An inducible gene from glycoside hydrolase one family of decreases larval survival when feeding on host plant

Glycoside hydrolase family 1 (GH1) members exhibit a broad substrate spectrum and play important roles in insect-plant interactions, such as the defensive β-glucosidase and β-thioglucosidase (so-called myrosinase). However, knowledge about the expression profiling and function of glycoside hydrolase family 1 members in a specialist pest of crucifers is still limited. In this study, 13 putative glycoside hydrolase family 1 members of were identified based on the sequence characteristics, while no myrosinase activity was detectable in using gas chromatography-mass spectrometry (GC-MS). Expression profiling of these glycoside hydrolase family 1 members identified the midgut-specific gene that is induced by host plant. Further experiments revealed that the expressed Px008848 protein had β-glucosidase activity and the survival rate of the larvae feeding on wounded leaves declined when leaves were treated with purified Px008848 protein. When CRISPR/Cas9-based homozygous mutant larvae of and wild-type larvae were respectively transferred onto the , the larval survival rate of the mutant larvae was significantly higher than that of the wild-type individuals. Our work showed that certain insect glycoside hydrolase family 1 gene may have negative effect on the development of larvae feeding on the host plant, which broadened our understandings on the evolutionary function of this gene family in the insect-plant interaction.