Yan Chen’s research while affiliated with Fujian Academy of Agricultural Sciences and other places

Oncidium hybridum is one of the important cut-flowers in the world. However, the lack of aroma in its cut-flower varieties greatly limits the sustainable development of the Oncidium hybridum cut-flowers industry. This paper is an integral investigation of the diel pattern and influencing factors of the aroma release of Oncidium Twinkle ‘Red Fantasy’. GC-MS analysis revealed that the release of 3-Carene peaked at 10:00, while Butyl tiglate and Prenyl senecioate did so at 14:00, with a diel rhythm. By analyzing the correlation network between aroma component synthesis and differentially expressed genes, 15 key structural genes were detected and regulated by multiple circadian rhythm-related transcription factors. Cluster-17371.18_TPS, Cluster-65495.1_TPS, Cluster-46699.0_TPS, Cluster-60935.10_DXS, Cluster-47205.4_IDI, and Cluster-65313.7_LOX were key genes in the terpenoid and fatty acid derivative biosynthetic pathway, which were co-expressed with aroma release. Constant light/dark treatments revealed that the diurnal release of 3-Carene may be influenced by light and the circadian clock, and Butyl tiglate and Prenyl senecioate may be mainly determined by endogenous circadian clock. Under constant light treatment, the TPS, DXS, IDI, and LOX genes seem to lose their regulatory role in the release of aroma compounds from Oncidium Twinkle ‘Red Fantasy’. Under constant dark treatment, the TPS genes were consistent with the release pattern of 3-Carene, which may be a key factor in regulating the diel rhythm of 3-Carene biosynthesis. These results laid a theoretical foundation for the study of floral transcriptional regulation and genetic engineering technology breeding of Oncidium hybridum.

The papaya mealybug, Paracoccus marginatus, is an invasive pest that causes significant damage to various tropical fruits and ornamentals worldwide. Lambda-cyhalothrin, an effective insecticide in integrated pest management (IPM) strategies, can control P. marginatus. This study evaluated the sublethal effect of lambda-cyhalothrin on the life table parameters and the detoxification enzymes activities of P. marginatus. Furthermore, transcriptome sequencing analysis revealed the potential mechanisms of the detoxification-related genes associated with enzymes activities. The study reported that lambda-cyhalothrin showed high activity against P. marginatus, with LC30 values of 8.98 mg/L. Two-sex life table results showed that the development duration of the second instar nymphs, preadults, and adult female longevity was significantly prolonged, and the fecundity was stimulated in the F1-CY of P. marginatus when the parental generation was exposed to LC30 lambda-cyhalothrin. Moreover, lambda-cyhalothrin treatment significantly increased the activities of Cytochrome P450 monooxygenases (P450) and glutathione-S-transferase (GST) enzymes. Additionally, significant expression levels of P450, GST, carboxylesterase, and esterase genes were observed in P. marginatus subjected to the sublethal lambda-cyhalothrin exposure. Our findings demonstrate that sublethal concentrations of lambda-cyhalothrin influenced the development and fecundity of P. marginatus, and changes in enzymes activities and differential expression of detoxifying genes might be involved in the response and detoxification metabolism of lambda-cyhalothrin in P. marginatus. These results could contribute to a comprehensive risk assessment and provide guidance for the scientific use of lambda-cyhalothrin in IPM strategies.

BACKGROUND Paracoccus marginatus has invaded many countries, spreading rapidly and causing significant economic losses to crops. Accurate detection during the monitoring process is critical to prevent its expansion into new areas, therefore it is necessary to develop efficient and reliable detection methods. Traditional detection methods are time‐consuming and instrument‐dependent owing to the morphological similarities and small sizes of P. marginatus and other mealybugs, therefore establishing an efficient, rapid, and sensitive method for field detection in resource‐limited settings is critical. RESULTS A sensitive and rapid detection system was developed to detect P. marginatus using recombinase polymerase amplification (RPA) combined with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a. The RPA‐CRISPR/Cas12a assay distinguished P. marginatus from 10 other mealybugs. The entire process can be completed in approximately an hour, and the identification results can be determined by the naked eye using lateral flow strips or a portable mini‐UV torch. A method was developed to extract DNA from P. marginatus within 5 min. This method was combined with the RPA‐CRISPR/Cas12a assay to achieve rapid and simple detection. In addition, two portable thermos cups with temperature displays were used to maintain the reagents and assay reactions in the field. CONCLUSION This assay represents the first application of portable and easily available items (mini‐UV torch and thermos cup) based on the combination of RPA and CRISPR/Cas12a for rapid pest detection. This method is rapid, highly specific, and instrument‐flexible, allowing for the early monitoring of P. marginatus in the field. This study provides guidance for the development of suitable management strategies. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.