Nocturnal Red Light Application Modulated the Fumonisin B1-Induced Changes in Glutathione Transferases of Different Wheat Cultivars

Plant defense responses against Fusarium infection can be controlled by light. In this study, the effects of nocturnal red light were investigated on glutathione transferases (GSTs) in the leaves of the moderate- and high- Fusarium resistant wheat cultivars, GK Ígéret and GK Arató, respectively. GST activity increased in the light phase during the day, while it decreased after midnight. Since GST activity was lowest at midnight, we examined whether red light application at midnight could prevent the night-time drop in enzyme activity. We found that 15-min-long nocturnal red light application was effective to increase GST activity at dawn. The effects of red light pretreatments on GST expression and activity, as well as the oxidative stress induced by fumonisin B1 (FB1), were investigated. FB1 exposure increased GST activity and the expression of GST genes at dawn but nocturnal red light application in combination with the mycotoxin also increased GST activity and the transcript levels of the selected GST s in the resistant GK Arató. In addition to its effects on GSTs, it was discovered that, depending on the degree of tolerance, nocturnal red light increased the activity of the major antioxidant enzymes at dawn in both of the chosen wheat genotypes. These decreased FB1’s oxidative stress-causing actions, resulting in lower lipid peroxidation and less cell viability loss when exposed to the mycotoxin. Pretreatment with nocturnal red light enhanced the activity of GST and antioxidant enzymes in wheat plant leaves, contributing to FB1 detoxification and reducing oxidative stress.