In almost all aerobic organisms, the superoxide dismutase (SOD) is considered as an important antioxidant enzyme regulating oxidative stress. Tetranychus cinnabarinus is an economically important polyphagous pest mite, which harms a variety of economic crops and ornamental plants. In the present study, the full-length cDNA sequences of cytoplasmic Cu/ZnSOD (TcSOD1), extracellular Cu/ZnSOD (TcSOD2) and mitochondrial MnSOD (TcSOD3) from T. cinnabarinus were cloned by combining RT-PCR and rapid amplification of cDNA ends (RACE). The corresponding open reading frames (ORFs) encode three putative polypeptides of 152, 232, 225 amino acid residues, respectively. These sequences share the conserved SOD functional domains, signature motifs and metal binding sites. Multiple alignment analysis revealed that cytosolic Cu/ZnSOD and mitochondrial MnSOD sequences are relatively conserved, while extracellular Cu/ZnSODs are more diverse. Phylogenetic analysis showed that SODs are organized into two major clades, corresponding to Cu/ZnSODs, and MnSODs. Cu/ZnSODs are subdivided into two branches, one being composed of cytoplasmic Cu/ZnSODs, and the other corresponding to extracellular Cu/ZnSODs. Expression profiles of the three genes were determined at different temperatures (4°C, 25°C, and 40°C) for 2 hours. The relative expression of TcSOD1, TcSOD2, and TcSOD3 were significantly down-regulated (0.344-, 0.287-, and 0.358-fold, respectively) at 4°C compared to 25°C (P<0.05). The relative expression levels of TcSOD1 and TcSOD2 genes were significantly down-regulated at 40°C (0.481- and 0.291-fold less than in the control group, respectively) (P<0.05), while there was no significant difference in the relative expression level of TcSOD3(P>0.05). Moreover, expression levels were altered after exposition to different acaricides. TcSOD1, TcSOD2, and TcSOD3 were significantly down-regulated (0.450-, 0.147- and 0.663-fold decreases, respectively) in the abamectin-treated group (P<0.05). TcSOD1 and TcSOD2 were down-regulated, in the fenpropathrin-treated group with 0.794- and 0.201-fold decreases, respectively. On the other hand, the expression of TcSOD3 was significantly increased (P<0.05), being 2.774-fold higher than in the control group. The expression of TcSOD2 was significantly down-regulated both the propargite- and cyflumetofen-treated groups (0.655- and 0.397-fold, respectively) (P<0.05). The data reported here indicate that SODs from T. cinnabarinus may play different and vital roles in anticipating the effects of oxidative damage at extreme temperatures and under different acaricides stress.

Vitellogenin (Vg) and Vitellogenin receptor (VgR) play key roles in the reproductive process and development of many arthropod species, including Amblyseius eharai, a dominant natural enemy of spider mites and other small pests. In this study, impacts of different food on A. eharai fecundity were investigated. Two Vg genes (AeVg1 and AeVg2) and AeVgR genes were cloned, with their expression pattern analyzed. When fed with different foods including Tetranychus cinnabarinus, Aleuroglyphus ovatus and Camellia oleifera pollen, the number of eggs for each female of A. eharai was influenced significantly (P<0.05), while the hatching rate of eggs not significantly (P>0.05). The open reading frames of AeVg1, AeVg2 and AeVgR were 5673, 5634 and 5597 bp, encoding 1857, 1851 and 1830 amino acids, respectively. Phylogenetic analysis of the amino acid sequences between the AeVgs and AeVgR and 35 other Vg and VgRs from other arthropod species showed that A. eharai AeVg1 was related most closely to Neoseiulus barkeri Vg1, AeVg2 was related most closely to Neoseiulus cucumeris Vg2, AeVgR was most similar to Varroa jacobsori VgR. AeVgs and AeVgR had similar expression patterns: the highest expression was observed in the oviposition female stage, and the highest expression was observed in A. eharai fed with C. oleifera pollen. Positive correlations between expression of AeVgs and AeVgR and fecundity were observed. These results will help us understand the molecular mechanism of the reproductive capacity in A. eharai.

Diflubenzuron, a benzoylphenylurea insecticide that interferes with chitin biosynthesis, causes arthropods to moult abnormally and die. However, its mechanism of action in Tetranychus cinnabarinus is still unclear. In order to explore the effects of different sublethal concentrations of diflubenzuron on T. cinnabarinus, we conducted a high-throughput RNA-seq technology to identify the variations in transcriptomic profile of T. cinnabarinus larvae. The results revealed that 470 and 49 differentially expressed genes were identified in LC50-and LC70-treated groups, comparing with the control. We also identified and analyzed the detoxification enzymes involved in the transcritome of T. cinnabarinus, including 34 cytochrome P450 genes, 17 glutathione-s-transferase genes (GSTs), 12 acetylcholinesterase genes (AChEs) and 9 ABC transporter genes. In addition, differentially expressed genes analysis showed that the gene expression levels of detoxification enzymes were generally enhanced. At the same time, seven and eleven genes were involved in chitin synthesis and degradation ways, respectively. The expression level of most genes involved in chitin synthesis and degradation pathway were generally up-regulated after exposure to sublethal concentrations of diflubenzuron. Moreover, for transcriptome validation, the mRNA expression results of ten specially expressed genes by quantitative real-time PCR demonstrated that these gene expression trends were consistent with that of the transcriptome data. Together, all these results suggested that sublethal concentrations of diflubenzuron exposure affected gene expression of major detoxification enzymes and chitin metabolism genes in T. cinnabarinus larvae. These findings may be helpful to further understand the possible molecular mechanism of benzoylphenylurea insecticides in T. cinnabarinus, as well as in other spider mites.