Genome-Wide Identification, Expression Profiling, and Characterization of Cyclin-like Genes Reveal Their Role in the Fertility of the Diamondback Moth

Tyrosine Hydroxylase Is Required for the Larval-Pupal Transformation and Immunity of Plutella xylostella: Potential for Pest Management

Plutella xylostella has developed high levels of resistance to many commonly used insecticides. Tyrosine hydroxylase (TH) is essential for insect survival; thus, we evaluated whether TH could be a potential target for controlling P. xylostella. In this study, PxTH was identified; further qPCR analysis showed that PxTH increased its expression during larval pupation and was highly expressed in the head and epidermis of prepupa in P. xylostella. Subsequently, we found a significant decrease in insect pupation and eclosion rates after injection of dsPxTH or a feeding diet supplemented with 3-iodo-tyrosine (3-IT) as a TH inhibitor in P. xylostella. Moreover, this study suggested that PxTH enzyme activity and dopamine concentrations were significantly decreased, agreeing with the blockage of larval-pupal cuticle tanning, with thinner puparium and less melanization after feeding 3-IT. In addition, expression levels of four antimicrobial peptide genes were significantly inhibited after P. xylostella feeding with 3-IT, and injection of Escherichia coli resulted in 73.3% mortality, indicating that PxTH was required for immune responses. In summary, these results confirmed that PxTH was involved in the development and immunity of P. xylostella, suggesting a critical potential novel insecticide target for RNAi-based pest control.

Exploring the role of the ovary-serine protease gene in the female fertility of the diamondback moth using CRISPR/Cas9

BACKGROUND

Oogenesis is a complex pathway necessary for proper female reproduction in insects. Ovary-serine protease (Osp) is a homologous gene of serine protease Nudel (SpNudel) and plays an essential role in the oogenesis and ovary development of Drosophila melanogaster. However, the function of Osp is not determined in Plutella xylostella, a highly destructive pest of cruciferous crops.

RESULTS

The PxOsp gene comprises a 5883-bp open-reading frame that encodes a protein consisting of 1994 amino acids, which contain four conserved domains. PxOsp exhibited a high relative expression in adult females with a specific expression in the ovary. Through the utilization of CRISPR/Cas9 technology, homozygous mutants of PxOsp were generated. These homozygous mutant females produced fewer eggs (average of 56 eggs/female) than wild-type (WT) females (average of 97 eggs/female) when crossed with WT males, and these eggs failed to hatch. Conversely, mutant males produced normal progeny when crossed with WT females. The ovarioles in homozygous mutant females were significantly shorter (5.02 mm in length) and contained fewer eggs (average of 3 eggs/ovariole) than WT ovarioles (8.09 mm in length with an average of 8 eggs/ovariole). Moreover, eggs laid by homozygous mutant females were fragile, with irregular shapes, and were unable to maintain structural integrity due to eggshell ruptures. However, no significant differences were observed between WT and mutant individuals regarding developmental duration, pupal weight, and mating behavior.

CONCLUSION

Our study suggesteds that PxOsp plays a vital role in female reproduction, particularly in ovary and egg development. Disrupting PxOsp results in recessive female sterility while leaving the male reproductive capability unaffected. This report represents the first study of a haplosufficient gene responsible for female fertility in lepidopteran insects. Additionally, these findings emphasize PxOsp as a potential target for genetically-based pest management of P. xylostella. © 2024 Society of Chemical Industry.

The Potential Role of the Piwi Gene in the Development and Reproduction of Plutella xylostella

Piwi proteins play a significant role in germ cell development and the silencing of transposons in animals by associating with small non-coding RNAs known as Piwi-interacting RNAs (piRNAs). While the Piwi gene has been well characterized in various insect species, the role of the Piwi (PxPiwi) gene in the diamondback moth (Plutella xylostella), a globally distributed pest of cruciferous crops, remains unclear. Expression analysis demonstrated the upregulation of PxPiwi in pupae and testes. Furthermore, we generated a PxPiwi-knockout mutant using CRISPR/Cas9 technology, which resulted in a significantly prolonged pupal stage and the failure of pupae to develop into adults. Additionally, the knockdown of PxPiwi, through RNA interference (RNAi), led to a substantial decrease in the oviposition and hatchability of P. xylostella. These findings indicate that PxPiwi is specifically expressed and essential for the development and reproduction of P. xylostella. This is the first report indicating the involvement of the Piwi gene in the development of lepidopteran insects, except for reproduction and germ cell development, which provides a foundation for future investigations into the functions of PxPiwi.

Genome-Wide Identification and Expression Analysis of the TIR-NBS-LRR Gene Family and Its Response to Fungal Disease in Rose (Rosa chinensis)

Roses, which are one of the world's most important ornamental plants, are often damaged by pathogens, resulting in serious economic losses. As a subclass of the disease resistance gene family of plant nucleotide-binding oligomerization domain (NOD)-like receptors, TIR-NBS-LRR (TNL) genes play a vital role in identifying pathogen effectors and activating defense responses. However, a systematic analysis of the TNL gene family is rarely reported in roses. Herein, 96 intact TNL genes were identified in Rosa chinensis. Their phylogenies, physicochemical characteristics, gene structures, conserved domains and motifs, promoter cis-elements, microRNA binding sites, and intra- and interspecific collinearity relationships were analyzed. An expression analysis using transcriptome data revealed that RcTNL genes were dominantly expressed in leaves. Some RcTNL genes responded to gibberellin, jasmonic acid, salicylic acid, Botrytis cinerea, Podosphaera pannosa, and Marssonina rosae (M. rosae); the RcTNL23 gene responded significantly to three hormones and three pathogens, and exhibited an upregulated expression. Furthermore, the black spot pathogen was identified as M. rosae. After inoculating rose leaves, an expression pattern analysis of the RcTNL genes suggested that they act during different periods of pathogen infection. The present study lays the foundations for an in-depth investigation of the TNL gene function and the mining of disease resistance genes in roses.