Overexpression of a nuclear receptor HR96 contributes to spirodiclofen susceptibility in Panonychus citri (McGregor).

The citrus red mite, Panonychus citri, is one of the most notorious and devastating citrus pests around the world that has developed resistance to multiple chemical acaricides. In previous research, we found that spirodiclofen-resistant is related to overexpression of P450, CCE, and ABC transporter genes in P. citri. However, the regulatory mechanisms of these detoxification genes are still elusive. This study identified all hormone receptor 96 genes of P. citri. 8 PcHR96 genes contained highly conserved domains. The expression profiles showed that PcHR96h was significantly upregulated in spirodiclofen resistant strain and after exposure to spirodiclofen. RNA interference of PcHR96h decreased expression of detoxification genes and increased spirodiclofen susceptibility in P. citri. Furthermore, molecular docking, heterologous expression, and drug affinity responsive target stability demonstrated that PcHR96h can interact with spirodiclofen in vitro. Our research results indicate that PcHR96h plays an important role in regulating spirodiclofen susceptibility and provides theoretical support for the resistance management of P. citri.

Application of multiplex competitive PCR combined with capillary electrophoresis in carrier screening of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is an autosomal recessive, fatal neurological disorder in children. The pathogenic gene of SMA is survival motor neuron1 (SMN1). There are many methods to detect SMN1 gene copy number, but few techniques are suitable for large-scale population screening. In order to find a rapid and accurate experimental technique for mass screening of SMA carriers in the population, the SMN1 gene copy number of 12 SMA patients and their parents was analyzed by multiplex competitive PCR combined with capillary electrophoresis. Meanwhile, the copy number of SMN1 gene in 151 healthy pregnant women in Jiangsu was screened with the MLPA technology to confirm their copy number of the SMN genes. The results showed that the 12 SMA patients had 0 copy of SMN1 gene, and all their parents had 1 copy of SMN1 gene only. Among 151 healthy subjects, 3 cases (2.0%) had 1 copy of SMN1 gene, and hence designated as SMA carriers. One hundred and thirty-four cases (88.7%) had 2 copies of the SMN1 gene. There were 14 cases (9.3%) with more than 2 copies of the SMN1 gene. Therefore, multiplex competitive PCR combined with capillary electrophoresis is a rapid, simple and accurate method for the detection of SMA carriers; and potentially applicable to mass screening of SMA carriers in the population.

A glutathione S-transferase PcGSTMu2 involved in the detoxification of bifenazate in Panonychus citri.

BACKGROUND: The citri red mite, Panonychus citri (McGregor), is an important citrus pest worldwide, causing enormous economic losses to citrus production. Bifenazate is a widely used acaricide for controlling P. citri. The detoxification mechanism of bifenazate is not clear in P. citri. RESULTS: PcGSTMu2, a significantly upregulated GST gene, was identified by the transcriptome analysis of P. citri after bifenazate exposure. The expression level of PcGSTMu2 was significantly increased after bifenazate exposure. By using RNAi of PcGSTMu2, the susceptibility of P. citri to bifenazate was significantly increased. Protein modeling and docking of PcGSTMu2 with GSH and bifenazate indicated the potential amino acid residues for binding in the active site. Heterologous expression and in vitro functional assays further revealed that PcGSTMu2 could deplete bifenazate. CONCLUSION: These results indicated that PcGSTMu2 plays an important role in the detoxification of bifenazate in P. citri and provides the molecular foundation for understanding bifenazate metabolism in P. citri. © 2024 Society of Chemical Industry.