Key VOCs from Pichia kluyveri and Pichia kudriavzevii: 2-phenylethyl acetate and 2-phenylethanol against Botrytis cinerea

Due to the increasing concerns over environmental pollution and health risks from synthetic fungicides, the search for sustainable plant pathogen control has intensified. Volatile organic compounds (VOCs) produced by yeasts offer a promising biocontrol method against phytopathogenic fungi. This study evaluated VOCs from Pichia kudriavzevii C(A4) and Pichia kluyveri B(F8), isolated from wild grapevines ( Vitis vinifera ssp. sylvestris ), against Botrytis cinerea B05.10. Solid-phase microextraction–gas chromatography–mass spectrometry (SPME-GC-MS) identified several VOCs, with isoamyl acetate, 3-methyl-1-butanol, 2-phenylethanol (2-PE), and 2-phenylethyl acetate (2-PEA) being the most abundant. Commercial 2-PE and 2-PEA, alongside the fungicide Folicur® 25 EW as a control, were also evaluated. The results demonstrated that yeast-derived VOCs and commercial 2-PE and 2-PEA inhibited B. cinerea B05.10 mycelial growth, spore germination, and viability, with 2-PEA exhibiting the strongest antifungal effect, achieving 100 % inhibition of growth and germination at 0.33 g L -1 air. This inhibition was confirmed through resazurin (RZ) viability assays and morphological alterations in spores observed via scanning electron microscopy (SEM). The findings also highlight the effectiveness of yeast VOCs in reducing B. cinerea B05.10 severity in white and red grapes and grapevine leaves, supporting their potential as eco-friendly alternatives to synthetic fungicides in agriculture. • VOCs from Pichia kluyveri and Pichia kudriavzevii inhibit Botrytis cinerea growth. • SEM analysis reveals spore wrinkling and membrane collapse after VOCs exposure. • 2-PEA reaches 100% inhibition of Botrytis cinerea at 0.33 g L -1 . • Ex and in vivo tests show VOCs reduce Botrytis cinerea in grapes and vine leaves. • Yeast VOCs could be sustainable biocontrol agents against fungal crop diseases.