RESUMO
The intestinal bacteria of longhorn beetles would be ideal targets for pest control and lignocellulosic resources by destroying or exploiting their cellulose-degrading function. This article aims to investigate the diversity and community structure of intestinal bacteria the oligophagous longhorn beetle Glenea cantor. Additionally, it seeks to identify the presence of lignocellulose-degrading bacteria in the gut, and explore their role in consuming host kapok trees Bombax malabaricum. In this study, the bacterial community from G. cantor was examined by Illumina sequencing of 16S ribosomal RNA (rRNA) targeting the V3 and V4 regions. A total of 563,201 valid sequences and 814 OTUs were obtained. The dominant phyla were Proteobacteria, and the dominant genera were Acinetobacter and Lactococcus. The analysis of microbial diversity revealed a high bacterial diversity in the samples, with the gut bacteria playing a crucial role in the physiological activities of the host, particularly, 9 genera of intestinal bacteria with cellulose degradation function were found, highlighting their vital role in cellulose degradation. Five strains of cellulose-degrading bacteria, belonging to the genus Pseudomonas, were obtained from the intestinal tract of G. cantor larvae using traditional isolation and culture techniques as well as 16S rDNA sequencing. Among these strains, A4 exhibited a cellulase activity of 94.42 ± 0.42 U/mL, while A5 displayed the highest filter paper enzyme activity of 127.46 ± 3.54 U/mL. These results offered valuable insights into potential targets for pest control through internal attack digestion and cellulose-degrading bacteria in longhorn beetles.
RESUMO
Diaphorina citri, a vector of citrus huanglongbing (HLB) disease, frequently leads to HLB outbreaks and reduces Rutaceae crop production. Recent studies have investigated the effects of RNA interference (RNAi) targeting the Vitellogenin (Vg4) and Vitellogenin receptor (VgR) genes, which are involved in egg formation in this pest, providing a theoretical foundation for developing new strategies to manage D. citri populations. This study presents RNAi methods for Vg4 and VgR gene expression interference and reveals that dsVgR is more effective than dsVg4 against D. citri. We demonstrated that dsVg4 and dsVgR persisted for 3-6 days in Murraya odorifera shoots when delivered via the in-plant system (IPS) and effectively interfered with Vg4 and VgR gene expression. Following Vg4 and VgR gene expression interference, egg length and width in the interference group were significantly smaller than those in the negative control group during the 10-30-day development stages. Additionally, the proportion of mature ovarian eggs in the interference group was significantly lower than that in the negative control group at the 10, 15, 20, 25, and 30-day developmental stages. DsVgR notably suppresses oviposition in D. citri, with fecundity decreasing by 60-70%. These results provide a theoretical basis for controlling D. citri using RNAi to mitigate the spread of HLB disease.
