Abstract
Humoral immunity is a fundamental component of the innate immune system, and it regulates the expression of key genes through signal transduction and immune pathways, resulting in the production of antimicrobial peptides and other effector molecules. Scorpions, whose fossil records dates back 430 million years, have adapted to moist environments over extensive periods. However, the expression profiles of immune-related genes across their different tissues remain poorly understood. This study identified 52 innate immune genes from 14 tissues, excluding repressors, within the transcriptome of Mesobuthus martensii collected from the Langya Mountain in Baoding using Illumina High-Throughput sequencing technology. Then we identified the transcriptome annotations and validated through online BLAST searches to confirm. We described four primary immune pathways in M. martensii: (I) Toll signaling pathway appeared relatively complete compared with that of Drosophila melanogaster; (II) the upstream components of the IMD pathway were missing and downstream genes were expressed to some extent in different tissues; (III) IMD homologous genes were found in most components of the JNK pathway; (IV) the JAK-STAT pathway had core genes JAK and STAT, but lacked the membrane receptor Dome. In this study, transcriptome analyses of different M. martensii tissues revealed significant variability in immune gene expression, particularly in the blood. The innate immune gene members of scorpions exhibited notable similarities to those found in Tetranychus urticae, Acanthoscurria gomesiana, and Acyrthosiphon pysum, while significantly differing from those of Drosophila melanogaster. These differences might reflect variations in innate immune capabilities influenced by evolutionary processes and behavioral adaptations.