Antimicrobial activity and unveiling PR10 gene expression modulation induced by Pinus sylvestris L. essential oil in plant-based food models: vapour phase chemical composition and molecular docking analysis

Essential oils are widely studied for their natural antimicrobial properties, which are suitable for different fields of postharvest food preservation and plant protection. This study evaluated the chemical composition, antimicrobial activity, and stress-response modulation induced by Pinus sylvestris L. essential oil (PSEO) in Petroselinum crispum M. and Pyrus communis L. plant models. Headspace-Gas chromatography–Mass Spectrometry (HS-GC-MS) analysis identified a total of 18 volatile compounds with β-pinene (22.8%) as the major constituent. The antibacterial activity of PSEO was assessed against five plant-associated bacterial strains. PSEO showed the highest antibacterial activity against Xanthomonas arboricola, whereas Pseudomonas syringae was the least susceptible strain. MIC50 and MIC90 values ranged from 0.69 to 1.12 mg/mL. In situ assays demonstrated a clear concentration-dependent antimicrobial effect of PSEO in both parsley and pear matrices, with inhibition rates exceeding 60% at the highest tested concentration (500 µL/L). The influence of PSEO on plant stress responses was analyzed by qRT-PCR, assessing fold changes in PR10 gene expression. In parsley tissues, bacterial inoculation generally caused significant upregulation, with Priestia megaterium showing an 85.86-fold change, followed by P. syringae (5.93-fold change). In pear tissues, the strongest induction of PycPR10 expression was recorded for Pectobacterium carotovorum (408.33 up-regulated fold change) and P. syringae (3.23 up-regulated fold change). The correlation between essential oil composition and docking predictions suggests that antibacterial activity may reflect the combined contribution of multiple monoterpenes rather than a single dominant compound. These findings suggest that P. sylvestris essential oil may contribute to antimicrobial protection in plant tissues, particularly under vapor-phase application, although its direct in vitro activity against the tested strains was comparatively modest. To our knowledge, this is the first study to combine chemical characterization, antibacterial testing, and PR10 gene expression analysis to evaluate the dual antimicrobial and plant defense-modulating potential of PSEO. Graphical Abstract