Phytate is the main phosphorus storage molecule in plants and plays an important role as phosphate donor in the plant-based nutrition of animals. Myo-inositol (MI) is the dephosphorylated form of phytate and represents a valuable carbon and energy source for bacteria. MI degradation and the related metabolic pathway has been studied in selected species such as Salmonella enterica and Bacillus subtilis, but has not yet been analysed for its prevalence in the whole bacterial kingdom.
In this work, we analysed the MI catabolic gene cluster (IolCatGC) in 193,757 bacterial genomes, covering a total of 24,812 species, with a focus on presence, organisation, and taxonomy. To identify the presence and composition of MI gene clusters within annotated genome sequences, we established an analysis pipeline which relies on hidden markov models (HMMs) that allowed us to assign inositol gene functions. This approach was combined with a proximity criterion to detect co-localized genes. As a result, we identified 7,384 (29.8%) species to harbour the IolCatGC. Within the groups of Actinobacteria and Proteobacteria, IolCatGC is highly abundant, while Bacteroidetes species possess the cluster less frequently. The clusters show a high diversity with regard to gene number and composition, while the order of core genes is highly conserved on the phylum level. In summary, 111 animal pathogens, more than 200 commensals, and 430 plant pathogens utilize MI, providing strong evidence for the beneficial properties of this metabolic capacity within different environments.