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Heavy metals (HMs) and microplastics (MPs) are two emerging factors threatening global food security. Whether long-term MPs pollution will affect the distribution of HMs and their resistance genes (MRGs) in soil is unknown. Here, metagenomic approach was used to decipher the fate of MRGs in cropland soils with long-term film MPs residues. Similar distribution pattern of MRGs was formed in long-term film MPs contaminated soil. A total of 202 MRG subtypes were detected, with resistance genes for Multimetal, Cu, and As being the most prevalent type of MRGs. MRGs formed a modular distribution of five clusters centered on MRGs including ruvB in long-term film MPs contaminated soil. MRGs also formed tight co-occurrence networks with mobile genetic elements (MGEs: integrons, insertions and plasmids). Redundancy analysis showed that HMs together with microbial communities and MGEs affected the distribution of MRGs in soil. Thirteen genera including Pseudomonas were identified as potential hosts for MRGs and MGEs. The research provides preliminary progress on the synergistic effect of HMs and MPs in affecting soil ecological security. The synergistic effect of MPs and HMs needs to be considered in the remediation of contaminated soils.

Integrated pest management is focused on combining biological and chemical controls. There is evidence of a negative impact of neonicotinoids on biological control, however, sulfoxaflor (SFX), a novel insecticide, its impact on parasitoid natural predator remain limited. Binodoxys communis is an important parasitic natural enemy of Aphis gossypii, which may have direct and indirect toxicity from the insecticides and aphids. Understanding the potential threat of SFX to B. communis is therefore essential to integrated pest management and the conservation of parasitoids. Here, the effects of sublethal doses of SFX on B. communis larvae and adults are presented for the first time. Sublethal SFX doses had a significant negative effect on the survival rate, adult life span, duration of development, and rate of parasitism. Moreover, exposure to sublethal SFX doses also had adverse effects on the biological performance of the next generation of B. communis. Based on the transcriptome analysis, the expression of genes involved in fatty acid metabolism, glycerolipid metabolism, glycerophospholipid metabolism, peroxidase, lysosomes, glutathione metabolism, drug metabolism, and CYP450 were significantly shifted by sublethal SFX exposure. These results indicate that sublethal SFX doses might adversely affect the biological performance of B. communis by altering gene expression related to the function of detoxification systems and energy metabolism. In conclusion, considering the beneficial ecological services of provided by parasitoids and the negative effects of sulfoxaflor across a greater usage scale, we emphasize the importance to optimize pesticide applications in IPM packages, in order to ensure the safety and survival of natural pest parasitoids.

While genetically modified (GM) crops bring economic benefits to human beings, their impact on non-target organisms has become an important part of environmental safety assessments. Symbiotic bacteria play an important role in eukaryotic biological functions and can adjust host communities to adapt to new environments. Therefore, this study examined the effects of Cry1B protein on the growth and development of non-target natural enemies of Pardosa astrigera (L. Koch) from the perspective of symbiotic bacteria. Cry1B protein had no significant effect on the health indicators of P. astrigera (adults and 2nd instar spiderlings). 16S rRNA sequencing results revealed that Cry1B protein did not change the symbiotic bacteria species composition of P. astrigera, but did reduce the number of OTU and species diversity. In 2nd instar spiderlings, neither the dominant phylum (Proteobacteria) nor the dominant genus (Acinetobacter) changed, but the relative abundance of Corynebacterium-1 decreased significantly; in adult spiders, the dominant bacteria genera of females and males were different. The dominant bacterial genera were Brevibacterium in females and Corynebacterium-1 in males, but Corynebacterium-1 was the dominant bacteria in both females and males feeding on Cry1B. The relative abundance of Wolbachia also increased significantly. In addition, bacteria in other genera varied significantly by sex. KEGG results showed that Cry1B protein only altered the significant enrichment of metabolic pathways in female spiders. In conclusion, the effects of Cry1B protein on symbiotic bacteria vary by growth and development stage and sex.

