Activity of the botanical compound thymol against kiwifruit rot caused by Fusarium tricinctum and the underlying mechanisms

Abstract

BACKGROUND Kiwifruit rot is an important disease caused by different fungal pathogens, which can lead to huge economic loss in the kiwifruit industry. The aims of this study were to discover an effective botanical compound that significantly inhibits the pathogens causing kiwifruit rot, evaluate its control efficacy against this disease, and reveal the underlying mechanisms. RESULTS A strain of Fusarium tricinctum (GF‐1), isolated from diseased kiwifruit, could cause fruit rot in both Actinidia chinensis var. chinensis and Actinidia chinensis var. deliciosa. Different botanical chemicals were used for antifungal activity test against GF‐1 and thymol was the most effective one with a 50% effective concentration (EC50) of 30.98 mg L−1. The minimal inhibitory concentration (MIC) of thymol against GF‐1 was 90 mg L−1. Control efficacy of thymol against kiwifruit rot was evaluated and the results indicated that thymol could effectively decrease the occurrence and spread of kiwifruit rot. The mechanisms underlying the antifungal activity of thymol against F. tricinctum were investigated, and it showed that thymol could significantly damage the ultrastructure, destroy the plasma membrane integrity, and instantaneously increase energy metabolisms of F. tricinctum. Further investigations indicated that thymol could extend shelf life of kiwifruit by increasing their storability. CONCLUSION Thymol can effectively inhibit F. tricinctum that is one of the causal agents of kiwifruit rot. Multiple modes of action are involved in the antifungal activity. The results of this study indicate that thymol can be a promising botanical fungicide to control kiwifruit rot and provide useful references for thymol application in agriculture system. © 2023 Society of Chemical Industry.

Antibacterial Mechanism, Control Efficiency, and Nontarget Toxicity Evaluation of Actinomycin X2 against Xanthomonas citri Subsp. citri

“…Therefore, the inhibition of these two enzymes by Act-X 2 might cause more damage to the cells rather than ROS accumulation. Similar to Act-X 2 , some antibacterial compounds, like limonene and thymol, have been reported to show biological effects by inhibiting the enzymatic activities of MDH and SDH. , …”

“…Similar to Act-X 2 , some antibacterial compounds, like limonene and thymol, have been reported to show biological effects by inhibiting the enzymatic activities of MDH and SDH. 39,40…”

Antifungal activity of the botanical compound rhein against Phytophthora capsici and the underlying mechanisms

“…For example, antifungal effects of botanical compound thymol on kiwifruit rot were achieved by reducing ergosterol content in the mycelia of Fusarium tricinctum. 42 Elsherbiny et al showed that ⊎-aminobutyric acid treatment significantly reduced the ergosterol and lipid contents of R. digitata mycelia, and then affected the cell membrane. 27 The result of this study revealed that rhein treatment could reduce the contents of phospholipids and cellulose in the mycelia of P. capsici, which would explain the severe damage to the cell membrane and cell well.…”

“…Several fungicides have been reported to restrict fungal growth by affecting the main structural component of their cell membrane or cell wall. For example, antifungal effects of botanical compound thymol on kiwifruit rot were achieved by reducing ergosterol content in the mycelia of Fusarium tricinctum 42 . Elsherbiny et al .…”

Honokiol inhibits Botryosphaeria dothidea, the causal pathogen of kiwifruit soft rot, by targeting membrane lipid biosynthesis

“…The mycelia of B. dothidea were cultured in a 150 mL PDB shaker for 3 days, filtered with gauze, and weighed to a constant wet weight. Mycelia were resuspended in PDB medium with various concentrations of honokiol (0, 10, 50, and 90 μg mL −1 ) and treatment times (2,6,12,24,48, 72 h), and 0.1 g of mycelia (wet weight) samples were collected to test enzyme activities of ⊎-1,3-glucanase, chitinase, MDH, and SDH enzyme activities using a kit provided by Beijing Solarbio Co., Ltd. and a multifunctional microplate reader (Varioskan LUX, Thermo). Measurements were repeated three times for each treatment.…”