Methyl-2,4-dihydroxybenzoate induces transcriptomic reprogramming in Fusarium oxysporum f. sp. cubense and defense gene responses in Kadali banana.

The emergence of fungicide resistance and environmental concerns with conventional chemicals necessitate the identification of novel antifungal compounds. Methyl-2,4-dihydroxybenzoate (MDHB), a hydroxybenzoate derivative, exhibits potent antifungal activity against Fusarium oxysporum f. sp. cubense, the causative agent of Panama disease in bananas. To uncover its molecular mechanism of action, we performed comprehensive transcriptomic profiling of Foc treated with 100 ppm MDHB using RNA sequencing technology. The analysis revealed 173 differentially expressed genes (DEGs), comprising 121 upregulated and 52 downregulated genes (|log2FC| > 1, FDR <0.05). Gene Ontology analysis showed that MDHB exerts multifaceted antifungal activity through membrane destabilization (47 membrane-associated genes affected), suppression of energy metabolism via downregulation of ATP-binding proteins and proton-pumping ATPases, oxidative stress induction through impairment of superoxide dismutase (SOD2) and antioxidant systems. It also disrupted protein synthesis machinery including ribosomal proteins and elongation factors. MDHB further compromised cellular transport by downregulating ABC transporters (STE6) and major facilitator superfamily transporters (PTR2), and disrupted N-glycosylation via repression of SRD5A3 and RFT1 genes. Plant defense gene expression analysis revealed enhanced immune responses in banana, with significant upregulation of WRKY transcription factors (5.9-fold), LECTIN receptors (5.3-fold), and MAPK signaling components (5.5-fold). Glasshouse trials confirmed MDHB's efficacy, reducing disease severity from 100 % to 4.4 % and limiting disease incidence to 16 % compared to 100 % in pathogen-inoculated controls. This study provides the first transcriptomic insights into Foc's response to MDHB, revealing a multi-target mechanism disrupting key cellular functions while enhancing plant defense, establishing MDHB as a promising antifungal candidate for sustainable Fusarium wilt management.