Novel physiological traits modulated by light in Acinetobacter baumannii assessed by whole transcriptome analysis.

We have shown recently that in the human pathogen Acinetobacter baumannii, light is able to modulate key aspects contributing to its success as a pathogen such as motility, biofilm formation and virulence in a way that depends on the BLUF photoreceptor BlsA at 24ºC. In addition, light can induce reduction in susceptibility to certain antibiotics such as minocycline and tigecycline in a photoreceptor-independent manner, directly inducing expression of resistance genes. In this work, we performed RNAseq studies to identify new traits modulated by light in this pathogen in A. baumannii strain ATCC 19606. We have found 226 differentially expressed genes between light and dark, which comprise not only important determinants related to pathogenicity/resistance, but also to the bacteria´s survival in the environment. A. baumannii ATCC 19606 cells were exposed to blue light or incubated in the dark at 24C in LB in stagnant conditions overnight. RNA was extracted from these cells and the whole transcriptome was determined.