Genome-Wide Identification and functional characterization of chitinase genes in the sorghum aphid (Melanaphis sacchari).

Insect chitinases are integral to a spectrum of vital physiological processes, including growth, development, molting, and metamorphosis. Consequently, chitin metabolic enzymes are potential targets for eco-friendly insecticide development. This study employed bioinformatics approaches to analyze the chitinase gene family in the sorghum aphid(Melanaphis sacchari), identifying seven MsCht genes. Phylogenetic distribution analysis revealed that the chitinases of the sorghum aphid are distributed across multiple clades, and the presence of several orthologous relationships with the pea aphid suggests a relatively closer evolutionary relationship between the two species. Collinearity analysis indicated minimal in the homologous evolutionary relationships among genes of closely related species. Age-stage and tissue expression analysis revealed relatively high expression levels of MsCht genes in 1L2d and 3L2d nymphs, along with the thoracic region, abdomen, and legs. Subsequent plant-mediated RNAi assays confirmed that silencing MsCht genes, effectively disrupted ecdysis, causing severe morphological defects and significantly increased mortality over time. These findings functionally validate chitinases as promising RNAi targets for sustainable management of M. sacchari.