Biocontrol potential of nicotinamide from Arachis hypogaea roots against Meloidogyne incognita

Root knot nematode disease is a global problem that causes significant economic losses to cash crops annually, and Meloidogyne incognita is the most destructive threat. The urgent need for reliable biocontrol agents is evident. This study evaluated the nematicidal effects of various tissue extracts from Arachis hypogaea, a non-host plant of M. incognita. Subsequently, the metabolic changes in peanut roots induced by M. incognita were analyzed, and the in vitro biological activity of differential metabolites were tested. The results indicated that peanut root extracts showed the highest inhibiting effect on M. incognita, the LC₅₀ values were 18.54 mg/mL, 11.58 mg/mL, and 8.05 mg/mL after treated 24, 36, and 48 h, respectively. Additionally, it was found that M. incognita infestation induced distinct metabolic changes in peanut roots. Among the differential metabolites, nicotinamide exhibited strong nematicidal effects on M. incognita, and the corrected mortality of second-stage juveniles and hatching inhibition of eggs could reach 99.65 % and 95.90 %, respectively at a concentration of 25 mg/mL. In conclusion, nicotinamide manifested distinctive advantages as a novel nematicide for the potential applications in sustainable agriculture.