A chromosome-level genome assembly of Stenchaetothrips biformis and comparative genomic analysis highlights distinct host adaptations among thrips.

Insects have a limited host range due to genomic adaptation. Thysanoptera, commonly known as thrips, occupies distinct feeding habitats, but there is a lack of comparative genomic analyses and limited genomic resources available. In this study, the chromosome-level genome of Stenchaetothrips biformis, an oligophagous pest of rice, is assembled using multiple sequencing technologies, including PacBio, Illumina short-reads, and Hi-C technology. A 338.86 Mb genome is obtained, consisting of 1269 contigs with a contig N50 size of 381 kb and a scaffold N50 size of 18.21 Mb. Thereafter, 17,167 protein-coding genes and 36.25% repetitive elements are annotated. Comparative genomic analyses with two other polyphagous thrips, revealing contracted chemosensory-related and expanded stress response and detoxification gene families in S. biformis, potentially facilitating rice adaptation. In the polyphagous thrips species Frankliniella occidentalis and Thrips palmi, expanded gene families are enriched in metabolism of aromatic and anthocyanin-containing compounds, immunity against viruses, and detoxification enzymes. These expansion gene families play crucial roles not only in adapting to hosts but also in development of pesticide resistance, as evidenced by transcriptome results after insecticides treatment. This study provides a chromosome-level genome assembly and lays the foundation for further studies on thrips evolution and pest management.