title: Field and laboratory studies on the impact of two Bt rice lines expressing a fusion protein Cry1Ab/1Ac on aquatic organisms.
abstract: Genetically modified (GM) rice expressing Bt toxins is at the edge of commercial release in China. However, little information is available concerning the impact of Bt rice on aquatic organisms which are abundant in paddy field. A two-year study was conducted to assess the effects of two GM rice lines expressing a fusion protein Cry1Ab/1Ac (Bt rice) on three groups of zooplankton, rotifers, cladocerans and copepods in field conditions. Multi-factor ANOVA revealed that the population densities of rotifers, cladocerans and copepods in paddy field varied significantly between years and rice developmental stages, but did not differ significantly between Bt and non-Bt rice treatments. In all the field investigations, only one significant difference was found on copepods in the tillering stage of 2009, but the difference was not related to the presence of the Cry toxin. Under open-air conditions, we simulated the farming practice of straw mulch, using Bt rice straw as a food source for the water flea Daphnia hyalina. After one and two months of culture, the density of D. hyalina did not differ between Bt rice treatments and non-Bt rice treatments. A laboratory experiment found that purified Bt toxins Cry1Ab and Cry1Ac had no toxic effect on D. hyalina even in the treatment in which the Bt toxin concentration was as high as 2500ng/ml. Those above results indicate that the two Bt rice lines have no negative effect on the three groups of zooplankton. However, further studies are needed to compare the effects of Bt rice and non-Bt rice on the paddy zooplankton community in the context of integrated pest management which includes the use of pesticides.
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Wuhan 430070, Hubei, PR China.
authors.forename: Yongmo
authors.initials: Y
authors.lastname: Wang
authors.forename: Jiacheng
authors.initials: J
authors.lastname: Huang
authors.forename: Huawei
authors.initials: H
authors.lastname: Hu
authors.forename: Jianhong
authors.initials: J
authors.lastname: Li
authors.forename: Biao
authors.initials: B
authors.lastname: Liu
authors.forename: Guoan
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000383:Agriculture; D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000633:toxicity; D002681:China; D033361:Cladocera / Q000187:drug effects; D033342:Copepoda / Q000187:drug effects; D004731:Endotoxins / Q000235:genetics* / Q000633:toxicity; D004784:Environmental Monitoring; D006460:Hemolysin Proteins / Q000235:genetics* / Q000633:toxicity; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism; D012403:Rotifera / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015048:Zooplankton / Q000187:drug effects
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D014874:Water Pollutants, Chemical; C030956:insecticidal crystal protein, Bacillus Thuringiensis