In this work, a carbon black (VXC-72R)/zirconia (ZrO₂) nanocomposite-modified glassy carbon electrode (GCE) was designed, and a VXC-72R/ZrO₂/GCE-based electrochemical sensor was successfully fabricated for the high-sensitivity detection of methyl parathion (MP). Electrochemical measurements showed that the VXC-72R/ZrO₂/GCE-based electrochemical sensor could make full use of the respective advantages of the VXC-72R and ZrO₂ nanoparticles to enhance the MP determination performance. The VXC-72R nanoparticles had high electrical conductivity and a large surface area, and the ZrO₂ nanoparticles possessed a strong affinity to phosphorus groups, which could achieve good organophosphorus adsorption. On the basis of the synergistic effect generated from the interaction between the VXC-72R and ZrO₂ nanoparticles, the VXC-72R/ZrO₂/GCE-based electrochemical sensor could show excellent trace analysis determination performance. The low detection limit could reach up to 0.053 μM, and there was a linear concentration range of 1 μM to 100 μM. Such a high performance indicates that the VXC-72R/ZrO₂/GCE-based electrochemical sensor has potential in numerous foreground applications.

In order to precisely assess gene expression level, a suitable internal reference gene must be chosen to quantify real-time reverse transcription polymerase chain reaction (RT-qPCR) data. For greenbug, Schizaphis graminum, a suitable reference gene for assessing the level of transcriptional expression of target genes has yet to be explored. In our study, eight reference genes, elongation fator 1 beta (Ef1β), TATA box binding protein (TBP), alpha-tubulin (α-TUB), 18S ribosomal (18S), 28S ribosomal (28S), glyceraldehyde-3-phosphate (GAPDH), actin (ACT), and ribosomal protein L18 (RPL18) were evaluated in S. graminum at different developmental stages, tissues, and insecticide treatments. To further explore whether these genes are suitable to serve as internal control, three software-based approaches (geNorm, BestKeeper, and NormFinder), ΔCt method, and one web-based comprehensive tool (RefFinder) were employed to analyze and rank the tested genes. The optimal number of reference genes was determined using the geNorm program, and the suitability of particular reference genes was empirically validated according to normalized gene expression data of three target genes, heat shock protein gene (HSP70), cytocrome P450 gene (SgraCYP18A1), and glutathione S-transferase (GST). We found that the most suitable reference genes varied considerably under different experimental conditions. For developmental stages, α-TUB and 28S were the optimal reference genes; for different tissues, 18S and ACT were suitable reference genes; for insecticide treatments, 28S and α-TUB were suitable for normalizations of expression data. In addition, 28S and α-TUB were the suitable reference gene as they had the most stable expression among different developmental stages, tissues and insecticide treatments. This should be useful for the selection of the suitable reference genes to obtain reliable RT-qPCR data in the gene expression of S. graminum.

Wheat refers to a critical grain crop in China, and ensuring the stable, high quality, high yielding production of wheat is of significance to China’s food security. Chitosan oligosaccharide (COS), i.e., amino-oligosaccharide, is a bio-pesticide readily absorbed by crop plants, capable of improving nutrient absorption and reproductive growth. This study aimed to determine the effects of COS on promoting wheat growth and its effect on the accumulation of malondialdehyde (MDA), as well as common antioxidant enzymes frequently related to plant tolerance. As indicated from the results, COS treatment (50–800 μg/mL) led to the significant (P < 0.05) increase in the height, root length, fresh and dry weight of all the tested wheat cultivars (Bainong 4199, Zhengyu 11 and Bainong 207). Moreover, the physiological analysis indicated that the activity of four antioxidant enzymes, i.e., catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) in leaves, achieved the similar improvements, and MDA accumulation was reduced significantly (P < 0.05). The above results confirmed that COS can significantly promote the growth of wheat, and under the condition of increased antioxidant enzyme activity, it can reduce lipid peroxidation and may also improve stress resistance. Thus, using COS in commercial wheat production may be noticeably conducive to sustaining future wheat yields and food security in China.