Trans-2-enals suppress Geotrichum citri-aurantii via targeted inhibition of ATP-citrate lyase and disruption of the TCA cycle

ACL is identified as the target of trans-2-enals in suppressing G. citri-aurantii . • Trans-2-enals bind ACL with high affinity by Lys76 and Arg84. • ACL is a target for trans-2-enals (C₅-C₁₀), enabling broad antifungal strategies. Postharvest sour rot caused by Geotrichum citri-aurantii severely compromises citrus quality and marketability. This study clarified the antifungal mechanism of trans-2-enals (C 5 –C 10 ) against G. citri-aurantii , using trans-2-hexenal as a model. Physiological and transcriptome analysis of G. citri-aurantii treated with trans-2-hexenal revealed mitochondrial dysfunction and pinpointed ATP-citrate lyase (ACL) as a key inhibited target within the tricarboxylic acid (TCA) cycle. Enzymatic assays and RT-qPCR confirmed ACL inhibition, leading to citric acid accumulation and depletion of downstream intermediates. Density-functional analysis identified the conjugated enal moiety as the essential pharmacophore for trans-2-enals. Crucially, molecular docking localized a high-affinity binding cavity on ACL, where trans-2-enals form critical hydrogen bonds with residues Lys76 and Arg84. All tested trans-2-enals were confirmed to suppress ACL activity and expression, thereby altering TCA cycle intermediates. Collectively, ACL is the primary target of trans-2-enals, providing a foundation for developing next-generation antifungal agents against G. citri-aurantii . Download: Download high-res image (192KB) Download: Download full-size image Created with BioGDP.com ( Jiang et al., 2025 ).