Skip to main content

Research Repository

Advanced Search

Probing differences in gene essentiality between the human and animal adapted

Gibson, Amanda J; Passmore, Ian J; Faulkner, Valwynne; Xia, Dong; Nobeli, Irene; Stiens, Jennifer; Clarke, Taane G; Sobkowiak, Ben; Willcocks, Sam; Werling, Dirk; Villarreal-Ramos, Bernardo; Wren, Brendan W; Kendall, Sharon L


Amanda J Gibson

Ian J Passmore

Valwynne Faulkner

Dong Xia

Irene Nobeli

Jennifer Stiens

Taane G Clarke

Ben Sobkowiak

Sam Willcocks

Dirk Werling

Bernardo Villarreal-Ramos

Brendan W Wren

Sharon L Kendall


Members of the Mycobacterium tuberculosis complex (MTBC) show distinct host adaptations, preferences and phenotypes despite being >99% identical at the nucleic acid level. Previous studies have explored gene expression changes between the members, however few studies have probed differences in gene essentiality. To better understand the functional impacts of the nucleic acid differences between Mycobacterium bovis and Mycobacterium tuberculosis we used the Mycomar T7 phagemid delivery system to generate whole genome transposon libraries in laboratory strains of both species and compared the essentiality status of genes during growth under identical in vitro conditions. Libraries contained insertions in 54% of possible TA sites in M. bovis and 40% of those present in M. tuberculosis, achieving similar saturation levels to those previously reported for the MTBC. The distributions of essentiality across the functional categories were similar in both species. 527 genes were found to be essential in M. bovis whereas 477 genes were essential in M. tuberculosis and 370 essential genes were common in both species. CRISPRi was successfully utilised in both species to determine the impacts of silencing genes including wag31, a gene involved in peptidoglycan synthesis and Rv2182c/Mb2204c, a gene involved in glycerophospholipid metabolism. We observed species specific differences in the response to gene silencing, with the inhibition of expression of Mb2204c in M. bovis showing significantly less growth impact than silencing its ortholog (Rv2182c) in M. tuberculosis. Given that glycerophospholipid metabolism is a validated pathway for antimicrobials, our observations suggest that target vulnerability in the animal adapted lineages cannot be assumed to be the same as the human counterpart. This is of relevance for zoonotic tuberculosis as it implies that the development of antimicrobials targeting the human adapted lineage might not necessarily be effective against the animal adapted lineage. The generation of a transposon library and the first reported utilisation of CRISPRi in M. bovis will enable the use of these tools to further probe the genetic basis of survival under disease relevant conditions.


Gibson, A. J., Passmore, I. J., Faulkner, V., Xia, D., Nobeli, I., Stiens, J., …Kendall, S. L. (2021). Probing differences in gene essentiality between the human and animal adapted. Frontiers in Veterinary Science,

Journal Article Type Article
Acceptance Date Nov 29, 2021
Publication Date Dec 24, 2021
Deposit Date Aug 17, 2021
Publicly Available Date Jan 12, 2022
Journal Frontiers in Veterinary Science
Publisher Frontiers Media
Peer Reviewed Peer Reviewed
Public URL