# Evolutionary Dynamics of Glycoside Hydrolase Family 1 Provide Insights into Insect–Plant Interactions in Lepidoptera

## TL;DR

This study explores how glycoside hydrolase family 1 (GH1) genes evolved in butterflies and moths, revealing their role in insect-plant interactions and adaptation to host plants.

## Contribution

The study provides the first comprehensive analysis of GH1 gene evolution in Lepidoptera, linking gene duplication patterns to insect adaptation to plant feeding.

## Key findings

- 996 GH1 genes were identified and grouped into 11 categories with distinct species diversity.
- Gene duplications, especially tandem and dispersed types, were found to be central to GH1 evolution in Lepidoptera.
- High GH1 gene expression in larval midgut and fat body suggests roles in digestion and detoxification.

## Abstract

Lepidopteran insects rely on special enzymes to break down plant materials and protect themselves from plant toxicants. One important group of these enzymes is glycoside hydrolase family 1 (GH1). In this study, we examined GH1 genes in 61 species of butterflies and moths to understand how these genes evolved and how they help insects interact with plants. We identified 996 GH1 genes and grouped them into 11 categories, with each displaying different species diversity. Most GH1 genes originated through gene duplications, especially tandem and dispersed duplications. In addition, we examined the expression of these genes in the silkworm and found certain highly expressed GH1 genes during larval stages, especially in tissues involved in digestion. These results showed that the evolutionary history of GH1 genes in Lepidoptera reflects their adaptation to plant feeding, providing insights for further investigation into plant–insect interactions.

Glycoside hydrolase family 1 (GH1) enzymes are essential for plant cell wall digestion and the detoxification of plant metabolites in insects, yet their evolutionary history in Lepidoptera remains unresolved. This study systematically identified GH1 genes across 61 Lepidopteran genomes and analyzed their evolutionary dynamics. In addition, the expression profiles of GH1 genes in the silkworm (Bombyx mori) across various developmental stages and tissues were related to their evolutionary histories. A total of 996 GH1 genes were annotated and classified into 11 groups, with each showing distinct species diversity. Gene duplication and loss analysis revealed frequent duplications and losses during Lepidoptera evolution; these duplications primarily originated through tandem and dispersed duplications and were located in syntenic regions. Transcriptomic analysis of the silkworm revealed that the groups and duplications of GH1 genes were correlated to their expression patterns, with high expression in the larval midgut and fat body. These findings suggest that GH1 gene duplications and losses and expression have played a significant role in Lepidopteran adaptation to diverse host plants. Overall, this study provides comprehensive insights into the evolutionary trajectories of GH1 genes, highlighting their potential contribution to insect–plant interactions in Lepidoptera.