Thioesterase modulates antibacterial Type VI secretion system via alteration in oxidative stress responses in Burkholderia
- 1BRIC-National Institute of Plant Genome Research ,New Delhi, India
Abstract
Bacteria utilize specialized protein secretion systems, particularly the type VI secretion system (T6SS), to dominate interbacterial competitions and kill the prey bacteria in a contact-dependent manner. Here, we report that disruption of the thioesterase gene encoded in the gramibactin (a bacterial siderophore) biosynthetic gene cluster activates the T6SS in the Burkholderia gladioli strain NGJ1, even in the absence of prey. The thioesterase mutant ( Δthio ) exhibits enhanced antibacterial activity, and ectopic expression of the gene complements the phenotype. Notably, Δthio mutant as well as thioesterase -complement strains show enhanced sensitivity to oxidative stress. The qRT-PCR analysis showed that the Δthio mutant had upregulated expression of RpoN1, a sigma factor, which positively regulates T6SS functions. We demonstrate that ΔrpoN1 is hypersensitive to oxidative stress and defective in T6SS activation, whereas overexpression of RpoN1 enhances oxidative stress tolerance in NGJ1 and activates T6SS. We propose that, during interbacterial conflicts encountered during plant colonization, NGJ1 faces an oxidative-stress-enriched environment that modulates thioesterase expression, induces RpoN1 , and activates T6SS. Overall, our study exemplifies the broader physiological role of Thioesterase in maintaining intracellular ROS homeostasis in bacteria and stimulating antibacterial activity.
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BibTeX
@misc{yadav2026thioesterase,
title = {{Thioesterase modulates antibacterial Type VI secretion system via alteration in oxidative stress responses in Burkholderia}},
author = {R. Yadav and K. Kabyashree and R. Kumar and M. Roy and G. Jha},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.05.756662},
url = {https://www.biorxiv.org/content/10.64898/2026.10.05.756662v1},
note = {Public domain},
}
RIS
TY - UNPB
TI - Thioesterase modulates antibacterial Type VI secretion system via alteration in oxidative stress responses in Burkholderia
AU - R. Yadav
AU - K. Kabyashree
AU - R. Kumar
AU - M. Roy
AU - G. Jha
PY - 2026
DA - 2026/10/05
PB - bioRxiv
DO - 10.64898/2026.10.05.756662
UR - https://www.biorxiv.org/content/10.64898/2026.10.05.756662v1
AB - Bacteria utilize specialized protein secretion systems, particularly the type VI secretion system (T6SS), to dominate interbacterial competitions and kill the prey bacteria in a contact-dependent manner. Here, we report that disruption of the thioesterase gene encoded in the gramibactin (a bacterial siderophore) biosynthetic gene cluster activates the T6SS in the Burkholderia gladioli strain NGJ1, even in the absence of prey. The thioesterase mutant ( Δthio ) exhibits enhanced antibacterial activity, and ectopic expression of the gene complements the phenotype. Notably, Δthio mutant as well as thioesterase -complement strains show enhanced sensitivity to oxidative stress. The qRT-PCR analysis showed that the Δthio mutant had upregulated expression of RpoN1, a sigma factor, which positively regulates T6SS functions. We demonstrate that ΔrpoN1 is hypersensitive to oxidative stress and defective in T6SS activation, whereas overexpression of RpoN1 enhances oxidative stress tolerance in NGJ1 and activates T6SS. We propose that, during interbacterial conflicts encountered during plant colonization, NGJ1 faces an oxidative-stress-enriched environment that modulates thioesterase expression, induces RpoN1 , and activates T6SS. Overall, our study exemplifies the broader physiological role of Thioesterase in maintaining intracellular ROS homeostasis in bacteria and stimulating antibacterial activity.
ER -