Brochosomes are proteinous structures that are uniquely found in leafhoppers. Although the exact biological function of brochosomes remains unknown, it has been hypothesized that they might involve waterproofing, camouflage, and preventing fungal infection. Previous transcriptomic analyses have shown proteins of brochosome are produced by a few orphan gene families in leafhoppers. However, research on the molecular basis of brochosomes is hampered by the lack of a high quality reference genome of leafhoppers. Here, we used PacBio long-read sequencing and Dovetail Omni-C technology to generate a chromosome-level genome assembly of the Glassy-Winged Sharpshooter (Homalodisca vitripennis, GWSS). We validated our genome assembly by empirically estimating the genome size using flow cytometry. In addition, we used karyotyping to determine the chromosome number, which corresponds to the number and sizes of large scaffolds. We also identified the X chromosome using relative depth of sequencing reads from males and females, generated by the i5K genome project. Using both differential gene expression in tissues producing brochsomes and proteomics of brochosomes themselves, we identified and confirmed genes and proteins that underlie brochosome production. Using our genome assembly, we investigated the chromosomal locations of these genes and found tandem duplications might play an important role in the diversification of brochosome-related genes. Thus, the high quality GWSS genome sheds light on the molecular basis of brochosomes, and will likely be useful in elucidating other aspects of GWSS biology.
