## 3 Discussion
With regard to these cultivars [40], it was found that waterlogging-sensitive plants experienced severe oxidative damage, while the tolerant one managed well with ROS production and avoided oxidative stress by increasing carotenoids and amino acids contents, which may balance the apparent decrease in Asc biosynthetic process. Sensitive and tolerant apple plants treated with ascorbate increased their resistance to waterlogging by improving their antioxidant activity and increasing their Asc recycling enzymes [59]. In this sense, L6138 wild tomato line's tolerance to waterlogging and its combination with heat was associated with higher protein synthesis and endogenous Asc production compared to sensitive genotypes [60]. Collectively, these findings show severe unbalancing of ascorbate biosynthesis process under stress; its apparent decrease under heat, salt, and osmotic conditions seems to be a result of the slowdown of the L-galactose pathway and the excessive use of Asc for protecting plants from cellular injury, as proposed by [PERSON] and collaborators [61]. Since ascorbate biosynthesis is down-regulated by such stresses, which virtually may result in reduced endogenous Asc content, its exogenous application has been successfully employed to prevent oxidative stress and confer plant tolerance by restoring it and triggering crucial priming of adaptive responses [62; 63]. In this sense, exogenous ascorbate improved cell turgidity, chlorophyll levels, and growth of strawberry plants subjected to heat [64]. Tomato seedlings exposed to severe saline stress showed improved plant recovery and 50% survival [65], while sweet pepper seedlings showed enhanced antioxidant status, growth, and yield under moderate-to-high NaCl concentration and drought stresses [66; 67; 68] after ascorbate application. Therefore, genotypes that maintain or improves antioxidant status may manage better the negative stress effects, as verified in this study in cold and waterlogging tolerant cultivars. Depending on the type of pathogens and strains, genes of the L-galactose and alternative pathways displayed particular up- or down-regulation behavior (Figures 9 and 10 and Tables S9 and S10). In fact, the poor responsiveness of genes to BPEV infection may be related to its weak pathogenicity [41]. However, infection with PMMoV, an acute virus, and the mixed infection (BPEV+/PMMoV) down-regulated various genes of the L-galactose pathway, despite the remarkable up-regulation of _GME1_ followed by _PMM_ and _GalDH_ (Figure 9 and Table S9). Furthermore, the inoculation with Mex21 and N strains, which cause moderate and severe disease, respectively, down-regulated various genes of the L-galactose pathway mostly at 14 dpi. Notably, both viruses substantially induced _GuILO_ and _MIOX3_ members from secondary pathways (Figures 9 and 10 and Tables S9 and S10). Studies related to non-enzymatic antioxidant response to virus-plant interaction are still scarce, and there is no record for peppers. Here, we speculate that PMMoV, Mex21, and N strains inhibited Asc biosynthesis process through the primary pathway, while L-glucose and myo-inositol pathways seem to be induced in an attempt to compensate it. In accordance, _Eggsplant Mottled Dwarf Virus_ (EMDV) substantially decreased total Asc in the leaves of two ecotypes at 7 and 21 dpi by suppression of genes of the L-galactose and D-galacturonate pathways [69]. Wounding treatment, as a simulation of biotic stress response, reduced ascorbate content in kiwifruit species, despite the up-regulation of _GPP_ and _GME_ genes [53; 61]. In acerola leaves, the up-regulation of L-galactose genes after wounding was interpreted as a molecular response for rescuing Asc depletion [27]. mainly ET induced them in almost all time points (Figure 11 and Table S11). With regard to genes encoding enzymes of alternative pathways, _GullO_ and _MIOX_ members were time-specific slightly or strongly expressed by SA, Meja, and ET.