Phytodetoxification of Lindane (γ-Hexachlorocyclohexane) With Plants Expressing a Bacterial Dechlorinase

The construction and performance of plants capable of detoxifying the organochlorine pesticide (lindane, γ-hexachlorocyclohexane or γ-HCH) is reported. To this end, the bacterial linA gene from Sphingobium japonicum strain UT26, which encodes a dehydrochlorinase initiating γ-HCH degradation, was engineered into Arabidopsis thaliana. The resulting lines expressing linA exhibited markedly enhanced tolerance to lindane compared to wild-type controls, both in synthetic media and in contaminated soils. Furthermore, thereby engineered plants also removed more than 90% of the pollutant from the medium within 4 weeks. Chemical analyses revealed not only the formation of 1,2,4-trichlorobenzene (TCB), the expected γ-HCH degradation intermediates, but also detected 1,4-dichlorobenzene (DCB), suggesting that native plant activities could further push the degradation process beyond the canonical microbial pathway. This points to a potentially synergistic interaction between the introduced bacterial enzyme and the endogenous plant detoxification systems. By combining bacterial catabolic activity with plant resilience and root-mediated soil interactions, our data advocate a new strategy for the remediation of γ-HCH contaminated environments and demonstrate the feasibility of designing plants for enhanced degradation of persistent organic pollutants.