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Transgenic Bacillus thuringiensis (Bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.

Li G, Wang Y, Liu B, Zhang G - PLoS ONE (2014)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

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Survival (A) and reproductive rate (B) of D. magna reared in water collected from non-Bt rice and Bt rice plots.Water was collected 6 days after the final pesticide sprays and the culture medium was renewed every 3 days with field water collected on that very day. Non-Bt and Bt rice plots were sprayed with pesticides when rice pests exceeded the action threshold (see Table S1). Error bars indicated standard error. Different letters capped on the bars indicate significant difference at p = 0.05 (LSD post hoc test after ANOVA).
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pone-0104270-g002: Survival (A) and reproductive rate (B) of D. magna reared in water collected from non-Bt rice and Bt rice plots.Water was collected 6 days after the final pesticide sprays and the culture medium was renewed every 3 days with field water collected on that very day. Non-Bt and Bt rice plots were sprayed with pesticides when rice pests exceeded the action threshold (see Table S1). Error bars indicated standard error. Different letters capped on the bars indicate significant difference at p = 0.05 (LSD post hoc test after ANOVA).

Mentions: We tested the survival of D. magna and P. caudatum in water collected from Bt and non-Bt rice plots in the laboratory. Daphnids (<24 hrs old) were reared in 100 ml field-collected water with Scenedesmus obliquus as feed, and every 3 days the culture medium was refreshed with field-collected water. Differences on survival rate were found between Bt and non-Bt field-collected water one day after the onset of this experiment (Fig. 2A). In following days, survival rate in the non-Bt treatment decreased gradually to zero by the end of this 13-day experiment, while survival rates in the two Bt treatments remained relatively stable at 52% and 60% by day 13. Repeated-measures ANOVA within RCBD found significant rice type effect (d.f. = 2,4; F = 34.393, p = 0.003) and measuring time effect (d.f. = 12,52; F = 59.489; p<0.001), and no significant block effect (d.f. = 2,4; F = 1.587; p = 0.311). The survival rate did not differ between the two Bt rice treatments (LSD test, p = 0.549), but did between non-Bt rice and Bt rice 1 or Bt rice 2 (LSD test, p = 0.002 and p = 0.003). Reproduction was observed in the culture medium on the 7th day of the experiment in all treatments, which indicated rice type had no effect on sexual maturity age of D. magna. A significant effect of rice type on average reproduction rate was observed (d.f. = 2,4; F = 8.963; p = 0.033), and LSD tests revealed significant differences between non-Bt rice and Bt rice 1 (p = 0.018) or Bt rice 2 (p = 0.026) (Fig. 2B). The growth (body length) of D. magna was also recorded, but no significant differences were found.


Transgenic Bacillus thuringiensis (Bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.

Li G, Wang Y, Liu B, Zhang G - PLoS ONE (2014)

Survival (A) and reproductive rate (B) of D. magna reared in water collected from non-Bt rice and Bt rice plots.Water was collected 6 days after the final pesticide sprays and the culture medium was renewed every 3 days with field water collected on that very day. Non-Bt and Bt rice plots were sprayed with pesticides when rice pests exceeded the action threshold (see Table S1). Error bars indicated standard error. Different letters capped on the bars indicate significant difference at p = 0.05 (LSD post hoc test after ANOVA).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126711&req=5

pone-0104270-g002: Survival (A) and reproductive rate (B) of D. magna reared in water collected from non-Bt rice and Bt rice plots.Water was collected 6 days after the final pesticide sprays and the culture medium was renewed every 3 days with field water collected on that very day. Non-Bt and Bt rice plots were sprayed with pesticides when rice pests exceeded the action threshold (see Table S1). Error bars indicated standard error. Different letters capped on the bars indicate significant difference at p = 0.05 (LSD post hoc test after ANOVA).
Mentions: We tested the survival of D. magna and P. caudatum in water collected from Bt and non-Bt rice plots in the laboratory. Daphnids (<24 hrs old) were reared in 100 ml field-collected water with Scenedesmus obliquus as feed, and every 3 days the culture medium was refreshed with field-collected water. Differences on survival rate were found between Bt and non-Bt field-collected water one day after the onset of this experiment (Fig. 2A). In following days, survival rate in the non-Bt treatment decreased gradually to zero by the end of this 13-day experiment, while survival rates in the two Bt treatments remained relatively stable at 52% and 60% by day 13. Repeated-measures ANOVA within RCBD found significant rice type effect (d.f. = 2,4; F = 34.393, p = 0.003) and measuring time effect (d.f. = 12,52; F = 59.489; p<0.001), and no significant block effect (d.f. = 2,4; F = 1.587; p = 0.311). The survival rate did not differ between the two Bt rice treatments (LSD test, p = 0.549), but did between non-Bt rice and Bt rice 1 or Bt rice 2 (LSD test, p = 0.002 and p = 0.003). Reproduction was observed in the culture medium on the 7th day of the experiment in all treatments, which indicated rice type had no effect on sexual maturity age of D. magna. A significant effect of rice type on average reproduction rate was observed (d.f. = 2,4; F = 8.963; p = 0.033), and LSD tests revealed significant differences between non-Bt rice and Bt rice 1 (p = 0.018) or Bt rice 2 (p = 0.026) (Fig. 2B). The growth (body length) of D. magna was also recorded, but no significant differences were found.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

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.

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.

Show MeSH
Related in: MedlinePlus