vitro growth. This suggests that its multi-host lifestyle was conserved following serial passage. Nonetheless, a few independently passaged lines showed an increase in larval killing speed, which in one case might be linked to choline uptake. To disentangle changes specific to the insect host from those arising due to the experimental system itself, we conducted parallel serial passages through the same system while omitting the insect host. In some of these lines, exposure to the background of the system led to changes in microbial antagonism and in in vitro growth, which likely are associated with mutations in regions encoding for regulatory systems. Our findings indicate that P. protegens CHA0 remains phenotypically stable in complex environments such as an insect host, suggesting that the multi-host lifestyle might also be conserved when applied in the field and supporting CHA0’s potential for reliable biocontrol performance against both plant diseases and insect pests. Author summary: Controlling insect pests with living organisms, known as biological control, offers an environmentally friendly alternative to chemical pesticides. The plant-beneficial bacterium Pseudomonas protegens CHA0 is a promising biocontrol candidate that not only colonizes plant roots but also infects and kills certain insect larvae. This ability to colonize different hosts appears to be a conserved trait also observed in other bacteria. To better understand the robustness of this multi-host lifestyle, we repeatedly exposed CHA0 to larvae of the insect pest Plutella xylostella and assessed the resulting physiological and genetic changes. Surprisingly, after ten cycles, CHA0 largely retained its insect-killing and plant-protective traits. Although a few populations showed minor changes, including slightly faster insect killing and traits associated with aspects of the experimental system, these changes were limited in scope. Overall, our findings suggest that P. protegens CHA0 does not change rapidly in complex environments such as an insect host, supporting its potential for reliable biocontrol performance in the field.
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BibTeX
@article{zwyssig2026insect,
title = {{The insect- and plant-associated lifestyles of Pseudomonas protegens CHA0 are preserved following serial passage through insect larvae}},
author = {Maria Zwyssig and Jana Schneider and Gijs Selten and Christoph Keel and Monika Maurhofer and Ronnie de Jonge},
journal = {PLOS Pathogens},
year = {2026},
month = sep,
doi = {10.1371/journal.ppat.1014101},
url = {https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014101},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The insect- and plant-associated lifestyles of Pseudomonas protegens CHA0 are preserved following serial passage through insect larvae
AU - Maria Zwyssig
AU - Jana Schneider
AU - Gijs Selten
AU - Christoph Keel
AU - Monika Maurhofer
AU - Ronnie de Jonge
PY - 2026
DA - 2026/09/21
JO - PLOS Pathogens
DO - 10.1371/journal.ppat.1014101
UR - https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1014101
AB - The plant-beneficial bacterium Pseudomonas protegens CHA0 (CHA0) is widely studied for the biological control of soil-borne plant diseases. Beyond its root-colonising capabilities, CHA0 can also infect and kill insect larvae and thus exhibits a multi-host lifestyle shared with other plant- and insect-colonising bacteria. To better understand the robustness of this multi-host lifestyle, we subjected CHA0 to ten consecutive passages through larvae of the pest insect Plutella xylostella via repeated cycles of insect colonisation and killing forcing it into an insect-only lifestyle. Overall, serial passaging did not result in consistent changes in insect killing speed, larval or root colonisation, plant protection efficiency, microbial antagonism or in vitro growth. This suggests that its multi-host lifestyle was conserved following serial passage. Nonetheless, a few independently passaged lines showed an increase in larval killing speed, which in one case might be linked to choline uptake. To disentangle changes specific to the insect host from those arising due to the experimental system itself, we conducted parallel serial passages through the same system while omitting the insect host. In some of these lines, exposure to the background of the system led to changes in microbial antagonism and in in vitro growth, which likely are associated with mutations in regions encoding for regulatory systems. Our findings indicate that P. protegens CHA0 remains phenotypically stable in complex environments such as an insect host, suggesting that the multi-host lifestyle might also be conserved when applied in the field and supporting CHA0’s potential for reliable biocontrol performance against both plant diseases and insect pests. Author summary: Controlling insect pests with living organisms, known as biological control, offers an environmentally friendly alternative to chemical pesticides. The plant-beneficial bacterium Pseudomonas protegens CHA0 is a promising biocontrol candidate that not only colonizes plant roots but also infects and kills certain insect larvae. This ability to colonize different hosts appears to be a conserved trait also observed in other bacteria. To better understand the robustness of this multi-host lifestyle, we repeatedly exposed CHA0 to larvae of the insect pest Plutella xylostella and assessed the resulting physiological and genetic changes. Surprisingly, after ten cycles, CHA0 largely retained its insect-killing and plant-protective traits. Although a few populations showed minor changes, including slightly faster insect killing and traits associated with aspects of the experimental system, these changes were limited in scope. Overall, our findings suggest that P. protegens CHA0 does not change rapidly in complex environments such as an insect host, supporting its potential for reliable biocontrol performance in the field.
SN - 1553-7374
ER -