Abstract
The environmental release and biosafety of transgenic Bt crops have attracted global attention. China has a large area of saline-alkali land, which is ideal for large-scale production of Bt transgenic rice. Therefore an understanding of the fitness of Bt transgenic rice in saline-alkaline soils and the ability to predict its long-term environmental effects are important for the future sustainable use of these crops. In the present study, we aimed to evaluate the fitness of cry1Ab/c transgenic rice in both farmland and natural ecosystems. Transgenic cry1Ab/c rice Huahui1, for which a national biosafety certificate was obtained, was grown on normal farmland and saline-alkaline soils in a glass greenhouse. The expression pattern of exogenous Cry1Ab/c protein, and vegetative and reproductive fitness of rice were assessed. The expression of the exogenous Cry1Ab/c protein in the transgenic rice grown on saline-alkaline soil was lower than that in the strain grown on farmland soil. Under both the soil conditions, vegetative growth abilities, as evaluated by tiller number and biomass, and reproductive growth abilities, as measured by filled grain number and filled grain weight per plant, showed a significantly higher fitness cost for Huahui1 than that for the parental rice Minghui63 grown under the same soil conditions. In saline-alkaline soil, the fitness cost of Huahui1was moderately higher than that of Minghui63. Therefore, the ecological risk of cry1Ab/c transgenic rice is not expected to be higher than that of parental rice Minghui63 if the former escapes into natural saline-alkaline soil. The results of the present study provide a scientific basis to improve environmental safety assessment of the insect-resistant transgenic rice strain Huahui1 before commercialization.
Highlights
In 2016, the global planting area of genetically modified crops reached 185.1 million ha
The expression pattern of exogenous Cry1Ab/c protein and the fitness performance of HH1 rice during vegetative and reproductive growth stages were evaluated on simulated farmland and salinealkaline soils
The results indicated that the ecological risk of cry1Ab/c transgenic rice as determined by vegetative and reproductive growth indices is not expected to be higher than that of the parental rice Minghui63, if the former escapes into regions with natural saline-alkaline soil
Summary
In 2016, the global planting area of genetically modified crops reached 185.1 million ha. During the past 20 years, numerous insect resistance genes have been identified, some of which have antilepidopteron activity (cry1Aa, cry1Ab, cry1Ac, cry1Ab/Ac, cry1C, cry2A, and CpT1), whereas others exhibit anti-helipterum activity (Galanthus nivalis agglutinin, gna, and Pinellia ternata agglutinin, pta). These genes have been introduced into rice to develop insect-resistant transgenic lines (Shu et al, 1998, 2000; Tan et al, 2011; Wang et al, 2012a,b; Jiang et al, 2013b; Jian et al, 2014). It is anticipated that these transgenic varieties will have relatively higher commercial value (Tu et al, 1998; Shu et al, 2002; Ye et al, 2003)
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