Xin Tianrong, Li Zhenzhen, Chen Jia, Wang Jing, Zou Zhiwen, Xia Bin
School of Life Sciences, Nanchang University, Nanchang 330031, China.
Insects. 2021 May 28;12(6):501. doi: 10.3390/insects12060501.
The carmine spider mite, (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 responds to insecticide exposure, we identified the chitin synthase 1 gene () and then explored the gene expression levels of at different developmental stages of . We also investigated the effects of sublethal concentrations of diflubenzuron on the toxicities and survivals of eggs and larvae as well as 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 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 revealed that 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 . The mRNA expression levels of from the eggs and larvae of were up-regulated in response to sublethal concentrations of diflubenzuron exposures. Together, all these results demonstrate that diflubenzuron has ovicidal and larvicidal effects and may play an important role in the growth and development of and may disrupt the chitin biosynthesis, thereby controlling populations.
二斑叶螨（Tetranychus urticae （Boisduval））是最重要的螨类害虫之一。目前，其防治主要仍依赖于在全球范围内的农作物上使用各种化学杀虫剂/杀螨剂。为阐明二斑叶螨对杀虫剂暴露的响应机制，我们鉴定了几丁质合成酶1基因（TcCHS1），然后探究了该基因在二斑叶螨不同发育阶段的表达水平。我们还研究了亚致死浓度的除虫脲对二斑叶螨卵和幼螨的毒性及存活情况以及TcCHS1表达水平的影响。该全长cDNA序列包含一个4881个核苷酸的开放阅读框（ORF），编码一个1474个氨基酸残基的蛋白质。预测的TcCHS1蛋白分子量为168.35 kDa，等电点为6.26，其氨基酸序列包含几丁质合成酶的所有特征基序（EDR、QRRRW和TWGTR）。系统发育分析结果表明，二斑叶螨假定的CHS1氨基酸序列与其他昆虫和螨类的几丁质合成酶具有高度相似性。此外，在分子水平上，通过实时定量PCR对二斑叶螨不同发育阶段进行转录分析表明，TcCHS1 mRNA在所有阶段均有表达，在卵和雌成螨中表达最高，但在若螨中表达最低。此外，毒性生物测定结果表明，除虫脲处理导致二斑叶螨卵和幼螨的死亡率很高。二斑叶螨卵和幼螨中TcCHS1的mRNA表达水平在亚致死浓度的除虫脲暴露后上调。总之，所有这些结果表明，除虫脲具有杀卵和杀幼虫作用，TcCHS1可能在二斑叶螨的生长发育中起重要作用，并且可能扰乱几丁质生物合成，从而控制二斑叶螨种群。
