Mechanistic Insight into Fungicidal Agent of Rosin-Based Derivative: Targeting Erg2/Erg5 to Disrupt Ergosterol Biosynthesis in Rhizoctonia solani

Abstract

Based on the excellent fungicidal activity of the rosin-based Schiff derivative, compound 3c (Co. 3c), against Rhizoctonia solani, this study further investigated its action mechanism via multiomics, computer-aided drug design, phenotype, and physiological indicators. Transcriptomic and proteomic analyses identified 2010 differentially expressed genes (DEGs) and 311 differentially expressed proteins (DEPs), respectively. Steroid biosynthesis was the most significantly enriched pathway, and the DEGs and DEPs involved in sterol biosynthesis were simultaneously upregulated. DFT calculations revealed that Co. 3c exhibited high chemical reactivity, enabling stable noncovalent interactions with biomacromolecules. Mycelial phenotypic observations and physiological measurements confirmed that Co. 3c disrupted mycelial cellular structures, induced lipid peroxidation, and reduced the intracellular ergosterol content by 45.0%. Molecular docking suggested that Co. 3c bound to the active pockets of C-8 sterol isomerase and sterol 22-desaturase through hydrogen bonds and hydrophobic interactions. Collectively, these findings provide a theoretical basis for the development of rosin-derived fungicides.