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Simple Summary: Aphis gossypii Glover is an important agricultural pest distributed worldwide, which can reduce the yield of cotton crops and cause huge economic losses. Binodoxys communis Gahan is the main parasitoid wasp of A. gossypii. Previous studies have shown that parasitization causes reduced egg production in A. gossypii, but the effects on the symbiotic bacteria of the host ovaries are unknown. In this study, we analyzed the microbial communities in cotton aphid ovaries by 16S rDNA sequencing and their changes before and after parasitization, performed a functional prediction analysis of the microbial communities in cotton aphid ovaries, and finally performed RT-qPCR on some core symbiotic bacteria. In summary, our results provide a framework for investigating shifts in the microbial communities in host ovaries and broaden our understanding of the interactions among aphids, parasitoid wasps, and endosymbionts. Background: Aphis gossypii Glover is an important agricultural pest distributed worldwide. Binodoxys communis Gahan is the main parasitoid wasp of A. gossypii. Previous studies have shown that parasitization causes reduced egg production in A. gossypii, but the effects of parasitism on the symbiotic bacteria in the host ovaries are unknown. Results: In this study, we analyzed the microbial communities in the ovaries of A. gossypii without and after parasitization. Whether parasitized or not, Buchnera was the dominant genus of symbiotic bacteria in the ovaries, followed by facultative symbionts including Arsenophonus, Pseudomonas, and Acinetobacter. The relative abundance of Buchnera in the aphid ovary increased after parasitization for 1 d in both third-instar nymph and adult stages, but decreased after parasitization for 3 d. The shifts in the relative abundance of Arsenophonus in both stages were the same as those observed for Buchnera. In addition, the relative abundance of Serratia remarkably decreased after parasitization for 1 d and increased after parasitization for 3 d. A functional predictive analysis of the control and parasitized ovary microbiomes revealed that pathways primarily enriched in parasitization were "amino acid transport and metabolism" and "energy production and conversion." Finally, RT-qPCR analysis was performed on Buchnera, Arsenophonus, and Serratia. The results of RT-qPCR were the same as the results of 16S rDNA sequencing. Conclusions: These results provide a framework for investigating shifts in the microbial communities in host ovaries, which may be responsible for reduced egg production in aphids. These findings also broaden our understanding of the interactions among aphids, parasitoid wasps, and endosymbionts. [ABSTRACT FROM AUTHOR]

The commercial utilization of genetically modified crops expressing Bacillus thuringiensis (Bt) insecticidal toxins requires careful assessment of the potential impact on non-target organisms. To assess the potential ecological impact of the Bt insect-resistant cotton variety A26-5 (expressing the Cry1Ac/1Ab protein), we tested whether there was transmission of Cry1Ac toxin through the food chain from cotton to the herbivorous prey Helicoverpa armigera (Hübner) through to the non-target predatory insect Arma chinensis (Fallou). A small amount of Cry1Ac protein was detected in H. armigera and A. chinensis, indicating that Cry1Ac could be transmitted to A. chinensis. However, no differences were found in survival rate, development, or fecundity of A. chinensis after treatment with Bt-fed or Bt-free H. armigera. Cry1Ac exposure did not affect detoxification genes expression in A. chinensis, which is likely related to our finding that Cry1Ac could not bind to receptors in the midgut. Taken together, these results show that the Bt cotton A26-5 has few, if any, toxic effects on A. chinensis. [ABSTRACT FROM AUTHOR]

Given the ever-increasing commercial planting of transgenic plants across the world, an evaluation of their impacts on non-target organisms is as an important part of the risk assessment process. Propylea japonica is a dominant non-target predator and pollen feeder insect that is prevalent in Bt cotton fields, and it is thus in direct contact with Bt proteins. However, the effect of Bt proteins on P. japonica has not received much attention. In this study, the effects of Cry1Ac and/or Cry2Ab proteins on P. japonica were investigated from three aspects. First, no significant differences in the diversity of the microbiota nor change in species composition and community structure were observed among Cry protein treatments. Firmicutes are the most abundant bacterial phylum present in P. japonica , followed by Proteobacteria and Actinobacteria. The most abundant genus was Staphylococcus. Second, the expression levels of the detoxification and digestion-related genes did not change significantly in any Cry protein treatment. Third, none of the Cry proteins affected the population fitness of P. japonica. These results indicated that P. japonica was not sensitive to Bt proteins, suggesting that growing Bt cotton expressing Cry1Ac and/or Cry2Ab will pose negligible risks to P. japonica. [ABSTRACT FROM AUTHOR]

