Assessing Zymoseptoria tritici Candidate Effectors in the Non-Host Nicotiana benthamiana Reveals Immune Recognition and Potential Host-Independent Activities.
- 1Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA.
- 2Crop Production and Pest Control Research Unit, USDA-Agricultural Research Service, West Lafayette, Indiana, USA.
- 3Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA.
Abstract
Zymoseptoria tritici is a significant wheat pathogen responsible for Septoria tritici blotch (STB) disease. Despite its economic impact, understanding of the molecular interactions between Z. tritici and its host remains limited, particularly the functions of many uncharacterized candidate effectors. Here, we assessed seven Z. tritici candidate effectors with elevated expression during the early biotrophic phase and transition to necrotrophy by transiently expressing them in the heterologous, non-host system Nicotiana benthamiana, with and without their predicted signal peptides. AlphaFold structural predictions revealed that two candidates share similarity with proteins of known function: a sterol-binding protein from Saccharomyces cerevisiae and a necrosis-inducing effector from Valsa mali. Effector-associated phenotypes did not always correlate with expression timing, and signal peptide presence significantly influenced observed activities. Because N. benthamiana is not a natural host of Z. tritici, observed responses may reflect conserved, host-independent activities of effectors or immune recognition by N. benthamiana, rather than their native functions in wheat. Consistent with this distinction, two candidate effectors, Mycgr3107904 and Mycgr394290, induced cell death in N. benthamiana while also modulating reactive oxygen species (ROS) burst, likely indicative of immune recognition. Some candidates attenuated ROS production, suggesting potential targeting of conserved cellular processes, whereas none suppressed PBR1-mediated cell death. Overall, our results indicate that candidate effector activities cannot be inferred from expression profiles alone, and that responses in the non-host N. benthamiana system reflect a combination of immune recognition and potential conserved activities, and primarily serve to prioritize candidates for validation in the native wheat-Z. tritici interaction.
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BibTeX
@article{gomezgutierrrez2026assessing,
title = {{Assessing Zymoseptoria tritici Candidate Effectors in the Non-Host Nicotiana benthamiana Reveals Immune Recognition and Potential Host-Independent Activities.}},
author = {Sandra V Gomez-Gutierrrez and Catalina Rodriguez-Diaz and Namrata Jaiswal and Michael Gribskov and Matthew Helm and Stephen B Goodwin},
journal = {Molecular plant pathology},
year = {2026},
month = oct,
doi = {10.1111/mpp.70344},
url = {https://europepmc.org/article/MED/42960485},
note = {CC BY},
}
RIS
TY - JOUR
TI - Assessing Zymoseptoria tritici Candidate Effectors in the Non-Host Nicotiana benthamiana Reveals Immune Recognition and Potential Host-Independent Activities.
AU - Sandra V Gomez-Gutierrrez
AU - Catalina Rodriguez-Diaz
AU - Namrata Jaiswal
AU - Michael Gribskov
AU - Matthew Helm
AU - Stephen B Goodwin
PY - 2026
DA - 2026/10/30
JO - Molecular plant pathology
DO - 10.1111/mpp.70344
UR - https://europepmc.org/article/MED/42960485
AB - Zymoseptoria tritici is a significant wheat pathogen responsible for Septoria tritici blotch (STB) disease. Despite its economic impact, understanding of the molecular interactions between Z. tritici and its host remains limited, particularly the functions of many uncharacterized candidate effectors. Here, we assessed seven Z. tritici candidate effectors with elevated expression during the early biotrophic phase and transition to necrotrophy by transiently expressing them in the heterologous, non-host system Nicotiana benthamiana, with and without their predicted signal peptides. AlphaFold structural predictions revealed that two candidates share similarity with proteins of known function: a sterol-binding protein from Saccharomyces cerevisiae and a necrosis-inducing effector from Valsa mali. Effector-associated phenotypes did not always correlate with expression timing, and signal peptide presence significantly influenced observed activities. Because N. benthamiana is not a natural host of Z. tritici, observed responses may reflect conserved, host-independent activities of effectors or immune recognition by N. benthamiana, rather than their native functions in wheat. Consistent with this distinction, two candidate effectors, Mycgr3107904 and Mycgr394290, induced cell death in N. benthamiana while also modulating reactive oxygen species (ROS) burst, likely indicative of immune recognition. Some candidates attenuated ROS production, suggesting potential targeting of conserved cellular processes, whereas none suppressed PBR1-mediated cell death. Overall, our results indicate that candidate effector activities cannot be inferred from expression profiles alone, and that responses in the non-host N. benthamiana system reflect a combination of immune recognition and potential conserved activities, and primarily serve to prioritize candidates for validation in the native wheat-Z. tritici interaction.
SN - 1364-3703
SN - 1464-6722
ER -