Exploring the antimicrobial and antioxidant properties of TdGASA2 protein: From molecular insights to a promising natural preservative for Tunisian cheese shelf-life enhancement

Abstract

Gibberellic acid-stimulated Arabidopsis (GASA) proteins, also known as Snakin proteins, have emerged as key players in plant development and stress tolerance. The investigation of the role of TdGASA2 in host defense responses revealed dynamic expression patterns under different stress conditions. TdGASA2 expression showed a consistent increase after wounding, methyl jasmonate (MeJA), and ethylene (ETP) treatments, peaking after 12–24 h for MeJA and ETP and after 1 h for pathogen elicitor (PA) treatment. Optimal expression conditions were determined, and the protein was successfully purified with a molecular weight of approximately 10 kDa. In vitro experiments demonstrated the potent antimicrobial activity of TdGASA2 against a range of pathogens, surpassing the efficacy of kanamycin. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values confirmed its bactericidal and bacteriostatic activity against various bacteria. Time-kill assays also highlighted its efficacy against Listeria monocytogenes and Salmonella enterica, underscoring its potential as a therapeutic agent. Additionally, TdGASA2 exhibited superior DPPH radical-scavenging activity compared to ascorbic acid, indicating its potential as a natural antioxidant. In situ experiments revealed dose-dependent effects of TdGASA2 treatment on microbial growth in cheese, suggesting its efficacy as a preservative to extend shelf life and enhance food safety. These findings underscore TdGASA2's multifaceted potential in both antimicrobial and antioxidant applications, positioning it as a promising candidate for food preservation and health promotion.