Assessing the potential effects of insecticides on beneficial biological control agents is key to facilitating the success of integrated pest management (IPM) approaches. Flupyradifurone (FPF) is a novel neonicotinoid insecticide that is replacing traditional neonicotinoids over a large geographical range to control pests. Binodoxys communis, is the dominant parasitic natural enemy of aphids. To date, no reports have addressed sublethal effects of FPF on B. communis. In this study, the lethal and sublethal effects of FPF on B. communis were investigated by indirect exposure to larvae and direct exposure to adults. Results showed that the sublethal LC10 and LC25 of FPF had negative effects on the biological parameters of B. communis, including significantly reducing survival rate, adult longevity, parasitism rate, and emergence rate, and significantly prolonging the developmental stages from egg to cocoons. In addition, we observed a transgenerational effect of FPF on the next generation (F1). RNA-Seq transcriptomic analysis identified a total of 1429 differentially expressed genes (DEGs) that were significantly changed between FPF-treated and control groups. These DEGs are mainly enriched in metabolic pathways such as peroxisomes, glutamate metabolism, carbon metabolism, fatty acid metabolism, and amino acid metabolism. This report is the first comprehensive evaluation of how FPF effects B. communis, which adds to the methods of assessing pesticide exposure in parasitic natural enemies. We speculate that the significant changes in pathways, especially those related to lipid synthesis, may be the reason for weakened parasitoid biocontrol ability. The present study provides new evidence for the toxic effects and environmental residue risk of FPF.

The lady beetle Propylea japonica is a dominant natural predator of insect pests in farmland ecosystems and an important non-target indicator insect for the environmental safety assessment of GM crops. The commercial cultivation of GM crops may cause P. japonica to frequently be exposed to the Bt protein environment. In this study, the biological characteristics, enzyme activity, and expression levels of detoxification and metabolism in P. japonica were studied after Cry1B protein treatment. No significant differences were observed in developmental duration, emergence rate, or body weight at different ages after feeding larvae 0.5 mg/mL of Cry1B protein compared with the control. Furthermore, there were no significant differences in the activities of glutathione S-transferase (GST), catalase (CAT), and peroxidase (POD) after feeding 0.25 mg/mL and 0.5 mg/mL Cry1B protein. However, when the concentration of Cry1B protein increased to 1.0 mg/mL, the activities of the GST, CAT, and POD increased significantly. Compared with the control group, there were no significant differences in the expression levels of most detoxification metabolism related genes; only a few genes had changed expression levels at the individual concentrations (CYP345B1, CYP4Q2, CYP9F2, GST, and microsomal GST). Overall, these results suggest that Cry1B protein has little or no effect on the biological characteristics of P. japonica. Genes related to enzyme activity and detoxification are differentially expressed at high concentration stimulation. Therefore, this research suggests that the potential risks of Cry1B for the predator P. japonica are negligible.

As microplastics became the focus of global attention, the hazards of plastic plasticizers (PAEs) have gradually attracted people's attention. Agricultural soil is one of its hardest hit areas. However, current research of its impact on soil ecology only stops at the microorganism itself, and there is still lack of conclusion on the impact of soil metabolism. To this end, three most common PAEs (Dimethyl phthalate: DMP, Dibutyl phthalate: DBP and Bis (2-ethylhexyl) phthalate: DEHP) were selected and based on high-throughput sequencing and metabolomics platforms, the influence of PAEs residues on soil metabolic functions were revealed for the first time. PAEs did not significantly changed the alpha diversity of soil bacteria in the short term, but changed their community structure and interfered with the complexity of community symbiosis network. Metabolomics indicated that exposure to DBP can significantly change the soil metabolite profile. A total of 172 differential metabolites were found, of which 100 were up-regulated and 72 were down-regulated. DBP treatment interfered with 43 metabolic pathways including basic metabolic processes. In particular, it interfered with the metabolism of residual steroids and promoted the metabolism of various plasticizers. In addition, through differential labeling and collinear analysis, some bacteria with the degradation potential of PAEs, such as Gordonia, were excavated.

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.

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. Capsule: Our study indicated that GM cotton varieties CCRI41 and CCRI45 have no adverse effects on insect predator C. sinica.