Biocontrol Activity of Alternaria angustiovoidea Against Trichothecium roseum Through Inhibiting Its Growth, Pathogenicity, and Gene Expression

Apple mold heart disease, primarily caused by Trichothecium roseum, is the most severe disease affecting stored apples. Developing biocontrol resources as an alternative to chemical pesticides is crucial for the advancement of green agriculture. This study demonstrated that a pathogenic fungus isolated from sunflower leaves exhibited specific inhibitory effects against T. roseum. Through morphological observation, identification, and the construction of a phylogenetic tree analysis, the fungus was identified as Alternaria angustiovoidea. GW2A was found to inhibit the spread of diseases on apple twigs. Additionally, GW2A has significant preventive and therapeutic effects on apple mold heart disease. Furthermore, GW2A can induce apple trees to upregulate defense-related genes, thereby enhancing resistance. Transcriptome analysis revealed that GW2A inhibits T. roseum growth by suppressing the function of polysaccharide hydrolases, oxidoreductases, and intermediate steps in carbohydrate metabolism. In conclusion, our research has effectively isolated and characterized A. angustiovoidea, revealing its significant potential as a biocontrol agent against T. roseum and apple mold heart disease, particularly in areas where sunflowers and apple trees are not co-cultivated. Additionally, we demonstrated its ability to induce resistance in apple trees, offering a sustainable approach to disease management in apple cultivation.