Analysis of the Humoral Immunal Response Transcriptome of Ectropis obliqua Infected by Beauveria bassiana

Abstract

Ectropis obliqua is a destructive masticatory pest in China’s tea gardens. Beauveria bassiana as microbial insecticides can effectively control E. obliqua larvae; however, the immune response of this insect infected by B. bassiana are largely unknown. Here, after isolating a highly virulent strain of B. bassiana from E. obliqua, the changes in gene expression among different tissues, including hemocytes and fat bodies, of E. obliqua larvae infected by the entomopathogen were investigated using transcriptome sequencing. A total of 5877 co-expressed differentially expressed genes (DEGs) were identified in hemocytes and fat bodies, of which 5826 were up-regulated in hemocytes and 5784 were up-regulated in fat bodies. We identified 249 immunity-related genes, including pattern recognition receptors, immune effectors, signal modulators, and members of immune pathways. A quantitative real-time PCR analysis confirmed that several pattern recognition receptors were upregulated in hemocytes and fat bodies; however, others were downregulated. The investigated immune effectors (ATT and PPO-1) were suppressed. The results showed that there were tissue differences in the expression of immune genes. This study provides a large number of immunity-related gene sequences from E. obliqua after being infected by B. bassiana, furthering the understanding of the molecular mechanisms of E. obliqua defenses against B. bassiana.

Preliminary Analysis of Transcriptome Response of Dioryctria sylvestrella (Lepidoptera: Pyralidae) Larvae Infected with Beauveria bassiana under Short-Term Starvation

“…We identified 238 immunity-related genes from 41,629 unigenes, and these were compared with known protein sequences in Anopheles gambiae [ 53 ], Drosophila melanogaster [ 54 ], Bombyx mori [ 55 ], Lymantria dispar [ 56 ], and Ectropis obliqua [ 39 ]. The immunity-related genes were classified on the basis of functions into categories of recognition, modulation, transduction, and effectors.…”

“…In this study, RNA-seq was used to analyze changes in the transcriptome expression of whole larvae subjected to short-term fasting or to fasting following infection with B. bassiana . In many studies, hemocytes and fat bodies are tested separately [ 39 , 56 ]. However, in our assessment, a transcriptome of the whole larva body can better reveal any comprehensive changes in the overall metabolic and physiological processes of larvae.…”

“…Each well plate was loaded with 1 μL cDNA. The reaction steps were as follows: 95 °C for 2 min; 40 cycles of 95 °C for 15 s; and 60 °C for 30 s. The data were analyzed using the 2 −ΔΔCt method [ 39 , 48 , 52 ]. The primers were described previously ( Table S1 ).…”

“…In addition, research into the immune systems and detoxification-enzyme systems of insects has mostly been based on model species such as Bombyx mori [ 36 ], Drosophila [ 37 ], or mosquito [ 38 ]. There have been few studies on the pest species that affect many cash crops in agriculture and forestry [ 39 , 40 , 41 ]. In this study, the larvae of D. sylvestrella were used as the research object, and the wild B. bassiana strain SBM-03 was isolated from cadavers of D. abietella , another species of Dioryctria found at the same site as our target pest.…”

The Entomopathogenic Fungus Beauveria bassiana Shows Its Toxic Side within Insects: Expression of Genes Encoding Secondary Metabolites during Pathogenesis

“…Transcriptomics approaches in B. bassiana -infected larvae have demonstrated the induction of several immunity-related genes, including those for AMPs in G. mellonella [ 62 ], hemocytes and fat bodies from both Ectropis obliqua [ 63 ] and Helicoverpa armigera [ 64 ], and in Ostrinia furnacalis [ 65 ]. Furthermore, in P. xylostella , ~15% of the host genome was found to be enriched with genes for various immune processes [ 34 ].…”