4 Discussion
Previous studies have reported that UV-B radiation can adversely
affect plants and cause oxidative damage (Kakani et al., 2003;
Shi & Liu, 2021). In this study, we confirmed that after UV-B
treatment (16 kJ m-2 d-1), the ROS
content in the leaves of G. hirsutum significantly increased, and
the leaf damage subsequently appeared after two days (Fig. 1). Although
flavonoids, glutathione, phenolic compound, terpenoid, and
phenylpropanoid (Dias et al., 2020; Xie et al., 2022) all played
critical roles in ROS scavenging under UV-B stress, few studies
have focused on the entire metabolic pathway of the antioxidants to
investigate their molecular operating mechanisms. Particularly in
polyploid plants, such as G. hirsutum, two separated and parallel
metabolic pathways are combined into a common nucleus through
hybridization and whole genome doubling. The evolutionary mechanism of
the duplicated pathways is still largely unknown. Here, using the GSH
pathway as an example, we investigated the gene composition, expression
pattern, and regulatory network of the duplicated pathway during
evolution and focused on the response performance of the pathway to UV-B
stress in the tetraploid cotton. This study lays the foundation for
better elucidation of the molecular dynamics of specific pathway in
polyploid plants.