4-nitrobenzaldehyde (4-NBA) is a widely used chemical intermediate for industrial application and an important photodegradation product of chloramphenicol. This compound represents a substantial threat to human health and ecosystem due to its genotoxic and mutagenic effect. In this study, the 4-NBA detoxification by transgenic rice overexpressing a bacterial nitroreductase gene, ElNFS1, from Enterobacter ludwigii were investigated. The cytosol-targeted ElNFS1 transgenic plants were selected to comprehensively examine their physio-biochemical responses and phytoremediation potential to 4-NBA. Our results showed that the transgenic plants exhibited strong tolerance to 4-NBA. Overexpression of ElNFS1 could significantly alleviate 4-NBA-induced damages of photosynthetic apparatus and reactive oxygen species overproduction in transgenic plants. The phytoremediation assay revealed that transgenic plants could remove more 4-NBA from the medium than wild-type plants. HPLC and LC-MS assays showed that 4-aminobenzaldehyde was found in the reductive products of 4-NBA. Altogether, the function of ElNFS1 during 4-NBA detoxification was characterized for the first time, which provides a strong theoretical support for the application potential of ElNFS1 transgenic plants on the phytoremediation of 4-NBA.

In the framework of the ICON project, environmental genotoxicity and cytotoxicity levels were assessed in blood erythrocytes of dab (Limanda limanda) and haddock (Melanogrammus aeglefinus) collected at 25 stations in the North Sea and near the coast of Iceland in August–October 2008. Micronuclei, nuclear buds and bi-nucleated cells with nucleoplasmic bridges were assessed as environmental genotoxicity biomarkers, and the frequency of fragmented-apoptotic and bi-nucleated erythrocytes were assessed as environmental cytotoxicity biomarkers. The lowest frequencies of genotoxic and cytotoxic abnormalities were detected in fish from the Icelandic study stations. The highest frequencies of abnormalities were recorded in dab from the Dogger Bank and the German Bight, in haddock from the Egersund Bank and from an area off the Firth of Forth (North Sea). In fish from the Icelandic reference area, frequencies of genotoxicity and cytotoxicity responses were significantly lower than in fish from most areas of the North Sea.