Response of young tomato plants to fertilization under tomato brown rugose fruit virus infection: growth, nutrient uptake and phenolic content

Tomato brown rugose fruit virus ( Tobamo virus fructirugosum , ToBRFV), poses a significant threat to tomato crops worldwide. While fertilizers do not affect viral spread, their proper usage can improve crop quality, enhance resilience and mitigate symptoms severity. The present study aimed to assess the impact of mineral nutrition on three different tomato varieties infected with ToBRFV : Monalbo, Mobaci and Momor. The varieties differ in the absence or presence of Tomato mosaic virus (ToMV ) resistance genes ( Tm1 and Tm2 2 ). Plants were mechanically inoculated at the first true leaf stage and grown until flowering under four different fertilization treatments (0x, 0.5x, 1x, and 2 × times the optimal dose), alongside a control group of non-inoculated plants. Plant growth parameters, macronutrient (Na, Mg, Ca, K) accumulation, chlorophyll contentand total phenolic content were evaluated. ToBRFV infection was confirmed in the three tested varieties 30 days post-inoculation, with distinct symptoms and changes in morphology, chlorophyll levels and phenolic content. The findings suggest that fertilization improved growth performance in ToBRFV-inoculated tomato plants as shown by increased biomass, height, and leaf number. While macronutrient accumulation remained largely unaffected by infection status, chlorophyll content and total phenolic content were significantly influenced by both fertilization and viral infection. Chlorophyll content remained lower in ToBRFV-inoculated plants, whereas total phenolic content increased in inoculated plants under “0.5x” and “1x” fertilization treatments, with the highest levels at “0x” and the lowest at “2x”treatment. These findings highlight the complex interaction between viral stress and mineral nutrition, suggesting that low fertilization may enhance defense-related phenolic responses, while higher fertilization supports vegetative growth.