Transcriptome analysis reveals biocontrol mechanisms of Acremonium sclerotigenum against Podosphaera xanthii in cucumber.

Cucumber (Cucumis sativus) is an economically important crop, but its production is severely threatened by Podosphaera xanthii, the causal agent of powdery mildew, significantly reduces yield and quality. This study evaluates the potential of Acremonium sclerotigenum as a biocontrol agent against P. xanthii in cucumber. A combination of in vitro assays and greenhouse experiments assessed its antifungal activity, disease control efficacy, and effects on plant growth. Transcriptome analysis and RT-qPCR were performed to identify and validate differentially expressed genes associated with biocontrol mechanisms and plant stress responses. A. sclerotigenum reduced P. xanthii incidence by up to 70 %, and enhanced cucumber growth, increasing leaf number by 25 %, plant height by 30 %, and chlorophyll content by 20 %. UHPLC-MS/MS confirmed the production of diverse secondary metabolites, including antimicrobial compounds such as oleanolic acid, virginiamycin, bialaphos, and sphinganine. Transcriptome profiling revealed significant upregulation of defense-related genes, including ERF1, REM, MYB10, PR-4, and RBOHA, which RT-qPCR further validated. These findings highlight the potential of A. sclerotigenum as an effective and sustainable alternative to chemical fungicides for managing powdery mildew while simultaneously promoting plant growth. This study provides valuable insights into the mechanisms underlying its biocontrol activity and supports its application as a promising tool for enhancing crop resilience and sustainable agriculture.