To mobilize nutrients entrapped into minerals and rocks, heterotrophic bacteria living in nutrient-poor environments have developed different mechanisms based mainly on acidolysis and chelation. However, the genetic bases of these mechanisms remain unidentified. To fill this gap, we considered the model strain Caballeronia mineralivorans PML1(12) known to be effective at weathering. Based on its transcriptomics and proteomics responses in Fe-depleted conditions, we pointed a cluster of genes differentially expressed and putatively involved in the production of siderophores. In this study, we report the characterization of this gene region coding for the production of a non-ribosomal peptide synthetase-independent siderophore (NIS). Targeted mutagenesis associated with functional assays and liquid chromatography coupled to high-resolution tandem mass spectrometry demonstrated the production of a single siderophore, identified as rhizobactin. This siderophore represents the first NIS containing malic acid in its structure. The evidence for the implication of rhizobactin in mineral weathering was demonstrated during a hematite dissolution assay. This study provides the first demonstration of the synthesis of a NIS in the genus Caballeronia and its involvement in mineral weathering. Our conclusions reinforce the idea that strain PML1(12) is particularly well adapted to nutrient-poor environments. [ABSTRACT FROM AUTHOR]