Abstract
BackgroundBt crops will face a new ecological risk of reduced effectiveness against target-insect pests owing to the general decrease in exogenous-toxin content in Bt crops grown under elevated carbon dioxide (CO2). The method chosen to deal with this issue may affect the sustainability of transgenic crops as an effective pest management tool, especially under future atmospheric CO2 level raising.MethodsIn this study, rhizobacterias, as being one potential biological regulator to enhance nitrogen utilization efficiency of crops, was selected and the effects of Bt maize (Line IE09S034 with Cry1Ie vs. its parental line of non-Bt maize Xianyu 335) infected by Azospirillum brasilense (AB) and Azotobacter chroococcum (AC) on the development and food utilization of the target Mythimna separate under ambient and double-ambient CO2 in open-top chambers from 2016 to 2017.ResultsThe results indicated that rhizobacteria infection significantly increased the larval life-span, pupal duration, relative consumption rate and approximate digestibility of M. separata, and significantly decreased the pupation rate, pupal weight, adult longevity, fecundity, relative growth rate, efficiency of conversion of digested food and efficiency of conversion of ingested food of M. separata fed on Bt maize, while here were opposite trends in development and food utilization of M. separata fed on non-Bt maize infected with AB and AC compared with the control buffer in 2016 and 2017 regardless of CO2 level.DiscussionSimultaneously, elevated CO2 and Bt maize both had negative influence on the development and food utilization of M. separata. Presumably, CO2 concentration arising in future significantly can increase their intake of food and harm to maize crop; however, Bt maize infected with rhizobacterias can reduce the field hazards from M. separata and the application of rhizobacteria infection can enhance the resistance of Bt maize against target lepidoptera pests especially under elevated CO2.
Highlights
With increased fossil fuel combustion and drastic changes in land utilization, the concentration of atmospheric carbon dioxide (CO2) has increased by more than 40%, How to cite this article Li et al (2018), Influence of elevated CO2 on development and food utilization of armyworm Mythimna separata fed on transgenic Bacillus thuringiensis (Bt) maize infected by nitrogen-fixing bacteria
Interactive effects of CO2 level, transgenic treatment, and rhizobacteria infection on food utilization of M. separata In addition to significant main effects of CO2 level, transgenic treatment, and rhizobacteria infection, two- and three-way interactions of these factors influenced the relative growth rate (RGR), relative consumption rate (RCR), approximate digestibility (AD), efficiency of conversion of digested food (ECD), and efficiency of conversion of ingested food (ECI) of M. separata larvae fed on Bt maize and non-Bt maize infected with A. brasilense and A. chroococcum under ambient and elevated CO2 in both years (P < 0.05, P < 0.01 or P < 0.001; Table 7)
In comparison with the CK, rhizobacteria infection with A. brasilense and A. chroococcum both significantly decreased RGR, ECD, and ECI of M. separata fed on Bt maize, and significantly increased RGR, ECD, and ECI of M. separata fed on non-Bt maize under the same CO2 level; and rhizobacteria infection with A. brasilense and A. chroococcum both significantly enhanced RCR and AD of M. separata fed on Bt maize, and significantly reduced RCR and AD of M. separata larvae fed on non-Bt maize under the same CO2 level
Summary
With increased fossil fuel combustion and drastic changes in land utilization, the concentration of atmospheric carbon dioxide (CO2) has increased by more than 40%, How to cite this article Li et al (2018), Influence of elevated CO2 on development and food utilization of armyworm Mythimna separata fed on transgenic Bt maize infected by nitrogen-fixing bacteria. Elevated atmospheric CO2 affects the crop production via direct or indirect impact on the physiology and feeding behavior of phytophagous insects (Zvereva & Kozlov, 2006; Massad & Dyer, 2010; O’Neill et al, 2010). These changes may lead to more severe and frequent outbreaks of pest insects in agricultural ecosystems (Percy et al, 2002). CO2 concentration arising in future significantly can increase their intake of food and harm to maize crop; Bt maize infected with rhizobacterias can reduce the field hazards from M. separata and the application of rhizobacteria infection can enhance the resistance of Bt maize against target lepidoptera pests especially under elevated CO2
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call