Boll size affects the insecticidal protein content in Bacillus thuringiensis (Bt) cotton

Wang, Yonghui; Ye, Guoyou; Luan, Na; Xiao, Jian; Yuan, Chen; Chen, Dehua

doi:10.1016/j.fcr.2008.07.008

Cited by 27 publications

(15 citation statements)

References 7 publications

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“…There are additional factors that have an impact on the concentration of Bt toxin in leaf tissue such as climatic conditions or the general plant health and N metabolism (Dong and Li, 2007). A recent study conducted by Wang et al (2009) has further shown a negative correlation between boll size and content of Cry1A insecticidal protein.…”

Section: Discussionmentioning

confidence: 96%

Long-term impact of Bt cotton: findings from a case study in China using panel data

Pemsl

Voelker

Wu³

et al. 2011

International Journal of Agricultural Sustainability

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Bt cotton has been cultivated in China for a decade. Studies have been conducted to assess theimpact on productivity and pesticide use. Limitations of these studies are the short time period considered and the reliability of data. This paper presents findings from monitoring 150 Bt cotton farmers in Shandong province in 2002 and 2005. Descriptive analysis reveals that pesticide use increased while seed price and Bt toxin concentration decreased. The Bt variable was consistently insignificant in the estimated production function with damage control specification and a fixed effects model. There is indication that poor standards in Bt varieties have caused this result. Due to market imperfections and emergence of a largely unregulated seed market for genetically modified crops, Bt toxin levels may be below the threshold required to effectively control target pests. Furthermore, rising cotton prices may have created additional incentive to increase pesticide applications. The emergence of secondary pests calls for further in-depth studies that should include local agro-ecological conditions. Our results indicate that farmers with more experience in Bt cotton cultivation apply less pesticides, confirming the findings of other studies that farmer knowledge and understanding of the Bt technology is an important condition for its success.

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Section: Discussionmentioning

confidence: 96%

Long-term impact of Bt cotton: findings from a case study in China using panel data

Pemsl

Voelker

Wu³

et al. 2011

International Journal of Agricultural Sustainability

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“…Wang et al [68] observed a variation in the levels of CRY1AB protein, measured by ELISA, among different cultivars of GM cotton. Luo et al [69] submitted two Bt cotton cultivars, expressing the CRY1AC protein, under salinity stress.…”

Section: Discussionmentioning

confidence: 99%

Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties

et al. 2016

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BackgroundPrior to their release in the environment, transgenic crops are examined for their health and environmental safety. In addition, transgene expression needs to be consistent in order to express the introduced trait (e.g. insecticidal and/or herbicide tolerance). Moreover, data on expression levels for GM events are usually required for approval, but these are rarely disclosed or they are considered insufficient. On the other hand, biosafety regulators do not consider epigenetic regulation (e.g. DNA methylation, ncRNAs and histone modifications), which are broadly known to affect gene expression, within their risk assessment analyses. Here we report the results of a DNA methylation (bisulfite sequencing) and transgene transcript accumulation (RT-qPCR) analysis of four Bt-expressing single transgenic maize hybrids, under different genetic backgrounds, and a stacked transgenic hybrid expressing both insecticidal and herbicide tolerance traits.ResultsOur results showed differences in cytosine methylation levels in the FMV promoter and cry2Ab2 transgene of the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids under the same genetic background showed differences in the 35S promoter sequence. The results of transgene transcript accumulation levels showed differences in both cry1A.105 and cry2Ab2 transgenes among the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids showed difference for the cry2Ab2 transgene only.ConclusionsOverall, our results show differences in DNA methylation patterns in all varieties, as well as in transgene transcript accumulation levels. Although the detection of changes in DNA methylation and transgenic accumulation levels does not present a safety issue per se, it demonstrates the need for additional studies that focus on detecting possible safety implications of such changes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12302-016-0097-2) contains supplementary material, which is available to authorized users.

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“…The synthesis of Bt protein is also controlled by nitrogen metabolism (Steward, 1965). Our previous work showed that the insecticidal proteins content in leaves was highly correlated with the nitrogen metabolism of the Bt cotton (Chen et al, 2004(Chen et al, , 2005Wang et al, 2009). Therefore, investigating the relationships between the rebound characteristics of the efficacy after terminating temperature stress and the nitrogen metabolism is important for elucidating the process of the efficacy recovery.…”

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confidence: 99%

The recovery of Bt toxin content after temperature stress termination in transgenic cotton

Chen

Wen²,

Zhang

et al. 2013

Span. j. agric. res.

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The insecticidal efficacy of Bt cotton under different environments has generated controversy in recent years. The objective of this study was to investigate possible reasons of the conflicting results caused by temperature stress. Two different types of Bt transgenic cotton cultivars (a Bt cultivar, Sikang1, and an hybrid Bt cultivar, Sikang3) were selected. The plants of the two Bt cultivars were exposed to high temperature (37°C), low temperature (18°C), and the control (27°C) for short (24 h) and long (48 h) periods of stress at peak boll stage, and then moved to the glasshouse where the control plants were maintained. The results showed that the leaf insecticidal toxin content fully recovered within 24 h to the level of control after the end of short duration high-temperature treatment, and recovered mostly within 48 h of the termination of 24 h low-temperature stress. Under long duration high temperature treatment the Bt toxin content required longer recovery periods (48 and 72 h for Sikang3 and Sikang1, respectively) to reach the control level. The Bt protein content only recovered partially at 96 h after the end of the long-duration low-temperature stress, and the concentrations of the Cry1Ac protein were 74% and 77% of the corresponding control for Sikang1 and Sikang3, respectively. The different recovery and increase slowly of the leaf nitrogen metabolic rates after ceasing the heat and cold stress may be possible reason for the above difference. In summary, the duration and type of temperature (cold or heat) stress may cause different Bt insecticidal protein recovery rate due to different recovery rate of enzymes.

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Boll size affects the insecticidal protein content in Bacillus thuringiensis (Bt) cotton

Cited by 27 publications

References 7 publications

Long-term impact of Bt cotton: findings from a case study in China using panel data

Long-term impact of Bt cotton: findings from a case study in China using panel data

Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties

The recovery of Bt toxin content after temperature stress termination in transgenic cotton

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