Abstract
The efficacy of thyme and savory essential oils were investigated against Botrytis cinerea on apple fruit. Apples treated with thyme and savory essential oils showed significantly lower gray mold severity and incidence. Thyme essential oil at 1% concentration showed the highest efficacy, with lower disease incidence and smaller lesion diameter. The expression of specific pathogenesis-related (PR) genes PR-8 and PR-5 was characterized in apple tissues in response to thyme oil application and B. cinerea inoculation. After 6 h of pathogen inoculation, thyme essential oil induced a 2.5-fold increase of PR-8 gene expression compared to inoculated fruits. After 24 h of inoculation, PR-8 was highly induced (7-fold) in both thyme oil-treated and untreated apples inoculated with B. cinerea. After 48 h of inoculation, PR-8 expression in thyme-treated and inoculated apples was 4- and 6-fold higher than in inoculated and water-treated apples. Neither thyme oil application nor B. cinerea inoculation markedly affected PR-5 expression. These results suggest that thyme oil induces resistance against B. cinerea through the priming of defense responses in apple fruit, and the PR-8 gene of apple may play a key role in the mechanism by which thyme essential oil effectively inhibits gray mold in apple fruit.
Highlights
Apple is one of the most important fruits in international trade; it can suffer from severe postharvest losses during long distance transport and storage
Six days after pathogen inoculation, gray mold rot diameter and disease incidence on apples treated with essential oils of T. vulgaris and S. montana were significantly diminished as compared to the control
The highest disease reduction was obtained when essential oils were applied at the highest concentration (1%), especially thyme, which showed a disease incidence and rot diameter of about 85% and 21 mm, respectively, compared to 100% and 38 mm of the inoculated control
Summary
Apple is one of the most important fruits in international trade; it can suffer from severe postharvest losses during long distance transport and storage. Botrytis cinerea, which causes gray mold, is one of the main pathogens causing postharvest losses of apples, especially for its conidial germination and mycelium growth at storage temperatures as low as 0 ◦ C [1]. Gray mold control strategies mainly rely on chemical treatments; the use of synthetic fungicides is limited by the emergence of resistant strains. Plant essential oils are gaining interest due to their apparently safe nature and their potential effectiveness as biopesticides for crop protection. On pome and stone fruit, as on table grapes, many plant essential oils have been effective against brown rot and gray mold rot [5,6]. Thyme and savory oils contain thymol, carvacrol, and p-cymene as volatile compounds, which have shown high
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
