No abstract

Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-associated gene Cas9 represent an invaluable system for the precise editing of genes in diverse species. The CRISPR/Cas9 system is an adaptive mechanism that enables bacteria and archaeal species to resist invading viruses and phages or plasmids. Compared with zinc finger nucleases and transcription activator-like effector nucleases, the CRISPR/Cas9 system has the advantage of requiring less time and effort. This efficient technology has been used in many species, including diverse arthropods that are relevant to agriculture, forestry, fisheries, and public health; however, there is no review that systematically summarizes its successful application in the editing of both insect and non-insect arthropod genomes. Thus, this paper seeks to provide a comprehensive and impartial overview of the progress of the CRISPR/Cas9 system in different arthropods, reviewing not only fundamental studies related to gene function exploration and experimental optimization but also applied studies in areas such as insect modification and pest control. In addition, we also describe the latest research advances regarding two novel CRISPR/Cas systems (CRISPR/Cpf1 and CRISPR/C2c2) and discuss their future prospects for becoming crucial technologies in arthropods.

The two‐spotted spider mite Tetranychus urticate is an important agricultural pest worldwide. It is extremely polyphagous and has developed resistance to many pesticides. Here, we assessed the pesticide resistance of seven field populations of T. urticae in China, their target site mutations and the activities of their detoxification enzymes. The results showed that abamectin and the traditional pesticides pyridaben, profenofos and bifenthrin had higher resistance or lower toxicity than more recently developed pesticides including chlorfenapyr, spinetoram, cyflumetofen, cyenopyrafen, bifenazate and B‐azolemiteacrylic. The frequency of point mutations related to abamectin resistance, G314D in the glutamate‐gated chloride channel 1 (GluCl1) and G326E in GluCl3, ranged 47%–70% and 0%–97%, respectively. The frequency of point mutations in A1215D and F1538I of the voltage‐gated sodium channel gene (VGSC), which may increase resistance to pyrethroids, ranged 88%–100% and 10%–100%, respectively. For target sites related to organophosphate resistance, mutation frequencies ranged 25%–92% for G119S and 0%–23% for A201S in the acetycholinesterase gene (Ace). Mutation G126S in the bifenazate resistance‐related cytochrome b gene (Cytb) was observed in three of the seven T. urticae populations. Higher activities of detoxification enzymes (P450, GST, CarEs and UGTs) were observed in two T. urticae populations, with significant difference in the XY‐SX population. These results provide useful information on the status of pesticide resistance of T. urticae in China and suggest that T. urticae field populations may have multiple resistance mechanisms.