The large-scale commercial cultivation of genetically modified (GM) cotton has brought significant economic and environmental benefits. However, GM crops must undergo strict environmental monitoring and long-term observation. An important natural enemy insect in cotton fields, Geocoris pallidipennis , can ingest the Bt protein expressed in GM cotton by feeding on herbivorous insects that feed on the cotton. However, the potential risk of GM cotton to G. pallidipennis is still unclear. We here evaluated the effects of Bt cotton expressing the Cry1Ac/1Ab protein on nymphs and adults G. pallidipennis. Cry1Ac protein was detected in the midgut of the cotton bollworm, Helicoverpa armigera, after it ingested Bt cotton, and in the midgut of G. pallidipennis nymphs and adults preying on Bt-fed H. armigera. However, the survival rate, growth, development, and fecundity of G. pallidipennis were not adversely affected. Furthermore, G. pallidipennis cadherins, and those genes related to detoxification, antioxidant activity, nutrient utilization, and immune function were not differentially expressed in response to Cry1Ac exposure. Finally, we showed that Cry1Ac could not bind to brush border membrane vesicles (BBMV) proteins in G. pallidipennis nymphs or adults. In summary, these results indicate that the potential negative effect of transgenic Cry1Ac/1Ab cotton on the insect redator G. pallidipennis is negligible. [Display omitted] • Cry1Ac toxin expressed by Bt cotton can be transmitted to the predator Geocoris pallidipennis. • Cry1Ac-expressing Bt cotton did not affect the survival, growth and reproductive ability of G. pallidipennis. • Cry1Ac-expressing Bt cotton did not affect the expression of genes related to the detoxification and immunity of G. pallidipennis. • No Cry1Ac binding protein was detected in the midgut of G. pallidipennis. [ABSTRACT FROM AUTHOR]

The widespread commercialization of genetically modified (GM) cotton makes it important to assess the potential impact of this recombinant crop on non-target organisms. As important natural enemies of cotton field predators, green lacewing Chrysoperla sinica larvae are exposed to Bt insecticidal proteins expressed by GM cotton by feeding on herbivorous pests, and adults are directly exposed to Bt proteins by cotton pollen consumption. However, potential impacts of transgenic Bt cotton on C. sinica remain unclear. In this study, we evaluated the effects of two transgenic cotton varieties, CCRI41 and CCRI45, which express Cry1Ac (Bt toxin) and CpTI (Cowpea Trypsin Inhibitor), on C. sinica larvae and adults. After being fed with cotton aphids Aphis gossypii reared on transgenic cotton, the survival rate, developmental duration, pupation rate, and emergence rate of larvae were not adversely affected. After being fed two types of transgenic cotton pollen, the 7-day weight of adults and the preoviposition period and the cumulative oviposition of females were not significantly different from control specimen. Taken together, these results indicate that the potential risks of the two tested GM cotton varieties for the predator C. sinica are negligible. Our study indicated that GM cotton varieties CCRI41 and CCRI45 have no adverse effects on insect predator C. sinica. • A dietary exposure assay for evaluating the effects of GM cotton on green lacewing Chrysoperla sinica. • Cry1Ac/CpTI cotton does not affect the survival, growth, and development of C. sinica larvae though prey cotton aphids. • Cry1Ac/CpTI cotton does not affect the body weight, preoviposition period and cumulative oviposition of C. sinica adults. • Planting Cry1Ac/CpTI-expressing cotton poses minimal risks to C. sinica. [ABSTRACT FROM AUTHOR]

