Biochemical Analysis of Tomato Plants Grafted onto Wild Brinjal Rootstocks under Fusarium-Nematode Infestation

Tomato (Solanum lycopersicum L.) cultivation is significantly constrained by the concurrent incidence of Fusarium oxysporum and Meloidogyne incognita, resulting in substantial yield losses. Grafting onto resistant rootstocks has emerged as an effective strategy to enhance resistance against these soil-borne pathogens. The present study investigated the biochemical responses of tomato plants grafted onto wild brinjal rootstocks under Fusarium-nematode infested conditions. Among several rootstocks screened in the screenhouse, brinjal roostock RB5 (Solanum torvum) and RB3 (a wild brinjal genotype) were identified as the most effective. RB5 exhibited the highest phenol content (0.420 mg/g FW in roots; 0.349 mg/g FW in stems) and peroxidase activity (2.19 µmol/min/g FW in roots; 1.47 µmol/min/g FW in stems). These biochemical substances are associated with enhanced structural defense and regulation of oxidative stress, contributing to increased resistance. Grafting tomato plants onto resistant wild rootstocks, particularly S. torvum (RB5), significantly strengthens biochemical defense mechanisms under Fusarium–nematode stress. This approach offers a sustainable, eco-friendly alternative to chemical control, improving plant resilience and supporting higher productivity in Fusarium-nematode infested soils.