The effect of terpinen-4-ol in controlling blueberry fruit rot causing by Alternaria tenuissima

• T4O inhibited the colony growth and spore germination of Alternaria tenuissima . • T4O damaged the membrane permeability of A. tenuissima. • T4O treatment induced resistance against A. tenuissima in blueberry. • T4O induced early hydrogen peroxide outbreak and activated ROS scavenging response. • T4O treatment up-regulated the activity and gene expression of antioxidant enzymes. Terpinen-4-ol (T4O) is the main ingredient of tea tree essential oil with a light aroma. This study examined its inhibition on Alternaria tenuissima, and controlling effects on blueberry Alternaria fruit rot (AFR) . The results demonstrated that 0.2 μL mL −1 T4O suppressed colony growth and increased relative conductivity due to nucleic acids and soluble proteins leakage and 0.4 μL mL −1 T4O suppressed spore germination of A. tenuissima . Furthermore, fumigation with 0.4 μL mL −1 T4O lowered the disease index in blueberries by 33.5 %, enhanced the accumulation of secondary metabolites and stimulated chitinase, and β-1, 3-glucanase enzyme activities and gene expression. Hydrogen peroxide was surged during early storage, inducing the production of reactive oxygen species. The T4O-treated group responded this issue earlier, and exhibited higher antioxidant enzyme activities and gene expressions than the control group. So that enhanced the ability of blueberries to scavenge reactive oxygen species. Such protective changes safeguarded blueberries against oxidative stress to combat AFR.