Abstract
Root rot is a very destructive soil-borne disease severely affecting the quality and yield of common name Angelica sinensis in its main production region (Gansu Province, China). Here, a new Trichoderma asperellum strain M2 with broad-spectrum antifungal activity was assessed for its biocontrol effects against Angelica root rot. This fungal strain produces various hydrolases enzymes, notably cellulase (highest activity), and secreted 12.8 mg/L of indole-3-acetic acid (IAA) in a medium enriched with tryptophan. Scanning electron microscopy showed that M2's mycelium surrounded or parasitized the pathogen's mycelium, leading to the pathogens hyphae collapse, morphological fracture, and shrinkage. Pathogenicity test confirmed that M2 had significant control effect against Fusarium acuminatum, with its prior inoculation being more effective (maximal inhibition rate: 57.61%). Compared with the control, treatment with strain M2 significantly increased the plant height, root length, fresh weight, and dry weight of A. sinensis seedlings by 30.2%, 67.0%, 33.5%, and 61.8%, respectively, while also increasing their enzyme activity for catalase (CAT), phenylalanine ammonia-lyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO) by 12.82, 0.52, 1.57, and 3.7 times, respectively. A fermentation broth of strain M2 was highly effectively at degrading the neosolaniol (NEO) toxin, achieving a remarkable degradation rate of 87.14% after 11 days of treatment. Degradation ratios of the active cell component (49.40%) and extracellular component (33.6%) both significantly exceeded that of the intracellular component (24.2%), suggesting NEO removal mainly via biodegradation. Four products were identified by liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) for NEO's degradation by the strain M2. This study's findings provide a fresh perspective and strategy for applying multi-functional T. asperellum M2 to the biological control of Angelica root rot.