This experiment investigated the role of the gut microbiota in the growth and development of Antheraea pernyi, isolated gut bacteria related to lignin degradation in oak trees, and preliminarily verified their lignin degradation ability, providing a new tool for the field of biodegradation. The changes in the structure of the gut microbial community of the oak silkworm Antheraea pernyi at different developmental stages were analyzed via high-throughput sequencing of the 16SrDNA genes of the gut microbiota of fifth-instar larvae. A series of biological analyses were conducted, including amplicon sequence variant (ASV), microbial community diversity, microbial community composition, species difference, and evolutionary analyses. Ralstonia, Achromobacter, Pseudomonas, Cupriavidus, Bacteroidetes, Enterococcus, and Bacillus were the dominant bacterial groups in the gut microbiota of the larvae, with Ralstonia comprising the highest proportion, thereby providing a reference basis for a deeper understanding of the functions of the gut microbiota in insect growth and development. In this study, we activated and identified the MYZ028 strain isolated from the fifth-instar larvae of Antheraea pernyi through molecular biology, and we determined that the strain belonged to Bacillus subtilis. In terms of performance, the strain exhibited a high lignin-degrading ability and could effectively degrade lignin in a short time and simple environment. Due to the complex and difficult nature of degrading the lignin structure, research on the degradation of lignin by composite strains can be explored in the field of biodegradation.

The midgut of Antheraea pernyi plays a critical role in antiviral defense. However, its transcriptional complexity remains poorly understood. Here, a full-length (FL) transcriptome atlas of A. pernyi midgut was developed by integrating PacBio Iso-Seq and RNA-seq techniques. The transcriptome sequences included 1850 novel protein-coding genes, 17,736 novel alternative isoforms, 1664 novel long non-coding RNAs (lncRNAs), and 858 transcription factors (TFs). In addition, 2471 alternative splicing (AS) events and 3070 alternative polyadenylation (APA) sites were identified. Moreover, 3426 and 4796 differentially expressed genes (DEGs) and isoforms were identified after ApNPV infection, respectively, besides the differentially expressed lncRNAs (164), TFs (171), and novel isoforms of ApRelish (1) and ApSOCS2 (4). Enrichment analyses showed that KEGG pathways related to metabolism were suppressed, whereas GO terms related to DNA synthesis and replication were induced. Furthermore, the autophagy and apoptosis pathways were significantly enriched among the upregulated genes. Protein–protein interaction network (PPI) analysis revealed the coordinated downregulation of genes involved in mitochondrial ribosomes, V-type and F-type ATPases, and oxidative phosphorylation, indicating the disruption of host energy metabolism and organelle acidification. Moreover, coordinated upregulation of genes associated with cytoplasmic ribosomes was observed, suggesting that the infection by ApNPV interferes with host translational machinery. These results show that ApNPV infection reprograms energy metabolism, biosynthetic processes, and immune response in A. pernyi midgut. Our study provides a foundation for elucidating the mechanisms of A. pernyi–virus interactions, particularly how the viruses affect host defense strategies.

Antheraea pernyi is a large silk-producing insect belonging to the family Saturniidae of the order Lepidoptera