Insects, Vol. 16, Pages 1010: Bt Exposure-Induced Death of Dioryctria abietella (Lepidoptera: Pyralidae) Involvement in Alterations of Gene Expression and Enzyme Activity
Insects doi: 10.3390/insects16101010
Authors:
Xiaomei Wang
Jiaxing Sun
Ya Xing
Ruting Chen
Defu Chi
Dioryctria abietella (Lepidoptera: Pyralidae) is a destructive forest pest for coniferous trees. Bacillus thuringiensis has been widely applied in forestry as a biological control agent to control it. However, the mechanisms of Bt-induced mortality in D. abietella, particularly its effects on gene expression and enzyme activities, remain unclear. Here, bioassay, enzyme assay, transcriptome sequencing, and gene expression profiling were employed to explore the relationship between the toxin-receptor, defense, and lethal mechanisms of D. abietella after Bt exposure. In a toxicity bioassay, Bacillus thuringiensis galleriae 05041 strain (Bt05041) was the most toxic insecticide to the larvae of D. abietella, with LC50 values of 3.15 × 108 Colony-Forming Units (CFUs) mL−1 at 72 h after treatment. Transcriptome analysis revealed that the gene expression patterns of D. abietella after 8 h of Bt05041 exposure (Bt8) varied considerably from the Bt05041-treated for 2 h group (Bt2). In the Bt2 group, differentially expressed genes were significantly enriched in cellular and bioenergy pathways of lysosome, insulin signaling, cGMP-PKG signaling, etc. Immune-related pathways were activated, namely cAMP, AMPK, MAPK, Rap1, IMD, and Toll pathways. Meanwhile, Bt8 treatment caused metabolic changes in basic substances such as amino acids, glucose, nucleic acids, and fatty acids. Bt05041 exposure activated the activities of defense enzymes and induced gene expression changes in D. abietella larvae. Among them, most Bt-receptor genes had higher expression levels than defense enzyme genes. Overall, these findings reveal a possible mechanism underlying Bt-mediated death in D. abietella larvae. This work provides valuable information in terms of biological control strategies.
Source link
Xiaomei Wang www.mdpi.com
