<p>This study is designed to demonstrate the divergent siderophore production among the strains of the entomopathogenic fungus <i>Beauveria bassiana</i> and enhance the siderophore production by overexpression of the biosynthesis-related genes. Chrome azurol S (CAS) assay indicated <i>B. bassiana</i> strains displayed divergent abilities to produce siderophores under the iron-limited conditions. A strain (Bb3153) did not produce enough siderophores detected by CAS assay and was considered as a non-siderophore-producing strain. Comparative transcriptomic analysis was conducted between the strains Bb3153 and Bb2860 (a siderophore-producing strain). The results indicated the significant difference in global expression between these two strains, in which the siderophore synthesis gene <i>sidL</i>, encoding <i>N</i>^<i>5</i>-hydroxyornithine acetylase, were significantly repressed in the strain Bb3153 when compared with the strain Bb2860. A recombinant strain (Bb3153^OE) was constructed by overexpressing <i>sidL</i> in Bb3153. CAS assay indicated that Bb3153^OE produced siderophores ahead of its parent strain. Mass spectrometry analysis indicated that the production of dimerumic acid was significantly increased. Phenotypic assays indicated the recombinant strain displayed the enhanced growth and virulence. This study highlights the genetic plasticity of siderophore biosynthesis in the filamentous entomopathogenic fungi, which serves as a promising strategy to enhance their biocontrol efficacy.</p>