Pseudomonas donghuensis P482 exhibits broad antibacterial and antifungal activity, primarily related to the production of 7-hydroxytropolone (7-HT). However, the restricted nutritional conditions (viz. mineral medium with single carbon source) diminished the antagonistic activity of P482. In this study, we unveil profiles of the secondary metabolites from P482 and its selected mutants, using nutrient-diluted (10% tryptone soy broth, TSB) and nutrient-restricted (M9 with either 0.4% glucose or 0.4% glycerol as a sole carbon source) media to explore differences in the quantity and quality of the secondary metabolites produced. No 7-HT was found to be synthetized by P482 under restricted nutritional conditions. However, both the wild-type and the tested mutants of P482 still did express some antagonistic activity towards the plant pathogenic bacteria tested. Based on these results, we postulate that 7-HT is not the sole antimicrobial compound produced by P. donghuensis P482 and that other antimicrobials may be involved in P482 antagonistic activity under limiting-nutrient conditions.