title: Transgenic Bacillus thuringiensis (Bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.
abstract: Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt) have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt) significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P.R. CHINA.
authors.forename: Guangsheng
authors.initials: G
authors.lastname: Li
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P.R. CHINA.
authors.forename: Yongmo
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Nanjing Institute of Environmental Science, Ministry of Environmental Protection of the People's Republic of China, Nanjing, P.R. CHINA.
authors.forename: Biao
authors.initials: B
authors.lastname: Liu
authors.affiliation: Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P.R. CHINA.
authors.forename: Guoan
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000383:Agriculture / Q000379:methods* / Q000592:standards; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D003621:Daphnia / Q000187:drug effects / Q000254:growth & development; D017753:Ecosystem; D004731:Endotoxins / Q000235:genetics*; D005618:Fresh Water / Q000737:chemistry*; D006460:Hemolysin Proteins / Q000235:genetics*; D012275:Oryza / Q000235:genetics*; D048488:Paramecium caudatum / Q000187:drug effects / Q000254:growth & development; D010575:Pesticides / Q000032:analysis / Q000494:pharmacology*; D030821:Plants, Genetically Modified / Q000235:genetics*; D011157:Population Dynamics; D016019:Survival Analysis; D015048:Zooplankton / Q000187:drug effects / Q000502:physiology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D010575:Pesticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis
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