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Background <p>Powdery mildew is a fungal disease threatening major global crops such as tobacco, rice, and grapes. Pathogens cause severe yield losses by disrupting photosynthesis and inducing premature plant senescence. Traditional chemical fungicides face challenges of drug resistance, environmental pollution, and health risks, urgently requiring low-toxic and sustainable alternatives. This study aims to identify novel sesquiterpenoids against powdery mildew from the high-trichome sun-cured tobacco variety (Huize Liuye) and elucidate their antifungal mechanisms.</p> Results <p>Sequential chemical extraction, chromatographic purification, and spectroscopic identification (NMR and HR-ESI–MS) led to the isolation and identification of seven novel (1–7) and four known (8–11) aromatic sesquiterpenes. Compounds 5 and 6 represent the first examples of sesquiterpenes containing a 4-methylfuran-2-yl moiety, while compound 7 is a rare sesquiterpene featuring a benzo[<i>c</i>]azepin-1-one skeleton. Antifungal assays revealed that compound 7 (250 μg/mL) exhibited the highest inhibitory activity against <i>Golovinomyces cichoracearum</i> with an inhibition rate of 86.2% ± 5.6, surpassing the positive control carbendazim (inhibition rate: 83.5% ± 6.0, 250 μg/mL). Analyses using microscopy and scanning electron microscopy (SEM) demonstrated that compound 7 disrupts conidial morphology and inhibits hyphal development. Transcriptomic and metabolomic studies further indicated that compound 7 may enhance induced immunity in tobacco by either directly acting as an inducer or indirectly by promoting the rupture of <i>G. cichoracearum</i> and the release of its pathogen-associated molecular patterns (PAMPs), thereby affecting various plant defense pathways, including salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) mediated plant hormone signaling, the MAPK signaling pathway, and the biosynthetic pathways of antifungal secondary metabolites. Molecular docking confirmed strong interactions between compound 7 and tubulin proteins, which also supported its efficacy. Additionally, compound 7 also showed activity against <i>Podosphaera pannosa</i> in rose.</p> Conclusion <p>This study establishes Huize Liuye tobacco as a valuable resource for natural sesquiterpene-based antifungal agents, with compound 7 demonstrating exceptional potential as an efficient fungicide due to its unique chemical structure, high antifungal activity, and broad-spectrum efficacy. The findings provide a theoretical basis for utilizing tobacco byproducts, such as trichomes, as renewable sources for biopesticide development, thereby underscoring the ecological value of high-trichome crops in sustainable agriculture as substitutes for synthetic chemicals.</p> Graphical abstract <p></p>

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Aromatic sesquiterpenes isolated from high-trichome sun-cured tobacco as potential inhibitors for powdery mildew

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年12月10日

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  • Hua-Yin Liu,
  • Yan-Qun Zhang,
  • Feng-Xian Yang,
  • Xin-Yao Huang,
  • Rong Zhang,
  • Wei-Guang Wang,
  • Guang-Yu Yang,
  • Qiu-Fen Hu,
  • Shi-Ping Zhou

摘要

Background

Powdery mildew is a fungal disease threatening major global crops such as tobacco, rice, and grapes. Pathogens cause severe yield losses by disrupting photosynthesis and inducing premature plant senescence. Traditional chemical fungicides face challenges of drug resistance, environmental pollution, and health risks, urgently requiring low-toxic and sustainable alternatives. This study aims to identify novel sesquiterpenoids against powdery mildew from the high-trichome sun-cured tobacco variety (Huize Liuye) and elucidate their antifungal mechanisms.

Results

Sequential chemical extraction, chromatographic purification, and spectroscopic identification (NMR and HR-ESI–MS) led to the isolation and identification of seven novel (1–7) and four known (8–11) aromatic sesquiterpenes. Compounds 5 and 6 represent the first examples of sesquiterpenes containing a 4-methylfuran-2-yl moiety, while compound 7 is a rare sesquiterpene featuring a benzo[c]azepin-1-one skeleton. Antifungal assays revealed that compound 7 (250 μg/mL) exhibited the highest inhibitory activity against Golovinomyces cichoracearum with an inhibition rate of 86.2% ± 5.6, surpassing the positive control carbendazim (inhibition rate: 83.5% ± 6.0, 250 μg/mL). Analyses using microscopy and scanning electron microscopy (SEM) demonstrated that compound 7 disrupts conidial morphology and inhibits hyphal development. Transcriptomic and metabolomic studies further indicated that compound 7 may enhance induced immunity in tobacco by either directly acting as an inducer or indirectly by promoting the rupture of G. cichoracearum and the release of its pathogen-associated molecular patterns (PAMPs), thereby affecting various plant defense pathways, including salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) mediated plant hormone signaling, the MAPK signaling pathway, and the biosynthetic pathways of antifungal secondary metabolites. Molecular docking confirmed strong interactions between compound 7 and tubulin proteins, which also supported its efficacy. Additionally, compound 7 also showed activity against Podosphaera pannosa in rose.

Conclusion

This study establishes Huize Liuye tobacco as a valuable resource for natural sesquiterpene-based antifungal agents, with compound 7 demonstrating exceptional potential as an efficient fungicide due to its unique chemical structure, high antifungal activity, and broad-spectrum efficacy. The findings provide a theoretical basis for utilizing tobacco byproducts, such as trichomes, as renewable sources for biopesticide development, thereby underscoring the ecological value of high-trichome crops in sustainable agriculture as substitutes for synthetic chemicals.

Graphical abstract