Dual function of itaconic acid from Trichoderma citrinoviride against Meloidogyne incognita

Root-knot nematodes (Meloidogyne spp.) cause catastrophic yield losses in global agriculture. This study identified itaconic acid (IA), through comparative metabolomic analysis (the study of small molecules in biological systems), as a key virulence-related metabolite produced by the fungus Trichoderma citrinoviride Snef1910. In vitro assays demonstrated potent nematicidal activity of IA, with an LC₅₀ of 243.4 mg/L against J2s of M. incognita and 78.4% egg-hatching inhibition at 800 mg/L, performance that is comparable to the structural analog trans-aconitic acid (TAA). Pot and greenhouse field trials demonstrated that IA has a significant impact against M. incognita, while enhancing tomato growth. Seed priming with IA compensated for the damage of nematodes to the photosynthetic pigments and activated systemic resistance of tomatoes, treatment with 100 mg/L IA enhancing catalase (CAT) and ascorbate peroxidase (APX) activities, while concurrently inhibiting H₂O₂/MDA accumulation. Crucially, IA production by T. citrinoviride positions this strain as a self-fertilizing organism for production of a nematicide with plant-growth-promoting properties. This study highlights the dual functionality of IA in nematode management, offering a sustainable alternative to synthetic agrochemicals.