RNA-Seq Analyses for Two Silkworm Strains Reveals Insight into Their Susceptibility and Resistance to Beauveria bassiana Infection.

Dongxu Xing,Qiong Yang,Liang Jiang,Mingqiang Ye,Yang Xiao,Qingrong Li,Qingyou Xia

doi:10.3390/ijms18020234

Abstract

The silkworm Bombyx mori is an economically important species. White muscardine caused by Beauveria bassiana is the main fungal disease in sericulture, and understanding the silkworm responses to B. bassiana infection is of particular interest. Herein, we investigated the molecular mechanisms underlying these responses in two silkworm strains Haoyue (HY, sensitive to B. bassiana) and Kang 8 (K8, resistant to B. bassiana) using an RNA-seq approach. For each strain, three biological replicates for immersion treatment, two replicates for injection treatment and three untreated controls were collected to generate 16 libraries for sequencing. Differentially expressed genes (DEGs) between treated samples and untreated controls, and between the two silkworm strains, were identified. DEGs and the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the two strains exhibited an obvious difference. Several genes encoding cuticle proteins, serine proteinase inhibitors (SPI) and antimicrobial peptides (AMP) and the drug metabolism pathway involved in toxin detoxification were considered to be related to the resistance of K8 to B. bassiana. These results revealed insight into the resistance and susceptibility of two silkworm strains against B. bassiana infection and provided a roadmap for silkworm molecular breeding to enhance its resistance to B. bassiana.

Highlights

The silkworm, Bombyx mori, is an important economic insect for silk production in many developing countries [1]
Investigating the silkworm response to B. bassiana infection is of particular interest since it provides a roadmap for silkworm molecular breeding to enhance its resistance against B. bassiana
We propose that the cytochrome P450, carboxylesterase, and UDP-glucuronosyltransferase function effectively in the detoxification of toxins such as cyclic peptide toxins secreted by B. bassiana, which delayed the death of the K8 strain

Summary

Introduction

The silkworm, Bombyx mori, is an important economic insect for silk production in many developing countries [1]. It is a lepidopteran model insect in the investigation of insect genetics and immunology [2,3,4]. Investigating the silkworm response to B. bassiana infection is of particular interest since it provides a roadmap for silkworm molecular breeding to enhance its resistance against B. bassiana. It gives useful information for genetic modification of the fungus to enhance its efficiency in pest

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Discussion

Conclusion