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 value of 243.4 mg/liter against J2s of M. incognita and 78.4% egg-hatching inhibition at 800 mg/liter, performance that is comparable with the structural analog trans-aconitic acid. 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, and treatment with 100 mg/liter of IA enhanced catalase and ascorbate peroxidase 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.