Essential oils combat Botrytis cinerea in apples: unveiling sugar, vitamin, and antioxidant dynamics

This study investigated the effects of individual and combination applications of EOCs against Botrytis Cinerea in apple fruits, with a focus on sugar, vitamin, and antioxidant enzyme dynamics. In protective and curative treatments, sucrose content varied between 18.9 and 87.9 g.L-1, with the “CT” group exhibiting significantly higher sucrose levels (87.9 g.L-1). Glucose content ranged from 6.2 g.L-1 (“CT” and “C + F”) to 35.5 g.L-1 (“T + C + E + F”). Fructose content varied significantly, with the “F + T + C + E” treatment showing the highest (11.4 g.L-1) and the “CT” group the lowest (2.5 g.L-1). Rhamnose content in the curative treatment reached 14.9 g.L-1 (“F + T”) and in the protective treatment, the “C + E + F” group had the highest (3.3 g.L-1). Galactose content ranged from 0.1 to 13.0 g.L-1. Xylose content in curative treatment ranged from 12.1 to 13.6 g.L-1, with the combination “F + T” displaying the highest. In preventive treatment, arabinose content ranged from 0.7 to 3.0 g.L-1, with the “T + C + F” group having the highest. In terms of vitamins, the combination “T + F” showed the highest B1 (25.4 mg.100 g-1) and B2 (24.6 mg.100 g-1) content. Vitamin A, B1, and B2 increased in the “F + T” group, and vitamin C increased in the “F + T + C” group (33.4 mg.100 g-1). The quantification of oxidative stress markers and antioxidant enzymes revealed significant reductions in H2O2, MDA, and proline levels in EOC applications. In preventive treatment, the combination “T + C + E + F” exhibited the most effective improvement in SOD activity (556.5 EU mg-1), CAT activity increased significantly in the “T + C + F” group (189.3 EU mg-1), and APX activity saw the highest increase in the “T + C + E + F” group (185.6 EU mg-1). Contrastingly, curative treatments showed higher H2O2, MDA, and proline levels. The most significant decrease in H2O2 level occurred in the “T + C + E + F” group (36.7 nmol.g-1), and a significant decrease in MDA level was noted in the same group. Notable changes were observed in the activities of antioxidant enzymes, with the “F + T + C + E” group displaying the highest SOD activity (440.7 EU mg-1), and the “F + T” group showing the highest GST activity (542.0 EU mg-1). This research provided comprehensive insights into the biochemical responses of apple fruits to EOC treatments, offering potential strategies for effective fungal management in agriculture.