Molecular Characterization of Chitin Synthase Gene in Tetranychus cinnabarinus (Boisduval) and Its Response to Sublethal Concentrations of an Insecticide

Abstract

The carmine spider mite, Tetranychus cinnabarinus (Boisduval), is one of the most important acarine pest species. At present, its control remains primarily dependent on using various chemical insecticides/acaricides in agricultural crops worldwide. To clarify the mechanism whereby T. cinnabarinus responds to insecticide exposure, we identified the chitin synthase 1 gene (TcCHS1) and then explored the gene expression levels of TcCHS1 at different developmental stages of T. cinnabarinus. We also investigated the effects of sublethal concentrations of diflubenzuron on the toxicities and survivals of T. cinnabarinus eggs and larvae as well as TcCHS1 expression levels. The full-length cDNA sequence contains an open reading frame (ORF) of 4881 nucleotides that encoded for a 1474 amino acid residues protein. The predicted TcCHS1 protein had a molecular mass of 168.35 kDa and an isoelectric point of 6.26, and its amino acid sequence contained all the signature motifs (EDR, QRRRW and TWGTR) of chitin synthases. The results of phylogenetic analyses demonstrated that the putative CHS1 amino acid sequence of T. cinnabarinus revealed high similarities with chitin synthases in other insects and mites. Additionally, at the molecular level, transcriptional analysis by real-time quantitative PCR in different developmental stages of T. cinnabarinus revealed that TcCHS1 mRNA was expressed in all stages, and highest in eggs and female adults, but lowest in deutonymphs. Furthermore, the results of toxicity bioassays indicated that diflubenzuron treatment resulted in high mortality rates in eggs and larvae of T. cinnabarinus. The mRNA expression levels of TcCHS1 from the eggs and larvae of T. cinnabarinus were up-regulated in response to sublethal concentrations of diflubenzuron exposures. Together, all these results demonstrate that diflubenzuron has ovicidal and larvicidal effects and TcCHS1 may play an important role in the growth and development of T. cinnabarinus and may disrupt the chitin biosynthesis, thereby controlling T. cinnabarinus populations.

The moulting arthropod: a complete genetic toolkit review

“…Despite the limited number of Chs genes, they are reported to have numerous exons, for example, 24 in Spodoptera exigua, thus being capable of generating multiple alternative splicing variants (Liu, Zhang & Zhu, 2019b). In Crustacea, the number of Chs genes is variable, with cirripedes and copepods having two or more genes with unknown specialisation, while most decapods possess a single Chs gene (Zhang et al, 2021;Xin et al, 2021). Chelicerates also seem to harbour one unique copy (Zhang et al, 2021;Xin et al, 2021).…”

“…In Crustacea, the number of Chs genes is variable, with cirripedes and copepods having two or more genes with unknown specialisation, while most decapods possess a single Chs gene (Zhang et al, 2021;Xin et al, 2021). Chelicerates also seem to harbour one unique copy (Zhang et al, 2021;Xin et al, 2021). Unfortunately, chitin synthases seem largely unexplored in spiders, compared to their preliminary explorations in ticks and mites, and information on these genes is also lacking for Myriapoda (Han et al, 2005;Li et al, 2015Liu et al, 2019a;Becchimanzi et al, 2020;Zhang et al, 2021;Song et al, 2021;Yuan et al, 2022b;Chen et al, 2023).…”

“…Enzymes identified in Insecta and Crustacea are further classified into several groups based on sequence diversity, but classifications might be refined as new genomes become available (Zhang et al, 2021). Studies in a few representative species of all these subphyla have described the expression of enzymes involved in chitin metabolism across different tissues and developmental phases and have shown that suppression of CHSs and CDAs significantly impairs the moulting cycle (Moussian et al, 2015;Ventura et al, 2015;Ali et al, 2020;Li et al, 2021e;Zhang et al, 2021;Xin et al, 2021;Song et al, 2021).…”

Optimization of Osthole in the Lactone Ring as an Agrochemical Candidate: Synthesis, Characterization, and Pesticidal Activities of Osthole Amide/Ester Derivatives and Their Effects on Morphological Changes of Mite Epidermis

“…Mythimna separata Walker (Lepidoptera: Noctuidae) is a typical long-distance migratory pest that poses a serious threat to the safe production of maize, wheat, and rice. It has a wide range of occurrences and many generations of damage, leading to crop yield reduction and failure in severe cases. − Tetranychus cinnabarinus Boisduval (Acari: Tetranychidae) is one of the most harmful mites in the world of agriculture and forest production, with a short life history, high reproductive capacity, and high resistance to many chemical active ingredients. − Blind pesticide abuse frequently occurs in an effort to increase crop yields, and manage pests and illnesses, which results in the emergence of pest resistance , and major environmental pollution issues. − Obviously, the development of new pesticides is still on the way. Botanical pesticides can control or obstruct pest development, reproduction, and behavior by nontoxic processes, thereby lowering the use of chemical pesticides, assuring the quality and safety of agricultural goods, and preserving ecological security. − Recently, the discovery of novel pesticides from natural products has received much attention. − …”

Design, Synthesis, Acaricidal Activities, and Structure–Activity Relationship Studies of Oxazolines Containing Ether Moieties

“…It is effective against Tetranychus mites, Panonychus mites, and other mites in cotton, fruit trees, flowers, and other crops, especially in killing mite eggs and larvae. , The main mode of action of etoxazole is to inhibit the synthesis of chitin . In recent years, studies have shown that its target may be the sulfonylurea receptor or chitin synthase-1. ,− Etoxazole is the only commercial acaricide having a 2,4-diphenyl-1,3-oxazoline skeleton. After it was put into the market, the development of acaricides with the same skeleton but higher activity and greater potential has never stopped. − Our group has designed and synthesized several series of 2,4-diphenyl-1,3-oxazolines, including those that contain an oxime ether, a thioether, a sulfonate, or a nitrogen-containing heterocycle at the para site of the 4-phenyl of the oxazoline ring, and quite a few compounds (Figure ) were found to exhibit better acaricidal activity than etoxazole. ,− However, considering the activity and production cost in general, they are not yet practical for industrial development.…”