Peroxidase Gene <i>CaPOD49</i> Suppresses Chilli Veinal Mottle Virus Infection and Increases Oxidative Stress Tolerance in Chilli Pepper

Chilli veinal mottle virus (ChiVMV) is the most important virus known to threaten chilli pepper (Capsicum annuum) growth and yield in Asia and Africa. Here, we identified the class III peroxidase gene CaPOD49 as a key regulator of chilli pepper immunity against ChiVMV. The CaPOD49 expression was strongly induced in response to ChiVMV infection at 48 h post-inoculation in both resistant and susceptible pepper cultivars. Silencing CaPOD49 via virus-induced gene silencing (VIGS) significantly increased disease severity, reduced plant survival rates and increased the disease index of ChiVMV infection. This susceptibility was associated with the elevated accumulation of reactive oxygen species (ROS), while the treatment with the ROS scavenger diphenyleneiodonium (DPI) recovered pepper resistance. Additionally, the defence-related genes CaPR2, CaPR5 and CaPR10 were significantly suppressed in CaPOD49-silenced plants, as well as increasing its lipid peroxidation level. Heterologous expression of CaPOD49 in yeast enhanced its oxidative stress tolerance, consistent with the protective effects demonstrated by its peroxidase activity in vitro assays. Our findings demonstrate that CaPOD49 positively regulates chilli pepper immunity by fine-tuning ROS levels and activating defence responses, offering potential genetic targets for disease-resistant chilli pepper breeding.