## 1 Introduction
Light is an essential signal for the activation of photosynthesis and Asc biosynthesis in _Arabidopsis_ by the up-regulation of GDP-mannose pyrophosph (_GMP_), GDP-Galactose phosphorylase (_GGP_), L-galactose-1-phosphate phosphatase (_GPP_), and L-galactono-1,4-lactone dehydrogenase (_GalLDH_) [26; 27]. The genetic manipulation of the Asc biosynthesis process by overexpression of _GME_ and _GGP_ genes of the D-mannose/L-galactose pathway in _Arabidopsis_ and rice leaves [28; 29] and _GalLDH_ in tobacco [30] increased the Asc content by 1.5 to 2.5-fold, conferring tolerance to salt and drought stresses. The overexpression of genes from alternative pathways, particularly, _MIOX4_ and _GuILO2_[31] in _Arabidopsis_ and _GalUR_[32] in tomato plants increased Asc by 1.6 to 3.0-fold and promoted tolerance to salt, cold, and heat. Therefore, a better comprehension of the regulatory mechanisms responsible for Asc accumulation in horticultural crops has been a topic of interest due to its vast practical application. Increases in Asc content by genetic manipulation may improve human vitamin C uptake from diet by biofortification of the most consumed foods, increase post-harvest time of fresh fruit and vegetables, and mainly improve crops' resilience to environmental stresses, contributing to sustainable production [6]. _Capsicum annuum_ L. is one of the most consumed vegetables worldwide known as a primary source of vitamin C for human diet due to its high ascorbate content (50-250 mg 100 g\({}^{-1}\) Fresh Weight) accumulated as the ripening progresses [33; 34]. Pepper germplasm comprises a large group of economically important crops used as vegetables (bell peppers) and as spices for conditions (chilli peppers), displaying a wide variety of sizes, shapes, colors, flavors, and antioxidant compounds [35; 36]. So far, few investigations have been performed to clarify the ascorbate metabolism in this species. These evidenced the contribution of the GDP-mannose pyrophosphorylase (_GMP_),  
Figure 1: Schematic representation of ascorbate metabolism pathways in plants using the Biorender webtool ([[https://www.biorender.com/](https://www.biorender.com/)]([https://www.biorender.com/](https://www.biorender.com/)) (accessed on 20 July 2022)). The enzymatic steps are numbered as follows: D-mannose/L-galactose pathway (A): 1, glucose-6-phosphate isomerase (PGI); 2, phosphomannose isomerase (PMI); 3, phosphomannose mutase (PMM); 4, GDP-mannose pyrophosphorylase (GMP); 5, GDP mannose-3’,5’-epimerase (GME); 6, GDP-L-galactose transferase (GGP); 7, L-galactose-1-phosphate phosphatase (GPP); 8, L-galactose dehydrogenase (GalDH); and 9, L-galactone-1,4-lactone dehydrogenase (GalLDH). L-glucose pathway (B): 10, phosphodiesterase (PDE); 13, L-gallono-1,4-lactone oxidase (GuILO). D-galacturonate pathway (C): 14, polygalacturonase (PG) and 15, D-galacturonate reductase (GaIUR). myo-inositol pathway (D): 17, L-myo-inositol-1-phosphate synthase (MIPS); 18, myo-inositol monophosphate (IMP); 19, myo-inositol oxygenase (MIOX); 20, glucuronate reductase (GLUR); and 21, Gulono-lactonase (GNL). Degradation and recycling pathways (E): 22, ascorbate peroxidase (APX); 23, ascorbate oxidase (AO); 24, monodehydro-droscorbate reductase (MDHAR); and 25, dehydrodroscorbate reductase (DHAR). Steps 11, 12, and 16 (7) indicate unknown enzymes. GDP mannose-3',5'-epimerase (_GME_) genes from the D-mannose/L-galactose pathway, and ascorbate oxidase (_AO_) from degradation process for the accumulation of ascorbate [33; 34]. Thus, studies are scarce regarding the regulatory mechanisms of ascorbate in peppers, and there is a lack of information about the participation of the proposed biosynthesis pathways. Recently, multiple genome and transcriptome sequencing analyses have been performed in this species, and data are released in public database as GenBank-NCBI. These large-scale datasets can drive relevant advances on major biological concerns like the improvement of plant adaptation and productivity under various challenging environmental conditions.