Global climate change is the impact of combined abiotic and biotic stresses negatively affecting plant health and productivity. This study investigated the molecular and cellular responses of Nicotiana benthamiana L. plants to wild-type tomato bushy stunt virus (wtTBSV) infection under conditions of pre-existing heat stress. The experiments were conducted under controlled temperature regimes of 30 °C and 37 °C in combination with virus challenge. Morphological and biochemical analyses in plants under the influence of combined stress showed the alleviation of disease symptoms, reduction in virus content and reduced expression levels of viral proteins P19 and P33. Under conditions of combined stress, accumulation of hydrogen peroxide and malondialdehyde, as well as activation of the antioxidant enzyme catalase, especially in root tissues, were observed. Notably, at 37 °C, virus infection was suppressed despite high levels of oxidative stress, whereas at 30 °C, a marked decrease in the expression of host factors was observed. The results indicate that thermal stress modulates virus–host interactions and activates defense mechanisms, including antioxidant and RNA interference pathways. Therefore, temperature adaptation can be considered as a promising strategy for enhancing plant resistance to viral pathogens under climate changes.

Ferroptosis-like cell death in plants is a recently described mechanism triggered by iron accumulation and lipid peroxidation; however, its role in viral infection remains unclear. In this study, we investigated the effect of iron (Fe-EDTA) treatment on Nicotiana benthamiana plants infected with wild-type tomato bushy stunt virus (wtTBSV). Morphological and biochemical analyses under combined stress revealed pronounced symptoms, including growth inhibition, necrosis, leaf yellowing, chlorosis, and leaf deformation, while the expression of the viral suppressor protein P19 was reduced. Biochemical assays showed that low Fe-EDTA concentrations maintained the photosynthetic apparatus and increased chlorophyll content, whereas high concentrations induced lipid peroxidation and ferroptosis-like cell death. Our results suggest that excess iron activates RNA interference and ferroptosis-like death, thereby suppressing viral infection, while low iron concentrations preserve photosynthetic activity and alleviate symptoms. In addition, combined stress led to reduced levels of HSP70 and HSP90, indicating that iron homeostasis may interfere with cellular chaperones essential for viral replication. These findings highlight the key role of ferroptosis-like cell death in plant-virus interactions.