The toxicity of clothianidin to non-target organisms has gradually attracted world-wide attention. It is essential to develop reliable methods for the on-site detection of clothianidin residue. In this study, analogue-based heterologous ic-ELISAs were designed to rapidly screen desirable hybridomas, which could be used for the construction of recombinant antibodies (RAbs) against clothianidin. Based on the antibody variable region genes, two full-length IgG RAbs (1F7-RAb and 5C3-RAb) were produced by the mammalian cell expression system. The performance of the two RAbs was characterized and compared by heterologous ic-ELISAs and non-competitive surface plasmon resonance (SPR) assays. Using heterologous ic-ELISAs, the 1F7-RAb exhibited highly specific and sensitive recognition to clothianidin with an IC₅₀ of 4.62 μg/L, whereas the 5C3-RAb could bind to both clothianidin and dinotefuran. The results of the non-competitive SPR assay further verified that the 1F7-RAb had a higher specificity and affinity to clothianidin than the 5C3-RAb. Finally, a gold immunochromatographic assay based on the novel antibody, 1F7-RAb, was developed for rapid detection of clothianidin with high sensitivity (visual detection limit of 2.5 μg/L), specificity, and good reproducibility, which can be used as an effective supervision tool for clothianidin residue in agricultural and environmental samples.

Hydroponics is currently one of the primary methods for soilless cultivation. Although the phenotype and quality of vegetables differ between hydroponic and soil-based systems, limited research has been conducted on the selection and breeding of pakchoi cultivars specifically suited for hydroponics. In this study, principal component analysis (PCA) and cluster analysis were performed on the commercial traits, agronomic characteristics, and nutritional quality of 20 pakchoi parental lines grown under hydroponic conditions to classify and screen suitable germplasm for breeding. PCA reduced the 11 agronomic traits into two independent principal components, accounting for a cumulative contribution of 79.22%. Cluster analysis grouped the 20 parental lines into four categories based on the composite scores of agronomic traits and nutritional quality. Group 3 was selected for breeding programs aiming to develop high-yielding cultivars with a desirable morphology. For breeding targets emphasizing darker leaves and petiole coloration, Group 4 presented the most suitable germplasm. Group 1 was ideal for enhancing nutritional quality by offering parent lines rich in calcium, magnesium, vitamin C, and amino acids. Alternatively, Group 2 contained lines with high levels of soluble proteins, amino acids, and soluble sugars.