Common varieties of genetically modified (GM) cotton increasingly display insect-resistant properties via expression of bacterial-derived toxins from Bacillus thuringiensis (Bt). This necessitates a deeper understanding of the possible effects of these crops on non-target insects. The mirid bug Apolygus lucorum is a major pest in cotton production in China, however, the effect of GM cotton on this non-target species is currently virtually unknown. This insect is exposed to these transgenic plants by consuming genetically modified (GM) leaves. In this study, laboratory experiments were conducted to assess the toxicity of CCRI41 and CCRI45, (genetically modified cotton varieties which express the toxins Cry1Ac and CpTI (Cowpea Trypsin Inhibitor)) on nymphs and adults of A. lucorum. There was no detectable increase in mortality after A. lucorum fed on GM cotton leaves for 20 days. While we detected trace amounts of Cry1Ac proteins in both A. lucorum nymphs and adults (<10 ng/g fresh weight), the expression of genes related to detoxification did not detectably differ from those feeding on non-GM cotton. Our binding assays did not show Cry1Ac binding to receptors on the midgut brush border membrane from either A. lucorum nymphs or adults. Our findings collectively indicate that feeding on leaves of the GM cotton varieties CCRI41 and CCRI45 have few toxic effects on A. lucorum. Image 1 • Bioassay results showed no effect of Cry1Ac -expressing cotton on Apolygus lucorum survival rate. • Cry1Ac -expressing cotton did not alter the detoxification genes expression of A. lucorum. • No cry1Ac binding protein was detected in the midgut of A. lucorum. • Planting transgenic Cry1Ac cotton will pose a negligible risk to A. lucorum. Capsule: Our study indicated that the GM cotton varieties CCRI41 and CCRI45 have few adverse effects on non-target insect pest A. lucorum. [ABSTRACT FROM AUTHOR]

Hoverflies, capable of abilities providing dual ecosystem services including pest control and pollination, are exposed to insecticidal proteins from transgenic plants via pollen and prey aphids. However, the effects of such exposures on hoverflies have never been adequately assessed. Here, we investigated impacts of the most widely used biotoxin Cry1Ac on a representative hoverfly species Episyrphus balteatus through food chain transmission and active toxin exposure. The results showed Cry1Ac can be transmitted into E. balteatus through feeding on Aphis gossypii reared by Bt insect-resistant cotton variety expressing the Cry1Ac toxin, but the biological parameters of E. balteatus including survival rate, growth, development, reproductive capacity, and detoxification-related gene expression, were not significantly affected. Furthermore, the exposure to high-dose Cry1Ac toxin (500 μg/mL) resulted in slight increase of 16.67 % in the activity of detoxification and antioxidant enzyme catalase in E. balteatus and inhibited the egg hatching, partially inducing stress responses. Notably, the exposure to Cry1Ac toxin disrupted the microbiota homeostasis in E. balteatus , and the relative abundances of three dominant symbiotic bacterial genera (Cosenzaea , Wolbachia , and Commensalibacter) in E. balteatus exhibited a 10 % ~ 40 % fluctuation under Cry1Ac toxin stress. Taken together, these results suggest Cry1Ac toxin is not lethal to E. balteatus , but it poses a potential threat to its endosymbiotic bacteria. • Cry1Ac toxin can be transmitted into Episyrphus balteatus through food chain transmission, but has not significant effects on the biological parameters. • Exposure to high-dose Cry1Ac toxin resulted in a slight increase of the catalase activity, inhibited egg hatching, and disrupted the microbiota homeostasis in E. balteatus. [ABSTRACT FROM AUTHOR]

Risk assessments of insecticidal Cry proteins from Bacillus thuringiensis (Bt) cotton in soils have been mainly based on microcosm and short-term experiments. There is a lack of longer-term field results, especially when Bt-cotton residues are incorporated into the soil. In this study, we used a six-year field trial to evaluate how cultivation duration and Cry1Ac-inputted modes of Bt-cotton affect the persistence of Cry1Ac proteins and soil microbe-mediated enzymatic properties. The results showed that the persistence of Cry1Ac proteins increased with cultivation duration and periodic residue incorporation of the transgenic Bt-cotton variety ZM41. Moreover, temporal residue incorporation had a relatively larger contribution to the persistence of Cry1Ac proteins in the soil than their release in the growth period. Regardless of Bt-cotton cultivation or residue incorporation, soil microbial biomass was significantly suppressed. However, the dehydrogenase activity was significantly stimulated in Bt-cotton cultivation but suppressed in residue incorporation. The activities of β -glucosidase, nitrate reductase, phosphomonoesterase and arylsulfatase were significantly stimulated in soils with Bt-cotton residue incorporation. Based on a structural equation model analysis, the change in enzymatic activity of these four enzymes was attributed to both a direct effect from Cry1Ac proteins and an indirect effect via dehydrogenase. [ABSTRACT FROM AUTHOR]