The development of site-specific genome-editing tools like CRISPR (clustered regularly interspaced short palindromic repeat) and its associated protein, Cas9, is revolutionizing genetic engineering with its highly efficient mechanism, offering the potential for effective pest management. Recently, CRISPR/Cas9 gene-editing has been extensively utilized in the management of the diamondback moth, Plutella xylostella (L.), a highly destructive pest of vegetable crops, for different purposes, such as gene function analysis and genetic control. However, the progress related to this gene-editing tool in P. xylostella has not yet been summarized. This review highlights the progress and applications of CRISPR/Cas9 in uncovering the genes critical for development, reproduction, and insecticide resistance in P. xylostella. Moreover, the progress related to the CRISPR/Cas9 gene drive for population suppression and modifications has also been discussed. In addition to the significant progress made, challenges such as low germline editing efficiency and limited homology-directed repair remain obstacles to its widespread application. To address these limitations, we have discussed the different strategies that are anticipated to improve the efficiency of CRISPR/Cas9, paving the way to it becoming a pivotal tool in sustainable pest management. Therefore, the present review will help researchers in the future enhance the efficiency of the CRISPR/Cas9 system and use it to manage the diamondback moth.

Acetyl-CoA, the precursor of sex pheromone biosynthesis in Helicoverpa armigera, is generated from glycolysis. As the first speed-limited enzyme in glycolysis, Hexokinase (HK) plays an important role in acetyl-CoA production. However, the function of HK in sex pheromone production remains unclear. This study employed H. armigera as material to explore the role of HK in sex pheromone production. Results demonstrated that the transcription profile of HaHK in female moth pheromone glands (PGs) was consistent with the release fluctuation of sex pheromone. Interference of HaHK prevented the increase of acetyl-CoA content induced by PBAN. Therefore, knockdown of HaHK in female PGs caused significant decreases in (Z)-11-hexadecenal (Z11-16:Ald) production, female capability to attract males, and mating rate. Furthermore, sugar feeding (5% sugar) increased the transcription and enzymatic activity of HK. Pheromone biosynthesis activating neuropeptide (PBAN) signal phospho-activated HaHK in PGs and Sf9 cells via protein kinase A (PKA), as shown by pharmacological inhibitor analysis. In general, our study confirmed that PBAN/cAMP/PKA signal activated HaHK, in turn promoted glycolysis to ensure the supply of acetyl-CoA, and finally facilitated sex pheromone biosynthesis and subsequent mating behavior.

Gametocyte-specific factor 1 (Gtsf1) plays a pivotal role in the gonadal development by transposon silencing via the piRNA pathway in Drosophila melanogaster and Bombyx mori, and is implicated in the female sex determination in B. mori. However, its function remains elusive in other insect species, including Plutella xylostella, a highly destructive pest in cruciferous crops. In this study, we characterized PxGtsf1, encoding a 27.84 kDa protein containing two conserved U11-48K-like CHHC zinc-finger domains. PxGtsf1 was predominantly expressed in male pupae, males and testes. Using CRISPR/Cas9 technique, we successfully generated a homozygous PxGtsf1-knockout strain (△PxGtsf1) with 11 bp deletion. △PxGtsf1 females exhibited normal morphology in terms of external genitalia, body weight, ovariole morphology, ovariole length, oocytes number, and internal ovarian structure, and maintained the expression levels of genes related to female sex determination and fertility. In contrast, △PxGtsf1 males displayed reduced testis size and enlarged eupyrene sperm bundles, whereas apyrene sperm bundles appeared normal. Wild-type (WT) or △PxGtsf1 females mated with △PxGtsf1 males had significantly smaller bursa copulatrix distention area compared to those mated with WT males. Furthermore, WT or △PxGtsf1 females mated with △PxGtsf1 males produced significantly fewer eggs with lower hatching rates than those mated with WT males. Co-immunoprecipitation assays revealed that PxGtsf1 specifically interacts with PxPiwi. Small RNA sequencing further showed that PxGtsf1 knockout resulted in transposon dysregulation in the testes without affecting overall piRNA abundance, suggesting that PxGtsf1 functions in piRNA-mediated transposon regulation rather than global piRNA biogenesis. PxGtsf1 is first reported to be specifically required for male fertility in Lepidoptera insects but is dispensable for female sex determination., PxGtsf1 regulates transposon homeostasis without affecting global piRNA biogenesis. These findings provide new insights into the diverse functions of Gtsf1 in Lepidopteran insects.