The transcriptomic profile of Spodoptera frugiperda differs in response to a novel insecticide, cyproflanilide, compared to chlorantraniliprole and avermectin

The pan-genome of Spodoptera frugiperda provides new insights into genome evolution and horizontal gene transfer

Spodoptera frugiperda is a common and severely damaging agricultural pest. In-depth analysis of its population genomics and transcriptomics is crucial for providing references for pest control efforts. This study, focused on the extensive variation in the genome size of S. frugiperda, constructed its pan-genome and identified 1.37 Gb of non-reference sequences, highlighting significant genetic variation within the population. Analysis of Long Terminal Repeat (LTR) Presence/Absence Variation (PAV) suggests that LTR alterations may be one of the driving factors for genome size variation. Additionally, population gene PAV analysis revealed that variable genes are enriched in functions like acetyltransferase activity, which might be associated with detoxification, implying diverse selection pressures related to detoxification in different S. frugiperda populations. Moreover, 19 horizontal gene transfer (HGT) acquired genes were identified in the reference genome used in this study, which responded to 16 different treatments. Notably, three HGT-acquired genes (SFR02618, SFR05248, and SFR05249) co-expressed with heat shock protein family and responded under treatments with Avermectin and Cypermethrin. This may indicate their involvement in a detoxification mechanism coordinated with heat shock proteins. These results offering new insights into its genomic evolution and the potential functions of HGT-acquired genes.

Impact of Sublethal Insecticides Exposure on Vespa magnifica: Insights from Physiological and Transcriptomic Analyses

Insecticides are widely used to boost crop yields, but their effects on non-target insects like Vespa magnifica are still poorly understood. Despite its ecological and economic significance, Vespa magnifica has been largely neglected in risk assessments. This study employed physiological, biochemical, and transcriptomic analyses to investigate the impact of sublethal concentrations of thiamethoxam, avermectin, chlorfenapyr, and β-cypermethrin on Vespa magnifica. Although larval survival rates remained unchanged, both pupation and fledge rates were significantly reduced. Enzymatic assays indicated an upregulation of superoxide dismutase and catalase activity alongside a suppression of peroxidase under insecticide stress. Transcriptomic analysis revealed increased adenosine triphosphate-related processes and mitochondrial electron transport activity, suggesting elevated energy expenditure to counter insecticide exposure, potentially impairing essential functions like flight, hunting, and immune response. The enrichment of pathways such as glycolysis, hypoxia-inducible factor signaling, and cholinergic synaptic metabolism under insecticide stress highlights the complexity of the molecular response with notable effects on learning, memory, and detoxification processes. These findings underscore the broader ecological risks of insecticide exposure to non-target insects and highlight the need for further research into the long-term effects of newer insecticides along with the development of strategies to safeguard beneficial insect populations.

Transcriptome analysis reveals mechanisms of metabolic detoxification and immune responses following farnesyl acetate treatment in Metisa plana

Metisa plana is a widespread insect pest infesting oil palm plantations in Malaysia. Farnesyl acetate (FA), a juvenile hormone analogue, has been reported to exert in vitro and in vivo insecticidal activity against other insect pests. However, the insecticidal mechanism of FA on M. plana remains unclear. Therefore, this study aims to elucidate responsive genes in M. plana in response to FA treatment. The RNA-sequencing reads of FA-treated M. plana were de novo-assembled with existing raw reads from non-treated third instar larvae, and 55,807 transcripts were functionally annotated to multiple protein databases. Several insecticide detoxification-related genes were differentially regulated among the 321 differentially expressed transcripts. Cytochrome P450 monooxygenase, carboxylesterase, and ATP-binding cassette protein were upregulated, while peptidoglycan recognition protein was downregulated. Innate immune response genes, such as glutathione S-transferases, acetylcholinesterase, and heat shock protein, were also identified in the transcriptome. The findings signify that changes occurred in the insect's receptor and signaling, metabolic detoxification of insecticides, and immune responses upon FA treatment on M. plana. This valuable information on FA toxicity may be used to formulate more effective biorational insecticides for better M. plana pest management strategies in oil palm plantations.

Screening and functional validation of the core detoxification genes conferring broad-spectrum response to insecticides in Spodoptera frugiperda

BACKGROUND

Fall armyworm, Spodoptera frugiperda, a formidable agricultural pest, has developed resistance to various synthetic insecticides. However, how S. frugiperda utilizes its limited energy and resources to deal with various insecticides remains largely unexplored.

RESULTS

We utilized transcriptome sequencing to decipher the broad-spectrum adaptation mechanism of S. frugiperda to eight insecticides with distinct modes-of-action. Analysis of the Venn diagram revealed that 1014 upregulated genes and 778 downregulated genes were present in S. frugiperda treated with at least five different insecticides, compared to the control group. Exposure to various insecticides led to the significant upregulation of eight cytochrome P450 monooxygenases (P450s), four UDP glucosyltransferases (UGTs), two glutathione-S-transferases (GSTs) and two ATP-binding cassette transporters (ABCs). Among them, the sfCYP340AD3 and sfCYP4G74 genes were demonstrated to respond to stress from six different insecticides in S. frugiperda, as evidenced by RNA interference and toxicity bioassays. Furthermore, homology modeling and molecular docking analyses showed that sfCYP340AD3 and sfCYP4G74 possess strong binding affinities to a variety of insecticides.

CONCLUSION

Collectively, these findings showed that S. frugiperda utilizes a battery of core detoxification genes to cope with the exposure of synthetic insecticides. This study also sheds light on the identification of efficient insecticidal targets gene and the development of resistance management strategies in S. frugiperda, thereby facilitating the sustainable control of this serious pest. © 2024 Society of Chemical Industry.

Immunomodulatory Activity and Its Mechanisms of Two Polysaccharides from Poria cocos

Polyporaceae is an important fungal family that has been a source of natural products with a range of pharmaceutical activities in China. In our previous study, two polysaccharides, PCWPW and PCWPS, with significant antioxidant and antidepressant activity were obtained from Poria cocos. In this study, we evaluated their potential molecular mechanisms in the immunomodulation of macrophages. PCWPW and PCWPS were characterized by GC-MS analysis to contain 1,3-linked Glcp. ELISA assays results demonstrated that the secretion of TNF-α was significantly enhanced by PCWPW/PCWPS. RNA-seq data demonstrated that PCWPS treatment modulated the expression of immune-related genes in macrophages, which was further confirmed by RT-qPCR assays. The activation of TNF-α secretion was found to be mannose receptor (MR) dependent and suppressed by MR inhibitor pretreatment. Moreover, the amount of TNF-α cytokine secretion in PCWPW/PCWPS-induced RAW264.7 cells was decreased when pretreated with NF-κB or MAPK signaling pathway inhibitors. Collectively, our results suggested that PCWPW and PCWPS possessed immunomodulatory activity that regulates TNF-α expression through the NF-κB/MAPK signaling pathway by binding to mannose receptors. Therefore, PCWPW and PCWPS isolated from Poria cocos have potential as drug candidates for immune-related disease treatment.