Background
Postharvest pathogens Botrytis cinerea and Penicillium expansum causes significant postharvest deterioration of fresh fruit, resulting in economic losses globally. Essential oils (EOs) are safe fungal biodeterioration alternatives compared to chemical fungicides. The aim of this study was to characterise and evaluate the additive and/or synergetic effects of lemon (Le‐), lemongrass (Lg‐), and peppermint (P‐EOs) against mycelial growth and spore germination of B. cinerea and P. expansum.
Results
GC–MS analysis depicted 7, 10 and 10 compounds being the major component for Le‐, Lg‐ and P‐EOs, respectively. Most abundant compound being δ‐limonene (71%), α‐citral (50.1%), and menthyl acetate (48%) in Le‐, Lg‐ and P‐EOs, respectively. In vitro investigation showed significant inhibition against mycelial growth and spore germination of B. cinerea and P. expansum with a MIC of 5 and 10 mg/L, respectively. P. expansum was more susceptible to the EOs compared to B. cinerea. The concentrations causing 50% reduction (EC50) in mycelial growth for P. expansum were 4, and 9 mg/L for P‐EO and Le‐EO, respectively. At the lowest concentration (0.62 mg/L), volatile phase treatment for P‐ and Lg‐EOs showed 100% inhibitory effects against all fungal mycelial growth compared to contact phase with ≈30% and 60% inhibitory effects, respectively, against P. expansum.
Conclusions
Combination of essential oils showed stronger antifungal efficacy compared to individuals. EOs were more effective in volatile phase than direct contact at low concentrations. This shows the potential of using EOs in fogging treatments.
IntroductionEssential oils (EOs) have been demonstrated as efficacious against B. cinerea. However, the underpinning enzymatic and proteomic mechanism for these inhibitory effects is not entirely clear.MethodsThus, this study examined the effects of lemon (Le) and lemongrass (Lg) EOs (individually and in combination) against B. cinerea based on enzymatic and proteomic analyses. Proteomics data are available via ProteomeXchange with identifier PXD038894.Results and discussionBoth EOs (individually and in combination) displayed abilities to induce scavenging as observed with the reduction of H2O2. Measured malondialdehyde (MDA) and superoxide dismutase (SOD) activity were increased in all EOs treated B. cinerea mycelia compared to the control. Ascorbate peroxidase (APX) activity was highest in Lg treated B. cinerea (206% increase), followed by combined (Le + Lg) treatment with 73% compared to the untreated control. Based on GC-MS analysis, the number of volatile compounds identified in lemon and lemongrass EOs were 7 and 10, respectively. Major chemical constituent of lemon EO was d-limonene (71%), while lemongrass EO was a-citral (50.1%). Based on the interrogated LC-MS data, 42 distinct proteins were identified, and 13 of these proteins were unique with 1, 8, and 4 found in Le-, Lg-, and (Le + Lg) EOs treated B. cinerea, respectively, and none in control. Overall, 72% of identified proteins were localized within cellular anatomical entity, and 28% in protein-complexes. Proteins involved in translation initiation, antioxidant activity, protein macromolecule adaptor activity and microtubule motor activity were only identified in the Lg and (Le + Lg) EOs treated B. cinerea mycelia, which was consistent with their APX activities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.