Altered proteome of a Burkholderia pseudomallei mutant defective in short-chain dehydrogenase affects cell adhesion, biofilm formation and heat stress tolerance

Onrapak Reamtong; Nitaya Indrawattana; Amporn Rungruengkitkun; Tipparat Thiangtrongjit; Taksaon Duangurai; Manas Chongsa-Nguan; Pornpan Pumirat

doi:10.7717/peerj.8659

Altered proteome of a Burkholderia pseudomallei mutant defective in short-chain dehydrogenase affects cell adhesion, biofilm formation and heat stress tolerance

PeerJ. 2020 Mar 19:8:e8659. doi: 10.7717/peerj.8659. eCollection 2020.

Authors

Onrapak Reamtong¹, Nitaya Indrawattana², Amporn Rungruengkitkun², Tipparat Thiangtrongjit¹, Taksaon Duangurai^{2

3}, Manas Chongsa-Nguan², Pornpan Pumirat²

Affiliations

¹ Department of Molecular Tropical Medicine and Genetics/Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
² Department of Microbiology and Immunology/Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
³ Department of Companion Animal Clinical Sciences/Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand.

Abstract

Burkholderia pseudomallei is a Gram-negative bacillus that causes melioidosis and is recognized as an important public health problem in southeast Asia and northeast Australia. The treatment of B. pseudomallei infection is hampered by resistance to a wide range of antimicrobial agents and no vaccine is currently available. At present, the underlying mechanisms of B. pseudomallei pathogenesis are poorly understood. In our previous study, we reported that a B. pseudomallei short-chain dehydrogenase (SDO; BPSS2242) mutant constructed by deletion mutagenesis showed reduced B. pseudomallei invasion and initial intracellular survival. This indicated that SDO is associated with the pathogenesis of melioidosis. In the present study, the role of B. pseudomallei SDO was further investigated using the SDO deletion mutant by a proteomic approach. The protein profiles of the SDO mutant and wild-type K96243 were investigated through gel-based proteomic analysis. Quantitative intensity analysis of three individual cultures of the B. pseudomallei SDO mutant revealed significant down-regulation of five protein spots compared with the wild-type. Q-TOF MS/MS identified the protein spots as a glutamate/aspartate ABC transporter, prolyl-tRNA synthetase, Hsp70 family protein, quinone oxidoreductase and a putative carboxypeptidase. Functional assays were performed to investigate the role of these differentially expressed proteins in adhesion to host cells, biofilm induction and survival under heat stress conditions. The SDO deletion mutant showed a decreased ability to adhere to host cells. Moreover, biofilm formation and the survival rate of bacteria under heat stress conditions were also reduced in the mutant strain. Our findings provide insight into the role of SDO in the survival and pathogenesis of B. pseudomallei at the molecular level, which may be applied to the prevention and control of B. pseudomallei infection.

Keywords: Adhesion; Biofilm formation; Burkholderia pseudomallei; Heat stress; Proteome; Short-chain dehydrogenase.

Grants and funding

This work was supported by research grants by Mahidol University, fiscal years 2016 and 2018. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.