Uncovering the transcriptome-wide RNA modifications in Acinetobacter baumannii.

Despite being a major human pathogen, limited studies have reported RNA modifications in Acinetobacter baumannii. These post-transcriptional modifications play crucial regulatory roles in bacteria and have also been shown to modulate bacterial virulence. Using nanopore sequencing, we characterized RNA modifications in a virulent A. baumannii strain (Ab-C98) under free-living (mid-exponential phase in vitro culture) and during an early stage of infection (3 h post-infection) in Galleria mellonella larvae. Analysis revealed that m⁵C methylations are essential for ribosome synthesis, while m⁶A and Ψ are involved in metabolic pathways and translation processes. Iron-chelating genes exbD (m⁵C and m⁶A) and feoB (m⁶A and Ψ) and RNA polymerase subunit rpoC (m⁶A and Ψ) were selectively modified during infection. This first transcriptome-wide study highlights the potential regulatory roles of m⁵C, m⁶A and Ψ modifications in A. baumannii during infection.