The overexpression of E. coli formaldehyde metabolism genes in Arabidopsis conferred varying degrees of resistance to oxidative stress induced by small organic compounds

Small organic compounds (SOCs) are widespread environmental pollutants that pose a significant threat to ecosystem health and human well-being. In this study, the FrmA gene from Escherichia coli was overexpressed alone or in combination with FrmB in Arabidopsis thaliana and their resistance to multiple SOCs was investigated. The transgenic plants exhibited varying degrees of increased tolerance to methanol, formic acid, toluene, and phenol, extending beyond the known role of FrmA in formaldehyde metabolism. Biochemical and histochemical analyses showed reduced oxidative damage, especially in the FrmA/B^OE lines, as evidenced by lower malondialdehyde (MDA), H₂O₂ and O₂^•− levels, indicating improved scavenging of reactive oxygen species (ROS). SOC treatment led to significantly higher levels of glutathione (GSH) and, to a lesser extent, ascorbic acid (AsA) in the transgenic plants than in the wild-types. After methanol exposure, GSH levels increased by 95 % and 72 % in the FrmA/B^OE and FrmA^OE plants, respectively, while showing no significant increase in the wild-type plants. The transgenic plants also maintained higher GSH:GSSG and AsA:DHA ratios, exhibited upregulated glutathione reductase (GR) and dehydroascorbate reductase (DHAR) activities, and correspondingly increased gene expression. In addition, the photosynthetic parameters of the transgenic plants were less affected by SOC stress, which represents a significant photosynthetic advantage. These results emphasize the potential of genetically engineered plants for phytoremediation and crop improvement, as they exhibit increased tolerance to multiple hazardous SOCs. This research lays the foundation for sustainable approaches to combat pollution and improve plant resilience in the face of escalating environmental problems.